Biodiversity of the Austral Islands, French Polynesia - Le blog de Li-An

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Biodiversity of the Austral Islands, French Polynesia - Le blog de Li-An
Terrestrial
Biodiversity of the Austral Islands,
French Polynesia
Jean-Yves Meyer (1) , Elin M. Claridge (2) (Editors)
(1)Délégation à la Recherche
B.P. 20981 - 98713 Papeete - Tahiti - French Polynesia
[email protected]
(2)B.P. 35 Moerai - Rurutu 98753 - French Polynesia
[email protected]
Publications scientifiques du Muséum national d’Histoire naturelle
Cette publication constitue le volume 72 de la collection Patrimoines naturels
Directeur de la publication : Thomas Grenon
Directeur général du Muséum national d’Histoire naturelle
Rédacteur en chef : Jean-Philippe Siblet
Secrétaire d'édition : Gwénaëlle Chavassieu
Photos 1re de couverture :        a : Pacifigeron
rapensis (photo J.-Y. Meyer)
a b c d e
        b : Lamellidea oblonga (photo O. Gargominy)
        c : Vini kuhlii (photo B. Fontaine)
        d : Ischnura rurutana (photo R. Englund)
        e : Mt Taraia cliffs, Raivavae (photo J.-Y. Meyer)
Photos 4e de couverture :        f : Freycinetia
arborea (photo J.-Y. Meyer)
f g h i j
        g : Partula hyalina (photo O. Gargominy)
k l m n
        h : Sophora tomentosa (photo J.-Y. Meyer)
        i : Rhyncogonus sp. (photo J.-Y. Meyer)
        j : Ripe sandalwood fruit (photo J.-F. Butaud)
        k : Puffinus pacificus (photo J.-C. Thibault)
        l : Pacifigeron rapensis (photo J.-Y. Meyer)
        m : Capparis cordifolia (photo J.-Y. Meyer)
        n : Microcystis fosbergi fosbergi (photo O. Gargominy)
Design : Catherine Lasnier
ISSN 1281-6213
ISBN 978-2-85653-761-9
© Publications scientifiques du MNHN, Paris 2014
Cet ouvrage doit être référencé comme suit :
Meyer J.-Y. & CLARIDGE E.M. (Eds) 2014. — Terrestrial Biodiversity of the Austral Islands, French Polynesia.
Muséum national d’Histoire naturelle, Paris , 224 p. (Patrimoines naturels ; 72).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
In Memoriam
Timothy J. Motley (1965-2013)
Jean-Yves Meyer
ornithologists) throughout the Austral islands to
continue further biotic surveys. This exhaustive
field research led to a conference in Tahiti, held
in 2005 at Institut Louis Malardé, on the biodiversity and richness of the natural history of the
Austral archipelago. Tim was an invited speaker to
this conference, where he presented a paper and
co-authored two others. He also contributed two
papers to this current volume and provided data
for use in a third chapter of this book, a book he
unfortunately will never read. Tim was an associate
professor of Botany at Old Dominion University in
Virginia, happily married, and had even recently
become a father, when he passed away suddenly
and quite unexpectedly, in March 2013.
(Photo R. Fenstemacher)
I first met Tim when we were both
"young" PhD students working in
Hawaii in the mid-1990s. We started
professionally collaborating in 1999,
when he came to French Polynesia to
study Kadua (syn. Hedyotis , Rubiaceae)
and other Pacific island plants. We
first conducted fieldwork together on
the high volcanic islands of Bora Bora,
Raiatea, and Tahiti (Society archipelago), searching for rare endemic species like Fitchia cordata on Mt Pahia
in Bora Bora, Geniostoma clavatum on
Temehani plateau in Raiatea, and Scaevola tahitensis
on Mt Marau in Tahiti.
While Tim was internationally recognized as an
excellent Pacific Island systematist and botanist, it
was his great enthusiasm for fieldwork and his conscientiousness in the lab that inspired and convinced
me, a plant ecologist and field botanist, of the fundamental importance of conducting phylogenetic
and phylogeographical studies for conservation purposes. Because of our common interest in Pacific
island floras, both Tim and I were selected as members on a panel studying "Extinction in the Islands
of Oceania" for a symposium held at the Australian
National University in Canberra, Australia, in 2006,
invited by a colleague, palaeoecologist Matiu Prebble,
who was also a member of the survey expeditions to
the Austral islands. Tim’s path and mine continued
to cross over the years, as we both remained focused
on research in the Pacific. Tim honored me in 2008,
by naming one of the newly discovered endemic
species of fern on Rapa, Elaphoglossum meyeri. We
last met at the "Evolution of Life in Pacific Islands"
conference in Honolulu in 2011, where we had kava
(Piper methysticum) with Ron Fenstemacher, as we
three had often done on Rapa after our long days of
fieldwork there. Tim’s last message to me came in
January 2013, with a final version of his paper on
taro cultivars… and a picture of his two-year old
son, Anton. He wrote that he was " happy the Austral
Islands book will be moving forward soon, I hope ".
In early 2001, Tim, then working for the New
York Botanical Garden, was awarded a grant from
the National Geographic Society to study the flora
of the remote island Rapa Iti, in the Austral archipelago. This fit in well with my nascent research
plans to survey the terrestrial biodiversity of the
entire archipelago which was poorly known. The
resulting two-month expedition from February
to March 2002 organized by Tim, was assisted
by field botanists Steven Perlman and Kenneth
Wood of the National Tropical Botanical Garden
(Kauai, Hawaiian Islands ?), ethnobotanist Ron
Fenstemacher, and by my logistical support on
the island for the first two weeks. The expedition’s
outcome was to expand the flora of Rapa by about
ten percent, with a dozen new island records for
indigenous plants that weren’t previously found
there and eight unique endemic species that were
new to science!
Through the time we worked together and the
adventures we shared, Tim became more than
a close research colleague, he was a true friend,
and so we had always expected to maintain our
rewarding professional collaboration for many
years to come, and, we had even hoped to revisit
Rapa together again, one fine day…
This expedition was a milestone in my career for
both its scientific impact and the human adventure
involved. In subsequent years I took other biologists (botanists, entomologists, malacologists, and
3
...
Mt Taraia cliffs and view on Vaianaua, Raivavae, March 2008 (Photo J.-Y. Meyer).
...
4
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Contents
Introduction: Multidisciplinary scientific expeditions to assess­
the terrestrial biodiversity of the Austral Islands ....................................      7
Jean-Yves Meyer & Elin M. Claridge
The Austral islands in french polynesia .................................................................      13
Jean-Yves Meyer
Geology ................................................................................................................................................................    19
An Atypical Hotspot Chain ......................................................................................................................   21
René Maury, Christelle Legendre, Chatherine Chauvel, Gérard Guille, Sylvain Blais, Hervé Guillou & Philippe Rossi
Fauna .......................................................................................................................................................................    39
The Birds: an Unbalanced but Unique Avifauna ..................................................................... 41
Jean-Claude Thibault
A Global Overview of the Terrestrial an Freshwater Molluscs .......................................... 55
Olivier Gargominy & Benoît Fontaine
Insects and Spiders ....................................................................................................................................................................  93
Elin M. Claridge, Jessica E. Garb, Rosemary G. Gillespie & Diana M. Percy
Odonata and Selected Aquatic Insect Taxa ......................................................................................................... 103
Ronald Englund
VEGETATION .................................................................................................................................................................................    115
Vascular Flora, General Traits and Main Threats ............................................................................................  117
Jean-Yves Meyer, Hervé Chevillote & Timothy J. Motley
Vegetation Types and Map of Rapa  ............................................................................................................................ 133
Timothy J. Motley, Alfred Luongo & Jean-Yves Meyer
The Paleobotanical Record of Rapa: Indications for the Phytogeography  ............................... 149
Matthew Prebble
Sandalwood, Current State of Knowledge and Implications
for Conservation and Enhancement ..........................................................................................................................  171
Jean-François Butaud, Jean-Pierre Bianchini, Jean-Marc Bouvet, Vincent Gaydou, Émeline Lhuillier,
Phila Raharivelomanana & Fanny Rives
"Mikaka Rapa": Taro Cultivars of Rapa ...................................................................................................................  191
Timothy J. Motley & Roland Fenstemacher
ANNEXES ........................................................................................................................................................................................... 205
Acknowledgements .................................................................................................................................................................. 207
Bibliography ..................................................................................................................................................................................  208
Addresses of the Authors ................................................................................................................................................... 219
5
...
Mts Hiro and Araua, Raivavae (Photo J.-Y. Meyer).
...
6
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Introduciton
Multidisciplinary Scientific Expeditions
Jean-Yves Meyer & Elin M. Claridge
to Assess
the Terrestrial Biodiversity
of the Austral Islands
Knowledge of terrestrial biodiversity
and ecosystem composition, structure and function, is crucial for the
sustainable management of natural resources and the conservation
of threatened endemic species and
native habitats. This is especially
true for small islands with limited
resources and human capacities,
which also often harbor high levels of endemism and unique biota
(Wagner & Funk 1995). The Austral
Islands (also called "the Australs")
are an isolated archipelago in French
Polynesia, a French territory in the
South Pacific, located between 500
and 1 250 km from the main island of
Tahiti (Society Islands, Fig. 1). The
most remote island in the chain, Rapa
(also called "Rapa Iti" as opposed to "Rapa Nui",
Easter Island, which is a Chilean territory located
to the southeast) can be considered a biodiversity
hotspot in and of itself. However, biological data
for this archipelago was outdated and/or highly
incomplete, and thus of limited use to land managers, research scientists, and other potential users
Raivavae from the Tuhaa Pae boat (Photo J.-Y. Meyer).
(e.g. conservationists from NGO's and local nature
protection groups). Therefore, a biodiversity inventory of the Australs would be research priority.
The most recent and most extensive scientific
expeditions to the Austral Islands were those of
the Bayard Dominick Expedition between 192122, and the Mangarevan Expedition in 1934,
both funded by the
Bernice P. Bishop
154°
152°48’ 151°20’
147°40’
144°20’
Museum, Honolulu
(Hawaii). More than
50 years afterwards,
in the 70s and 80s
525 km
the Service Mixte de
665 km
Contrôle Biologique
22°00’
Maria
(SMCB) of the
640 km
RURUTU
1250 km
Direction des Centres
22°27’
710 km
d’Expérimentations
22°40’
N u c l é a i r e s
RIMATARA
(DIRCEN), Centre
23°27’
Tropic ofCapricorn
TUBUAI
195 km
d’Expérimentation
23°52’
du Pacifique (CEP),
RAIVAVAE
organized a series
550 km
of expeditions with
French marine and
RAPA
terrestrial biologists
27°37’
from IRD (formerly
called ORSTOM)
and the Muséum
Figure 1: Map of the Austral Islands and distances from the
main island of Tahiti (Society).
national d’Histoire naturelle in Paris. However, little
7
...
Introduction: Multidisciplinary Scientific Expeditions
to Assess the Terrestrial Biodiversity of the Austral Islands
.. .....
data was published relating to terrestrial ecosystems, and that which was focused primarily on
vascular plants (see DIRCEN 1986 and references
in chapter by Meyer et al., this volume).
During the past 20 years, other contemporary research surveys were conducted by lone
researchers­
, including botanical field trips by J.
Florence in 1988 and 1992 funded by IRD, by
J.-Y. Meyer in 1998 (Tubuai, Rurutu) and 1999
(Rurutu), funded by the Délégation à la Recherche
de la Polynésie française (French Polynesia
Department of Research), and an expedition to
Rapa by T. Motley, R. Fenstemacher, S. Perlman
and K. Wood in 2002 funded by the National
Geographic Society. However, no comprehensive
assessment was ever published on the flora of the
Austral Islands. By comparison, a special issue on
the vascular flora of the Marquesas was compiled
by Lorence in 1997 following a series of botanical
expeditions between 1988 (a collaborative program with IRD, the National Tropical Botanical
Garden in Hawaii and the Smithsonian Institution
of Washington) and 2005 (with the Délégation à la
Recherche and the Délégation à l’Environnement de
la Polynésie française, Tahiti), which has resulted
in a website dedicated to the Marquesan flora,
housed by the Smithsonian Institution (Wagner &
Lorence 2002).
GOALS
The main goals of these expeditions, as stipulated
in the contracts signed between ILM with each
participant (or "missionaries"), were to:
• Map the different terrestrial and freshwater native
habitats, to assess their conservation status, and to
localize the natural areas of high ecological value;
• Conduct inventories (as exhaustive as possible) of native and alien vascular plants and
animals (mammals, birds, molluscs, insects and
arthropods);
• Estimate the distribution and abundance of
the threatened species, and to assess their conservation status;
• Identify the past and current threats on species and their habitats;
• Study the dynamics and evolution of the terrestrial biota compared with historic data;
• Propose recommendations for biodiversity
conservation and natural resources management to both the local community and authorities (mayors offices) and the Government of
French Polynesia (mainly the Ministries of
Environment and Agriculture).
In order to address these gaps in our knowledge and
growing environmental concerns a series of multidisciplinary scientific expeditions were conducted
in 2002 (November-December), 2003 (NovemberDecember) and 2004 (November) to the five inhabited islands of Raivavae, Rapa, Rimatara, Rurutu
and Tubuai. The uninhabited small rocky islets of
Marotiri, located 75 km southeast of Rapa, and the
atoll of Maria, about 210 km north of Rimatara,
were not surveyed because of the extreme difficulty of accessing them by boat. The expeditions were funded by the Contrat de Développement
Etat-Polynésie française 2000-2004 (France-French
Polynesia Development Contract) through a larger
research program aimed to inventory and evaluate
the biodiversity of French Polynesia (Inventaire
et Valorisation de la Biodiversité en Polynésie française) proposed by the Délégation à la Recherche de
la Polynésie française. The total budget allocated
to the Expéditions scientifiques aux Australes was
10 million XPF, i.e. about 84 000 $, managed by
the Institut Louis Malardé (ILM).
Table 1: Participants and their affiliation.
Raivavae Rapa
(2002)
(2002)
Tubuai
(2003)
Rurutu Rimatara Symposium
(2003)
(2004) Tahiti (2005)
Institutions
Country
Number
Délégation à la Recherche de la Polynésie
française & Institut Louis Malardé, Tahiti
French
Polynesia
1
x
x
x
x
x
x
Muséum national d’Histoire naturelle, Paris
France
2
x
x
x
x
x
x
Bernice Pauahi Bishop Museum, Honolulu
USA
1
x
x
x
x
x
x
French
Polynesia
1
x
-
x
x
x
x
USA
2
x
x
-
-
x
x
IRD, Paris
France
1
-
-
x
x
x
x
Parc naturel régional de Corse
France
1
x
-
-
-
-
x
University of British Columbia, Vancouver
Canada
1
-
-
x
x
-
-
Australian National University, Canberra
Australia
1
-
-
-
-
x
x
Université de Polynésie française & Service
du Développement Rural, Tahiti
University of California, Berkeley
...
8
.......
J.-Y. Meyer, hired as research scientist at the
Délégation à la Recherche in 2002, was appointed
as the expedition leader, and in charge of setting
up a team of local, French and foreign scientists
(Table 1) with field experience in French Polynesia
and/or the Pacific Islands (e.g. Hawaii), and with
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
recognized expertise on specific taxa (e.g. vascular
plants, forestry, birds, mollusks, insects, spiders,
fossil pollen). Some of the expedition members
were senior scientists, other were PhD students at
that point in time.
OUTCOMES
The expeditions were unique for several reasons:
they were the first to be conducted in French
Polynesia during the 21st century; the small fieldteams (seven-eight people) were able to travel
to remote islands (Rimatara and Rapa by cargo
boat), survey all the different habitat types (from
low elevation coastal areas to high elevation cloud
forests) including rough terrains (limestone cliffs,
wetlands and precipitous peaks and ridges) in a
minimum amount of time; they were well-integrated into the Polynesian lifestyle and adapted to
the local logistic constraints in these islands (small
planes, boat travels, guesthouses). Expedition
members were able to synthesize collection data,
sharing their results with the local authorities and
communities during meetings at the local mayor's
offices ("mairies"). The expeditions were covered
by the local media (local newspapers La Dépêche
de Tahiti, local television TNTV) on the most
inhabited islands of Rurutu and Tubuai.
The results obtained during these scientific expeditions, have greatly improved the knowledge
of the ecology, biogeography, evolutionary and
Survey on summital ridge in Raivavae, November 2002
(Photo J.-Y. Meyer).
Survey on limestone cliffs in Rurutu, November 2003
(Photo J.-Y. Meyer).
9
...
Introduction: Multidisciplinary Scientific Expeditions
to Assess the Terrestrial Biodiversity of the Austral Islands
.. .....
Landing boat to Rimatara, October 2004 (Photo J.-Y. Meyer).
conservation biology of the Austral Islands terrestrial biota: several plant and invertebrate (insects
and molluscs) species previously unknown to
science were discovered, species that were only
collected during the 20's and 30's expeditions
were found again, new records for some Austral
Islands endemic or native species were reported
for other islands, there were only a few contemporary extinctions recorded, but many historical
extinctions, based on palynological studies (see
chapter by Prebble, this volume) and subfossil
land snail deposits (see chapter by Gargominy &
Fontaine, this volume). The conservation status
of many of the endemic taxa was revised.
A symposium entitled the "Austral Islands
Biodiversity Conference" was organized in Tahiti
in 2005 (8-10 Nov.) at the Institut Louis Malardé
(Papeete), hosted by both the Ministry of Education
and Research and the Ministry of Environment, to
synthesize and share the main results. A total of
15 talks were given, including additional talks
from invited speakers who didn’t participate in
the 2002-2004 field expeditions, dealing with vegetation mapping of Tubuai using satellite images
Meeting with the local autorities in Rimatara (Photo J.-Y. Meyer).
...
10
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Symposium at Institut Louis Malardé in Tahiti, Novembre 2005 (Photo J.-Y. Meyer).
(B. Stoll from the Université de Polynésie française), phylogeny and evolution of reed-warblers
in the Eastern Pacific (A. Cibois, Natural History
Museum of Geneva, Switzerland), marine biodiver-
sity (R. Galzin, Université de Perpignan, France, and
CRIOBE-EPHE biological marine station, Moorea)
and the marine algal flora of Rapa (A. N'Yeurt,
Université de Polynésie française).
CONCLUSIONS
It took almost five years for all the participants to
write the 11 scientific papers (including this one)
and five more years for the two editors and the publisher (Service des Publications scientifiques of the
Muséum national d'Histoire naturelle) to prepare this
book entitled Terrestrial Biodiversity of the Austral
Islands, dedicated to science for conservation and
management. Very few other fieldtrips and conservation projects were carried out during this past
decade (a palaeoecological study conducted in the
wetlands of Rurutu and Raivavae by the Australian
National University of Canberra in 2008, the construction by the "Association Raumatariki" of a
fence to protect a semi-dry forest remnant on Rapa
in 2011, a plant and bird inventory on Maria atoll in
2013, all projects conducted in collaboration with
J.-Y. Meyer of the Délégation à la Recherche), demonstrating the importance of publishing this book,
as a baseline for existing knowledge, and highlighting the urgent need to promote conservation action
in the archipelago. There are still no protected terrestrial areas in the Austral Islands, compared with
11
the Society Islands, which has a single natural park
(Te Faaiti on Tahiti since 1989), a management
area (Temehani Ute Ute plateau, Raiatea, created in
2010) and natural uninhabited reserves since 1971
(Scilly and Bellinghausen atolls); or the Marquesas
(Eiao, Hatutu, Mohotani have been natural reserves
since 1971, Vaikivi natural park and reserve created in 1997), and the Tuamotus (the Fakarava
Biosphere Reserve since 2006).
An online database of the terrestrial biodiversity of
the Austral Islands, based on a model developed for
the Cook Islands, located some 700 km to the west
in Rarotonga (McCormack 2007) would be very
useful, and the Cook Islands database could even
be used as a starting point, as most of the terrestrial
native biota is shared with the Austral Islands.
The results of this scientific, but also human adventure, have greatly improved the knowledge of the
ecology, biogeography, evolutionary and conservation biology of the Austral Islands terrestrial biota,
and we hope this book will inspire further research,
conservation and management programs.
...
Coralleous islets ("motus") in the lagoon of Tubuai (Photo J.-Y. Meyer).
...
12
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
The Austral Islands
in French Polynesia
The Austral Islands
(or Australs, formerly
known as the Tubuai
Islands) are located
between 21-28° S latitude and 144-155° W
longitude. The archipelago along with the
Society, the Tuamotu,
the Marquesas and the
Gambier Islands makes
up the French Overseas
Territory known as
French
Polynesia
(Fig. 2). The Australs
and the Gambier form
the southernmost part
of this territory.
Jean-Yves Meyer
Table 2: Characteristics of the Austral Islands and comparison with the three largest
islands of French Polynesia
* Data from Maury et al. this volume; ** data from Clouard & Bonneville 2005.
Island
Island type*
Maria
atoll
Rimatara
Age
(Myr)
Area
(km2)
Max. elev.
(m)
4.8-28.6**
0.53
3
composite
> 15**
8.06
106
Rurutu
composite
12.7-12
32.35
389
Tubuai
High volcanic
8.9-10
45.00
422
Raivavae
High volcanic
6.4-5.4
20.35
483
Rapa
High volcanic
4.8-4.1
40.50
650
Marotiri
Rocky islets
3.8-3.1
0.11
113
Total
147.44
Tahiti (Society)
High volcanic
0.43-1.17**
1 045.10
2 241
Moorea (Society)
High volcanic
1.50-1.86**
141.80
1 207
The Austral archipelago Nuku Hiva (Marquesas) High volcanic
3.59-4.38**
339.50
1 227
is a chain of seven oceanic islands stretching over 1 300 km
These volcanic islands are between 3 and 30 Myr
(from west to east: Maria, Rimatara,
in age, and are the result of the activity of colinear
Rurutu, Tubuai, Raivavae, Rapa and
hostpots (Table 2). Although politically the Austral
Marotiri), more than 5 400 km disand Cook Islands are two separate entities, geologitant from the coast of Australia and
cally they are part of the same volcanic chain: the
over 7 300 km from the coast of South
Cook-Austral chain which extends from Mangaia
America. The archipelago is located
in the Cook Islands to the Macdonald Seamount
between 575 km and 1 275 km from
(Maury et al. this volume).
the main island of Tahiti (Society).
Maria atoll and its coralleous islets ("motus"),
(Photo J.-Y. Meyer).
13
...
The Austral Islands in French Polynesia
.. .....
Figure 2: The Austral archipelago in French Polynesia (Map ORSTOM - LCA).
Coastal limestone vegetation, Rimatara
(Photo J.-Y. Meyer).
...
14
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
View of Mts Maunanui, Araua and Hiro from
Mt Taria cliffs, Raivavae (Photo J.-Y. Meyer).
The total surface area of the seven islands of the
Australs combined is only c. 148 km2, i.e. almost
equivalent to the surface area of Moorea (Society),
and represents only 4 % of the total land area of
French Polynesia (Table 2).
Within the Australs there are three volcanic high
islands (Tubuai with its summit Mt Taitaa, 422 m,
Raivavae with Mt Hiro, 438 m, and Rapa with Mt
Perau, 650 m, the highest peak in the archipelago),
with associated sandy islets ("motus" in Tubuai
and Raivavae which are formed on the barrier
reef) or offshore rocky islets (e.g. Karapoo Rahi
near Rapa, Hotuatua near Raivavae). There are two
composite islands ("makatea" islands sensu Nunn
1994) (Rurutu with its summit Mt Taatioe, 389 m
Motu Hotuatua, a volcanic rocky islet
of Raivavae (Photo J.-C. Thibault).
and Rimatara with Mt Uahu, 84 m) made up of a
volcanic center surrounded by raised limestone or
coralline substrate (called "mato"). At the southeastern end of the archipelago there are a group of
ten extremely isolated rocky islets, Marotiri, the
highest reaching 110 m elevation and at the northwestern end the remote atoll, Maria, 230 km from
Rimatara, and made up of four small "motus". The
diversity of geomorphological features and associated natural habitats include impressive raised
coral limestone karst cliffs on Rurutu, large marsh
areas containing some of the largest intact wetlands
in French Polynesia on Tubuai, steep and dissected
reliefs on Rapa reminiscent of those found on the
high volcanic islands of the Marquesas and the
Society Islands.
Coastal limestone cliffs, Rurutu
(Photo J.-Y. Meyer).
15
...
The Austral Islands in French Polynesia
.. .....
Mts Tonarutu and Anareho and lowland wetlands,
Tubuai (Photo J.-Y. Meyer).
The climate is subtropical to tropical, with mean
annual temperatures of c. 23° C (20-26° C) on
Tubuai and Rurutu, and 20.6° C on Rapa (18-23° C).
The minima recorded on Tubuai and Rurutu are at
9.2-9.4° C and 8.5° C on Rapa (Laurent et al. 2004).
Rapa is the coldest and the wettest island of French
Polynesia with 2 560 mm average annual rainfall (and a maximum of 3 798 mm in 1965), and
Rimatara is the driest of the Australs (1 663 mm
average annual rainfall) (Laurent et al. 2004). The
rainy season is typically between December and
April, except for Rapa where precipitation is continuous throughout the year.
Five of the Austral Islands (Tubuai, Rurutu,
Raivavae, Rimatara and Rapa) are inhabited, whence
the Polynesian name "Tuhaa pae" (litterally the
five pieces); Marotiri and Maria atoll are currently
uninhabited. The archipelago’s population is 6 820,
3 % of the population of French Polynesia. Rurutu
and Tubuai are the most densely populated (with
over 2 000 inhabitants each), though Rimatara has
the highest population density, with more than
100 inhabitants per square kilometer. Rapa is the
least populated island, with only 515 inhabitants
living in two villages (Haurei or Ahurei, and Area)
a population density of only 13 inhabitants per
square kilometer (Table 3).
For a long time the Australs were among the most
isolated islands of French Polynesia, though now
airports are found on four of the inhabited islands,
two being recently opened (2002 in Raivavae, 2006
in Rimatara). Rapa is only accessible by cargo boat
Anarua bay from Mt Perau,
Rapa (Photo J.-Y. Meyer).
...
16
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Children of Rimatara (Photo R. Englund).
Taro fields near Moerai village, Rurutu, (Photo J.-Y. Meyer).
(the Tuhaa Pae), with one rotation every 2 months.
Because of their small size (45 km2 being the area of
the largest island, Tubuai) and relatively low elevation (650 m being the highest summit on Rapa), the
Austral Islands are particularly vulnerable to anthropogenic disturbances, past and present. Population
densities upon European discovery, during the late
18th and early 19th century, were at least twice the
current levels (Table 3) and while Polynesians are
considered to have colonized the Australs later than
the Society and the Marquesas Islands, the impact
they had on the natural habitat were profound,
especially in the lowland for agriculture (e.g. taro
fields). Likewise, recent development projects, such
as airport construction on Raivavae and Rimatara,
raise important environmental concerns as well
as socio-economic issues. The long-term impacts
of land management practices (e.g. gravel extraction at the foot of Mt Tonarutu, rubbish dumps in
the wetlands of Tubuai and Rimatara, agricultural
development on Rurutu) and associated human
disturbances (e.g. invasion of Strawberry guava
Psidium cattleianum on the summits of Tubuai and
Rapa, widespread burning of the summits of Rurutu
in 2004 and the wetlands of Tubuai in 2010) may be
equally profound.
Table 3: Characteristics of the Austral Islands human population. * Institut de la Statistique de Polynésie française (www.ispf.pf).
Approx.
population size
upon discovery
Polynesian
Colonization
European
discovery
?
1824 (Gardner)
10-14th century
Rurutu
Island name (ancient name)
Maria
Population Population
Density
(2002)*
(2012)*
(inhab./km2)
0
0
0
-
1811 (Henry)
1 200
791
873
108.3
10th century
1769 (Cook)
6 000
2 098
2 322
71.8
Tubuai (Tupuai)
10th century
1777 (Cook)
3 000
1 979
2 170
48.2
Raivavae (Vavitu)
10th century
1775 (Gayangos)
3 000
991
940
46.2
Rapa (Oparo)
1515-1635
1791 (Vancouver)
2 000
470
515
12.9
Marotiri (Bass)
?
1800 (Bass)
0
0
Total
14 700
6 329
6 820
46.3
100 000
168 773
183 480
175.6
8 000
2 649
2 967
8.8
Rimatara
Tahiti (Society archipelago)
500 B.C.
1769 (Wallis)
Nuku Hiva (Marquesas archipelago)
150 B.C.
1791 (Ingraham)
17
...
-
Geology
.......
....
Southern rock, Marotiri islets, the youngest emerged land of the Australs archipelago
(Photo C. Debitus).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
An Atypical
Hotspot Chain
René C. Maury, Christelle Legendre, Catherine Chauvel, Gérard Guille,
Sylvain Blais, Hervé Guillou & Philippe Rossi
The Southeastern Polynesian oceanic domain is characterised by an
unusual density of volcanic islands,
seamounts and atolls. The Marquesas,
Tuamotu, Pitcairn-Gambier, Society
and Austral-Cook archipelagoes highlight the importance of past and present volcanic activity in the area. All
these linear chains are built on top of
a Pacific oceanic crust, which is 250
to 750 m shallower than expected
given its age. Thus, the Southeastern
Polynesian islands lie on top of a
huge oceanic bulge, the largest of
the planet, called the "South Pacific
Superswell" (McNutt & Fischer
1987). It corresponds to a region of
anomalously hot mantle (Cazenave
& Thoraval 1994) that is also characterised by unusual geochemical
features (Duncan & Compston 1976; Hart 1984),
sometimes referred to as the South Pacific Isotope
and Thermal Anomaly or "SOPITA" (Staudigel et
al. 1991). Recent seismic tomography results show
that the thermal anomaly is due to the presence in
the lower mantle of unusually hot materials rising
from the core-mantle boundary (Zhao 2001) and
called "superplumes" by Courtillot et al. (2003).
In Southeastern Polynesia, the surface expression of
the "superplume" is not a giant and very active volcanic edifice such as Hawaii, but a number of rather
quiet young volcanoes, sometimes emerged such as
Mehetia ("Me’eti’a") but more commonly immerged
as shallow seamounts (Adams SE of Pitcairn, Moua
Pihaa near Mehetia, Macdonald and Arago in the
Austral Islands). Most of them are located at the
South-East end of a volcanic chain and are thought
to indicate the present positions of the corresponding hotspots; however, the recently discovered Arago
seamount is located in the central part of the AustralCook linear chain. This is not the only originality of
the Austral Islands chain, which is also the longest in
Southeastern Polynesia (2 300 km from Macdonald
to Aitutaki in the Cook Islands). It includes very
old volcanic islands with ages of c. 10 Ma for Tubuai
and Raivavae, 12 Ma for Rurutu and even 19 Ma for
Mangaia (Cook Is.), while in the other Southeastern
Polynesian archipelagoes volcanic edifices older than
6 Ma have been converted to atolls.
Finally, the Austral Islands are famous among the
international community of geochemists for the
very unusual composition of most of their lavas,
which display abnormally radiogenic lead isotopic
compositions, due to their mantle source with a
high U/Pb ratio. As the U/Pb ratio is called µ, this
uncommon geochemical signature is often referred
to as High µ (HIMU, Zindler & Hart 1986). Since
the discovery of this imprint in Tubuai lavas (Vidal
et al. 1984), c. 35 studies of the Austral-Cook lavas
have dealt with their geochemical characteristics to
understand their origin. Unfortunately, the geological knowledge of the Austral Islands has not taken
this path, and the early reconnaissance investigations (Chubb 1927; Obellianne 1955; Aubert de
la Rüe 1959) have been followed by a surprisingly
small number of field studies (Mottay 1976) compared to the Society and Marquesas Islands. The
only available recent geological maps are those of
Rurutu, Tubuai and Raivavae Islands (Maury et al.
2000, 2011; Guille et al. 2011).
The Austral-Cook volcanic chain
……General features and submarine
geology
The Austral-Cook volcanic chain (Fig. 3A) extends
over 2300 km from Macdonald Seamount to
Aitutaki, and as the Society and Pitcairn-GambierMururoa linear chains, it follows an ESE-WNW
direction (N 115° E) with an active seamount at
the SE end. The alignment is related to the 11 cm/
yr motion of the Pacific plate over the hotspot
(Duncan & McDougall 1976). However, the Austral
Islands chain displays many unusual features
besides its uncommon length and the presence of
several very old volcanic islands. In particular, the
21
relationship­between age and distance to Macdonald
plot (Fig. 3B) is very abnormal and does not show
a single and good linear trend, as is normally the
case elsewhere and, in particular, for the Society
chain (Guillou et al. 2005) and the Pitcairn-Gambier
chain. Indeed, young volcanic activity (<2 Ma) is
observed not only at the SE end of the chain but also
in the central part (Rurutu-Arago) and even at the
NW end (Rarotonga and Aitutaki, Cook Is.).
The archipelago is cut in the middle by a major
discontinuity, the Austral Fracture Zone (AFZ)
which represents a fossil transform fault linked
to the Pacific-Farallon oceanic ridge (the ancestor
...
.. .....
An Atypical Hotspot Chain
A
20°
Aitutaki
Manuae
Mitiaro
Takutea
Mauke
Atiu
Rarotonga
Mangaia
ZEP2-12
Tubuai
Maria Rurutu
ne
re Zo
Arago
ractu
ral F
Aust
Rimatara
Raivavae
25°
Macdonald
ZEP2-19
Rapa
Marotiri
30°
B
160°
155°
150°
ua
Age (Ma)
en
d
16
Rimatara
14
Rurutu
12
ren
d
Tubuai
Atiu
10
ZEP2-19
8
Arago
ZEP2-12
rot
on
Rarotonga
2500
ga
tre
6
Rapa
Mauke
Aitutaki
Ra
20
18
i tr
?
ut
140°
Mangaia
Tu
b
Ati
145°
Raivavae
Marotiri
4
Rurutu
Arago
2
0
Macdonald
nd
2000
1500
1000
Distance to Macdonald (km)
500
0
Figure 3: The Austral-Cook archipelago.
A: Location and bathymetry. The dotted lines correspond to the
2 400 fathoms (i.e. 4 400 m) isobath, and the full lines to the
2 000 fathoms (3 650 m) isobaths.
B: Plot of age versus distance to the Macdonald seamount.
Fig. 3A and 3B are modified from Chauvel et al. (1997).
Diagram (B) is adapted from Diraison (1991) and includes
data from Dalrymple et al. (1975), Duncan & McDougall (1976),
Turner & Jarrard (1982), Matsuda et al. (1984), Diraison (1991),
Maury et al. (1994, 2000, 2009), McNutt et al. (1997) and
Bonneville et al. (2002, 2006). When available, ages measured
on groundmass or on separated phases have been preferred to
those measured on bulk rocks (Laughlin et al. 1994).
of the presently active East Pacific Rise or EPR).
Finally, the chain is only approximatively linear,
and some authors have distinguished a northern
trend of islands (from Raivavae to Aitutaki) from a
southern trend, Marotiri to Mangaia and Rarotonga
(Diament & Baudry 1987; Bonneville et al. 2006).
The Austral-Cook chain lies over a rather old
Pacific crust formed at the axis of the PacificFarallon ridge: its ages, calculated using the crustal
magnetic anomalies, increase towards the northwest from c. 42 Ma at Macdonald, 56 Ma at Rapa,
63 Ma at Raivavae to 70 Ma at Tubuai and 82 Ma
at Rurutu (Mayes et al. 1990; Munschy et al. 1998;
Bonneville et al. 2002). The bulge of the oceanic
crust below the archipelago is small compared to the
Tuamotu bulge (Sichoix et al. 1998), and its highest
point lies about 4 500 m below sea level (Sichoix
& Bonneville 1996; Sichoix 1997; Bonneville &
Sichoix 1998). The elastic thickness of the AustralCook lithosphere has been considered abnormally
low (Calmant & Cazenave 1986), a feature attributed to its thermal rejuvenation acquired during
its passage over underlying hot spots (Cazenave
& Thoraval 1994). However, a recent study taking
...
into account all the volcanic events which affected
this lithosphere (Adam & Bonneville 2008) concludes that its elastic thickness is normal.
Figure 3A may give an impression of relative simplicity, because almost all of the hundreds of seamounts,
which disturb the seafloor topography, are not shown.
The understanding of their distribution and ages is
still very weak, as evidenced by the recent discovery
of the potentially active seamount Arago (cruise in
1999, publication in 2002), halfway between Tubuai
and Rurutu. However, the combination of satellitederived altimetric data and oceanographic cruises
quickly increases our knowledge relative to the early
studies of Lambeck & Coleman (1982) and Baudry
et al. (1988). In particular, McNutt et al. (1997) discovered two chains of "old" seamounts southeast of
the Australs, and named them the Ngatemato and
Taukina chains after the ruling families of Rapa. The
ages of these seamounts range from c. 34 to 22 Ma,
and most likely they formed close to the Pacific ridge
axis (near the present location of the Foundation
Seamounts) on an oceanic lithosphere which was
only about 10 Ma old at the time. More recent investigations (Clouard et al. 2003; Adam et al. 2005;
Bonneville et al. 2006) led to the recognition of a
number of other seamounts, belonging to three volcanic stages with ages ranging respectively, between
58 and 40 Ma, 33 and 20 Ma and less than 20 Ma.
The youngest set (e.g., seamounts ZEP2-12 West of
Rimatara and ZEP2-19 South of Raivavae, Fig. 3)
coincides with the activity of the Macdonald and
Arago hotspots, and the 33-20 Ma with that of the
near-ridge Ngatemato and Taukina plumes, but the
origin of the oldest seamounts remains unclear. They
were necessarily emplaced very close to the active
ridge, possibly through ridge-plume interactions,
because their ages are only slightly younger than that
of the oceanic crust on which they lie. "Old" samples
were also dredged from the flank of Marotiri and
Raivavae, suggesting that some, if not many, of the
Austral-Cook islands are built over older seamounts
resulting from the activity of previous plumes.
……
Lava types
Austral island lavas are mostly basaltic, and they
show the typical characteristics of Ocean Island
Basalts (OIB). Relative to Mid Ocean Ridge Basalts
(MORB) they display selective enrichments in
incompatible elements, e.g. alkali and alkaline earth
elements (K, Rb, Ba, Sr) as well as in high field
strength elements (Nb, Zr, Ti, Hf) and light rare
earth elements (La, Ce, Nd) (Dupuy et al. 1988,
1989). Within a given island, the major element
compositions are also usually variable, the critical
point being the ratio between total alkalis (Na2O +
K2O) and silica (SiO2). With increasing values of
this ratio, five types of basalts can be distinguished:
• Quartz tholeiites, which contain silica in
excess with respect to the sum of alkalis,
• Olivine tholeiites, which are silica-saturated,
22
.......
14
12
Na2O + K2O
14
Na2O + K2O
RURUTU
12
RAPA
Trachyte
10
10
8
Tephrite
8
6
Basanite
2
Picrobasalt
Basalt
SiO2
Na2O + K2O
14
Phonolite
Tephriphonolite
TUBUAI
12
Hawaiite
4
Basanite
2
Picrobasalt
14
12
Benmoreite
Tephrite
6
Hawaiite
4
Mugearite
Basalt
SiO2
Na2O + K2O
MAROTIRI
10
10
8
Tephrite
8
6
Basanite
Nephelinite Picrobasalt
14
12
Basalt
Na2O + K2O
SiO2
Phonolite
RAIVAVAE
Basanite
2
Picrobasalt
14
Trachyte
12
10
8
8
Basanite
Hawaiite
Mugearite
0
35
Nephelinite
40
Picrobasalt
Basalt
45
50
SiO2
55
Basalt
MACDONALD
Tephrite
Hawaiite
4
Basanite
2
Picrobasalt
0
35
60
SiO2
Na2O + K2O
6
4
2
Hawaiite
4
10
6
Tephrite
6
Hawaiite
4
2
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
40
Basalt
45
50
SiO2
55
60
Figure 4: Total alkalies-silica (TAS) plots adapted from Le Bas et al. (1986) and Le Maitre et al. (1989), and showing the compositional
variations of lavas from Austral islands and seamounts. Alternative names: nephelinite = foïdite; hawaiite = trachybasalt; mugearite
= basaltic trachyandesite; benmoreite = trachyandesite.
i.e. the proportions of silica and alkalis are
equilibrated;
• Alkali basalts, which have a slight excess of
alkalis, and can contain small amounts of feldspathoids (e.g. less then 5 % nepheline);
• Basanites, which are strongly silica-undersaturated, and often bear rather high percentages
of feldspathoids in their groundmass (nepheline, sodalite, analcite);
• Nephelinites, which are so silica-poor that
they are feldspar-free and contain only ferromagnesian minerals (olivine, pyroxenes, iron
oxides) plus feldspathoids and glass.
These basaltic types can be distinguished on a total
alkali-silica (TAS) plot (Fig. 4) by their variable
contents in (Na2O + K2O) and SiO2. Such associations may be explained by variable partial melting
degrees of a peridotitic mantle source: for very low
23
melting degrees (e.g. 1-3 %), the liquids are very
rich in alkalis (nephelinites), and with increasing
fusion the SiO2/(Na2O + K2O) ratios of the melts
increases up to quartz tholeiites (for c. 15 % melting). In addition, many Polynesian basalts have
accumulated large crystals of olivine and/or clinopyroxene (up to 50 % or even 60 %), and are thus
alkali- and silica-poor but very rich in MgO (up to
25 %). These are called picrobasalts, among which
two varieties are often distinguished: olivine-rich
picrobasalts ("oceanites") and pyroxene-rich picrobasalts ("ankaramites").
The evolution of basaltic magmas usually involves
separation of olivine, pyroxenes, plagioclase feldspars, etc. and leads to more alkali- and silicarich derived melts, which are also classified using
the TAS diagram (Fig. 4). Alkali basaltic magmas
commonly evolve towards hawaiites, mugearites,
...
An Atypical Hotspot Chain
.. .....
benmoreites and trachytes, while the differentiation of basanitic magmas usually leads to tephritic,
tephriphonolitic and phonolitic magmas. These
correlations were demonstrated in 1927 for French
Polynesian magmas par Alfred Lacroix, and they
are still accepted.
……Isotopic compositions: HIMU and the
other pieces of the Austral puzzle
The considerable isotopic heterogeneity of
Polynesian magmas (Vidal et al. 1984) mimics that
of their mantle sources, because isotopic ratios are
not affected by partial melting processes. At least
four kinds of isotopic end-members are required to
describe their composition (Zindler & Hart 1986),
providing that these end-members can mix in variable proportions: DMM (Depleted MORB Mantle),
EM 1 (Enriched Mantle type 1), the composition of
which is usually considered as resulting from the
ancient incorporation of pelagic sediments, EM 2
(Enriched Mantle type 2) which is thought to contain an old detrital sedimentary component, and
finally the famous High µ (HIMU) end-member,
identified for the first time in Tubuai lavas by Ph.
Vidal et al. (1984). This discovery has triggered a
number of geochemical studies on Austral-Cook
lavas, with the aim of understanding the meaning
of such unusual compositions for the heterogene-
ity of the Earth’s mantle and the origin of mantle
plumes (Matsuda et al. 1984; Palacz & Saunders
1986; Dupuy et al. 1988, 1989; Nakamura &
Tatsumoto 1988; Vidal et al. 1989; McDonough
& Chauvel 1991; Staudigel et al. 1991; Chauvel et
al. 1992; Vidal 1992; Hauri & Hart 1993; Hauri et
al. 1993; Hémond et al., 1994; Hanan & Graham
1996; Woodhead 1996; Chauvel et al. 1997; Kogiso
et al. 1997; Dostal et al. 1998; Salters & White
1998; Hanyu et al. 1999; Hanyu & Nakamura
2000; Schiano et al. 2001; Bonneville et al. 2002;
Lassiter et al. 2003; Nishio et al. 2005; Bonneville et
al. 2006; Pfänder et al. 2007; Jackson & Dasgupta
2008; Chan et al. 2009; Parai et al. 2009; Vlastélic
et al. 2009).
Although there is still a debate concerning the
origin of HIMU end-member, the most widely
accepted opinion is that it comes from the ancient
(1 or 2 Ga) incorporation into the mantle of residues of subducted oceanic crust that experienced
selective extraction of lead with respect to uranium during the dehydration process accompanying their subduction (Chauvel et al. 1992; Kogiso
et al. 1997; Kawabata et al. 2011). Most authors
envision that these residues were carried down to
the mantle-core boundary and stored there until
their incorporation into ascending mantle plumes
(Hofmann 1988).
Geological features and history of the Austral Islands
…
…Macdonald Seamount
This active seamount was discovered in 1967 from
hydrophone records of acoustic signals during
eruption (Norris & Johnson 1969), and named
in honor of the American volcanologist Gordon
Macdonald. Since its discovery, the seamount was
monitored by the French Polynesia seismic network (Talandier & Okal 1984). It has been very
active from 1977 to 1989, with more than 20
eruptive events (among which 8 from June 1987
to April 1988), including spectacular shallow submarine explosions in September 1988 and January
1989 (Cheminée et al. 1991).
Macdonald volcano is a large submarine cone,
with a basal diameter of 45 km at a depth of
3 950 m, which lies over Eocene (c. 42 Ma old)
Pacific crust. Several volcanic ridges, which from
submersible observations correspond to lava channels and/or lava flows, extend in a radial fashion
from the top down the slopes (Stoffers et al. 1989).
These ridges define a star-shaped pattern with a
preferential N-S orientation which coincides with
a regional fault pattern of the underlying oceanic
crust (Binard et al. 1991), and they are similar to
the rift zones of Hawaiian volcanoes. The summit
is a rather flat plateau (150 m x 100 m) lying at
a depth of 39-40 m, and made of basaltic flows
covered by recent lapilli. It is capped by small (and
...
s­hort-lived) spatter cones which form steep-sided
pinnacles reaching depths of 23 to 30 m only. It
seems likely that Macdonald will emerge at the
surface in the near future. Soon after its discovery,
it has been proposed that it marks the present
position of the hotspot responsible for the formation of the Austral-Cook archipelago (Johnson &
Malahoff 1971).
Numerous volcanic samples have been collected
from Macdonald by dredging, during submersible
explorations and even directly from pyroclastic
falls (Brousse & Richer de Forges 1980; Barsczus &
Liotard 1985; Hekinian et al. 1991; Hémond et al.
1994). They show a considerable diversity (Fig. 4),
largely because the 20th century pyroclastic explosions deposited on the summit and on the flanks of
the volcano blocks of older materials (Hékinian et
al. 1991), on which ages up to 0.35 Ma have been
measured. Basalts range from olivine tholeiites
to nephelinites through alkali basalts, basanites
and picrobasalts. Hawaiites, tephrites and a single mugearite have also been identified. Debris of
granular rocks (dolerites and olivine gabbros) are
thought to have been removed from deep intrusions by the explosive eruptions. Much older (c. 34
to 22 Ma) samples have also been dredged on the
slopes of several seamounts close to Macdonald,
e.g. on Ra seamount (29.21 ± 0.62 Ma, McNutt et
24
.......
al. 1997), and it is possible that the active volcano
……Rapa
This rather large island (c. 40 km ) has been
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
itself was built on an older edifice belonging to the
the Ngatemano volcanic chain.
…
…Marotiri
The ten very small islets collectively referred to as
Marotiri (or Bass) are the southermost emerged
lands of French Polynesia. They represent the still
emerged parts of a c. 50 m deep circular plateau
5 km in diameter, which corresponds to the top of
a conical volcanic edifice. These islets reach altitudes of 8 to 113 m, and their surfaces range from
a few m2 to 0.035 km2. They are composed of a pile
of subaerial basaltic flows, the individual thickness
of which range from 50 cm to 10 m, with occasional interbedded pyroclastic deposits (reddish
ash layers and tuffs). The massive parts of the lava
flows are usually separated by autoclastic breccias,
and their dips are lower than 15°.
Twelve samples have been collected by N.O. Marara
in 1979 and 1982 from islets NW (alt. 10 m), SE
(alt. 113 m) and W (alt. 99 m) and described by
Liotard & Barsczus (1985) and Dupuy et al. (1988,
1989). They include picrobasalts (oceanites), basanites, tephrites and hawaiites (Fig. 4), and a granular rock (plagioclase-rich olivine gabbro) has also
been recovered. The ages of these samples range
from 3.29 ± 0.16 to 3.21 ± 0.32 Ma (Diraison 1991).
In addition, two samples dredged from the submarine slopes of the volcano have been dated at
3.78 ± 0.18 Ma and 31.95 ± 0.82 Ma, respectively
(McNutt et al. 1997). The latter age indicates that the
Pliocene (3.8-3.2 Ma) Marotiri volcano growed on
the top of a much older seamount belonging to the
Late Eocene-Oligocene Ngatemato volcanic chain.
2
less studied from a geological point of view than
Tubuai and Rurutu, because of its remote location
1 240 km South of Papeete and the lack of airport facilities. Early investigators (Marshall 1918;
Chubb 1927; Obellianne 1955) spent only a few
days in the island. The first detailed study of Rapa
was that of Mottay (1976), who collected samples
analysed by Maury et al. (1978) and Brousse et al.
(1981). During the DIRCEN-SMCB Expedition in
1984, R. Brousse and P. Gelugne collected many
samples that were later dated by Diraison (1991),
and they published in 1986 a detailed account of
the geology and petrology of Rapa. A simplified
version of their map (Brousse & Gelugne 1986) is
shown in figure 5.
Rapa has an unusual shape because of the very deep
Ahurei bay that penetrates into the core of the island.
There, a rather flat zone interpreted as the bottom
of a caldeira is rimmed by two almost vertical
ridge lines: the inner one is rather continuous and
encircles almost completely Ahurei bay; the outer
one, which culminates at Mt Maurua, Mt Perau
(650 m) and Mt Pukumia, is interrupted by the Iri
and Anarua bays and lacks in the northern part of
the island. These ridge lines have been interpreted
by Mottay (1976) as the caldeira walls of two successive volcanoes, the inner one being the youngest
and having grown inside the caldera of the older
(and outer) volcano. However, the study of their
geomorphologic features led Brousse & Gelugne
(1986) to consider them as two nested caldeiras,
with respective diameters of 6 and 3 km, belonging
to a single volcanic edifice. This ­interpretation has
The 113 m-thick subaerial basaltic flow pile of the Southern Rock, the largest islet of Marotiri
(Photo C. Debitus).
25
...
An Atypical Hotspot Chain
.. .....
Figure 5: Geological map of Rapa, simplified from Brousse & Gelugne (1986).
been supported by ten 40K-40Ar ages (Diraison
1991) which indicate a relatively short period of
subaerial activity (4.8 to 4.1 Ma), consistent with
the lifetime of a single shield volcano.
Rapa island lies on a rather flat submarine plateau
of ovoid shape, c. 16 km in diameter at a depth of
50 m: the size of the island should thus have been
several times its present one during the sea leval
minima related to Quaternary glaciations (Brousse
& Gelugne 1986). The rather dissymetric shape of
Rapa, with its higher summits in the western half
of the island, its north-south trending and almost
linear east coast, the opened eastwards caldeiras
and the unusual configuration of Ahurei bay, all
suggest that one, or more likely, several sector collapse events have affected its eastern and central
zone. They probably led to the destruction of the
eastern part of the initial shield volcano by submarine debris avalanches, as envisioned for other
Polynesian islands, e.g. Moorea (Le Dez et al. 1998)
or Nuku Hiva (Maury et al. 2006). Smaller collapse
...
events may have been responsible for the formation
of the Ahurei bay by connecting the central (inner)
caldeira with the eastern coast. The dissymetric
shape of the island is still partly responsible for the
numerous recent landslides that affected the inner
caldera wall (Brousse & Gelugne 1986). Another
noticeable tectonic feature of Rapa lies in the orientations of the numerous dykes, which show two frequency maxima corresponding to the NW-SE trend
of the archipelago and to the conjugate NE-SW
direction (Brousse & Gelugne 1986).
Rapa is mostly made of a pile of subaerial basaltic flows, the individual thickness of which range
from 1 to 10 m, which dip gently (8°-15°) towards
the periphery of the island. Following Brousse &
Gelugne (1986), the distinction shown in figure 5
between an outer and an inner volcano is purely
morphologic, as these areas represent two parts of a
single shield edifice separated by the collapse of the
inner caldeira. Indeed, the lithology of the two parts
is identical, and there is no reliable age difference
26
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
according to the ten available
40K-40Ar ages (Diraison, 1991)
ranging from 4.76 ± 0.24 Ma to
4.13 ± 0.21 Ma. Rapa is exceptional because of the abundant
granular and doleritic rocks
(mostly olivine gabbros) corresponding either to thick
(> 10 m) sill-type intrusions
or less commonly to unusually
thick lava flows. Most intrusions lie along a NW-SE trend
parallel to the island elongation
(Brousse & Gelugne 1986); one
intrusion is exposed in the center of the caldeira (Motu Tapui
inside Ahurei or Haurei bay).
Pyroclastic breccias are not very
abundant in Rapa: the most common type corresponds to strombolian-type scoria, lapilli and
The inner volcanic ridge encircling Ahurei village and bay, Rapa. From left to right:
ash deposits occuring in several
Mts Orongo, Tautautu, Tevaitu and Pukutaketake (Photo G. Mesere).
locations shown in figure 5, the
largest ones being in Iri bay and
that the lignite was deposited into a small lake
in the southernmost part of Rapa (Karapoo Nui and
or swamp, possibly within a previous lava lake
Karapoo Iti islands). The Puputa parasitic cone in
(Brousse & Gelugne 1986).
the NE of Rapa is relatively well preserved: it consists
Rapa is devoid of coral reef barrier or of fringing
of strombolian breccias with intercalated basanitic
reef, and its shores are composed of volcaniclaflows containing numerous xenoliths of depleted
stic sands mixed with biodetritic debris (mostly
mantle rocks, i.e. harzburgites (Berger et al. 1986).
Lithothamnium and shells). A Quaternary shore terSubmarine (hydromagmatic) pyroclastic breccias
race has been identified at + 5 to + 15 m in Tupuaki
have been identified in Agaira (Angairao) bay.
Rapa lavas are chemically very heterogeneous
bay (Chubb 1927; Brousse & Gelugne 1986).
(Fig. 4). Although the most common lavas are
Raivavae
basanites, tholeiitic basalts, alkali basalts and
Raivavae is a 16 km2 volcanic island that culminephelinites occur as well as olivine- or clinopynates at 438 m at Mt Hiro and is rimmed by a
roxene-rich varieties (picrobasalts). The basaltic
typical barrier reef delineating a 2 to 3 km wide
magmas evolve towards intermediate melts (tephlagoon. Unlike most of the other Austral islands,
rites, hawaiites, mugearites, benmoreites), and ultiit has an elongated shape trending WSW-ENE,
mately into trachytic and phonolitic melts. The
parallel to the nearby Austral Fracture Zone (AFZ)
genesis of the Rapa series is ascribed to fractional
which lies only c. 35 km to the NW. It represents
crystallisation of basaltic magmas under almost
the emerged remnants of a much larger volcano,
anhydrous and oxygen-poor conditions, leading to
which has collapsed generating two large subdelayed fractionation of titanomagnetite and strong
marine debris avalanches (Clouard & Bonneville
enrichment in iron of olivines and pyroxenes
2004). A 50 km long submarine ridge prolon(Maury et al. 1978; Brousse et al. 1981; Brousse
gates the island towards the South-West (Adam &
& Gelugne 1986). Intermediate lavas commonly
Bonneville 2008). Gravimetric data (Clouard et al.
occur as flows intercalated within the basaltic pile.
2000) document positive residual isostatic anomaTrachytes and phonolites form intrusions, e.g. Mt
lies centered on this ridge, which might correspond
Ruatara and Mt Vairu; the largest massif is located
to a set of mafic intrusions or to the summit of a
in Agaira (Angairao) bay (Fig. 5).
magma reservoir.
An unusual deposit of lignite (brown coal), up to
The salient geomorphological feature of Raivavae is
2 m thick, associated with volcaniclastic sand and
a continuous 200 to 400 m high cliff facing north,
clay-rich layers, occurs at an altitude of 180 m
connecting Mt Maunanui, Mt Araua, Mt Hiro, Mt
south of Mt Vairu, below the inner ridge line
Mouatapu and Mt Turivao (Fig. 6). Fieldwork by
(Fig. 5). It is interbedded within the basaltic pile
Obellianne (1955) and Mottay (1976) led to the
and cut by a picrobasaltic (ankaramitic dyke),
identification of two distinct volcanic centers: an
whose glass is converted into palagonite (Lacroix
eastern (and old) volcano located east of a line
1927), a typical product of interaction between
connecting Mt Maunanui to Mt Rareterepa, and
basaltic magma and water. These features suggest
……
27
...
.. .....
An Atypical Hotspot Chain
ANATONU
ms
MAHANATOA
Mt Taamora
Mt Hiro
Mt Araua
Mt Maunanui
Mt Rareterepa
RAIRUA
VAIURU
Mt Tapioi
Mt Matotea
Mt Tavaetu
Mt Turivao
Mt Mouatapu
M.
Hotuatua
Scree breccias
Bioclastic sands and
alluvial deposits
Phonolitic and
trachytic domes
Mt Taraia
Basaltic flows from
Anatonu shield volcano
0
1
Basaltic flows from
Rairua volcano
2 km
Rairua submarine breccias
crosscut by dykes
Figure 6: Geological map of Raivavae, simplified from Guille et al. (2011). Miocene sediments outcropping beneath the scree
breccias near Anatonu are denoted by the letters ms.
including­the northern cliff as well as the Vaiuru area;
and a western (and younger) one centered around
the Rairua-Mahanatoa depression, interpreted as
a caldeira (Mottay op. cit.). However, such a view
has not been corroborated by K-Ar dating. Five ages
measured by Duncan and McDougall (1976) range
from 6.96 ± 0.35 Ma to 6.07 ± 0.30 Ma, and do not
support the hypothesis of a westward migration of
emplacement ages. Four out of five additional ages
measured by Diraison (1991) are also very close
to 6.5 Ma (6.45 ± 0.32 Ma to 6.32 ± 0.32 Ma). In
addition, a tholeiitic basalt dredged on the SW
flank of the Raivavae edifice, at a depth of 2 950 m,
was dated at 33.3 ± 0.5 Ma and 31.9 ± 0.5 Ma on
separated plagioclase (Bonneville et al. 2006). The
latter ages suggest that the Late Miocene Raivavae
volcanoes were emplaced over a much older seamount belonging to the Ngatemato chain. Lassiter
et al. (2003) published detailed informations on the
geochemistry of Raivavae lavas, including major,
trace elements and Sr, Nd, Hf, Pb, and Os isotopes.
Although these authors did not try to decipher the
geological structure of the island, they identified
two geochemical groups:
• Lavas derived from a HIMU-type mantle
source, which include mainly basanites and
picrobasalts (ankaramites);
• Lavas derived from a mantle containing an
important DMM (Depleted MORB Mantle)
component.
The simplified geological map of Raivavae shown
in figure 6 has been drawn from the results of a
mapping program conducted from 2005 to 2010
(Guille et al. 2011; Maury et al. 2011). We recognise two distinct volcanoes:
• The old Rairua volcano, made of nephelinites, basanites, alkali basalts and picrobasalts
...
(clinopyroxene-rich ankaramites) derived from
HIMU-type mantle sources;
• The younger, although dissected, Anatonu
shield volcano built of plagioclase-phyric
tholeiitic and less commonly alkalic basalts,
which originated from partial melting of a
more depleted mantle with a subdued (DMMHIMU-EM) signature (Maury et al. 2013).
The Anatonu basaltic magmas evolved towards trachytic and phonolitic melts (Fig. 4) through intermediate (hawaiitic, mugearitic and benmoreitic)
lava compositions. From a petrologic point of view,
the Anatonu series resembles in many respects the
Rapa series (Maury et al. 1978, 2009).
The oldest exposed unit of Rairua volcano is a more
than 200 m thick pile of basaltic breccias crosscut
Rairua submarine autoclastic breccias, Raivavae.
Small basaltic pillows are set in a palagonite-rich
(yellow) glassy matrix (Photo A.-M. Marabal).
28
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
View of the pass (altitude 200 m) separating the Mouatapu-Turivao ridge from the
Mt Hiro ridge, Raivavae. Submarine autoclastic breccias are overlain successively by
laharic breccias, conglomerates and clay-rich layers (white), and then by Mt Hiro
plateau basal flows dated at 6.35 ± 0.13 Ma (Photo R.-C. Maury).
by a dense network of basanitic and alkali basaltic
dykes, most of which trend WSW-ENE, parallel to
the AFZ and the trend of the island. They outcrop
along the axis of the island, and are overlain either:
•  By the Rairua basanitic flows which form the Mt
Tavaetu plateau in the western part of Raivavae;
• Or by the younger plateaus of Anatonu volcano, e.g. below Mt Maunanui, Mt Taraia and
Mt Matotea.
These breccias also crop out at the pass (altitude
200 m) separating the Mt Hiro ridge from its eastern equivalent, i.e. the Mouatapu-Turivao ridge. In
this latter location, they occur as a c. 20 m thick pile
of volcaniclastic (laharic) breccias and conglomerates interbedded with clay-rich layers, both of them
deposited in a lacustrine or shallow submarine environment. This pile is probably overlain by Miocene
northwards-dipping sediments (bioclastic limestones; ms in Fig. 6) emplaced on the lower slopes
near Anatonu village (Obellianne 1955; Maury et al.
2011). However, most of the breccias outcropping
at lower altitudes do not appear reworked. Their
characteristics resemble those of shallow submarine autoclastic or hydromagmatic basaltic deposits,
and they contain small (often fragmented) pillows
set into a palagonite-rich matrix. Because of their
common yellowish color, they were apparently
mistaken for trachytic breccias by former authors
(Obellianne 1955; Mottay 1976). The occurrence
of chlorine-rich melt inclusions in the olivine crystals from old Raivavae lavas (Lassiter et al. 2002)
29
suggests that these melts have interacted with seawater. Two fresh basanitic and alkali basaltic dykes
crosscutting these breccias have given unspiked
K-Ar ages of 10.58 ± 0.23 Ma and 9.12 ± 0.19 Ma,
respectively. They display a typical HIMU signature
(Maury et al. 2011, 2013), as well as other dykes
in the same position and the Tavaetu plateau lava
flows (Lassiter et al. 2003). The basal (picrobasaltic) and summital (basanitic) flows of the Tavaetu
lava pile have given significantly younger unspiked
K-Ar ages of 7.41 ± 0.16 Ma and 7.37 ± 0.16 Ma,
respectively.
The Anatonu shield volcano is mostly composed of
an up to 400 m thick pile of flows of plagioclasephyric tholeiitic basalts, with intercalated alkali
basaltic, hawaiitic, mugearitic and benmoreitic
flows, up to 10 m thick. These flows form six
gently dipping plateaus, which are, by order of
decreasing size, those culminating at Mts Hiro,
Taraia, Matotea, Mouatapu, Taamora, and Tapioi,
respectively (Fig. 6). Their unspiked K-Ar ages
range from 6.41 ± 0.14 Ma to 5.36 ± 0.11 Ma. The
youngest of them is the Tapioi plateau, the basal
and summital flows of which have been dated to
5.74 ± 0.12 Ma and 5.36 ± 0.11 Ma, respectively
(Maury et al. 2011, 2013). All these lavas display
a subdued isotopic signature intermediate between
DMM, HIMU and EM end-members (Maury et
al. 2013), as well as other Anatonu volcano flows
and dykes and the phonolitic and trachytic plugs
(Lassiter et al. 2003). The variations of the dips and
...
An Atypical Hotspot Chain
.. .....
The northern coast of Raivavae viewed from Mt Taamora. The summits behind
Mahanatoa village are, from right to left: Mt Rareterepa trachytic plug; Mts Maunanui,
Araua and Hiro basaltic to benmoreitic lava piles, dipping gently towards the North
(Photo R.C. Maury).
the thickness of the Mt Hiro plateau pile along the
northern cliff of the island suggest that these flows
were emplaced into a paleodepression dug into
the Rairua breccias. Other witnesses of Anatonu
volcanic activity are six phonolitic and trachytic
domes and plugs, which crosscut either the Rairua
breccias (Mt Rareterepa trachytic plug, dated at
6.42 ± 0.14 Ma) or more commonly the Anatonu
shield plateaus (e.g. Mt Turivao). They define a
WSW-ENE trend, from Mt Rareterepa to the two
phonolitic plugs of Motu Hatuatua at the eastern
edge of the island. This trend is parallel to the AFZ
and to the main direction of the dykes crosscutting
the Rairua breccias. All these features suggest that a
deep fracture parallel to the nearby AFZ controlled
closely the emplacement of Raivavae magmas.
Figure 7: Geological map of Tubuai, simplified from Maury et al. (1994, 2000a).
...
30
.......
The geological evolution of Raivavae is therefore
characterized by two temporally distinct volcanic
events with constrasted geochemical signatures, separated by a c. 1 Myr long time gap. The development
of Rairua submarine breccias in Raivavae suggests a
c. 200 m uplift of the island after the first event.
…
…Tubuai
Tubuai, the largest of the Austral islands (45 km ),
2
has an ovoid shape (9.5 x 5 km) and is encircled
by a large barrier reef (16 x 10.5 km) that isolates
a wide lagoon. The morphology of Tubuai is typical of an old volcanic edifice: two residual reliefs
corresponding to the western Hanareho volcano
and to the central/eastern strongly dissected Herani
volcano emerge from a thick cover of Quaternary
biodetrital sands and alluvial deposits. The island
represents the summit of a large conical volcanic
edifice, the base of which has an average diameter
of 100 km (Monti & Pautot 1975) and lies over a
4 500 m deep oceanic crust of Upper Cretaceous
age (c. 70 Ma; Mayes et al. 1990; Munschy et al.
1998). This edifice is characterised by gentle submarine slopes (8° to 10°) and a very flat summit
(above the -500 m isobath), the shape of which
indicates an important coral reef limestone cover.
Tubuai has been quoted very early for the occurrence
of nephelinites, basanites and phonolites (Lacroix
1927, 1928) but the first geological descriptions of
the island (Marshall 1918; Chubb 1927; Obellianne
1955; Aubert de la Rüe 1959) were very brief. In
1976, R.A. Duncan and I. McDougall published
the first accurate K-Ar datings of Tubuai lavas,
and G. Mottay collected a sample set extended by
R. Brousse in 1979. This set was used for detailed
geological and petrologic investigations (Brousse
1980; Brousse & Maury 1980) together with additional datings (Bellon 1980). It allowed P. Vidal et
al. (1984) to document the first occurrence in the
South Pacific of lavas displaying a highly radiogenic lead isotopic signature (later called HIMU).
The name of Tubuai became famous to geochemists
for its unusual composition, and this discovery was
followed by numerous other studies. The geological mapping of the island was completed between
1989 and 1995 (Maury et al. 1994, 2000a, 2000b).
Tubuai mafic lavas range in composition from alkali
basalts and picrobasalts (mostly clinopyroxenerich ankaramites) to basanites and nephelinites
(Fig. 4). These types of lavas were emitted more
or less successively: alkali basalts and picrobasalts
were emplaced at 10 Ma (Fig. 7), and were followed by basanites between 10 and c. 9.4 Ma.
Both types were only emplaced within the eastern
Herani volcano, where basanitic flows systematically overlie alkali basaltic flows. The alkali basalt
sequence, up to 350 m thick, makes up the basal
part of the Herani volcano, and this pile of individual 1 to 10 m thick flows crosscut by numerous
dykes crops out in the radial valleys diverging from
31
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Mt Taitaa. Their main vents were located north
of Mt Panee, where strombolian alkali basaltic
breccias reach a thickness of 170 m. Individual
basanitic flows are generally thicker (c. 10 m) than
alkali basaltic ones, but they made a thinner pile
(< 130 m). They were mostly emitted from the
summit of Mt Panee and from the ridge located
north of Mt Taitaa, where basanitic strombolian
scoriae, lapilli and bombs are common. These
flows form three plateaus dipping gently towards
the periphery of the island: the main one, dated at
9.37 ± 0.07 Ma, corresponds to the rige connecting Mt Panee to Mt Taitaa and extends towards the
north coast (Fig. 7), while the two others cap the
Mt Herani (West) plateau (10.04 ± 0.07 Ma and
9.56 ± 0.06 Ma) and the Mt Herani (East) plateau
(9.62 ± 0.06 Ma), respectively.
Nephelinite eruptions occurred only within the
western Hanareho volcano. They were either contemporaneous (9.68 ± 0.07 Ma) with basanites or
younger (8.89 ± 0.06 Ma). These rocks occur as
individual decametric flows forming a more than
300 m thick pile. Crosscut by several nephelinitic
necks and radial dykes, they make the frame of
the crescent-shaped ridge of the western Hanareho
volcano, which connects Mts Haurii, Tonarutu,
Mt Pahatu 8.9 Ma old phonolitic needle, Tubuai (Photo S. Blais).
...
.. .....
Tavaetu, Hanareho and Mareura, and is prolon……Arago Seamount
The occurrence of a young seamount between
An Atypical Hotspot Chain
gated northwards by the Mt Piritia tephritic flows
and the Piritia and Pahatu phonolitic dykes. The
east-facing (concave) cliff is interpreted as a remnant of the caldeira wall of the Hanareho volcano
(Maury et al. 2000a, 2000b), in agreement with the
occurrence of a positive gravimetric anomaly east
of it (Clouard et al. 2000).
Basanitic and nephelinitic magmas evolved towards
tephritic melts (e.g. TB9 from Mt Piritia dated
at 9.46 ± 0.07 Ma, Fig. 7), and ultimately towards
phonolites, emplaced as intrusions along a WSWENE trending fracture parallel to the AFZ. The
latter include the Piritia, Pahatu and Petit Pahatu
dykes (8.89 ± 0.06 Ma) within the Hanareho
volcano, the large Mt Taitaa intrusive needle
(8.78 ± 0.06 Ma) and the phonolitic islet Motu
Ofai located west of Tubuai (not shown in Fig. 7).
All the lavas exposed on the island likely derive
from a single type of enriched mantle source displaying a strong HIMU imprint (Vidal et al. 1984;
Dupuy et al. 1989; Chauvel et al. 1992). Enriched
mantle xenoliths are rather abundant in Tubuai
lavas (Berger & Brousse 1980; Berger 1985). Those
found in Mt Piritia tephrites show evidence for
enrichments linked to interaction with carbonatite
melts (Liotard & Barsczus 1989; Hauri et al. 1993).
Strongly enriched mantle clinopyroxenites, found
within nephelinites, could represent an analog of
their source (Caroff et al. 1997). As a whole, the
mafic lava succession observed on the island could
result from variable degrees of melting of an isotopically homogeneous mantle source, which decreased
through time from 8-5 % (alkali basalts) to 3-1.5 %
(nephelinites) while depth of melting was simultaneously decreasing (Caroff et al. op. cit.). Thus,
alkali basaltic and basanitic lavas from the Herani
volcano likely derived from the partial melting, at a
depth of c. 60 km, of asthenospheric plume-related
garnet+spinel lherzolites, while the Hanareho nephelinites resulted from the low-degree fusion at c.
50 km of lithospheric spinel pyroxenites previously
contaminated by plume melts (Caroff et al. op. cit.).
The post-magmatic geological history of Tubuai
appears quite simple. It was mostly marked by
the subsidence of the volcanic massif, which was
progressively drowned beneath coral reef limestones and related bioclastic sands. The latter
accumulated around the volcanic massifs, delineating swamps into which clay-rich sediments were
deposited, especially between Mt Hanareho and
Mt Panee (Fig. 7). The occurrence of fossil knolls
0.3 to 0.6 m above sea level in the lagoon does not
imply a recent uplift: it is consistent with Holocene
sea level variations (Dickinson 1997, 1998). The
unusual size (2 km) of the phonolitic scree breccia
stripe NE of Mt Taitaa is rather intriguing: it might
indicate that this phonolitic needle was initially
very high, like some of the Pliocene protrusions of
Ua Pou in the Marquesas (Guille et al. 2002).
...
Tubuai and Rurutu, marking the present position
of the Rurutu hotspot, was predicted before its
discovery (Turner & Jarrard 1982; Chauvel et al.
1997; Guille et al. 1998). During the ZEPOLYF2
cruise in 1999, samples were dredged from a very
shallow seamount, with its top only 26.5 m below
sea level, located at 23° 26.4’ S and 150° 43.8’ W,
(Bonneville et al. 2002, 2006). Already called Arago
Seamount after a French Navy ship that discovered
its summit in 1993, it was also known from the
local fishers as Tino Mana. This submarine edifice
shows three rift zones equivalent to those recognised for Macdonald. Their principal orientations,
N170° and N70°, correspond to that of structural
discontinuities inherited from the Farallon ridge,
and to that of the nearby AFZ, respectively. The
edifice is composed of three coalescent volcanoes,
among which the highest (Arago) is a regular
cone overlapping the two lower and older ones.
Samples of nephelinite and hawaiite, both occurring as pillow-lavas, were collected between depths
of 900 and 600 m on its southern flank. Nepheline
crystals and groundmass separated from a nephelinite gave K-Ar ages of 0.230 ± 0.004 Ma and
0.013 ± 0.002 Ma, respectively (Bonneville et al.
op. cit.), allowing to designate Arago as the potentially active seamount overlying the Rurutu hotspot
(Fig. 3). This conclusion is supported by the lead
isotopic signature, which is rather similar to that of
young Rurutu lavas (Bonneville et al. 2002).
Another hawaiitic sample was dated at
8.89 ± 0.13 Ma and 7.71 ± 0.11 Ma on separated
plagioclase (Bonneville et al. 2006), suggesting that
the active Arago seamount growed over an older
seamount, probably related to the Tubuai trend
(Fig. 3).
……
Rurutu
Rurutu, a 38.5 km2 island culminating at 389 m (Mt
Manureva) is from a geological point of view the
most unusual among the Austral islands, because it
is made of two volcanic series of very different ages,
Upper Miocene (12.7 to 12.1 Ma) and Pleistocene
(1.1 to 1.0 Ma), separated by a 100 m thick uplifted
Late Miocene carbonate platform. Already quoted
by Charles Darwin (1842), the latter was the subject of a very long controversy regarding its origin
(Marshall 1913, 1929; Chubb 1927; Hoffmeister
1930), which ended only rather recently (Stoddard
& Spencer 1987; Dickinson 1998). The first geological sketches of Rurutu were drawn by Chubb (1927)
and Obellianne (1955), but Duncan & McDougall
(1976) and Duncan & Compston (1976) were the
first to date two very distinct volcanic events in
Rurutu, later confirmed by Turner & Jarrard (1982)
and Diraison (1991). The discovery of HIMU-type
lavas in the nearby island of Tubuai led to a number
of geochemical studies including Rurutu samples
32
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
(Chauvel et al. op. cit.). The two
types show rather contrasted major
and trace element features, and
N
thus can be easily distinguished
(and mapped) using simple geochemical diagrams, e.g. TAS (Fig. 4
Guille et al. 1998). The origin of
the attenuated HIMU signature of
Pleistocene lavas is attributed to the
interactions between plume-related
asthenospheric magmas derived
from the Arago hotspot and the
Rurutu lithospheric mantle, which
had previously been enriched by
carbonatite melts during the Late
Miocene volcanic episode (Chauvel
et al. op. cit.).
Three main geological units are
exposed in Rurutu (Fig. 8):
• The Late Miocene volcanics,
which constitute the central
NS trending ridge of the island,
from Moerai to Naairoa;
• The Late Miocene limestones,
which overlie unconformably the
old volcanics, forming a series of
plateaus up to 100 m high along
the coasts of Rurutu, and which
dip gently (15°-20°) towards the
periphery of the island;
• And finally the Pleistocene lava
pile, which overlies unconformably either the limestones or
directly the old volcanics. Their
maximal thickness (150 m) and
largest development are observed
at Mt Manureva, but they also
Figure 8: Geological map of Rurutu, simplified from Guille et al. (1998).
cap several other plateaus in the
southern part of the island.
(quoted in Chauvel et al. 1997). The geological map
The Late Miocene volcanics from the base of the
shown in figure 8 results from fieldwork conducted
exposed pile were emplaced in a shallow water
between 1992 and 1996 (Guille et al. 1998; Maury
environment, as pillowed alkali basaltic flows, pilet al. 2000a, 2000b).
low breccias and less commonly as layered hyaRurutu island represents the summit of a large
loclastic (surtseyan-type) tuffs made of basaltic
submarine edifice (with a diameter of 100 km at
-4500 m) which displays a five-starshaped morphology corresponding probably to the rift zones
of the initial volcano. Dredgings on a 1 350 m deep
seamount (ZEP2-7) located slightly west of Rurutu
recovered basalts similar in age and geochemistry to the Late Miocene lavas cropping out in
the island (12.2 ± 0.2 Ma, Bonneville et al. 2006).
Rurutu lavas are exclusively mafic (Fig. 4): the
Late Miocene ones, which display a strong HIMU
signature, consist of alkali basalts, hawaiites and
picrobasalts, although a single tholeiitic basalt has
also been identified (Chauvel et al. 1997; Guille et
A dense network of dykes crosscutting altered
al. 1998). Pleistocene mafic lavas are more silicapillowed basaltic flows along the road from
undersaturated, and include basanites and tephMoerai to Avera, Rurutu (Photo R.-C. Maury).
rites. They display an attenuated HIMU imprint
33
...
An Atypical Hotspot Chain
.. .....
glass shards altered to yellowish palagonite. These units are
crosscut by a dense network of
dykes. Then, ­volcanic activity
became subaerial, emplacing
at the top of the pile columarjointed alkali basaltic flows,
up to 10 m thick, which often
fill up paleodepressions dug
into the submarine units.
Some laharic breccia deposits
are also intercalated within
this sequence.
The contact between the Late
Miocene volcanics and the
overlying (transgressive) bioclastic limestones is marked
by layers of volcaniclastic
breccias with abundant basaltic pebbles set into a clay-rich
Toarutu uplifted limestone plateau, eastern coast of Rurutu. Note the
matrix. In the southern part of
gentle eastward dip (15-20°) of the Miocene bioclastic limestone
the island, near Nairoa, manbeds. The cliff at the left of the photograph shows Quaternary notches
ganese-rich deposits occur
(dated at 122 ka) at altitudes of +8 to +10 m (Photo S. Blais).
in this contact zone (Chubb
1927; Obellianne 1955).
These limestones are rich in coral debris and
northwards, with an up to 150 m thick breccia pile
show discrete layering. They contain abundant
made of lapilli, red scoriae and occasional fusiform
Lepidocyclina sp., the occurrence of which demonbombs.
strates their Miocene age, and their faunistic assoThe common occurrence of Late Miocene shalciations indicate deposition between c. 10.5 and
low submarine volcanics and biodetritic limestones
6.5 Ma (Bourrouilh-Le Jan 1984). They form steep
clearly indicates that Rurutu has been uplifted after
cliffs facing either the periphery or the central part
the end of deposition of the limestones, i.e. at less
of the island. The origin of the latter (internal)
than 6.5 Ma (Guille et al. 1998). On the other hand,
cliffs has been a matter of considerable debate,
a coastal Pleistocene lava flow near the airport shows
and is now explained by the erosion/dissolution
evidence for autofragmentation by interaction with
processes caused by suface waters draining the old
seawater, indicating that the sea level at 1.1 Ma was
volcanic edifice (Stoddard & Spencer 1987). These
similar to the present-day level, and thus that the
circulations led to the development of a typical
uplift of Rurutu had already ended (Maury et al.
karstic morphology with dolines, lapiés, caves,
2000b). In addition, the coastal limestone cliffs show
exits of underground streams, etc.
very distinct notches at altitudes of + 8 to + 10 m,
The Pleistocene (1.1 to 1.0 Ma) volcanic activity
dated at 122 ka by the Th/U method (Pirazzoli &
emplaced mainly basanites and tephrites. Basanitic
Veeh 1987; Pirazzoli & Salvat 1992). Such age and
flows are usually c. 10 m thick and often disposition are consistent with the Riss-Würm interglaplay columnar jointing. They crop out below the
cial period of high sea level (Dickinson 1997, 1998),
tephritic pile of Manureva plateau in the north of
and suggest a lack of recent uplift of the island. Thus,
Rurutu, and as isolated flows near the southern
the origin of the surrection of Rurutu is probably
edge of the island. They also occur as hydromaglinked to its passage over the Arago hotspot, leading
matic breccias forming the beautifully preserved
to a thermal rejuvenation of the underlying lithomaar structure of Nairoa (Fig. 8). These breccias,
sphere and corresponding local uplift of the seafloor.
up to 30 m thick, were emplaced either above the
Rimatara and Seamount ZEP2-12
biodetritic limestones or the old volcanics. They
The westernmost among the Austral islands, and
are layered, with occasional base surge features
the smallest among the inhabited ones, displays
and gentle peripherical dips (< 10°), and contain
an almost circular shape, with an average diameter
basanitic cauliflower bombs together with abunof 3 km, and a typical residual morphology. It is
dant angular limestone blocks. The tephritic lava
rimmed by coral sands and by an uplifted coral reef
flows range in thickness from 10 up to 30 m,
limestone unit, up to 500 m wide and reaching an
especially when they fill up paleodepressions, and
altitude of 11 m (Obellianne 1955). The central
often display columnar jointing. They were emitpart of the island, which is usually separated from
ted from strombolian cones, the biggest of which
the uplifted reefal limestone by swamps, reaches an
(Mt Manureva) shows a preserved crater opened
……
...
34
.......
altitude of 90 m at Mt Uahu. It consists of deeply
altered and eroded basaltic flows, covered by very
thick ferralitic soils.
Fresh samples collected from blocks and boulders
in temporary river beds, include alkali basalts,
basanites and hawaiites (Liotard 1986; Dupuy et
al. 1988). Three Rimatara samples were dated by
Turner & Jarrard (1982), but they were contaminated by atmospheric 36Ar. Thus, they gave highly
scattered ages ranging from 28.6 to 4.78 Ma, which
obviously have no geological significance (Diraison
1991; Chauvel et al. 1997; Bonneville et al. 2006).
During ZEPOLYF2 cruise in 1999, samples were
dredged on a shallow seamount labelled ZEP2-12,
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
the 300 m deep summit of which is located at
22° 28.8’ S and 153° 6.7’ W, i.e. west of Rimatara.
These samples gave K-Ar ages of 2.63 ± 0.06 Ma
and 2.57 ± 0.05 Ma, respectively (Bonneville et
al. 2006), which plot on the Atiu trend in figure 3. Thus, they can be related to the activity
of the hotspot presently located beneath Arago
seamount, and represent the oldest witness of it
in the Australs. However, given the residual morphology and strong alteration of Rimatara lavas, it
seems unlikely that this island formed during the
Pliocene: it could represent either the summit of a
Tubuai trend-related edifice as shown in figure 3,
or that of an older seamount.
Discussion
…
…An atypical hotspot chain
The presence beneath Macdonald Seamount of a
hotspot responsible for the edification of at least
some of the Austral-Cook Islands (Johnson &
Malahoff 1971) is not questioned. However, since
Duncan & McDougall (1976) and Turner & Jarrard
(1982), all authors agree that the Austral-Cook linear hotspot chain is not as simple as the Hawaiian
or Society archipelagoes, as it obviously lacks their
progressive age variation (e.g. Guillou et al. 2005)
and geomorphologic evolution (Dickinson 1998).
The complex age-distance relationships depicted in
figure 3B are rather intriguing, especially regarding
the succession, in some islands (Rurutu, Aitutaki)
or seamounts (Arago), of two volcanic events separated by more than 5 Ma. Rejuvenation of volcanism may occur in Hawaiian-type islands well after
the end of the main building stage, when the island
passes over a plume "tail" deflected away from the
hotspot by overlying lithosphere motion (Ribe &
Christensen 1999; Thoraval et al. 2006). However,
the spatial and temporal scales of such a process (c.
150 km and 1.5 Ma in the Marquesas, Legendre et
al. 2006) are not consistent with those observed in
the Austral-Cook chain.
An alternative possibility is to envision a more
or less continuous volcanic activity along a c.
2 300 km long hot line, as proposed by Bonatti &
Harrison (1976) and Bonatti et al. (1977) for the
Easter island chain. However, this hypothesis is
not consistent with the three relatively regular age
trends shown in figure 3B, which have been termed
the Tubuai, Atiu and Rarotonga trends (Chauvel et
al. 1997). The occurrence of such trends, recently
supported by age data on seamounts discovered
during the ZEPOLYF2 cruise (Bonneville et al.
2006), is consistent with the hypothesis of at least
three coeval hotspots (Fig. 3) respectively located
beneath Macdonald, Arago, and in a still unknown
position SE of Rarotonga (Turner & Jarrard 1982;
Diraison 1991; Chauvel et al. 1997). Of course, the
incoming difficulty is then to explain how and why
35
three hotspots could be aligned precisely in the
ESE-WNW direction corresponding to the Pacific
plate motion. The geometric technique of relocating hotspots from seamount tracks (Wessel &
Kroenke 1997, 1998) does not help to solve these
problems, because it relocates adequately RurutuArago and Rarotonga, but surprisingly not the most
obvious hotspot in the region, i.e. Macdonald.
Other authors (e.g. Diament & Baudry 1987;
Bonneville et al. 2002, 2006; Adam & Bonneville
2008) consider two separate trends corresponding to
the northern and southern rows of islands, respectively (Fig. 3A). In this hypothesis, the southern
row, from Macdonald to Marotiri, Rapa, Mangaia and
Rarotonga, should be credited of two coeval hotspots
and presents an apparent 1 500 km gap between
Rapa and Mangaia. For the northern one, Raivavae
to Tubuai, Arago, Rurutu, Rimatara, Mauke, Atiu and
Aitutaki, the situation becomes even more complicated because the young volcanism in Aitutaki (and
of course at Arago) needs to be explained, and it is
also necessary to postulate that an unknown hotspot
located SE of Raivavae became extinct after the edification of this island. In addition, the HIMU signatures and petrologic types of Mangaia, Rimatara,
Rurutu (old), Tubuai and Raivavae (old) lavas are
quite unusual but very similar, and point out to their
derivation from the same mantle plume. Finally, the
present-day diameters of the Macdonald (100 km)
and Society (160 km) hotspots are smaller than the
bulk width of the Cook-Austral chain (200 km), but
the latter size is considered acceptable for a mantle
plume (Morgan 1972; Wyllie 1988).
……Unusual mantle sources of Austral
magmas
Recent geochemical data on Austral islands
(Schiano et al. 2001; Lassiter et al. 2003) and
seamounts (Bonneville et al. 2006) have lead to
the recognition of mantle heterogeneities much
larger than previously expected (Vidal 1992)
beneath the archipelago. From seamount data, this
...
An Atypical Hotspot Chain
.. .....
heterogeneity­increased through time to reach its
maximum at less than 20 Ma. Such a feature is
consistent with a progressive heterogeneity of the
Pacific lithospheric mantle, induced by its passage
over several different hotspots (Dupuy et al. 1993).
The "contamination" of young Rurutu (and probably Arago) plume-derived magmas by the overlying lithosphere, which acquired its HIMU signature
during the Late Miocene volcanic activity (Chauvel
et al. 1997) is a good example of such interactions
leading to increased heterogeneities.
If the origin of the HIMU signature of many AustralCook lavas appears no more as a controversial topic,
its distribution within the archipelago is still not
well understood. The most extreme HIMU imprint
is documented at Mangaia (Woodhead 1996); it is
still very strong in Tubuai, "old" Rurutu (Chauvel
et al. 1992) and "old" Raivavae lavas (Lassiter et al.
2003; Maury et al. 2013), but attenuated in "young"
Rurutu lavas (Chauvel et al. 1997) and in Arago
lavas (Bonneville et al. 2002). The HIMU flavor is
much weaker in the other Cook islands, as well as
in "young" Raivavae, Rapa, Marotiri and Macdonald
(Hémond et al. 1994). The hypothesis that the
Austral Fracture Zone might represent a major
mantle limit (Lassiter et al. 2003) is clearly not
consistent with the location of Raivavae south of it
(Fig. 3A). Complex geochemical models involving:
• melting of highly heterogeneous mantle plume
materials,
• followed by variable contamination of these
melts by the Pacific lithosphere,
have been proposed (Lassiter et al. 2003; Bonneville
et al. 2006). A temporal evolution of the composition of the Macdonald mantle plume, involving the
recent contribution of mantle containing a younger
sediment component has also been considered
(Hémond et al. 1994). Additional hypotheses postulate the contribution of other materials, e.g. old
subcontinental lithosphere (Schiano et al. 2001) or
subduction-modified mantle (Lassiter et al. 2003).
However, the dating of HIMU-type "old" Raivavae
(Rairua) lavas to 10.6-7.4 Ma allows us to propose
a much simpler explanation for the HIMU-type
lavas. Indeed, the "strong" HIMU signature, documented since 19 Ma in Mangaia (Woodhead 1996)
seems to disappear after the edification of Tubuai
and Rairua volcanoes. In Raivavae Island, a 1 Myr
long gap is documented between their emplacement and that of the "young" Anatonu volcano
which displays a more subdued DMM-HIMU-EM
isotopic signature. This gap, much shorter than
that observed in Rurutu, seems inconsistent with
the hypothesis of a passage of Raivavae over two
different hotspots (Maury et al. 2013). Moreover,
the oldest (4.8 Ma) Rapa lavas, isotopically rather
similar to those of Marotiri and Macdonald, were
emplaced only 0.6 Myr after the youngest ones
from Raivavae (5.4 Ma), although they lie 500 km
closer to the present Macdonald hotspot (Fig. 3).
...
Therefore, the whole volcanic history of Raivavae
seems related to the late stages of activity of a
predominantly HIMU plume which generated successively Mangaia, Rurutu (old) and Tubuai lavas.
Numerical simulations of the evolution of thermal and thermo-chemical plumes (Farnetani et
al. 2002; Farnetani & Samuel 2005; Farnetani &
Hofmann 2009, 2010) suggest that small heterogeneous mantle domains are present in the thermal
boundary layer feeding the plume. During the
ascent of the latter, they are converted into longlived elongated and narrow filaments within the
plume conduit. Such filaments would melt sporadically, and then eventually communicate their
specific geochemical fingerprint to small volumes
of basaltic lavas (Farnetani & Hoffmann 2009).
The changes which occurred in Raivavae between
7.4 and 6.4 Ma involved an increase of partial
melting degrees (from basanitic and alkali basaltic
to tholeiitic magmas) and an attenuation of their
HIMU signature. They could be ascribed to the
contribution of a new filament of specific composition within a predominantly HIMU plume.
……
Superplume and plumelets
The very deep origin, close to the core-mantle
boundary, of HIMU type plume component is generally admitted. Despite the considerable length
of the Austral-Cook archipelago, it does not fit
the characteristics of hotspot chains derived from
mantle plumes arising directly from the core-mantle boundary, e.g. those of Hawaii, La Réunion and
Iceland (Clouard & Bonneville 2001; Courtillot
et al. 2003). Analogical (Davaille 1999; Davaille
et al. 2002, 2005) and numerical (Ogawa 2007)
models show that large thermochemical plumes
("superplumes") can ascend within the lower mantle as very large domes of hot materials, and remain
anchored there for more than 100 Myrs (type 2
plumes of Courtillot et al. 2003). A number of
much smaller and short-lived plumes ("plumelets") can form from the top of the "superplume"
and uprise through the asthenospheric upper mantle. They can be chemically heterogeneous, and
display variable geochemical signatures, as they tap
very different regions of the lower mantle and may
include several filaments with specific geochemical
signatures (Farnetani & Hoffmann 2009).
The short tracks of Arago (Atiu trend) and
Rarotonga suggest that the corresponding plumes
are young and potentially short-lived "plumelets"
(e.g. Dickinson 1998). Given the existence of a
"superplume" in the lower mantle beneath French
Polynesia, as evidenced by its very hot character
(Zhao 2001), one may consider the Macdonald,
Arago and Rarotonga (?) "plumelets" emanated
from it, as short-lived columns of hot mantle
materials ascending through the upper mantle
(Courtillot et al. 2003). The ascent of such plumelets is likely favored by existing discontinuities and
36
.......
zones of weakness in the upper mantle, and the
track left by a previous plume can certainly create
such weaknesses. Indeed, recent numerical models
(Sleep 2008) demonstrate that hot plume materials
can be channeled at the top of the asthenosphere.
There, they can be guided by the track of an older
hospot along which the oceanic lithosphere has
been thermally eroded. It is thus possible to explain
the three coeval present-day hotspots by considering that the oldest plumelet, i.e. the Macdonald
HIMU-type one, started to create an ESE-WNW
island/seamount chain (the Tubuai trend) c. 20 Ma
ago (Mangaia), and at the same time left its track
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
in the upper mantle as a weakness zone extending from Mangaia to Raivavae. There, its strong
HIMU imprint vanished at 7.4 Ma; between 6.4
and 5.4 Ma, a different filament of more subdued
DMM-HIMU-EM isotopic signature melted to form
Anatonu lavas. More or less simultaneously:
• another plumelet (the present Macdonald plumelet) generated Rapa and then Marotiri lavas,
• and the Arago plumelet ascended along the
same track beneath Aitutaki and Atiu (Fig. 3),
creating the Atiu trend. They were later followed,
at less than 4 Ma, by the still poorly known
Rarotonga plumelet.
CONCLUSION
The spatial, temporal and geomorphologic evolutions from the active Macdonald Seamount to
Marotiri, Rapa, Raivavae and Tubuai are relatively
simple, as expected from a Hawaiian-type hotspotrelated linear volcanic chain. However, the presence in the row of the Austral-Cook Islands of a
second hotspot, presently located beneath Arago
Seamount, led to the uplift of Rurutu more than
10 Ma after the end of its Late Miocene activity,
and to the emplacement of young volcanics over
the old ones and the uplifted limestones. The complexity of the mantle sources of Austral magmas is
attributed:
37
• To the ascent through the upper mantle of
several heterogeneous plumelets sometimes
made of distinct filaments, tapping different
source regions located within the South Pacific
superplume;
• And to heterogeneities in the Pacific lithospheric mantle, created during its successive
passage over several mantle plumes. We propose that the location of several hospots along
the same track is due to the channelling of hot
plumelet materials at the top of the asthenosphere, where they were guided by the thermally eroded base of the oceanic lithosphere.
...
Fauna
.......
....
Adult Red tailed tropicbird (Phaethon rubricauda) sitting in ferns, Tubuai
(Photo J.-Y. Meyer).
...
40
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
The Birds
an Unbalanced but Unique Avifauna
Jean-Claude Thibault
Hunting, introduction of predators
(e.g. dog, pig, the Polynesian rat
Rattus exulans), and habitat destruction (e.g. burning for cultivation) by
the early Polynesian inhabitants has
resulted in the decline and extinction of numerous bird species on the
small and remote islands of Polynesia
(Steadman 2006). In the past, birds
were a significant source of protein
for Polynesians as well as an important component of their everyday life,
being celebrated culturally in songs,
legends, and sculptures (Lavondès
1975; Steadman 1997); see cradle
song on the right. Many species
which survived the changes induced by the first
human settlers (e.g. parrots Cyanoramphus spp.,
shorebirds Prosobonia spp., etc.) disappeared after
the arrival of Europeans, this second wave of
extinction coincided with the introduction of the
Black rat (Rattus rattus) and raptors, the destruction of habitat by grazing animals (cattle, goat,
sheep), and possibly the arrival of introduced
avian disease (see van Riper & Scott 2001 for
Hawaii Islands). The process continues today, as
demonstrated by the recent decline and extinction of several species of monarchs (Pomarea spp.)
(Thibault et al. 2002; Cibois et al. 2004) on islands
in the Marquesas (e.g. Ua Pou, Fatu Hiva), following the documented arrival of the Black rat.
Similarly the recent introduction of behaviorally
dominant birds, such as the Red vented bulbul
(Pycnonotus cafer) threatens native landbird species in Tahiti (Thibault et al. 2002).
In the Austral Islands the incomplete knowledge of
the avifauna, up to now, has prevented the evaluation of the levels of endemicity and population
status, necessary for developing appropriate conservation strategies. Two expeditions to the Austral
Islands in 2002 and 2004 funded by the Délégation
à la Recherche (French Polynesia Government)
in collaboration with the Institut Louis Malardé
"Cradle song"
Manu manu Hiri, manu manu no Rehie, te rere maira
I Tutara, kati kati te monamona, tāti haki koe na te
kotokoto, tama mai koe, aue koe
Petite bête de Hiri, petite bête qui habite Rehie, qui
vient en volant de Tutara, manger les framboises, mon
petit poussin de kotokoto, viens mon petit enfant, oh
toi !
Little bird of Hiri, Little bird from Rehie, Flying from
Tutara, eating sweet berries, Little chick from kotokoto,
come to me my little child, my dear one!
By young women in Rapa. Recorded in December 1989,
then translated into French by Albert Varney
(Tahiti), in order to address the gaps in our knowledge. In this chapter we present a synthesis of historical and field data on the avifauna of each island,
(landbirds, seabirds and introduced birds), evaluating population densities and the status of species,
when possible, and finally proposing conservation
priorities for the archipelago.
The historical data for the birds of the Austral
Islands was collected from a variety of scattered
sources, dating from the beginning of the 20th
century. Some of the data comes from published
literature; other data comes from unpublished
manuscripts and letters written by several ornithologists (Table 4 gives details of these sources).
The islands of Rapa and Raivavae have been the
most frequently and intensely studied by ornithologists, Maria has been visited just twice and
Marotiri’s rocky islets just once. The historical data
gives a reasonable overview of the species found in
the archipelago, but the data is too scattered and
inconsistent to provide an insight into population
trends for most species, especially seabirds, where
abundance fluctuates dramatically during breeding
cycles and between years, depending on the abundance of food sources.
AVIFAUNA OF THE AUSTRAL ISLANDS
…
…Landbird assemblages
Only six native landbird species inhabit the Austral
Islands (Table 5). Three have a wide range in the
Pacific and are found in most archipelagos (Pacific
reef heron Egretta sacra, Pacific black duck Anas
41
superciliosa, Spotless crake Porzana tabuensis). Two
species are endemic to a single island: the Fruit
dove Ptilinopus huttoni (locally called "koko")
inhabits Rapa and the Reed warbler Acrocephalus
rimitarae, Rimatara. Another species, Kühl’s
...
.. .....
The Birds: an Unbalanced but Unique Avifauna
Table 4: Chronology of main historical sources relating ornithological work since the early 20th century for which a report, book or paper were
accessible.
References
Maria
Rimatara
Rurutu
Tubuai
Seale (undated)
Raivavae
Rapa
Marotiri
24-26 Apr. 1921
9-11 Feb. 1922
14-20 Apr. 1921
15-26 Feb. 1922
27 Feb. 1922
16 Feb. - 27 Mar. 1902
Whitney South Seas
Expediton (WSSE)
Bryan (undated)
24 Mar. - 1st Apr. 1921
5-8 Apr. 1921
2-4 May 1921
21-23 Mar. 1921
Fosberg (1972)
22 July 1934
Lacan (1968)
25-28 Apr. 1968
J.-C. Thibault (this work)
30 Apr. - 3 May 1968
27 Sept. - 12 Oct. 1974
J.-C. Thibault (Thibault &
Varney 1991a, b)
15 Oct. - 17 Dec. 1974
Ehrhardt (1980)
16-21 Feb. 1980
Ehrhardt (1986)
Jan. - Feb. 1984
Seitre & Seitre (undated)
9-12 Dec. 1989
17-19 Dec. 1989
Thibault & Varney (1991a)
15-16 Dec. 1989
18 Dec.1989 - 6 Jan. 1990
A. Guillemont (pers. comm.)
10-23 Feb. 1993
McCormack & Künzlé (1996),
McCormack (pers. comm.)
5-11 Aug. 1992
Feb. 1993
July 1992
Second hand data reported
in Te Manu (39): 5
Apr. 1999
McCormack et al. (2000)
June 2000
Sanford & Raust (2002)
21-28 Apr. 2002
Blanvillain (2002)
3-23 Aug. 2002
J.-C. Thibault (this work)
18 Nov. - 18 Dec. 2002
Fontaine (2002)
Pierce et al. (2003)
9-17 Dec. 2002
11-12 Apr. 2003
Fontaine (2003)
J.-C. Thibault (this work)
A. Gouni (Anonymous 2005)
Y. Gentilhomme pers. comm.
Soc. Ornith. Polynésie
16 Dec. 1989
16-30 Nov. 2003
10-16 Nov. 2003
25 Oct. - 6 Nov. 2004
30 Nov. - 10 Dec. 2004
2002-2007
Gaskin (2007)
21 Sept. 2006
Raust (2007)
18-31 Mar. 2007
lorikeet­ Vini kuhlii (locally called "vini 'ura"), has
a disjunct distribution, being present on Rimatara
and two islands in the Kiribati archipelago, where
population numbers are estimated to be in excess
of one thousand (King 1973); bones of fossil
remains attributed to this species have also been
found in the Cook Islands (Steadman 2006). The
Rimatara reed warbler was originally described as
a sub-species of Acrocephalus vaughani from the
Pitcairn Islands group, on the basis of morphometrics (Murphy & Mathews 1929). However, recent
molecular phylogenetic work shows that the species is more closely related to the Reed warblers of
Mangaia (A. kerearako) and Mitiaro (A. kaoko) in
the Cook Islands (Cibois et al. 2007).
...
Group of Pacific black ducks (Anas superciliosa),
Raivavae (Photo J.-C. Thibault).
42
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
……Landbird population sizes, trends and
habitat
Where available, data on estimated population size
are presented in Table 5. The Pacific reef heron is
widespread in Polynesia, but does not breed in the
most southern islands (Rapa and Pitcairn group,
except Oeno atoll [Brooke 1995a]). Although it is
a common visitor. The Pacific black duck is present on all Austral Islands excepted Marotiri, taking
advantage of wetlands associated with taro cultivation. The Spotless crake occupies the same islands
in small numbers, except on Rapa, where the population was relatively large in 1989.
It seems that the Rapa fruit dove was only observed
at low densities in the early 20th century during
the Whitney South Sea Expedition (WSSE)’s visit.
In 1989, the population was small (Table 5), its
range corresponding to patches of the native forest.
The extent of which has continued to decrease in
size, due to fires and grazing by feral animals (cattle, horses, and goats). The dove occupies less than
10 forest patches with and area over 10 ha each
(Thibault & Varney 1991b). In 2002, the Fruit
dove was observed in several patches, especially
the forest which covers the slope of the main summit (Mt Perau, 650 m) (B. Fontaine pers. comm.).
Adult male of Rimatara reed warbler
(Acrocephalus rimitarae) in hand,
Rimatara (Photo J.-C. Thibault).
Table 5: Presence and abundance of breeding landbird species on islands in the Austral Islands. Vérin (1969) mentions the occurrence of a Fruit-dove
attributed to Ptilinopus purpuratus on Rurutu, but he fails to give details of the source data.
References: (1) Thibault (2005). (2) Sanford & Raust (2002). (3) Anonymous (2005). (4) McCormack & Künzlé (1996). (5) Thibault & Cibois (2006).
(6) Fontaine (2003). (7) Y. Gentilhomme (unpublished). (8) Holyoak & Thibault (1984). (9) Thibault (2003). (10) J.-C. Thibault (unpublished).
(11) Fontaine (2002). (12) Thibault & Varney (1991b). (13) Vérin (1969). (14) Jaunez (1966). (15) Seale (undated).
Rimatara
Rurutu
Tubuai
Raivavae
Rapa
Pacific reef heron
(Egretta sacra)
2004: 5-15 pairs (1)
2003: present (6), (7)
2003: present (6)
2002: < 50 individuals (9) Rare visitor recorded
once in 1974 (10)
Pacific black duck
(Anas superciliosa)
2004: < 10 pairs (1)
Mentioned by Vérin (13).
2003: present (6), but
decreasing owing to natural
drying of a wetlands (7)
1789: duck attributed to
2002: < 10 pairs (9)
this species (14).
1902: very common (15).
1974: 20-25 pairs
2003: present (6)
1989: 35-40 pairs (10)
2002: present (11)
Spotless crake
(Porzana tabuensis)
Despite active searching Quayle Present, but seems very rare (7)
(undated) failed to find it in 1921.
One record only, in 2002 (2)
1974: common in
fern-land, taro cultivation
and wetlands (8).
No recent data
1989: common
on mainland (taro
cultivation, fern-land)
and islets (Tarakoi,
Tauturou)
2002: present inland (9)
Discovered during the
19th century.
1974-1990: 175-368
individuals (12)
2002: present in woody
areas up to 600 m (11)
Rapa fruit dove
(Ptilinopus huttoni)
Kühl’s lorikeet
(Vini kuhlii)
Discovered in the 19th century.
See Table 6
Rimatara reed warbler
(Acrocephalus
rimitarae)(1)
Discovered by the WSSE.
2004: 1 777-2 567 individuals
well-distributed in all habitats (5)
(1) Correct name is rimitarae and not rimatarae (cf. IUCN 2004); use of rimitarae by Murphy & Mathews (1929) is not a mistake, as people used also the name Rimitara at the beginning of the 20th century
(Jourdain 1970).
Total number of species
5
3
3
43
...
3
3
The Birds: an Unbalanced but Unique Avifauna
.. .....
The Rapa fruit dove is threatened with extinction
due to the loss of the remaining patches of suitable
habitat, which will only persist if grazing by feral
goats and cows is controlled.
Population numbers of the Kühl’s lorikeet and
the Reed warbler on Rimatara are relatively high
(Table 5). Several counts of the Lorikeet were
attempted during the last few years (Table 6), but
no trend was detected and differences most likely
reflect the different methods used by the different
observers. Both species occupy disturbed habitats: cultivated areas and secondary forest. Recent
observations suggest that their populations remain
stable. The Lorikeet is able to utilize both wild
and cultivated plants opportunely (flower, nectar,
fruit) (Table 7). The Warbler is present almost
everywhere on the island, it was even observed
in the swamp and the central fern-covered hill,
though breeding occurs mainly in wooded areas
(coconut groves with undergrowth, in cultivated
areas, coastal forest, and natural forest on limestone [Thibault & Cibois 2006]). Most of the
island’s surface is covered with agricultural plantations or coconut groves with undergrowth, these
habitats are relatively stable in range and suitable
for the Reed warblers, though the common use of
fire to clear vegetation is clearly a threat to these
birds. Native forest is restricted to a limestone area
that constituted, until recently, c. 21 % of the total
surface of the island (170 ha). The building of an
airport in 2002 has cleared c. 65 ha of the most
representative part of this forest (i.e. 40 % according to Meyer et al. 2005). Thus we estimate that the
habitat of several dozen Reed warblers and Kühl’s
lorikeet has been permanently destroyed by this
development.
Pair of Kuhl’s lorikeet (Vini kuhlii),
Rimatara (Photo J.-Y. Meyer).
Kelsall in 1925 and the WSSE in 1921, respectively).
There is also a petrel that was found on Raivavae that
may constitute a new taxa, related to Pterodroma leucoptera (Bretagnolle 2001). Molecular studies have
recently showed that Puffinus myrtae, described initially as part of the P. assimilis species-group, is in fact
related to P. newelli from Hawaii (Austin et al. 2004).
Fregettta grallaria titan, a sub-species described on
the basis of its large size (Murphy 1928), might
constitute a full species on the basis of its specific
vocalization, which is very distinct from those of
Seabird endemicity
­others p
­ opulations (V. Bretagnolle pers. comm.), but
The Austral Islands are characterized by a high divermolecular analyses will be necessary to confirm this
sity of seabirds, especially in the Procellariiformes:
hypothesis. The Small petrel that probably breeds
most of the species breeding in Eastern Polynesia
on the ridges of Raivavae has been tape-recorded in
can be found in the Austral Islands (i.e. at least
1989 (Seitre & Seitre undated), then photographed
12 species; Table 8). Breeding seabirds include two
in 1993 (A. Guillemont unpublished data), but no
endemic species (Puffinus [newelli] myrtae, Fregetta
biometric data are available (except the dismembered wings of an individual killed by a cat, held at
[grallaria] titan) from Rapa and possibly Marotiri
the National Museum, Wellington, New Zealand)
(both discovered in the early 20th century, by H.J.
and as yet, no molecular analyTable 6: Comparisons of population estimates of Kühl’s lorikeet, made between 1992 and ses have been performed.
2004. No definite trend can be extrapolated.
As most species of petrels are
nocturnal and often breed in
Estimated
Date
Method
Reference
inaccessible areas, knowledge is
numbers
far from complete and several
(individuals)
populations will probably be dis905
5-11 August 1992
transect
McCormack & Künzlé (1996)
covered in the future. An unidentified petrel was photographed on
c. 750
2000
transect
McCormack et al. (2000)
Mt Hanaheno (Tubuai) in 1980
648
21-28 March 2002
transect
Sanford & Raust (2002)
(Ehrhardt 1980) and an unfamiliar vocalization was heard at dusk
1042
3-23 August 2002
point-counts Blanvillain (2002)
on Mt Perau (Rapa) in December
609
30 Nov./10 Dec. 2004 transect
Anonymous (2005)
2002 (B. Fontaine pers. comm.).
……
...
44
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 7: List of plant species observed as a food source of Kühl’s lorikeet. The majority of species are cultivated plants, observers have rarely
visited the native forest, though there are several species present there which could provide food resources (namely: Hernandia nymphaeifolia,
H. moerenhoutiana [Hernandiaceae], Barringtonia asiatica [Lecythidaceae], Calophyllum inophyllum [Guttiferae], Homalium sp. [Salicaceae],
Procris pedunculata [Urticaceae], Capparis cordifolia [Capparaceae]).
Plant species (Family)
McCormack & Künzlé (1996) Blanvillain (2002)
August 1992
August 2002
Thibault (2005)
October-November 2004
Falcataria molucanna (= 
Albizia molucanna,
Paraseianthes falctaria) (Mimosaceae)
X
Adenanthera pavonina (Mimosaceae)
X
Albizia lebbeck (Mimosaceae)
X
Inga feuilleei (= I. ynga, I. edulis) (Mimosaceae)
X
X
Casuarina equisetifolia (Casuarinaceae)
X
X
Mangifera indica (Anacardiaceae)
X
X
Ceiba pentandra (Malvaceae)
X
X
Erythrina variegata (Fabaceae)
X
X
Syzygium jambos (Myrtaceae)
X
X
Musa spp. (Musaceae)
X
X
X
Cocos nucifera (Arecaceae)
X
X
X
Hibiscus rosa-sinensis/tiliaceus (Malvaceae)
X
X
X
Persea americana (Lauraceae)
X
Cordyline fruticosa (Lilaceae)
X
Barringtonia asiatica (Lecythidaceae)
X
X
Guettarda speciosa (Rubiaceae)
X
X
Morinda citrifolia (Rubiaceae)
X
Ficus tinctoria (Moraceae)
X
Passiflora maliformis (Passifloraceae)
X
Bauhinia monandra (Fabaceae)
X
Psidium guajava (Myrtaceae)
X
The taxonomic status of the Blue gray noddy,
Procelsterna cerulea, needs revision. Holyoak &
Thibault (1984) considered that plumage color
variation in P. cerulea populations in the South
Pacific was clinal, with a gradient from darker birds
in Hawaii in the north of the range to lighter birds
in the southeast in Lord Howe and Easter Island.
However, Gochfeld & Burger (1996) separated
the taxon into two species; populations from the
north of the range (Hawaii to the Austral Islands)
were included in P. cerulea and populations from
the south (Lord Howe to San Ambrosio, through
Easter Island) were included in P. albivitta.
……Comparison of seabird diversity
between islands
Among the Austral Islands, Raivavae has the highest species diversity, including many Sternidae and
Procellariiformes, although absolute numbers are
very low, approaching local extinction in three species (Murphy’s, Kermadec and the Herald petrel).
45
Old chick of Murphy’s petrel (Pterodoma ultima),
Rapa (Photo J.-Y. Meyer).
...
.. .....
The Birds: an Unbalanced but Unique Avifauna
Table 8: Presence and abundance of breeding seabird species on islands in the Austral Islands. For details on islets of Raivavae see Table 9, and for
data on Rapa’s islets obtained in 1974 and 1990 see Thibault & Varney (1991a).
References: (1) Pierce et al. (2003). (2) Thibault (2005). (3) Fontaine (2002). (4) Y. Gentilhomme (Te Manu 39: 2-3 and pers. comm.). (5) J.-C.
Thibault (unpublished). (6) Fontaine (2003). (7) Thibault (2003). (8) Thibault & Varney (1991a). (9) WSSE. (10) Seitre & Seitre (undated). (11) Te
Manu 39: 5. (12) C. Serra pers. comm. (13) Gaskin (2007). (14) Raust (2007).
Maria
(1)
Rimatara
(2)
Murphy’s petrel
Pterodroma ultima
Rurutu
(3), (4)
Tubuai
Possible breeder
Possible breeder
in small number
on islets (2003)
(6)
Raivavae
(7), (14)
Rapa
(6), (8)
Marotiri
< 10 pairs.
Definitely known
only from Motu
Papararuu (J.-J.
Philipponeau);
possible breeder
inland (F. Lacan)
Breeding on 5 islets.
(< 100 pairs)
Several breeders
collected (9).
Several thousands
displaying (11),
"abundant" (13)
Kermadec petrel
Pterodroma neglecta
Several sightings;
but no breeding
record
Breed on mainland
and 4 islets.
(> 500 < 1 000 pairs)
Several seen in fly
(10), "breeding
possible"
Herald petrel
Pterodroma (arminjoniana)
heraldica
One collected by
WSSE. Probable
breeder in low
number inland (G.
McCormack pers.
comm., (14))
Breed on 2 islets.
(> 250 < 1 645 pairs)
Collected at sea
(9) and recorded
offshore (11)
Breed on 4 islets.
(> 150 < 1 000 pairs)
Breeder (13)
Black winged petrel
Pterodroma nigripennis
Collared petrel
Pterodroma cf. leucoptera
Founded on
ridges inland, but
breeding sites
unknown (Seitre
& Seitre undated;
A. Guillemont
unpublished)
Tahiti petrel
Pseudobulweria rostrata
Insufficient data
Heard song,
possible breeder
Christmas shearwater
Puffinus nativitatis
Insufficient data
Breeding in
small number on
Motu Ofai (6)
< 10 pairs on
Motu Hotuatua
Wedge tailed shearwater
Puffinus pacificus
Insufficient data
Bred on a coral
islet according
to Quayle
(undated); breed
in low numbers
on Motu Ofai (6)
70-130 pairs
breeding on Motu
Hotuatua and on
mainland
Tropical shearwater
Puffinus bailloni
Probable breeder.
< 10 pairs, inland
at Raraterepa
Newell’s shearwater
Puffinus (newelli) myrtae
Breed on 4 islets.
(> 250 < 1 000 pairs)
White bellied storm petrel
Fregetta (grallaria) titan
Breed on 4-5 islets.
(> 300 < 550 pairs)
"Breeding most
likely" (13)
Polynesian storm petrel
Nesofretta fuliginosa
Breed on 2-4 islets.
(> 200 < 1 000 pairs)
"Breeding most
likely" (13)
Breed on mainland
and 5 islets.
(> 500 < 1 000 pairs)
Several seen
displaying (10)
Red tailed tropicbird
Phaethon rubricauda
442
White tailed tropicbird
Phaethon lepturus
Masked booby
Sula dactylatra
Present, but no
proof of breeding
Probable
breeder in the
natural forest
(< 5 pairs)
Fairly common
Several tens of
pairs (12)
30-50 pairs in cliffs
on mainland
Breed in the
natural forest
(< 1 0 pairs)
Fairly common
Present
30-50 pairs in cliffs
on mainland
Once recorded,
but no breeding
...
46
"A couple of
White tailed
tropicbirds" cited
by Fosberg (1972)
.......
Brown booby
Sula leucogaster
88
Red footed booby
Sula sula
397
Regular visitor
Great frigatebird
Fregata minor
220
Roosting place;
possible breeder
Sooty tern
Sterna fuscata
Present, but no
proof of breeding
Possible breeder
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Possible breeder
on islets
Small number
(10), roost but no
breeding record
(13)
"Breeding most
likely" (13)
Spectacled tern
Sterna lunata
Probable breeding
on West rock (10)
(or confusion with
sooty tern?
Brown noddy
Anous stolidus
72
Breeder
(< 200 pairs)
Black noddy
Anous minutus
31
Probably breed,
but number
unknown
Blue gray noddy
Procelsterna cerulea
Common fairy tern
Gygis alba
Number of species
Common
breeder in
coconut trees
Breeder on
mainland
(Tonarutu
cliffs) and islets
(Motiha, Tohena)
< 500 pairs on
mainland and
coral islets
Breeder on Motu
Tohena (several
ten pairs)
580-720 pairs on
islets
Present in small
number in cliffs;
recent breeder
according to (4)
265
Breeder
(< 300 pairs)
7-9
5
Fairly common
Present (200
pairs on Toena
and Roa islands
in 1974) (5)
6
7-9
Seabird assemblages on Rapa include mostly
Procellariiformes, with seven species recorded,
which is the highest diversity on the Australs
Islands. The bird assemblage of Marotiri seems to
be very similar to Rapa, but the small surface of the
three rocks that form the island is a limits population size (Gaskin 2007). An unidentified nocturnal
petrel has been heard on Rurutu, and further investigation will be required to verify this (Te Manu
vol. 39 2002). Few data are available for Maria
atoll (Table 8). No large seabird colonies have been
recorded, but the island has, until recently, been
exploited for coprah and may provide a futurebreeding site for Murphy’s petrel.
Raivavae and Rapa-Marotiri are the most important islands for seabirds in the Austral Islands,
in terms of species diversity, population densities
and levels of endemicity (Tables 8-9). When compared with other eastern Polynesian archipelagos
(Society, Tuamotus and Marquesas), we noticed an
abundance of Procellariiformes species, a moderate
number of boobies and the absence of important
colonies of Sooty tern.
Among species breeding in Austral Islands, only
three (the Red tailed tropic bird, the Brown noddy,
and the Common fairy tern) are distributed on
every island (Table 8). The presence of Newell’s
47
Breed on mainland
and 7 islets
(> 1 000 < 10 000
pairs)
"Breeding most
likely" (13)
30-50 pairs in
cliffs on mainland
and Motu
Hotuatua
Breed on mainland
and 5-6 islets
(> 1 000 < 10 000
pairs)
"Breeding most
likely" (13)
< 500 pairs on
mainland and
coral islets
Breeding on
mainland and 3
islets
(< 1 000 pairs)
"Breeding most
likely" (13)
12-14
11
c. 12
Table 9: Population sizes of Sternidae on the mainland and islets
off Raivavae (nb. pairs) observed in November-December 2002
(Thibault 2003).
Locality
Brown
noddy
Black
noddy
Common
fairy tern
Mainland
100-200
100-200
Hotuatua
< 5
5-10
Otaha 3
> 100
Otaha 4
> 10
Tou
2
Vaiamanu
< 5
Aha
< 5
Ruahota Iti
5
Ruahota Rahi
Mano Iti
< 5
20
152-170
10
Mano
50
?
?
Arae
10
330-400
35-50
Ruahune
10
100-150
27-35
...
.. .....
The Birds: an Unbalanced but Unique Avifauna
Table 10: Distribution of introduced birds on islands of the Austral Islands. (1) According to Paulay (1982) "a hawk-sized raptor was
seen several times during my visit" suggesting that the Australian harrier (Circus approximans) introduced in the Society Islands
might be an accidental visitor in the Austral Islands. Although, the Peregrine falcon, never recorded in Austral-Society Islands has
been recorded in the Pitcairn Group (Brooke 1995a).
Rimatara
1st record
References
Rurutu
Present status
Holyoak & Thibault (1984); Thibault (2005)
J.-C. Thibault (unpublished)
Red jungle fowl
Gallus gallus
1st record
WSSE, Seitre & Seitre (undated)
Present status
Y. Gentilhomme (pers. comm.)
common (2004)
common
quite common
Rock dove
Columba livia
?
localized (2004)
Common myna
Acridotheres tristis
? present (1973)
none (2004)
low number (1921)
none (1983-2004)
1st record in 1984 (Pratt et al. 1987) common
Silvereye
Zosterops lateralis
Chestnut breasted manikin
Lonchura castaneothorax
2002
< 100 individuals (2004)
shearwater and White bellied storm petrel is due
to the presence of cooler sub-tropical water currents. Great frigatebirds are only thought to breed
on Maria atoll, but the two Pacific species visit
the other islands regularly and in good numbers,
except on Rapa (and Marotiri) where they are rare
visitors.
…
…Seabird population sizes
Most seabird species occur at low densities in
the Austral Islands, most probably because of
human pressure rather than any limitation of
resources. For instance, all Procellariiformes populations are small, when compared with uninhabited islands in the Pitcairn archipelago (Brooke
1995b); most populations are restricted to very
small areas (steep cliffs, mountain ridgetops and
islets), because they were eliminated from more
accessible areas by hunting, introduced predators
and habitat destruction.
The uninhabited islet of Marotiri, while only rarely
visited by humans, is not host to a large population
of seabirds simply because of its small size (several
hectares).
There are significant populations of the Blue gray
noddy on Rapa, with comparable population sizes
to those found in the Marquesas.
…
…Introduced birds
Five introduced bird species inhabit the Austral
Islands (Table 10). Humans intentionally introduced three of these species. The early Polynesians
brought Red junglefowl, Gallus gallus, and more
recently in the 20th century Europeans introduced the domestic pigeon, Columbia liva and
Common myna, Acridotheres tristis. It is unclear
whether the Chestnut breasted manikin, Lonchura
...
common (2003)
present
castaneothorax, recorded in the archipelago since
the 1980’s, was deliberately introduced or arrived
from Tahiti by itself. The Silvereye (Zosterops lateralis) has been recorded on Tubuai, Raivavae and
Rurutu since 1984 (Pratt et al. 1987), probably
colonizing independently from Tahiti (Thibault &
Monnet 1990). Curiously this species has not been
yet reached or become established on Rimatara,
although the distance from Tahiti is equivalent to
the distance to Raivavae or Tubuai. Rapa is probably too remote to be colonized rapidly. It seems
more probable that the Silvereye colonized each
of the three islands separately from Tahiti, which
constitutes an important source with several hundred thousand individuals, rather than by intraisland colonization within the Austral Islands,
where numbers remained low during the 1980’s
(Thibault & Monnet 1990). On Raivavae, the
Silvereye inhabits all woody areas: Hibiscus tiliaceus thickets, agricultural plantations (e.g. banana
groves), Pinus caribaea (Pinaceae) and Casuarina
equisetifolia (Casuarinaceae) forests, patches of
native forests dominated by Metrosideros collina (Myrtaceae) and Hernandia moerenhoutiana
(Hernandiaceae) on Mt Hiro. This species is common everywhere on the mainland with a mean
density of several pairs per hectare where vegetation is above 4 m high. Population size was estimated to be more than one thousand pairs in 2002.
The Silvereye also breeds on islets, but only in low
densities (Thibault 1976).
……
Landbird extinctions
No historical extinctions have been recorded in
Austral Islands since the WSSE. Scattered data
indicates that several species were probably extirpated on the Austral Islands soon after the arrival
48
.......
Tubuai
1st record
WSSE, Seitre & Seitre (undated)
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Raivavae
Present status
1st record
Rapa (1)
Present status
1st record
Present status
Fontaine (2003)
Thibault (2003)
J.-C. Thibault (unpublished),
Fontaine (2002)
common up to 300 m (2003)
common up to 320 m
common up to 400 m
1974
localized (2003)
none (2002)
none (1974-2003)
common (1921)
common (2003)
none (1921-2002)
none (1974-2002)
common (2003)
Lacking in 1974 (obs. pers);
1st record in 1984 (Pratt et al. 1987)
Lacking in 1968 (Lacan 1968);
> 1 000 pairs (2002)
1st record in 1984 (Pratt et al. 1987)
< 20 individuals (2002)
present (2003)
of the first Polynesian settlers (Steadman 2006;
M. Prebble pers. comm.). Table 11 shows that
several species of pigeons (Ptilinopus spp., Ducula
spp., Gallicolumba spp.), rails (Gallirallus spp.,
Rallus spp.), Reed warblers (Acrocephalus spp.),
one or several Lorikeets (Vini spp.), and a shorebird (Prosobonia sp.) occupied most of the southern Polynesian islands and we can hypothesize
that species belonging to most of these genera also
occupied the Austral Islands.
We don’t know to what extent some species which
have a large range in Polynesia, also inhabited the
Austral Islands in the past. The only example,
Kühl’s lorikeet, had a larger range formerly, extending into the Cook Islands as shown by subfossil
records (Steadman 1985). However, Polynesians
carried Lorikeets between islands, and it is difficult
to know where the natural range was. A similar
case is found in flying foxes, Pteropus tonganus,
whose distribution in Central Polynesia may have
been human-mediated (Flannery 1995). The natural or anthropogenic origin of the specimen for
which bones were recently discovered on Rurutu
remains unknown (Weisler et al. 2006).
none (1974-2002)
none (1974-2002)
Adult Christmas shearwater (Puffinus nativitatis)
and its young chick, Raivavae (Photo J.-C. Thibault).
……
Seabird extinctions
Comparison with lists of extinct taxa from other
southern Polynesian islands does not suggest an
important rate of extinction (Table 12), compared
with landbirds. On Rapa, we know that during
the 20th century seabirds were actively hunted
as a food source, sometimes on dangerous cliffs,
whereas ducks and Fruit-doves were not (Paulay
1982); in the 1920s, Quayle (undated) found
charred petrel bones. However, Thibault & Varney
(1991a) noticed that while chicks of some petrels
(Pterodroma neglecta, P. ultima, Puffinus nativitatis)
49
Adult Wedge tailed shearwater (Puffinus pacificus) at the
entrance of its burrow, Raivavae (Photo J.-C. Thibault).
...
The Birds: an Unbalanced but Unique Avifauna
.. .....
Table 11: Comparison of landbird assemblages on Mangaia (Cook Islands), and the Austral Islands combined, Mangareva
(Gambier) and Henderson (Pitcairn Group) from actual (X) and extinct birds [historic and sub-fossils data (†)].
References: (1) Steadman (1985). (2) J.-C. Thibault (this work). (3) Holyoak & Thibault (1984). (4) Worthy & Tennyson (2004). (5)
Wragg (1995).(6) Worthy & Wragg (2003).
Species
Mangaia
Austral Is.
Mangareva
Henderson
(21° 55’ S) (1) (22° 28’-27° 26’ S) (2) (23° S) (3), (4) (24° 22’ S) (5), (6)
Egretta sacra
X
X
Anas superciliosa
X
X
Porzana tabuensis
X
X
X
†
X
Porzana atra
Porzana rua
†
Gallirallus ripleyi
†
Prosobonia sp.
†
†
Prosobonia cancellata
Gallicolumba erythroptera
†
Gallicolumba nui
†
†
Gallicolumba leonpascoi
Ptilinopus sp.
†
X
Ptilinopus insularis
Ptilinopus rarotongensis
X
X
Ptilinopus huttoni
†
Ducula harrisoni
Ducula cf. galeata
†
Ducula sp.
†
X
Vini stepheni
Vini kuhlii
†
Vini vidivici
†
X
†
Halcyon gambieri
Halcyon mangaia
X
†
Hirundo tahitica
Acrocephalus sp.
Acrocephalus kerearako
visitor
†
X
X
Acrocephalus rimitarae
X
Acrocephalus taiti
Number of species today
6
6
1
4
Number of known extinct species
7
0
6
6-7
and eggs of the Tropicbird were collected until the
1970’s, they were no longer eaten in the 1990’s.
Improvements in the standards of living have permitted a dietary switch from wild birds to frozen
chicken, a change in human activities very beneficial to the petrel populations. Agricultural cultivation on Tarakoi islet in 1993 probably destroyed
at least one third of the breeding habitat of a
large colony of Storm petrels (A. Guillemont pers.
...
comm.). Observations in 2002 confirm this (J.-Y.
Meyer pers. comm.; B. Fontaine pers. comm.).
……
Causes of extinction
Three main causes of extinction have been identified. Firstly, habitat modification or destruction, especially the clearing of natural forests by
non-woody vegetation (e.g. fern covered slopes).
Secondly, hunting of wild birds as a food source or
50
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 12: Comparison of seabird assemblages from actual (X) and extinct birds (†) on Mangaia (Cook Islands), Austral Islands
combined and Henderson (Pitcairn Group).
References: (1) Steadman (1985). (2) J.-C. Thibault (this work). (3) Wragg (1995).
Species
Mangaia (1)
Australs Is. (2)
Henderson (3)
X
Pterodroma ultima
X
Pterodroma externa
†
Pterodroma alba
†
Pterodroma neglecta
X
Pterodroma heraldica
X
X
Pterodroma atrata
Pterodroma nigripennis
X
†
X
†
†
Unidentified small petrel
Pterodroma cf. leucoptera
X
Pseudobulweria rostrata
X
Puffinus nativitatis
X
X
Puffinus pacificus
X
†
Puffinus bailloni
†
X
Puffinus (newelli) myrtae
X
†
Puffinus «assimilis/lherminieri»
Fregetta (grallaria) titan
Nesofretta fuliginosa
X
†
Phaethon rubricauda
Phaethon lepturus
X
X
†
X
X
X
Sula sula
X
Sula leucogaster
X
Sula dactylatra
?
X
Fregata minor
X
X
Sterna fuscata
X
X
Sterna lunata
?
Fregata ariel
Anous stolidus
X
†
X
Anous minutus
X
X
X
X
Procelsterna cerulea
X
X
X
Gygis alba
X
X
X
Gygis microrhyncha
†
Adult White tailed tropicbird at nest (Phaethon lepturus),
Raivavae (Photo J.-C. Thibault).
Chick of White tern (Gygis alba), Raivavae
(Photo B. Fontaine).
51
...
The Birds: an Unbalanced but Unique Avifauna
.. .....
for the use of feathers for fishing or as ornamentation. Lastly, the advent of introduced species, as
predators or competitors, has been an important
cause of extinction on oceanic islands (Atkinson
1989), and is probably also the case in the Austral
Islands. The presence of the domestic cat and
Black rat still constitutes a significant threat to
native bird species in French Polynesia.
CONSERVATION
……The need for conservation of Austral
Islands birds
Seven species which occur in the Austral Islands
are recognized by the IUCN (2009) as threatened:
three landbirds, Kühl’s lorikeet (Endangered),
the Rapa fruit dove and Rimatara reed warbler
(Vulnerable); and four seabirds, the Collared petrel
and Polynesian storm petrel (Vulnerable), Tahiti
petrel and Murphy’s petrel (Near Threatened).
Recommendations are given for the conservation
of these endangered taxa. As for plants and other
animals, conservation of the last patches of natural forests is essential to maintain healthy populations of native landbirds on every island; this can
be achieved by prohibiting forest clearing, fires
and the planting of exotic trees, e.g. Pinus caribaea
(Pinaceae).
…
…Translocation of landbirds
Translocations can restore the historical avifauna
of islands and increase the survival chances of
birds only found on single islands (Franklin
& Steadman 1991; Steadman & Martin 2003),
although it is imperative that the carrying capacities of the habitat is assessed prior to translocation, as well as a thorough understanding of the
causes of the historical and current distributions
of the taxa, in order to ensure that the causes of
extinction are managed and monitored at any
given translocation site. For example, the translocation of the Marquesas lorikeet, Vini ultramarina,
from Ua Huka to Fatu Hiva was initially successful (Lieberman et al. 1997), but the subsequent
Murphy's petrel (Near Threatened),
Rapa (Photo B. Fontaine).
...
Kuhl's lorikeet (Endangered), Rimatara
(Photo B. Fontaine).
introduction of the Black rat has resulted in the
near extinction of this new population (Thibault
& Meyer 2000, pers. obs. 2009). In the Austral
Islands 27 individuals of Kühl’s lorikeet from
Rimatara have already been successfully translocated to Atiu in the Cook Islands (Gouni & Kape
2007; www.cookislands.bishopmuseum.org), but
continued surveillance of the population is vital
to its persistence. A second feasible project would
be the translocation of the Rimatara reed warbler,
which is the only known warbler in the Austral
Islands. It is highly likely that specific forms
inhabited all the other islands in the chain in
the recent past, if we consider their colonization
ability and the high rate of differentiation among
Polynesian reed warblers (Cibois et al. 2007).
Taking into account the presence of suitable habitat and the absence of the behaviorally dominant,
introduced Common myna and Red vented bulbul, Raivavae is the only promising translocation site. The Seychelles warbler, Acrocephalus
sechellensis, provides an encouraging example of
a successful translocation habitat restoration on
the islands of Cousine and Aride have allowed
52
.......
successful translocation of the species from its
range on Cousin and an encouraging increase in
population size (Komdeur & Pels 2005).
…
…Conservation priorities for seabirds
Four important priorities need to be realized to
assist in the conservation of seabird species in the
Austral Islands:
• Protect the identified breeding sites with the
prohibition of habitat destruction (by deforestation or cultivation of breeding sites, etc.).
• Control the introduced predators (cats and
rats); two cases must be distinguished:
- Eradication on islets far enough from the coast
to ensure that they will not be easily re-colonized
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
from mainland (e.g. islets off Tubuai, Raivavae
and Rapa); special attention should drawn to
Maria atoll where eradication of rats or cats on
the entire is possible;
- Control of species within inhabited islands
(e.g. controlling the populations of feral cats responsible for the decline of petrels on Raivavae).
• Restrict access to certain important breeding
sites (especially the islets off the coast of Rapa
and the cliffs, and several islets of Raivavae,
Table 9).
• Regular monitoring of important breeding
sites in order to evaluate long-term trends in
population size.
conclusions
Landbird species have probably been affected by
extinctions in the recent past as a result of human
disturbances: hunting, introduction of alien species and habitat destruction. However, real data to
support these hypothesized extinctions is elusive.
It is, therefore, important to promote palaeontological and archaeological studies that might shed
light on prehistoric extinctions. Seabird diversity
53
is high in the Austral Islands, although population
sizes are small. For both landbirds and seabirds,
the presence of several endemic species, listed as
threatened, highlights the importance of conserving the birds of the Austral Islands. It is essential
that conservation priorities should be put into
practice, along with the long-term monitoring of
breeding populations.
...
...
54
Almost forgotten: 12 already extinct recently described endodontids species from Rurutu (Photos O. Gargominy).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
A Global
Overview of the Terrestrial and
Olivier Gargominy & Benoît Fontaine
Freshwater Molluscs
With some 557 species or subspecies
of which 508 (91 %) are endemic, the
land snail fauna of French Polynesia
is of high conservation value, but
is highly threatened: 112 molluscs
species from French Polynesia are
recorded as extinct or threatened
by the IUCN (2010). Recent fieldwork in the Gambier Islands (French
Polynesia) showed that most of the
native malacofauna is extinct: in
Mangareva, 30 Endodontidae species,
two Assimineidae species and two
Euconulidae species are reported as
being extinct (Abdou & Bouchet 2000; Bouchet
& Abdou 2001, 2003). In this context, a malacological survey of the Austral Islands was undertaken
between 2002 and 2004, in the framework of a terrestrial biodiversity inventory of this archipelago,
funded by the French Polynesia government. The
aims of this survey were to:
• Produce an inventory of the terrestrial and
freshwater malacofauna of the archipelago,
including distribution maps;
• Clarify the conservation status of endemic
species;
• Identify key sites for mollusc conservation.
The earliest known collection of land snail from the
Austral Islands dates from 1828 when H. Cuming
visited Rurutu, Tubuai and Rapa (St. John 1940).
In 1838, 15 species were recorded from Rapa (Beck
1837; Anton 1838), then a review of the fauna of
Rurutu was published by Garrett (1879). In his
compilation, Kobelt (1879) mentionned 11 species
from Rapa but totally ignored the other Austral
Islands. In 1921, M. Stokes collected in Rapa (32 species) and Raivavae (13 species) (Cooke in Gregory
1935). The first major malacological sampling in
the Austral Islands was performed in 1934, during
the Bishop Museum's Mangarevan Expedition. This
pluridisciplinary expedition visited 25 high islands
and 31 atolls all over Southeastern Polynesia. Two
of its members were malacologists (C.M. Cooke
Jr., expedition leader, and D.W. Anderson). Rapa,
where they stayed for 32 days, was the climax of
the expedition, with 37 593 specimens collected,
followed by Mangareva in the Gambier (30 695
specimens) and Raivavae (19 227 specimens). All
the other islands, including Rurutu, Tubuai and
Rimatara, yielded less than 3 000 specimens altogether (Gregory 1936). Despite the high quality of
the sampling done in Rapa, C.M. Cooke considered
their mission in Rapa as an exploration rather than a
thorough investigation, and believed that the island
should be revisited, as they "probably collected about
half the species inhabiting this island" (Cooke in
Gregory 1935). The Mangarevan Expedition material was deposited in the Bishop Museum collections
in Honolulu (Hawaii), and led to the publications
of major monographs covering the most speciose
families: Euconulidae (Baker 1938, 1940, 1941),
Achatinellidae (Cooke & Kondo 1961; Kondo 1962)
and Endodontidae (Solem 1976). Other families
were also covered: Hydrobiidae (Hubendick 1952),
Partulidae (Crampton & Cooke 1953), Charopidae
(Solem 1983) and Assimineidae (Cooke & Clench
1943). For several families, nothing has ever been
published based on the Mangarevan Expedition
material, including all the introduced species
(Subulinidae, Streptaxidae, Bradybaenidae in particular), as well as some other important (either
in number of species or in number of specimens)
families such as Hydrocenidae, Helicinidae and
Vertiginidae.
At the end of the 1960s, a marine malacologist,
H. Rehder, took the opportunity of being in Rapa
to sample terrestrial snails. He could not find any
endodontids, and as the original vegetation was
known to be severely damaged, A. Solem (1976)
suggested that "it may well be that the Rapan radiation has joined the ranks of the extinct". In 1980, G.
Paulay opportunistically collected some land snails
during his study of Rapan weevils. His collection is
deposited at the Yale Peabody Museum.
This paper presents the main results of a 20022004 survey, listing all taxa, clarifying the status
of endemic species, giving the first ever account of
introduced snail species in the Austral Islands, and
presenting a list of critical sites for the conservation of this unique malacofauna.
Methods
…
…Collecting effort
Sampling took place in November and December
2002 (19 days in Raivavae, 10 days in Rapa), in
55
November 2003 (7 days in Tubuai, 14 days in
Rurutu) and in October and November 2004 (12
days in Rimatara). Because Rapa is isolated in the
...
A Global Overview of the Terrestrial and Freshwater Molluscs
.. .....
south, we use the term "northern islands" hereafter
to refer to Raivavae, Tubuai, Rurutu and Rimatara.
Altogether, 80 stations (sampling localities) were
sampled in Raivavae, 69 in Rurutu, 49 in Rapa, 46
in Tubuai and 42 in Rimatara (Fig. 9). We believe
all islands were reasonably well sampled, except for
Rapa, where the field trip was too short. The survey
focused on sampling remnants of natural vegetation on ridges, upraised limestones or other remote
areas. Agricultural areas were opportunistically
sampled but appeared to by very poor in native
molluscs. Fossil or subfossil shells were also collected in limestone areas in Rurutu and Rimatara.
In the northern Austral Islands, type localities of
every species described from these islands, as given
in the relevant literature (Baker 1938, 1940, 1941;
Cooke & Clench 1943; Crampton & Cooke 1953;
Cooke & Kondo 1961; Kondo 1962; Solem 1976,
1983), were systematically visited. As the northern
islands were well sampled, we suggest that species for which we did not find live specimens or
fresh shells could be extinct. We do not make this
assumption for species from Rapa, which was less
well sampled.
A station is defined as a collecting locality, spread
over 5-10 m2 at most, in a single habitat. At each
station, c. 30 minutes was spent searching at
ground level for live snails, then leaf-litter and
a few millimeters of topsoil were collected. This
sample was processed at the collecting location
with a Winkler sieve (1 cm mesh), the coarse material being checked for shells (empty shells and live
animals) and discarded. The remaining material
was bagged and sun-dried as soon as possible. The
molluscs collected alive were drowned overnight
and fixed in 70 % ethanol, for future dissection.
Once dried, the bagged leaf-litter material was
passed through 5 mm, 2 mm and 0.6 mm sieves.
The two larger fractions were thoroughly searched
with the naked eye, the third one sorted under a
dissecting microscope. Material passing through
the 0.6 mm sieve was checked, but as it contained
no molluscs, as was the case in earlier studies
(e.g. Tattersfield 1996; De Winter & Gittenberger
1998), it was subsequently discarded.
For each station, we recorded geographical coordinates using a GPS GARMIN 12CX, as well as the
habitat, microhabitat, exposure, altitude as given
by the GPS and date.
Almost all species for which live specimens were
collected were photographed on the spot, to supplement shell drawings of original descriptions that
were the only existing illustrations for these species.
……
Taxonomic
processing and data
analysis
TAA
HU
AIA
ta
MATAURA
pu
All specimens were sorted
u
P
Cape Arei
to morphospecies, or
Mt Puturani
Mt Taapanui
Mato Arei
Ruahoina Mt Manureva
Recognizable Taxonomic
Mt Taitaa
Mt Rereti
Peva Iti
Mt Teape
Units (New 1999), accordHuahine
Mt Rurutu
Mt Panee
ing to shell characters,
assigned to a family
AVERA
Mt Hanareho
Turiarata
and, when possible, to a
Mt Erai
MAHU
HAUTI
described genus or species.
Cape Toarepe
Most of our RTUs are equivMt Rairiri
alent to species as generally
understood by mollusc taxRAPA
onomists, and in the Results
and Discussion sections,
"RTUs" and "species" refer
ANAPOTO
Mt Ruatara
to the same concept. In the
AMARU
Oromana
many instances where we
Mt Perahu
Mt Namuere
did not allocate a specific
RIMATARA
Cape Pukitarava
MUTUAURA
Anarua bay
name to our morphospeAREA
cies, they were identified by
Haurei bay
RAIVAVAE
a number.
Mt Hiro
Hiri bay
Mt Turivao
Mt Arua
HAUREI
In our analyses, we comMt Maunanui
bined animals collected
U
UR
Mt Maugaoa
VAI
live and those collected
RAIRUA
Mt Matotea
dead, for two reasons:
Mt Taraia
we collected more
• 
dead shells than live animals, and did not want to
Figure 9: Sampling localities in the Austral islands. Islets on the
exclude the bulk of our data from the analyses,
barrier reef, which were sampled in Raivavae and Tubuai, are
RURUTU
TUBUAI
Te
i
va
a
Va
I
RA
OE
M
ri
Pa
ati
y
ba
500 1000 m
Puoro
bay
0
not represented.
...
56
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
In this study we follow the higher classification of
Mollusca proposed by Bouchet & Rocroi (2005).
Voucher material collected during this collecting
trip is deposited at the Muséum national d'Histoire
naturelle, Paris (France).
• shells being sun-dried and sometimes sorted
out long after collecting, it is difficult to know
whether the individuals were alive when they
were collected, particularly for minute species.
results
…
…Species richness
A total of 218 species or subspecies are known from
Assimineidae and Hydrobiidae. These families are
dominated by single island endemic species, i.e.
in situ speciation after rare colonisation events is
the main source of diversity. Rapa culminates both
in terms of diversity and endemism, and is the
only Austral Island with generic speciation: 16 of
the 26 endemic genera from French Polynesia are
restricted to Rapa, and another genus is endemic
from the Australs (Rapa, Raivavae).
Several taxa are new records for the Austral
Islands, including introduced species (Subulinidae,
Achatina fulica, Euglandina rosea, Streptaxidae,
Carychium sp., Bradybaena similaris), as well
as some species in the families Hydrocenidae,
Helicinidae, Assimineidae and Vertiginidae. The
common species were probably also collected by
the Mangarevan Expedition, though the material
has not yet been studied.
the archipelago, including 181 islands endemics, 9
archipelago endemics and 22 introduced species.
This fauna is thus characterised by very high speciation level. Species diversity and endemism per
island and for the archipelago are summarized in
Table 13. No freshwater bivalves were recorded.
Most of the material collected during our surveys
was sorted to species level, except for the family
Achatinellidae.
A well-known island biogeography phenomenon is
that island faunas are depauperate when compared
with adjacent continents. Indeed, many families
of land and freshwater snails have not reached the
remote Austral Islands. Families with the highest
number of species are Achatinellidae, Endodontidae
and Euconulidae, and to a lesser extent Helicinidae,
Table 13: Austral Islands diversity, endemism, extinction and threats of terrestrial and freshwater molluscs in terms of terminal taxa
(species or subspecies). Indigenous includes cryptogenic (sensu Carlton 1996). Morphospecies recognized as new species still to be
described are included.
Rimatara Rurutu Tubuai
Raivavae
Rapa
TOTAL
Diversity
Indigenous
25
62
26
44
108
217
Indigenous / km²
2.9
1.9
0.6
2.5
2.7
1.5
Single island endemics
7
33
13
29
100
182
Archipelago endemics
2
3
1
4
1
5
Endemism
Endemism
37.5 %
59 %
56 %
77 %
93.5 %
87 %
Endemics / km²
1.0
1.2
0.3
1.8
2.45
1.0
Single island endemic genera
0
0
0
0
16
16
7
14
7
8
2
38
78 %
39 %
50 %
24 %
2 %
20 %
Threatened
0
6
3
10
94
114
Threat ratio of extant endemic fauna
-
25 %
43 %
37 %
93 %
61 %
78 %
64 %
93 %
61 %
95 %
81 %
14
18
15
13
10
22
44 %
27 %
44 %
27 %
9 %
11 %
Extinct taxa
Extinct
Extinction ratio of endemic fauna
Threatened taxa
Threat and extinction ratio of endemic fauna
Introduced taxa
Introduced
Ratio of introduced taxa on current fauna
57
...
A Global Overview of the Terrestrial and Freshwater Molluscs
.. .....
……Family records and checklists of species
Superfamily HELICINOIDEA Férussac, 1822
Family HELICINIDAE Férussac, 1822
At least five different Helicinidae species were collected live in the Austral Islands. On each island except
Rapa, Helicina pacifica was found to be abundant from sea level to the highest ridges. It was one of most
common species on Rimatara and Rurutu "mato" (limestone rock faces). Generic assignation of Pacific
Helicinidae is not yet stabilized (Richling 2009, 2011; Richling & Bouchet 2013) and needs the female
genital apparatus anatomy to be reviewed. Meanwhile, we keep here original names except for species
treated by Richling & Bouchet (2013).
It is questionable that Garrett (1879) did not mention neither Nesiocina solidula nor Helicina aff. trochlea
but only minuta as "very abundant", while these two species are by far the most abundant nowadays.
Helicina Lamarck, 1799
Helicina minuta G.B. Sowerby II, 1842
Status unclear: Rurutu (Garrett 1879), Tahiti and Moorea (Garrett 1884).
Helicina pacifica Pease, 1865
Range in the Australs: Rimatara. Rurutu. Tubuai. Raivavae.
Remarks: Cited from the Australs by Brook (2010), this species may belong to the Nesiocina solidula species
complex mentionned by Richling & Bouchet (2013).
Helicina aff. trochlea A.A. Gould, 1847
Austral Islands endemic?: Rimatara*. Rurutu*.
Remark: Very abundant on rocks in limestone areas in Rurutu and Rimatara. It probably represents a species new
to science (I. Richling pers. comm.). Helicina trochlea is currently only known from Makatea in the Tuamotus
(Gould 1847; Cooke 1934).
Helicina villosa Anton, 1839
Island endemic?: Rapa.
Nesiocina Richling & Bouchet, 2013
Nesiocina cf. villosa (Anton, 1839)
Range in the Australs: Raivavae (Richling & Bouchet 2013)
Nesiocina solidula (G.B. Sowerby I in J.E. Gray, 1839)
Range in the Australs: Rurutu* (Richling & Bouchet 2013).
Superfamily HYDROCENOIDEA Troschel, 1857
Family HYDROCENIDAE Troschel, 1857
Georissa species were found on all islands, and were abundant on rocks and on dead leaves. At least two
species were found in Rurutu, and Chondrella striata Pease, 1871 was recorded on Rurutu by Garrett
(1879). All were found live. Georissa species were less abundant on Tubuai.
Georissa Blanford, 1864
Georissa (Chondrella) striata (Pease, 1871)
Widespread in eastern Polynesia.
Range in the Australs: Rurutu.
Georissa sp.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*. Rapa*.
Superfamily CERITHIOIDEA Fleming, 1822
Family THIARIDAE Gill, 1871 (1823)
Melanoides Olivier, 1804
Melanoides tuberculata (O.F. Müller, 1774)
Introduced species.
Range in the Australs: Rimatara*. Rurutu. Tubuai. Raivavae. Rapa.
Remarks: A widespread introduced species, found on each island, abundant in streams, even when polluted.
* Represents a new island record issued from this fieldwork.
...
58
.......
59
...
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
A Global Overview of the Terrestrial and Freshwater Molluscs
.. .....
Superfamily RISSOOIDEA Gray, 1847
Family ASSIMINEIDAE H. Adams & A. Adams, 1856
Nine taxa were known from the archipelago, of which we found five, all live: Rapanella andersoni, Assiminea
pupoides, Omphalotropis dubia (all from Rapa), as well as Assiminea nitida and Omphalotropis subimperforata
from Rurutu and Rimatara. In addition, two unidentified Omphalotropis species (one from Rurutu and one
from Rapa) were found live, as well as one Rapanella species (Rapa). Omphalotropis curta (Rurutu) and
Omphalotropis albescens (Rapa) were not found, but no precise type locality was given with the description.
Electrina succinea was known from Rapa with two subspecies. We went to the type localities of both, and
did not find them. Consequently, we consider that this species could be extinct.
Subfamily ASSIMINEINAE H. Adams & A. Adams, 1856
Assiminea Flemming, 1828
Assiminea parvula (Mousson, 1865)
= Assiminea nitida (Pease, 1865)
Cryptogenic.
Range in the Australs: Rimatara*. Rurutu.
Assiminea lucida Pease, 1869
Range in the Australs: Rurutu.
Electrina Baird, 1850
Island endemic: Rapa.
Electrina succinea succinea (Sowerby, 1846)
Island endemic: Rapa.
Electrina succinea orites Cooke & Clench, 1943
Island endemic: Rapa.
Subfamily OMPHALOTROPIDINAE Thiele, 1927
Omphalotropis L. Pfeiffer, 1851
Omphalotropis albescens (L. Pfeiffer, 1855)
Island endemic: Rapa.
Omphalotropis curta Garrett, 1879
Island endemic: Rurutu.
Omphalotropis dubia (L. Pfeiffer, 1846) comb. nov.
Island endemic: Rapa.
Omphalotropis pupoides (Anton, 1839)
= Hydrocena oparica L. Pfeiffer, 1848
Island endemic: Rapa.
Omphalotropis subimperforata C. Boettger, 1916
Austral Islands endemic: Rimatara, Rurutu*.
Omphalotropis sp.1
Island endemic: Rapa*.
Omphalotropis sp.2
Island endemic?: Rurutu*.
Rapanella Cooke & Clench, 1943
Island endemic: Rapa.
Rapanella andersoni Cooke & Clench, 1943
Island endemic: Rapa.
Rapanella sp.
Island endemic: Rapa*.
Family HYDROBIIDAE Stimpson, 1865
Two species of Fluviopupa were known, one from Rapa, the other from Rapa and Rurutu. We found Fluviopupa on
each island except Rimatara, and there appear to be different species on each island: two from Rapa (previously
described), two from Raivavae, one each from Tubuai and Rurutu, all new to science and described elsewhere
(Haase et al. 2005). Where present, these species are abundant on rocks and submerged dead leaves. Rimatara,
being the oldest and westernmost (i.e. closest to western source populations) island in the group, was also probably host to Fluviopupa spp. However, the island no longer has any permanent flowing water, all the springs
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having been diverted, and thus any Fluviopupa species
from this island must now be extinct.
Fluviopupa Pilsbry, 1911
Fluviopupa crassiuscula Frauenfeld, 1863
Island endemic: Rapa.
Fluviopupa deflexa Frauenfeld, 1863
Island endemic: Rapa.
Fluviopupa jeanyvesi Haase, Gargominy &
Fontaine, 2005
Island endemic: Raivavae*.
Fluviopupa raivavaeensis Haase, Gargominy &
There is no permanent running water in Rimatara anymore,
Fontaine, 2005
all springs having been diverted (Photo O. Gargominy).
Island endemic: Raivavae*.
Fluviopupa rurutua Haase, Gargominy &
Fontaine, 2005
Island endemic: Rurutu*.
Fluviopupa tubuaia Haase, Gargominy & Fontaine, 2005
Island endemic: Tubuai*.
Superfamily LYMNAEOIDEA Rafinesque, 1815
Family LYMNAEIDAE Rafinesque, 1815
Pseudosuccinea F.C. Baker, 1908
Pseudosuccinea columella (Say, 1817)
Introduced species.
Range in the Australs: Rurutu*. Tubuai*. Rapa*.
Remarks: Found in low altitude streams.
Superfamily PLANORBOIDEA Rafinesque, 1815
Family PHYSIDAE Fitzinger, 1823
Physella Haldeman, 1843
Physella acuta (Draparnaud, 1805)
Introduced species.
Range in the Australs: Rimatara*. Rurutu. Tubuai.
Remarks: Species known from Rurutu and Tubuai (Marquet 1993). We did not find it on Rurutu, but it was
present at low altitude on Tubuai and Rimatara.
Family PLANORBIDAE Rafinesque, 1815
One species was found in a ditch on a roadside in Rurutu. It probably belongs to Ferrissia noumeensis, an
introduced species on other Pacific islands (New Caledonia, Fiji, American Samoa - Haynes 2001). Pointier
& Marquet (1990) mentionned the presence of this species from Tahiti only.
Ferrissia Walker, 1903
Ferrissia noumeensis (Crosse, 1871)
Introduced species.
Range in the Australs: Rurutu*.
Superfamily ELLOBIOIDEA L. Pfeiffer, 1854 (1822)
Family ELLOBIIDAE L. Pfeiffer, 1854 (1822)
Subfamily CARYCHIINAE Jeffreys, 1830
This is the first record of this European subfamily in French Polynesia.
Carychium O.F. Müller, 1773
Carychium sp.
Introduced species.
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Range in the Australs: Rimatara*.
Remarks: Three shells of Carychium sp. were found in degraded vegetation at sea level in Rimatara.
Superfamily VERONICELLOIDEA Gray, 1840
Family VERONICELLIDAE Gray, 1840
Laevicaulis Simroth, 1913
Laevicaulis alte (Férussac, 1822)
Introduced species.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*. Rapa*.
Remarks: Always present at low altitude, as well as on mountains in Raivavae and Rurutu.
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A specimen collected in 2004 in Rimatara (north of Amaru),
tentatively identified as Quickia concisa (Photo O. Gargominy).
Superfamily SUCCINEOIDEA Beck, 1837
Family SUCCINEIDAE Beck, 1837
Historically, a single species was recorded in Rurutu, Succinea degagei Garrett, 1879, which was thereafter synonymised with Succinea pudorina A.A. Gould, 1846 (Garrett, 1884: 86). Later on, Quickia concisa
(Morelet, 1868) has been shown to have spread over Polynesia recently, including Rimatara in the Australs
(Brook 2010).
Quickia Ohdner, 1950
Quickia concisa (Morelet, 1868)
Introduced species.
Range in the Australs: Rimatara.
Succinea Draparnaud, 1801
Succinea pudorina A.A. Gould, 1846 ?
= Succinea degagei Garrett, 1879
French Polynesia endemic.
Range in the Australs: Rurutu.
Remarks: This species was not found during our survey.
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Subclade Orthurethra
Superfamily PARTULIDOIDEA Pilsbry, 1900
Family PARTULIDAE Pilsbry, 1900
Partula hyalina is common at sea level, sometime very abundant locally. In Raivavae and Tubuai, it is also
found in altitude, as well as on one islet on the barrier reef in Tubuai. It was present in 42 % to 47 % of our
stations in Raivavae, Rurutu and Rimatara, but only in 19 % of the stations in Tubuai. This might be due to
the presence of the predatory Euglandina rosea in Tubuai.
In Rimatara, another partulid species, now extinct, was found in subfossil cave deposits. In Rapa, Samoana
margaritae is not rare in forests, even if slightly degraded. The species was found on several tree species:
Celtis, Zanthoxylum, Merita, Nesoluma, and even on invasive Psidium. In Raivavae, three Samoana species
have been described (Crampton & Cooke 1953). Samoana dryas was found alive at its type locality, unlike
S. oreas or S. hamadryas for which only old shells were found. A previously unknown population of a live
Samoana sp.was discovered on the southern slope of the western peninsula. All these localities are among
the last remnants of native forests, reduced in size, and the persistence of these endemic species is entirely
dependent on conservation measures, such as fencing against goats.
Partula Férussac, 1821
Partula hyalina Broderip, 1832
Originally endemic from Tahiti.
Range in the Australs: Rimatara*. Rurutu. Tubuai. Raivavae*.
Remarks: Introduced in the Australs (Lee et al. 2007).
Samoana Pilsbry, 1909
Samoana dryas (Crampton & Cooke, 1953)
Island endemic: Raivavae.
Samoana hamadryas (Crampton & Cooke 1953)
Island endemic: Raivavae.
Samoana oreas (Crampton & Cooke, 1953)
Island endemic: Raivavae.
Samoana sp.
Island endemic? Subfossil material.
Range in the Australs: Rimatara*.
Samoana margaritae (Crampton & Cooke, 1953)
Island endemic: Rapa.
Superfamily ACHATINELLOIDEA Gulick, 1873
Family ACHATINELLIDAE Gulick, 1873
The family is represented by 92 described species in the Austral Islands, including 58 restricted to Rapa.
As mentioned above, the Achatinellidae were not fully sorted. Cryptogenic species such as Elasmias apertum, Tornatellides oblongus and Lamellidea oblonga were found in abundance in the northern Australs. The
endemic Strobilus acicularis raphis was found under the only known Rapan specimen of the highly threatened tree Zanthoxylum tahitense (Meyer 2003), in a remnant patch of mesophilic forest. The snails were
abundant under the tree, but completely absent in the surrounding vegetation. In Rimatara, the endemic
Tubuaia voyana oromanaensis was only known from its type locality, the "Oromana hills" (Kondo 1962),
at 80 m. This area is now completely degraded and transformed into agricultural fields, no snails (even
introduced species) were found. We consider this subspecies extinct.
In addition to the following list, several undescribed taxa are mentioned in the litterature: Tubuaia sp.?
from Rurutu (Kondo 1962: 17) and Celticola (Meryticola) arborea ssp.? from Rapa (Cooke & Kondo
1961: 140).
Subfamily LAMELLIDEINAE Cooke & Kondo, 1961
Lamellidea Pilsbry, 1910
Lamellidea (Lamellidea) oblonga (Pease, 1865)
Large range in the Pacific.
Range in the Australs: Rimatara. Rurutu. Tubuai. Raivavae. Rapa.
Lamellidea (Lamellidea) pusilla (A.A. Gould, 1847)
Large range in the Pacific.
Range in the Australs: Rurutu.
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Pacificella Odhner, 1921
Pacificella variabilis Odhner, 1921
Large range in the Pacific.
Range in the Australs: Rapa.
Tornatellinops Pilsbry & Cooke, 1915
Tornatellinops concolorans Cooke & Kondo, 1961
Island endemic: Rapa.
Tornatellinops philippii (L. Pfeiffer, 1850)
Large range in the Pacific.
Range in the Australs: Rimatara. Rurutu. Tubuai. Raivavae. Rapa.
Subfamily PITYSINAE Cooke & Kondo, 1961
Antonella Cooke & Kondo, 1961
Island endemic: Rapa.
Antonella pfeifferi Cooke & Kondo, 1961
Island endemic: Rapa.
Antonella tenuis Cooke & Kondo, 1961
Island endemic: Rapa.
Antonella trochlearis fusiforma Cooke & Kondo, 1961
Island endemic: Rapa.
Antonella trochlearis nesiotica Cooke & Kondo, 1961
Island endemic: Rapa.
Antonella trochlearis radicula Cooke & Kondo, 1961
Island endemic: Rapa.
Antonella trochlearis trochlearis (L. Pfeiffer, 1842)
Island endemic: Rapa.
Apopitys Cooke & Kondo, 1961
Island endemic: Rapa.
Apopitys andersoni Cooke & Kondo, 1961
Island endemic: Rapa.
Celticola Cooke & Kondo, 1961
Austral Islands endemic: Raivavae. Rapa.
Celticola (Celticola) pilsbryi incerta Cooke & Kondo, 1961
Island endemic: Rapa.
Celticola (Celticola) pilsbryi latior Cooke & Kondo, 1961
Island endemic: Rapa.
Celticola (Celticola) pilsbryi pilsbryi Cooke & Kondo, 1961
Island endemic: Rapa.
Celticola (Celticola) pilsbryi proxima Cooke & Kondo, 1961
Island endemic: Rapa.
Celticola (Meryticola) arborea arborea Cooke & Kondo, 1961
Island endemic: Rapa.
Celticola (Meryticola) arborea sororcula Cooke & Kondo, 1961
Island endemic: Rapa.
Celticola (Nesonoica) anatonuensis Cooke & Kondo, 1961
Island endemic: Raivavae.
Celticola (Nesonoica) conoides Cooke & Kondo, 1961
Island endemic: Rapa.
Lamellovum Pilsbry, 1910
Island endemic: Rapa.
Lamellovum (Lamellovum) globosum (Petit de la Saussaye, 1843)
Island endemic: Rapa.
Lamellovum (Maitua) auricullela Cooke & Kondo, 1961
Island endemic: Rapa.
Lamellovum (Maitua) costata Cooke & Kondo, 1961
Island endemic: Rapa.
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Lamellovum (Maitua) leptospira Cooke & Kondo, 1961
Island endemic: Rapa.
Lamellovum (Maitua) solitaria Cooke & Kondo, 1961
Island endemic: Rapa.
Mangaoa Cooke & Kondo, 1961
Island endemic: Rapa.
Mangaoa perissa Cooke & Kondo, 1961
Island endemic: Rapa.
Mitiperua Cooke & Kondo, 1961
Island endemic: Rapa.
Mitiperua simplex convexior Cooke & Kondo, 1961
Island endemic: Rapa.
Mitiperua simplex simplex Cooke & Kondo, 1961
Island endemic: Rapa.
Mitiperua simplex subcostata Cooke & Kondo, 1961
Island endemic: Rapa.
Perahua Cooke & Kondo, 1961
Island endemic: Rapa.
Perahua bakeri Cooke & Kondo, 1961
Island endemic: Rapa.
Perahua grandis Cooke & Kondo, 1961
Island endemic: Rapa.
Pitys Mörch, 1852
Pitys alpestris Cooke & Kondo, 1961
Island endemic: Rapa.
Pitys pagodiformis (E.A. Smith, 1892)
Island endemic: Rapa.
Pitys scalaris Cooke & Kondo, 1961
Island endemic: Rapa.
Pukunia Cooke & Kondo, 1961
Pukunia acuta Cooke & Kondo, 1961
Island endemic: Rapa.
Pukunia margaritae Cooke & Kondo, 1961
Island endemic: Rapa.
Pukunia pellucida Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus Anton, 1839
Island endemic: Rapa.
Strobilus (Strobilus) acicularis acicularis Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Strobilus) acicularis raphis Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Strobilus) opeas intermedius Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Strobilus) opeas opeas Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Strobilus) subtilis similaris Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Strobilus) subtilis subtilis Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Strobilus) turritus basalis Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Strobilus) turritus turritus Anton, 1839
Island endemic: Rapa.
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Strobilus (Tanga) brevis brevis Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Tanga) brevis pumilus Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Tanga) brevis subsimilis Cooke & Kondo, 1961
Island endemic: Rapa.
Strobilus (Tautautua) perfragilis Cooke & Kondo, 1961
Island endemic: Rapa.
Taitaa Cooke & Kondo, 1961
Taitaa (Taitaa) arauana Cooke & Kondo, 1961
Island endemic: Tubuai.
Taitaa (Taitaa) dacryma Cooke & Kondo, 1961
Island endemic: Tubuai.
Taitaa (Taireva) striatula Cooke & Kondo, 1961
Island endemic: Rurutu.
Taitaa (Taireva) zimmermani Cooke & Kondo, 1961
Island endemic: Tubuai.
Taitaa (Taireva) neanica Cooke & Kondo, 1961
Island endemic: Raivavae.
Taitaa (Taireva) terebriformis Cooke & Kondo, 1961
Island endemic: Raivavae.
Tubuaia Cooke & Kondo, 1961
Tubuaia affinis (Garrett, 1879)
Island endemic: Rurutu.
Tubuaia amoebodonta Kondo, 1962
Island endemic: Rurutu.
Tubuaia bakerorum Kondo, 1962
Island endemic: Rurutu.
Tubuaia coprophora coprophora Kondo, 1962
Island endemic: Raivavae.
Tubuaia coprophora diminuta Kondo, 1962
Island endemic: Raivavae.
Tubuaia cremnobates Cooke & Kondo, 1961
Island endemic: Rapa.
Tubuaia cylindrata cylindrata Cooke & Kondo, 1961
Island endemic: Rapa.
Tubuaia cylindrata philolichen Cooke & Kondo, 1961
Island endemic: Rapa.
Tubuaia hygrobia Kondo, 1962
Island endemic: Raivavae.
Tubuaia inconstans Cooke & Kondo, 1961
Island endemic: Rapa.
Tubuaia myojinae Kondo, 1962
Island endemic: Raivavae.
Tubuaia perplexa (Garrett, 1879)
Large range in the Pacific
Range in the Australs: Rimatara. Rurutu.
Tubuaia saintjohni Kondo, 1962
Island endemic: Raivavae.
Tubuaia voyana manurevae Kondo, 1962
Island endemic: Rurutu.
Tubuaia voyana matonaaensis Kondo, 1962
Island endemic: Rurutu.
Tubuaia voyana oromanaensis Kondo, 1962
Island endemic: Rimatara.
Tubuaia voyana rapaensis Cooke & Kondo, 1961
Island endemic: Rapa.
Tubuaia voyana teutuensis Kondo, 1962
Island endemic: Rapa.
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Tubuaia voyana turivaoensis Kondo, 1962
Island endemic: Raivavae.
Tubuaia voyana vaiaunanae Kondo, 1962
Island endemic: Raivavae.
Subfamily TORNATELLIDINAE Cooke & Kondo, 1961
Tornatellides Pilsbry, 1910
Tornatellides (Tornatellides) oblongus oblongus (Anton, 1839)
Large range in the Pacific.
Range in the Australs: Rimatara. Rurutu. Tubuai. Raivavae. Rapa.
Subfamily TORNATELLININAE Sykes, 1900
Elasmias Pilsbry, 1910
Elasmias amphodon Cooke & Kondo, 1943
Island endemic: Rurutu.
Elasmias apertum (Pease, 1865)
Cryptogenic.
Range in the Australs: Rimatara*. Rurutu*. Tubuai. Raivavae*.
Elasmias ovatum exiguum Cooke & Kondo, 1961
Island endemic: Rapa.
Elasmias ovatum ovatum (Anton, 1839)
Island endemic: Rapa.
Elasmias simplicinum Cooke & Kondo, 1961
Austral Islands endemic: Raivavae. Rapa.
Tornatellina L. Pfeiffer, 1842
Tornatellina bilamellata (Anton, 1839)
Island endemic: Rapa.
Superfamily PUPILLOIDEA Turton, 1831
Family VALLONIIDAE Morse, 1864
Pupisoma Stoliczka, 1873
Pupisoma orcula (Benson, 1850)
Cryptogenic.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*.
Remarks: Species not known previously from the Austral Islands, but found to be common in the northern islands. It lives on tree trunks and is often found at the base of pinnae, on the rachis of Angiopteris
fronds.
Family GASTROCOPTIDAE Pilsbry, 1918
Subfamily GASTROCOPTINAE Pilsbry, 1918
Gastrocopta Wollaston, 1878
Gastrocopta servilis (A.A. Gould, 1843)
Cryptogenic.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*. Rapa*.
Gastrocopta pediculus (Shuttleworth, 1852)
Cryptogenic
Range in the Australs: Rimatara*. Rurutu. Tubuai*. Raivavae*. Rapa*.
Subfamily NESOPUPINAE Steenberg, 1925
Several species of Nesopupa are present: at least two species in Raivavae, two in Tubuai, four in Rurutu
and three in Rimatara. Here we mention Costigo saparuana for the first time in French Polynesia.
Pronesopupa is represented by one species in each of the following islands: Rapa, Raivavae and Rurutu.
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Costigo saparuana, new record from the Austral Islands. A - B: Mato Naa, Rurutu. C: Anatonu, Raivavae (Photo O. Gargominy).
Family VERTIGINIDAE Pilsbry, 1918
Subfamily NESOPUPINAE Steenberg, 1925
Nesopupa Pilsbry, 1900
Nesopupa (Nesopupa) pleurophora (Shuttleworth, 1852)
Large range in the eastern Pacific.
Range in the Australs: Rurutu*. Raivavae*.
Nesopupa (Nesopupa) cf. armata (Pease, 1871)
Range in the Australs: Rurutu*.
Nesopupa (Nesopupa) cf. paivae (Crosse, 1865)
Range in the Australs: Rurutu*.
Nesopupa (Nesopupa) cf. tongana (Boettger, 1881)
Range in the Australs: Rurutu*.
Nesopupa (Nesopupa) sp.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*.
Costigo O. Boettger, 1891
Costigo saparuana (O. Boettger, 1891)
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*.
Brook (2010) was the first to report this indonesian species from Pacific islands with populations from Cook
Islands and Niue inferred to be of anthropogenic origin in prehistoric time. This species is always found at
low density and mixed together with much more abundant Nesopupa spp., so is difficult to record. Its range
extends much further East: we have also recorded it from Moorea (Society — sequenced in the framework of
the Moorea Biocode Project) and Makatea (Tuamotus).
Pronesopupa Iredale, 1913
Pronesopupa sp.1
Island endemic?: Rapa*.
Pronesopupa sp.2
Island endemic?: Raivavae*.
Pronesopupa sp.3
Island endemic?: Rurutu*.
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Superfamily ACHATINOIDEA Swainson, 1840
Family ACHATINIDAE Swainson, 1840
Achatina Lamarck, 1799
Achatina fulica Bowdich, 1822
Introduced species.
Range in the Australs: Tubuai*.
Remarks: The giant African snail Achatina fulica was found in Tubuai. According to local people, it was introduced in 1984 by a nurse near Mataura health center. The snails became invasive, and staff of the Service
du Développement Rural tried to eradicate them (manual eradication and introduction of Euglandina rosea)
­without success. After an initial explosion, the populations dropped (P. Paccou pers. comm.). It was not abundant when we were in Tubuai, but several live individuals were collected. Shells were only found at low altitude.
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Family FERUSSACIIDAE Bourguignat, 1883
Subfamily FERUSSACIINAE Bourguignat, 1883
This is the first record of this family in French Polynesia.
Geostilbia Crosse, 1867
Geostilbia aperta (Swainson, 1840)
Found in almost all tropical regions.
Range in the Australs: Rurutu*. Tubuai*.
Family SUBULINIDAE P. Fischer & Crosse, 1877
Subulinidae are now one of the main components of the malacofauna in French Polynesia, both in terms
of abundance and ubiquity. Several species were found in all the northern islands, where they are common,
especially at low altitude and in degraded areas: Subulina octona, Opeas hannense, Paropeas achatinaceum,
Allopeas gracile, Allopeas oparanum and Allopeas clavulinum. Leptinaria unilamellata was only found in Rurutu
and Raivavae, and is much less common than the other Subulinidae. In Rapa, the subtropical climate is probably less suitable for Subulinidae which are less abundant. Allopeas gracile is widespread and very abundant
in the Austral Islands, a fact supporting the idea that it was spread throughout the Pacific islands by early
polynesians (Christensen & Kirch 1981). The type locality of Bulimus beckianus L. Pfeiffer, 1846 is "Opara?"
(= Rapa), which must be an error since Beckianum beckianum is now known to occur in tropical America
(Massemin et al. 2009), and has never actually been collected in Polynesia. It is not included here.
Allopeas H.B. Baker, 1935
Allopeas clavulinum (Potiez & Michaud, 1838)
Introduced species.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*. Rapa*.
Allopeas gracile (Hutton, 1834)
Introduced species.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*. Rapa*.
Allopeas oparanum (L. Pfeiffer, 1846)
Cryptogenic.
Range in the Australs: Rimatara*. Rurutu. Tubuai*. Rapa.
Leptinaria Beck, 1837
Leptinaria unilamellata (d'Orbigny, 1837)
Introduced species.
Range in the Australs: Rurutu*. Raivavae*.
Opeas Albert, 1850
Opeas hannense (Rang, 1831)
= O. pumilum (L. Pfeiffer, 1840)
Introduced species.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*. Rapa*.
Paropeas Pilsbry, 1906
Paropeas achatinaceum (L. Pfeiffer, 1846)
Introduced species.
Range in the Australs: Rimatara*. Rurutu*. Raivavae*.
Subulina Beck, 1837
Subulina octona (Bruguière, 1792)
Introduced species.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*. Rapa.
Superfamily TESTACELLOIDEA J. Gray, 1840
Family OLEACINIDAE H. Adams & A. Adams, 1855
Euglandina Crosse & P. Fischer, 1870
Euglandina rosea (Férussac, 1821)
Introduced species.
Range in the Australs: Tubuai*.
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Remarks: Euglandina rosea was introduced in Tubuai in 1985 (P. Paccou pers. comm.) to eradicate Achatina
fulica, without success. It is present in all habitats, from sea-level to the highest ridges.
Superfamily STREPTAXOIDEA J. Gray, 1860
Family STREPTAXIDAE J. Gray, 1860
Two introduced species are present in the northern islands: Streptostele musaecola is common in all four
islands while Huttonella bicolor is much rarer and was only found in Rurutu and Raivavae. The impact of
these carnivorous species on the native invertebrate fauna is unknown.
Huttonella L. Pfeiffer, 1856
Huttonella bicolor (Hutton, 1834)
Introduced species.
Range in the Australs: Rurutu*. Raivavae*.
Streptostele Dohrn, 1866
Streptostele (Tomostele) musaecola (Morelet, 1860)
Introduced species.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*.
Superfamily PUNCTOIDEA Morse, 1864
Family PUNCTIDAE Morse, 1864
Punctum Morse, 1864
Punctum polynesicum Solem, 1983
Austral Islands endemic: Tubuai. Raivavae.
Family CHAROPIDAE Hutton, 1884
Discocharopa Iredale, 1913
Discocharopa aperta (Möllendorff, 1888)
Cryptogenic.
Range in the Australs: Rurutu.
Sinployea Solem, 1983
Sinployea? sp.
Island endemic: Raivavae*.
Family ENDODONTIDAE Pilsbry, 1895
In Rapa, we found Opanara bitridentata, Orangia cookei montana, Rhysoconcha variumbilicata and several other
as yet undetermined species. A species found on the coast, at the base of a cliff, only accessible by boat, is a species new to science, illustrating the fact that coastal habitats once harboured a unique fauna that has been wiped
out, possibly when early Polynesians settled there. Apart from this case, all extant Endodontidae in Rapa were
found in high elevation native forest, or in remnants of native vegetation protected from fire and introduced
herbivores (such as crevices in cliffs).
In Raivavae, three genera (one archipelago endemic, Australdonta) and eight species (all endemic) were previously
known (Solem 1976). In particular, northeastern side of the island (east of Anatonu village) was very rich, with six
syntopic species (Solem 1976), possibly due to the presence of a restricted limestone outcrop. However, the area
was completely degraded by the encroachment of the village, and no live Endodontidae was found. In consequence,
we suggest that the following species, only known from this area, could be extinct: Minidonta micraconica (one
locality with old shells near the type locality); Minidonta anatonuana (type locality visited without success, one very
old shell could belong to this species), Minidonta gravacosta, Minidonta sulcata, Minidonta planulata, Mautodontha
ceuthma, Australdonta ectopia (type localities visited without success). Considering the condition of the holotype,
Australdonta ectopia may have been already extinct in 1934. Another species of Minidonta, new to science, was found
near Anatonu, but it is also probably extinct, as we only found old shells. By contrast, Australdonta raivavaeana was
found in several localities in the island, always above 80 m a.s.l. (live individuals), but not necessarily in native forest. Live individuals were found at the base of cliffs in herbaceous vegetation at the base of grass stems.
In Tubuai, two species and one subspecies were known, all endemic. We found Australdonta radiella radiella in abundance, with fresh shells. Australdonta tubuaiana was found in two localities in the western part
of the island, including the type locality, but only old shells were found. Only one fragment of Australdonta
...
76
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Terrestrial Biodiversity of the Austral Islands,
French Polynesia
pharcata was found, not in the type locality. The type locality, now in Taahuaia village, could not be found.
We suggest that Australdonta tubuaiana and A. pharcata should be classified as extinct.
Two genera and seven species were known from Rurutu prior to our survey. Litter sieving and thorough
surveying of limestone areas revealed 12 other species new for science which have been described elsewhere (Zimmermann et al. 2009; Sartori et al. 2013). Up to 11 species were found in syntopy, north of
Hauti village. However, no live specimen or very fresh shell was found. In consequence, we believe that
a large part of the Endodontidae radiation in Rurutu is extinct. However, Australdonta pseudplanulata,
Australdonta magnasulcata, Australdonta yoshii, Australdonta radiella rurutuensis, Australdonta tapina,
Australdonta degagei could still be extant, as we found some shells, which could be recent (though it is hard
to be certain). If they live in rock crevices, we could have missed them. Three species were very abundant
and widespread: we found 2 687 shells in 38 localities for A. pseudplanulata, 3 472 shells in 40 localities for
A. tapina, 7 948 shells in 39 localities for A. degagei.
The east coast of Rurutu, and in particular between cape Arei and cape Toarepe, seems to be a micro-center
of endemism for this island, eight of the 12 new species being restricted to this area. On the other hand, a
few species had a wide distribution on the island, from sea-level to the mountain tops (A. degagei, A. pseudplanulata, A. tapina); these three species are the most widespread and abundant Endodontidae collected.
Two species were known from Rimatara (Australdonta rimatarana, A. degagei), which were found in 2004,
but no live individuals were observed. We suppose they are extinct. Libera fratercula rarotongensis was
found in huge quantities on the northeastern coast, but only old shells were found. This species previously
only known from the Cook Islands (Solem 1969) is obviously extinct today on Rimatara on which it might
represent an ancient introduction by early Polynesians. Three other species, new to science, were found as
subfossils in a cave deposit. These are considered to be extinct species.
Australdonta Solem, 1976
Australdonta anneae Sartori, Gargominy & Fontaine, 2013
Island endemic: Rurutu*.
Australdonta collicella Zimmermann, Gargominy & Fontaine, 2009
Island endemic: Rurutu*.
Australdonta degagei (Garrett, 1879)
Australs: Rimatara. Rurutu; Cook Islands: Mauke.
Australdonta ectopia Solem, 1976
Island endemic: Raivavae.
Australdonta florencei Sartori, Gargominy & Fontaine, 2013
Island endemic: Rurutu*.
Australdonta magnasulcata Solem, 1976
Island endemic: Rurutu.
Australdonta magnasulcatissima Zimmermann, Gargominy & Fontaine, 2009
Island endemic: Rurutu*.
Australdonta microspiralis Zimmermann, Gargominy & Fontaine, 2009
Island endemic: Rurutu*.
Australdonta oheatora Sartori, Gargominy & Fontaine, 2013
Island endemic: Rurutu*.
Australdonta pakalolo Sartori, Gargominy & Fontaine, 2013
Island endemic: Rurutu*.
Australdonta pharcata Solem, 1976
Island endemic: Tubuai.
Australdonta pseudplanulata Solem, 1976
Island endemic: Rurutu.
Australdonta radiella radiella (L. Pfeiffer, 1846)
Island endemic: Tubuai.
Australdonta radiella rurutuensis (Garrett, 1879)
Island endemic: Rurutu.
Australdonta raivavaeana Solem, 1976
Island endemic: Raivavae.
Australdonta rimatarana Solem, 1976
Island endemic: Rimatara.
Australdonta sibleti Sartori, Gargominy & Fontaine, 2013
Island endemic: Rurutu*.
Australdonta sulcata Zimmermann, Gargominy & Fontaine, 2009
Island endemic: Rurutu*.
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A Global Overview of the Terrestrial and Freshwater Molluscs
.. .....
Australdonta tapina Solem, 1976
Island endemic: Rurutu.
Australdonta teaae Sartori, Gargominy & Fontaine, 2013
Island endemic: Rurutu*.
Australdonta tubuaiana Solem, 1976
Island endemic: Tubuai.
Australdonta yoshii Solem, 1976
Island endemic: Rurutu.
Australdonta sp.1
Island endemic: Rimatara*.
Australdonta sp.2
Island endemic: Rimatara*.
Australdonta ? sp.3
Island endemic: Rimatara*.
Kondoconcha Solem, 1976
Island endemic: Rapa.
Kondoconcha othnius Solem, 1976
Island endemic: Rapa.
Libera Garrett, 1881
Libera fratercula rarotongensis Solem, 1976
Australs: Rimatara*. Cook Islands: Rarotonga.
Mautodontha Solem, 1976
Mautodontha (Mautodontha) ceuthma Solem, 1976
Island endemic: Raivavae.
Minidonta Solem, 1976
Minidonta anatonuana Solem, 1976
Island endemic: Raivavae.
Minidonta bieleri Sartori, Gargominy & Fontaine, 2013
Island endemic: Rurutu.
Minidonta boucheti Sartori, Gargominy & Fontaine, 2013
Island endemic: Rurutu.
Minidonta gravacosta Solem, 1976
Island endemic: Raivavae.
Minidonta haplaenopla Solem, 1976
Island endemic: Rurutu.
Minidonta micraconica Solem, 1976
Island endemic: Raivavae.
Minidonta planulata Solem, 1976
Island endemic: Raivavae.
Minidonta sulcata Solem, 1976
Island endemic: Raivavae.
Minidonta sp.
Island endemic: Rimatara*.
Opanara Solem, 1976
Island endemic: Rapa.
Opanara altiapica Solem, 1976
Island endemic: Rapa.
Opanara areaensis areaensis Solem, 1976
Island endemic: Rapa.
Opanara areaensis densa Solem, 1976
Island endemic: Rapa.
Opanara areaensis microtorma Solem, 1976
Island endemic: Rapa.
Opanara bitridentata Solem, 1976
Island endemic: Rapa.
Opanara caliculata Solem, 1976
Island endemic: Rapa.
Opanara depasoapicata Solem, 1976
Island endemic: Rapa.
...
78
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Opanara duplicidentata Solem, 1976
Island endemic: Rapa.
Opanara fosbergi Solem, 1976
Island endemic: Rapa.
Opanara megomphala megomphala Solem, 1976
Island endemic: Rapa.
Opanara megomphala tepiahuensis Solem, 1976
Island endemic: Rapa.
Opanara perahuensis Solem, 1976
Island endemic: Rapa.
Orangia Solem, 1976
Island endemic: Rapa.
Orangia cookei cookei Solem, 1976
Island endemic: Rapa.
Orangia cookei montana Solem, 1976
Island endemic: Rapa.
Orangia cookei tautautuensis Solem, 1976
Island endemic: Rapa.
Orangia maituatensis Solem, 1976
Island endemic: Rapa.
Orangia sporadica Solem, 1976
Island endemic: Rapa.
Rhysoconcha Solem, 1976
Island endemic: Rapa.
Rhysoconcha atanuiensis Solem, 1976
Island endemic: Rapa.
Rhysoconcha variumbilicata Solem, 1976
Island endemic: Rapa.
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Terrestrial Biodiversity of the Austral Islands,
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A Global Overview of the Terrestrial and Freshwater Molluscs
.. .....
Ruatara Solem, 1976
Island endemic: Rapa.
Ruatara koarana Solem, 1976
Island endemic: Rapa.
Ruatara oparica normalis Solem, 1976
Island endemic: Rapa.
Ruatara oparica oparica (Anton, 1839)
Island endemic: Rapa.
Ruatara oparica reductidenta Solem, 1976
Island endemic: Rapa.
Superfamily GASTRODONTOIDEA Tryon, 1866
Family EUCONULIDAE H.B. Baker, 1928
Several species were found alive in Rapa in native forests, including Philonesia tenuior, P. zimmermani zimmermani and Hiona orbis.
In all the northern islands, several species have probably been introduced by early inhabitants and are widespread: Lamprocystis cf. vitrinella, Liadertia discordiae (except in Rimatara), Diastole conula (except in Rimatara).
In Raivavae, where four endemic species were known, Microcystis lenticula and M. aspera are still often
encountered alive on the leaves in relict forests and Hibiscus tiliaceous forests.
In Tubuai, six endemic species were previously known. We found Microcystis saintjohni at the type locality,
"north-east slope of Mt Pane" (Baker 1938), despite the fact that this area is now a pine plantation, with a
Psidium understorey. M. saintjohni lives on Psidium leaves. However, its distribution seems to be very restricted,
and it qualifies to be classified as Critically Endangered. The five other endemic species are believed to be
extinct, as we did not find them anywhere, including the type locality: Cookeana vindex, Cookeana anathesis,
Microcystis adusta, Microcystis andersoni (an old shell was found near Mataura) and Microcystis kondoi.
In Rurutu, Lamprocystis rurutuana was not found at the type locality, which is degraded by invasive
Kalanchoe sp., and we suggest it could be extinct.
No Euconulidae species was known from Rimatara, though there is no reason they should not be there,
like in the other Austral Islands. We found an arboreal species in the northern "mato", on epiphytic ferns
on Pisonia grandis, probably new to science.
Subfamily MICROCYSTINAE Thiele, 1931
Cookeana H.B. Baker, 1938
Cookeana anathesis H.B. Baker, 1938
Island endemic: Tubuai.
Cookeana vindex H.B. Baker, 1938
Island endemic: Tubuai.
Diastole Gude, 1913
Diastole (Diastole) conula (Pease, 1861)
Cryptogenic.
Range in the Australs: Rurutu. Tubuai*.
Diastole (Diastole) rurutui H.B. Baker, 1938
Austral Islands endemic: Rurutu. Raivavae.
Coneuplecta Möllendorf, 1893
Coneuplecta calculosa (A.A. Gould,1852)
Cryptogenic.
Range in the Australs: Rimatara*.
Hiona Cooke in H.B. Baker, 1940
Hiona (Opara) orbis (Beck, 1837)
Island endemic: Rapa.
Lamprocystis Pfeffer, 1883
Lamprocystis (Kerakystis) punctifera (Garrett, 1879)
Island endemic: Rurutu.
Lamprocystis (Kerakystis?) vitrinella rapana H.B. Baker, 1938
Island endemic: Rapa.
Lamprocystis (Kerakystis?) vitrinella vitrinella (Beck, 1837)
Island endemic: Rurutu.
Lamprocystis (Manureva) rurutuana H.B. Baker, 1938
Island endemic: Rurutu.
...
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Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Liardetia Gude, 1913
Liardetia (Oceanesia) discordiae (Garrett, 1881)
Cryptogenic.
Range in the Australs: Rurutu.
Microcystis Beck, 1837
Microcystis (Cnesticystis) aspera H.B. Baker, 1938
Island endemic: Raivavae.
Microcystis (Cnesticystis) kondoi H.B. Baker, 1938
Island endemic: Tubuai.
Microcystis (Facorhina) adusta H.B. Baker, 1938
Island endemic: Tubuai.
Microcystis (Facorhina) andersoni H.B. Baker, 1938
Island endemic: Tubuai.
Microcystis (Facorhina) lenticula H.B. Baker, 1938
Island endemic: Raivavae.
Microcystis (Leurocystis) saintjohni H.B. Baker, 1938
Island endemic: Tubuai.
Microcystis (Microcystis) benesculpta H.B. Baker, 1938
Island endemic: Rapa.
Microcystis (Microcystis) fosbergi fosbergi H.B. Baker, 1938
Island endemic: Raivavae.
Microcystis (Microcystis) fosbergi taraiae H.B. Baker, 1938
Island endemic: Raivavae.
Microcystis (Microcystis) ornatella ornatella (Beck, 1837)
Island endemic: Rapa.
Microcystis (Microcystis) ornatella parva H.B. Baker, 1938
Island endemic: Rapa.
Microcystis (Microcystis) perahui H.B. Baker, 1938
Island endemic: Rapa.
Philonesia Sykes, 1900
Philonesia (Rapafila) tenuior karaporahi H.B. Baker, 1940
Island endemic: Rapa.
Philonesia (Rapafila) tenuior tenuior H.B. Baker, 1940
Island endemic: Rapa.
Philonesia (Rapafila) zimmermani tautautui H.B. Baker, 1940
Island endemic: Rapa.
Philonesia (Rapafila) zimmermani zimmermani H.B. Baker, 1940
Island endemic: Rapa.
Superfamily LIMACOIDEA Lamarck, 1801
Family AGRIOLIMACIDAE H. Wagner, 1935
Deroceras Rafinesque, 1820
Deroceras laeve (O.F. Müller, 1774)
Introduced species.
Range in the Australs: Rurutu*. Raivavae*. Rapa*.
Superfamily HELICOIDEA Rafinesque, 1815
Family BRADYBAENIDAE Pilsbry, 1934 (1898)
Bradybaena Beck, 1837
Bradybaena similaris (Férussac, 1821)
Introduced species.
Range in the Australs: Rimatara*. Rurutu*. Tubuai*. Raivavae*. Rapa*.
Remarks: Common in all the Austral Islands. In Rapa, it is very abundant around Haurei village, and in
Raivavae, it is one of the most abundant snails, everywhere even on ridges, in forests and in degraded areas.
Because the family Achatinellidae was not sorted to species level, all the results and analyses hereafter
exclude this family.
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A Global Overview of the Terrestrial and Freshwater Molluscs
.. .....
...
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……Introduced species
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 14: List of first recordings of introduced species in the Austral Islands, ordered by date.
Compiled using data from our samples, specimens at the Bishop Museum and accounts in
and extinctions
the literature (Pfeiffer 1846; Pease 1871; Garrett1879). 1902 = species collected by A. Seale,
No data has been published small land snails found by washing dirt found in Partula shells (except for M. tuberculata).
on introduced snail species in 1921 = species collected by A.M. Stokes, Bayard Dominick Expedition. 1934 = Mangarevan
the Austral Islands. However, Expedition. Bishop Museum data gathered by Robert Cowie, University of Hawaii.
the collections of the Bishop * cryptogenic species - 1 Gastrocopta sp. - 2 Lamellidea sp. - 3 labelled "Physa" in BPBM
Museum reveal that previ- collection.
ous collectors had already
Raivavae Tubuai Rurutu Rimatara Rapa
found them, some data dating
1934
1934
1879
1921
1828
from more than a century ago Allopeas gracile / oparanum
(Table 14). Several nowadays Gastrocopta pediculus*
1934
1902
1879
1934
1934 1
common species that would Gastrocopta servilis*
1934
1902
1934
1934
1934 1
not have been mistaken for
Melanoides tuberculata
2002
1902
1934
2004
1934
something else, nor missed
1934
1902
1934
1934
by experienced collectors, Pupisoma sp.*
Allopeas
clavulinum
1934
1934
1934
2004
1921
seem to be recent introduc1921
1934
1921
1934
1921
tion (at least after 1934), since Opeas hannense
they were not collected by the Subulina octona
1921
1934
1921
1921
1934
Mangarevan Expedition. These Lamellidea oblonga
1934
1934
1934
1934
1934 2
include: Pseudosuccinea coluPhysella acuta
1934 3
1934 3
2004
mella, Physella acuta, Laevicaulis
1984
alte, Achatina fulica, Euglandina Achatina fulica
1985
rosea, Paropeas achatinaceum, Euglandina rosea
Allopeas clavulinum, Streptostele Bradybaena similaris
2002
2003
2003
2004
2002
musaecola, Huttonella bicolor, Deroceras laeve
2002
2003
2003
Bradybaena similaris. Even if Huttonella bicolor
2002
2003
some of these species are small,
2002
2003
2003
2004
2002
they are now widespread on at Laevicaulis alte (?)
Leptinaria
unilamellata
2002
2002
least one of the Austral Islands,
2002
2003
2003
and an expert collector such as Paropeas achatinaceum
J.M. Cooke would have found Pseudosuccinea columella
2003
2003
2002
them. Streptostele musaecola Streptostele musaecola
2002
2003
2003
2004
can be mistaken for a subulinid: Luntia insignis Smith, 1898 has been described
from Trinidad and until very recently thought to
Rimatara
be a Subulinidae. It has now been placed in the
Rurutu
synonymy of Streptostele musaecola which has thus
been recognized as a tramp species (Hausdorf &
Tubuai
Bermudez 2003).
The Bishop Museum collections, however, do not conRaivavae
tain unsorted Subulinidae (R. Cowie pers. comm.). As
0
10
20
30
40
Percentage of stations
alcohol material was not checked, we do not know
whether slugs were collected in the early 20th century.
Figure 10: Percentage of stations with Partula hyalina in
Nothing is known of the impact of Euglandina rosea
the northern Austral Islands. Tubuai, the only island with
Euglandina rosea has the lowest abundance of Partula hyalina.
Rimatara
Rurutu
Tubuai
Raivavae
Rapa
Makatea
Tahiti
0
10
20
30
40
Percentage of stations
Figure 11: Percentage of stations with introduced Bradybaena
similaris in the Austral Islands. Results from Makatea (Tuamotu
Islands) and Tahiti (Society Islands) are included for comparison.
83
on native species in Tubuai, but it could
have an impact on Partula hyalina, has
we found this species to be less abundant
than in other islands without Euglandina
(Fig. 10). Its impact on smaller species
is known but not quantified (Gargominy
2007).
Worth being noted, alien species have had
50%
various rate of success in the different
islands (Fig. 11), but no single explanation is evident. Introduction date could
simply explain this, but we have no indication about
it, except that it was after 1934 (Table 14). Climate
...
50%
.. .....
could play a role, but Rapa with its subtropical climate has a similar rate of abundance for Bradybaena
similaris than tropical Tubuai and Rurutu, but much
more than Rimatara and much less than Raivavae,
where the climate is also tropical.
The dominance of non-endemic species in the current fauna is demonstrated if we consider the number
of live individuals collected of all mollusc species,
according to their status (endemic, introduced and
so on - Fig. 12). Introduced species account for
43 % of the collected
material, cryptogenic/
9%
large range species for
13 %. Endemic spe12%
cies represent less than
one-fourth of the data.
2%
If we consider the
76%
northern
Austral
Islands­ only,
as A
Rapa was less thoroughly sampled, and
excluding­the whole
15%
Achatinellidae, 66
species were found
9%
43%
either alive or recently
Figure 12:
A: Faunal composition.
B: Species/localities pairs
throughout the archipelago
for species found alive.
This way of counting
gives more weight to the
abundant species, which
happen to be the alien.
Endemic species represent
less than one fourth of the
species/localities data.
33%
B
Island endemics
Austral endemics
Indigenous /
Cryptogenic
Introduced
120
Island endemic
Austral endemic
Unknown
Large range
Introduced
100
Number of species
A Global Overview of the Terrestrial and Freshwater Molluscs
80
60
40
20
0
?
Historical
Today
Tomorrow?
Figure 13: Evolution of the fauna in the northern Australs,
according to the status of taxa. The original fauna composition
is based on historical data (1934 and before), to which were
added species new to science found during the fieldwork.
Achatinellidae are not included. The current fauna is based on
species found alive, or recently dead (fresh empty shells), and is
a conservative estimate. Future fauna is based on current fauna,
minus species only found in native vegetation and/or in one or
two localities only.
dead (fresh shells), including 25 endemic. We
consider the other endemic species to be extinct,
representing a loss of 17 to 60 % of the native fauna
depending the island. Among species found alive
or freshly dead, 16 were found only in one or two
stations, or only in natural vegetation, and as such
are candidate for a not-too-distant extinction: we
might have a future fauna made of 50 indigenous
taxa, only one fourth of them being endemics
(Fig. 13). This percentage is conservative, as it
implies that the number of introduced species does
not increase, which is unlikely, as observations in
Hawaii have shown (R. Cowie pers. comm.).
Discussion
Our results show that biodiversity inventories with
adapted extensive methods can yield new data,
even in areas where focussed sampling has already
been performed. The Mangarevan Expedition spent
11 days in Rurutu (we stayed 14 days on this
island), but collected less than in other islands:
2 353 specimens, vs 19 227 in Raivavae or 37 593
in Rapa (Gregory 1936). Cooke (in Gregory 1935)
considered "that [their] landshell collections are
nearly complete from most of the islands and that
these need not be revisited [….] For further collecting in the southern islands, Raivavae comes second in importance to Rapa and Tubuai third." He
thought that the forest was so degraded in Rurutu,
Mangareva and Rimatara that very few new species could be found there. However, eight species
new to science were described following fieldwork
in Mangareva in 1997 (Abdou & Bouchet 2000;
Bouchet & Abdou 2001), and we added 12 new
endodontid species to the fauna of Rurutu: Cooke
...
and his colleagues were very good collectors, but
our advantage certainly lies in the fact that we used
a very efficient collecting method, namely littersieving, whereas they only collected specimens
found with the naked eye, and missed several rare
and/or minute species. In Rurutu, several new species are large, but they are very localised, and were
found in the "matos" where shells of common species are extremely abundant: finding them directly
in this mass of shells is a matter of luck without
the systematic searching of sieved litter in the lab.
We observed that mollusc populations can survive
in tiny pockets of remaining habitats (one or two
square meters can be enough), and this is confirmed
by other authors (Solem 1988): in this context,
we may have missed some living populations of
endemic species. However, the northern Australs
have been well covered (Fig. 9) and after the 20022004 field trips their fauna can be considered as
reasonably well known. Rapa, on the other hand,
84
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has not been thoroughly surveyed for lack of time.
A longer period would have allowed to survey more
areas. In particular, Mts Pukutakatake and Koara,
visited by the Mangarevan Expedition, were not surveyed this time, nor most of the north of the island
(Mts Pukunia, Taga, Vairu and Ruatara). Some islets
have never been prospected to our knowledge, and
could be interesting (the last sandalwoods from Rapa
are on one of these islets, J.F. Butaud pers. comm.).
Nevertheless, the major known mollusc hotspots
discovered in Rapa by the Mangarevan Expedition
(Mt Perau and Maitua/Peupeu valley) were visited.
……The Austral Endodontidae: contrasting
situations among islands
In Rapa, according to the Mangarevan Expedition
samples, eight taxa were restricted to the highest
summit ridge (Mt Perau), between 400 m and 600 m
a.s.l.; one species was restricted to the Mangaoa ridge
(350-400 m); two were found between 150 m and
600 m a.s.l. and 10 were collected at mid-altitudes,
between 100 m et 250 m a.s.l. Only one taxon has
been collected from sea level to the summit of Perau.
The endodontid fauna was mostly found at mid to
high altitudes in 1934. Our collections were inadequate to confirm whether these species survive.
However, the lack of species at low altitude can be
explained in two ways: most of the low altitude areas
are highly degraded, and this was already the case in
1934 (Cooke in Gregory 1935), thus the native fauna
has disappeared; secondly, most of the native vegetation is restricted to high altitude ridges and gulleys,
collectors (both the Mangarevan Expedition and
ourselves) concentrated their efforts on these areas,
and the absence of data from low altitude could be
a sampling bias. This hypothesis is supported by the
fact that we found a new species of Endodontidae at
sea level, at the base of a cliff only accessible by boat,
and a population of a still unidentified Endodontidae
was found in a ferny cliff crack, out of reach from
goats, at 260 m. The amount of suitable habitat
(ferns) was much reduced, a few square meters only,
but Endodontidae were abundant there. There must
be several tiny pockets of remnant habitats spread all
over the island, acting as refugia for native snails, but
we did not stay long enough to have a better idea of
the true distribution of Endodontidae on Rapa.
On Raivavae, one species survives (Australdonta raivavaeana), and is found living from 40 m to 300 m.
It was present at sea level, but only empty shells were
found in that locality. All the other species found by
the Mangarevan Expedition lived at low altitude (up
to 40 m), except Minidonta anatonuana, which had
been collected from 30 m to 100 m. All these species seem to be extinct today. In particular, the very
rich localities of the Mangarevan Expedition around
Anatonu village, with up to six co-existing species,
are now degraded being part of the village. This rich
fauna probably lived in dry coastal forests, which
were destroyed when man settled there.
85
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
In Tubuai, only coastal species are known, and no
species has ever been found in high altitude forests.
In 1934, A. radiella radiella was already the commonest species, and A. pharcata the rarest (Solem
1976). A. radiella radiella seems to have survived
human disturbance, as it is still abundant in coastal
areas, though we never found any live individuals. However, the presence of many fresh shells
suggests the species still survives. This coastal distribution is similar to the situation in Mangareva,
where the richest localities are close to the sea on
sand (Abdou & Bouchet 2000).
In Rurutu, the Endodontidae fauna is extremely rich,
even more so than Rapa: 17 species are known from
Rapa, 19 in Rurutu. This must be due to the abundance of the upraised coral reef outcrops, which act
as micro-centers of endemism, especially the eastern
ones. Except for three widespread species, most
species are found on limestone, at low altitude. It
is remarkable that the Mangarevan Expedition did
not notice this amazing radiation. They stayed 11
days in Rurutu and visited the "matos", where they
noticed that "landshells were exceedingly abundant
alive" (Cooke in Gregory 1935) but probably concentrated their efforts on the mountains. However,
the main difference probably resides in the way
they sampled: litter sieving is never mentioned in
their reports, and it is most probable that they collected only by hand. They collected 602 endodontid
specimens in Rurutu and only collected three of the
most abundant species. By litter-sieving we collected
16 908 individuals. Given that many species are rare,
a large amount of material is necessary to find them.
It is notable that the Mangarevan Expedition failed
to collect eight of the rarer species.
Biological rarity sensu Bouchet et al. (2002) is the
total number of specimens found of a given species, while ecological rarity is given by the number
of stations where a species has been collected. It
was estimated for Rurutu Endodontidae (Fig. 14)
(Zimmermann 2006), which show a typical pattern
(Gaston 1994), with a few abundant species and
many rare ones.
In Rimatara, both previously known species were
abundant in the "mato", but they seem to be extinct
now. Another species, Libera fratercula rarotongensis,
previously only known from the Cook Islands, was
found to be extremely abundant in northeastern
coastal areas where the soil was removed for road
building. Dredging off Rimatara by the research vessel Alis (campagne BENTHAUS) at 900 m depth
in 2002 also found some shells. This is consistent
with the high densities of this species recorded from
Rarotonga; in 1965 a single site had 429 individuals per square meter, i.e. "a total population of
the colony [...] estimated at about 43 000 000 living
snails" (Solem 1976). This figure covers a fraction
of Rarotonga population, which could be "several
times the 43 000 000 estimated for part of one colony" (Solem 1969). Today, the species is extinct in
...
A Global Overview of the Terrestrial and Freshwater Molluscs
45
.. .....
Ecological rarity
9000
40
number of specimens
8000
35
number of stations
Biological rarity
30
25
20
15
10
5
7000
6000
5000
4000
3000
2000
1000
0
0
species
species
Figure 14: Ecological rarity and biological rarity of Rurutu Endodontidae. Stars indicate species that were already known before the
2002-2004 work.
Rimatara, probably because of coastal habitat degradation. Three new Endodontidae species found in
a cave as subfossils in the northern "mato" demonstrate that the original fauna used to be richer. The
"matos" are now without soil, the only remaining
large trees being huge cryptogenic Barringtonia asiatica (Lecythidaceae). We hypothesize that the "mato"
used to be covered with forest, with a real soil. The
forest cover would have been destroyed (fires, plantations), and the soil was subsequently eroded leading
to the extinction of litter species.
On Rurutu and Rimatara, the karstic relief is good
for the preservation of shells, which get washed
into subfossil remains in caves, these deposits provide a valuable insight into the historical diversity
of these islands. There are no limestone caves on
Rapa, Raivavae and Tubuai, thus we cannot be sure
what has been lost from these islands.
…
…IUCN Red List status
Data collected during these surveys lead us to
update the global conservation status of endemic
(restricted to Austral Islands) species, according
to Red List criteria (IUCN 2001). Status are summarized in Table 15, while figures of threatened
and extinct species per island and for the whole
archipelago are given in Table 13.
Thirty-two species or subspecies, all endemic, are considered Extinct (EX), as they were actively searched
for in their type localities, without success (Sartori et
al. 2013). While it is impossible to prove that a species is extinct, as we could simply have missed live
individuals, it seems unlikely in this instance, due to
thorough and targeted collection methods. If there
were some surviving individuals, they represent relictual populations on the brink of extinction. Around
100 other endemic species have not been found alive,
but were not the subject of a focused search in their
type locality. We give them the benefit of the doubt
and suggest they might still be extant and should
be classified as Critically Endangered (see below).
A conservative estimate of extinction in the Austral
would be 20 % of the endemic fauna being extinct,
...
but this figure is probably higher and could reach
over two thirds.
Fluviopupa rurutua, found in five localities on the
northern half of the island, qualifies to be classified
as Vulnerable, as it has a very restricted distribution (less than 20 km2). Fluviopupa raivavaeensis,
found in six localities in the main mountain range of
Raivavae, qualifies to be classified as Vulnerable, as it
has a very restricted distribution (less than 20 km2).
Fluviopupa tubuaia and Fluviopupa jeanyvesi, known
from a single locality, should be classified as Critically
Endangered.
Australdonta magnasulcata occurs in several dispersed
locations, isolated from each other, on Rurutu. The
species has a distribution of less than 10 km2, its
populations are severely fragmented, and there is a
continuing decline in habitat quality. It should then
be classified as Critically Endangered. However, as we
did not actually find live individuals, it could already
be extinct.
Australdonta yoshii occurring on several sites distant
from each other in Rurutu, this species has an area
of occupancy of less than 10 km2, its populations are
severely fragmented, and there is a continuing observed
decline in the quality of habitat. It should then be classified as Critically Endangered. However, as we did not
find live individuals, it could already be extinct.
Australdonta pseudplanulata occurring only on
the northern part Rurutu, this species has a very
restricted area of occupancy (typically less than
20 km2), and thus is classified as Vulnerable.
However, this is a conservative classification, as we
did not find live individuals, and this species could
be extinct. If it survives, it does not meet the criteria to be classified as Critically Endangered.
Australdonta radiella rurutuensis, occurring on several sites distant from each other in Rurutu, has an
area of occupancy of less than 10 km2, its populations are severely fragmented, and there is a continuing observed decline in the quality of habitat. It
should then be classified as Critically Endangered.
However, as we did not find live individuals, it could
already be extinct.
86
.......
Australdonta radiella radiella only occurs along
the coast in Tubuai. It has a very restricted area
of occupancy (typically less than 20 km2), and
thus is classified as Vulnerable. However, this is a
conservative classification, as we did not find live
individuals, and this species could be extinct. If it
survives, it does not meet the criteria to be classified as Critically Endangered (population does not
seem to be fragmented).
Australdonta raivavaeana, endemic from Raivavae,
is Critically Endangered as it extent of occurrence is
less than 100 km2, severely fragmented and shows
a continuing projected decline.
Libera fratercula rarotongensis is extinct in Rimatara.
It is still extant in Rarotonga, but the population has suffered a severe (though not quantified)
decline since the 1960's (Brook 2010). It should be
listed as Data Deficient.
Lamprocystis vitrinella, occurring on three sites
distant from each other in Rurutu, has an area of
occupancy of less than 10 km2, its populations
are severely fragmented, and there is a continuing
observed decline in the quality of habitat. It should
be classified as Critically Endangered.
Microcystis saintjohni has a very restricted distribution, probably less than one square kilometer on
Tubuai. There is only one population, and its habitat could be destroyed, if the pine plantation where
it occurs is either logged or burnt. Microcystis saintjohni should be classified as Critically Endangered.
Microcystis lenticula, still widespread in Raivavae,
occurs on a 17.9 km2 island: this species has a distribution of less than 20 km2, and thus is classified
as Vulnerable.
Microcystis aspera, still widespread in Raivavae,
occurs in a 17.9 km2 island: this species has an area
of occupancy less than 20 km2, and thus is classified as Vulnerable.
Rapa endemics all qualify to be classified as CR,
according to the IUCN criteria, as their distributions are less than 100 km2, the populations
are severely fragmented (most of the island is
covered by grassland, and native vegetation is
restricted to small patches), and habitat degradation continues. Considering the perilous state of
the island's natural habitats, this classification
is a conservative one: several of these species,
undoubtedly, are extinct.
…
…Conservation areas
Austral Islands native forests are among the most
interesting areas for molluscs, insects (E. Claridge,
R. Englund, D. Percy pers. comm.) and plants (J.-Y.
Meyer pers. comm.). As such, they need protection
against cattle, goats and fires, which are the main
cause of degradation and fragmentation. Degraded
areas can sometime harbour indigenous species,
such as Vertiginidae on marae (early Polynesian
religious sites) stones, but they are usually very
poor habitats (the worst being pine plantations,
87
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
agricultural areas and gardens). In lowlands, where
human impact has been the most intense (plantations and settlements), native habitats have almost
completely disappeared, along with any species
they supported.
As is the case everywhere, people in the Austral
Islands are not aware of most of the mollusc species which surround them. They only know the
large partulid species, often considered as pests,
and Omphalotropis spp. and Helicinidae (collectively
called "pupu"), which are used to make necklaces.
Small species are completely unknown to them.
For this reason, mollusc species cannot be used
as flagship species, and their conservation must
be done through the conservation of sites. Actions
focussing on single species are not suitable, because
species are too numerous, and their requirements
are unknown. The only exception in the Australs is
probably Microcystis saintjohni. In Tubuai, this large
and colourful species is highly threatened, and it
could be used to highlight the fate of invertebrate
native fauna among local people. The same may be
true of Samoana spp. on Raivavae. Ex situ conservation, which has been done for Society Islands partulids (Coote & Loeve 2003; IUCN 2010), is not a
solution either, as threatened species are too numerous. On the other hand, site protection aiming at
mollusc conservation could be quite easy, as tiny
pockets of relict habitat, which would be considered
as lost in a vertebrate conservation perspective, can
still harbour viable populations of endemic species
and thus deserve targeted actions. Fencing against
introduced herbivores and fire prevention would be
necessary to protect these sites.
Another obvious conservation measure is the public awareness and the enforcement of strict controls
at the harbours/airport to prevent the introduction
of Euglandina rosea and Achatina fulica, which currently are only known from Tubuai in the Austral
Islands. Raivavae's Samoana would certainly not
survive the introduction of Euglandina on this
island. Public education campaigns are essential to
inform the local populations about the disastrous
impact this could have on indigenous.
Figure 15 shows important areas for molluscan
conservation deserving protection:
Raivavae
1 - Gulley with natural forest (Metrosideros,
Hernandia, Psychotria) south of pass between Mt
Araua and Mt Hiro, type locality of Samoana oreas
(23.85902° S, 147.6568° W).
2 - Degraded forest (Thespesia, Celtis, Psidium,
Citrus) at the base of the cliff south of Anatonu,
type locality of Samoana hamadryas (23.85631° S,
147.64443° W).
3 - Gulley with natural Metrosideros SSW of Mt
Maunanui, type locality of Samoana dryas, with live
Samoana sp. (23.8658° S, 147.66493° W).
...
.. .....
A Global Overview of the Terrestrial and Freshwater Molluscs
RURUTU
TUBUAI
Te
a
Va
va
ta
i
M
P
HU
AIA
Cape Arei
RA
OE
Mt Puturani
12
I
Mt Taapanui
Ruahoina Mt Manureva
TAA
MATAURA
u
up
Mato Arei
Mt Taitaa
Peva Iti
Mt Teape
Huahine
Mt Rurutu
10
Mt Rereti
11
Mt Panee
12
AVERA
Turiarata
Mt Hanareho
Mt Erai
MAHU
HAUTI
Cape Toarepe
Mt Rairiri
12
ay
ti b
ria
Pa
500 1000 m
ANAPOTO
7
y
13
ba
0
RAPA
Pu
Oromana
oro
AMARU
9
Mt Perahu
RIMATARA
MUTUAURA
Mt Ruatara
8
Mt Namuere
Cape Pukitarava
Anarua bay
AREA
Haurei bay
RAIVAVAE
Mt Hiro
Mt Arua
Mt Maunanui
3
2
1
U
VAI
Hiri bay
Mt Turivao
6
HAUREI
Mt Maugaoa
RU
RAIRUA
Mt Matotea
4
Mt Taraia
5
Figure 15: Important areas for molluscan conservation in the Austral Islands. Dark grey: sites having priority. Light grey: sites of lesser
importance.
4 - Remnants of mesophilous Metrosideros SW of
Mt Matotea, with a live Samoana sp. population
(23.87589° S, 147.69399° W).
5 - Gulley on the northern slope of Mt Taraia, sole
locality for a new species of Sinployea (23.87817° S,
147.67085° W).
should protect it against grazing by horses, goats
and cattle (27.58104° S, 144.36634° W).
8 - Mt Perau, with its exceptional cloud forest.
9 - Cliff bottom of the Puoro bay still harbours a
littoral fauna, in particular with hydrobiids in small
resurgences.
Rapa
6 - Endemic live species were found in a rocky
area in Peupeu valley, which is otherwise very
degraded and covered with invasive species such
as Hedychium flavescens (Zingiberaceae) and pine
plantations. This particular location should be protected (27.6264° S, 144.34257° W).
7 - C. one hectare of semi-xerophilous forest remnants above Pariati bay, NE of Mt Pukumape still
has very localized live endemic species. Fencing
Tubuai
10 - The type locality of Microcystis saintjohni, NE
of Mt Pane. Very degraded (pine plantation with
a Psidium understorey), it still harbours the only
known population of this beautiful large species.
However, a single fire could wipe out the species
which managed to survive a drastic environmental
change (23.37405° S, 149.4776° W).
11 - River harbouring island endemic species of
hydrobiid, Fluviopupa tubuaia.
...
88
.......
Rurutu
12 - East coast "matos" (Mato Naa, and from Mato
Arei to Mato Toarutu) appear to be micro-centers
of endemism, with several Endodontidae species
restricted to these areas. They should be protected.
Moreover, Paparai area, in the south-east part of
the island, is an area of outstanding beauty, rich in
molluscs, which should be protected even if only
for tourism purposes.
Rimatara
13 - Rimatara native fauna has almost completely
disappeared. The northern "mato", where the airstrip­
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
was recently built, is the only area where a patch
of native vegetation remains (Meyer et al. 2005).
It is also there that we have found fresh shells of
an unknown Euconulidae, probably native. Last
but not least, a cave in this "mato" (22.63776° S,
152.80036° W) revealed several extinct species: it
represents a unique opportunity to study Rimatara
former fauna, which was much richer than today (at
least three endemic Endodontidae species new to science and a Partulidae different from Partula hyalina
have been found in cave deposits). For these reasons,
the areas south of the airstrip that have escaped
destruction should be given a protection status.
Table 15: Proposed or current IUCN status for Austral Island endemic mollusc species.
Proposed
IUCN
status
Island
Australdonta anneae
EX
Rurutu
Tubuaia voyana oromanaensis
Australdonta collicella
EX
Rurutu
Australdonta ectopia
EX
Rurutu
Name
Current
IUCN
status
Proposed
IUCN
status
Island
EX
Rimatara
Antonella pfeifferi
CR B1ab(iii)
Rapa
Antonella tenuis
CR B1ab(iii)
Rapa
Name
Current
IUCN
status
Australdonta florencei
EX
Rurutu
Antonella trochlearis
CR B1ab(iii)
Rapa
Australdonta magnasulcatissima
EX
Rurutu
Antonella trochlearis fusiforma
CR B1ab(iii)
Rapa
Australdonta microspiralis
EX
Rurutu
Antonella trochlearis nesiotica
CR B1ab(iii)
Rapa
Australdonta oheatora
EX
Rurutu
Antonella trochlearis radicula
CR B1ab(iii)
Rapa
Australdonta pakalolo
EX
Rurutu
Antonella trochlearis trochlearis
CR B1ab(iii)
Rapa
Australdonta pharcata
EX
Tubuai
Apopitys andersoni
CR B1ab(iii)
Rapa
Australdonta rimatarana
EX
Rimatara
Australdonta magnasulcata
CR B1ab(iii)
Rurutu
Australdonta sibleti
EX
Rurutu
Australdonta radiella rurutuensis
CR B1ab(iii)
Rurutu
Australdonta sulcata
EX
Rurutu
Australdonta raivavaeana
CR B1ab(iii)
Raivavae
Australdonta teaae
EX
Rurutu
Australdonta yoshii
CR B1ab(iii)
Rurutu
Australdonta tubuaiana
EX
Tubuai
Celticola arborea
CR B1ab(iii)
Rapa
Cookeana anathesis
EX
Tubuai
Celticola arborea arborea
CR B1ab(iii)
Rapa
Cookeana vindex
EX
Tubuai
Celticola arborea sororcula
CR B1ab(iii)
Rapa
Electrina succinea
EX
Rapa
Celticola conoides
CR B1ab(iii)
Rapa
Electrina succinea succinea
EX
Rapa
Celticola pilsbryi
CR B1ab(iii)
Rapa
Electrina succinea orites
EX
Rapa
Celticola pilsbryi incerta
CR B1ab(iii)
Rapa
Lamprocystis rurutuana
EX
Rurutu
Celticola pilsbryi latior
CR B1ab(iii)
Rapa
EX
Raivavae
Celticola pilsbryi pilsbryi
CR B1ab(iii)
Rapa
Microcystis adusta
EX
Tubuai
Celticola pilsbryi proxima
CR B1ab(iii)
Rapa
Microcystis andersoni
EX
Tubuai
Elasmias ovatum
CR B1ab(iii)
Rapa
Microcystis kondoi
EX
Tubuai
Elasmias ovatum exiguum
CR B1ab(iii)
Rapa
Minidonta anatonuana
EX
Raivavae
Elasmias ovatum ovatum
CR B1ab(iii)
Rapa
Minidonta bieleri
EX
Rurutu
Fluviopupa crassiuscula
CR B1ab(iii)
Rapa
Mautodontha ceuthma
CR A1c
Minidonta boucheti
EX
Rurutu
Minidonta gravacosta
EX
Raivavae
Fluviopupa jeanyvesi
Minidonta haplaenopla
EX
Rurutu
Fluviopupa tubuaia
Minidonta micraconica
EX
Raivavae
Hiona orbis
Minidonta planulata
EX
Raivavae
Kondoconcha othnius
Minidonta sulcata
EX
Raivavae
Lamellovum auricullela
Fluviopupa deflexa
89
...
DD
CR B1+2abcd
CR B1ab(iii)
Rapa
CR B2ab(ii, iii)
Raivavae
CR B2ab(ii, iii)
Tubuai
CR B1ab(iii)
Rapa
CR B1ab(iii)
Rapa
CR B1ab(iii)
Rapa
A Global Overview of the Terrestrial and Freshwater Molluscs
Proposed
IUCN
status
Island
Lamellovum costata
CR B1ab(iii)
Rapa
Lamellovum globosum
CR B1ab(iii)
Lamellovum leptospira
Lamellovum solitaria
Name
Current
IUCN
status
.. .....
Proposed
IUCN
status
Island
Philonesia tenuior
CR B1ab(iii)
Rapa
Rapa
Philonesia tenuior karaporahi
CR B1ab(iii)
Rapa
CR B1ab(iii)
Rapa
Philonesia tenuior tenuior
CR B1ab(iii)
Rapa
CR B1ab(iii)
Rapa
Philonesia zimmermani
CR B1ab(iii)
Rapa
Name
Current
IUCN
status
Lamprocystis vitrinella rapana
CR B1ab(iii)
Rapa
Philonesia zimmermani tautautui
CR B1ab(iii)
Rapa
Mangaoa perissa
CR B1ab(iii)
Rapa
Philonesia zimmermani zimmermani
CR B1ab(iii)
Rapa
Microcystis benesculpta
CR B1ab(iii)
Rapa
Pitys alpestris
CR B1ab(iii)
Rapa
Microcystis fosbergi
CR B1ab(iii)
Raivavae
Pitys pagodiformis
CR B1ab(iii)
Rapa
Microcystis fosbergi fosbergi
CR B1ab(iii)
Raivavae
Pitys scalaris
CR B1ab(iii)
Rapa
Microcystis fosbergi taraiae
CR B1ab(iii)
Raivavae
Pukunia acuta
CR B1ab(iii)
Rapa
Microcystis ornatella
CR B1ab(iii)
Rapa
Pukunia margaritae
CR B1ab(iii)
Rapa
Microcystis ornatella ornatella
CR B1ab(iii)
Rapa
Pukunia pellucida
CR B1ab(iii)
Rapa
Microcystis ornatella parva
CR B1ab(iii)
Rapa
Rapanella andersoni
CR B1ab(iii)
Rapa
Microcystis perahui
CR B1ab(iii)
Rapa
Rhysoconcha atanuiensis
VU D2
CR B1ab(iii)
Rapa
Microcystis saintjohni
CR B1ab(iii)
Tubuai
Rhysoconcha variumbilicata
CR A2e B1+2c
CR B1ab(iii)
Rapa
Mitiperua simplex
CR B1ab(iii)
Rapa
Ruatara koarana
CR A2e B1+2c
CR B1ab(iii)
Rapa
VU D2
Mitiperua simplex convexior
CR B1ab(iii)
Rapa
Ruatara oparica
CR B1ab(iii)
Rapa
Mitiperua simplex simplex
CR B1ab(iii)
Rapa
Ruatara oparica normalis
CR B1ab(iii)
Rapa
Mitiperua simplex subcostata
CR B1ab(iii)
Rapa
Ruatara oparica oparica
CR B1ab(iii)
Rapa
Omphalotropis albescens
CR B1ab(iii)
Rapa
Ruatara oparica reductidenta
CR B1ab(iii)
Rapa
Omphalotropis dubia
CR B1ab(iii)
Rapa
Samoana dryas
CR B2ac(ii,iii)
CR B1ab(iii)
Raivavae
Omphalotropis pupoides
CR B1ab(iii)
Rapa
Samoana hamadryas
CR B2ab(ii,iii)
CR B1ab(iii)
Raivavae
VU D2
CR B1ab(iii)
Rapa
CR B2ab(ii,iii)
CR B1ab(iii)
Raivavae
Opanara altiapica
CR B1+2abc
CR B1ab(iii)
Rapa
Samoana margaritae
Opanara areaensis
CR A2e B1+2c
CR B1ab(iii)
Rapa
Samoana oreas
Opanara areaensis areaensis
CR B1ab(iii)
Rapa
Strobilus acicularis
CR B1ab(iii)
Rapa
Opanara areaensis densa
CR B1ab(iii)
Rapa
Strobilus acicularis acicularis
CR B1ab(iii)
Rapa
Opanara areaensis microtorma
CR B1ab(iii)
Rapa
Strobilus acicularis raphis
CR B1ab(iii)
Rapa
Opanara bitridentata
CR A2e B1+2c
CR B1ab(iii)
Rapa
Strobilus brevis
CR B1ab(iii)
Rapa
Opanara caliculata
CR A2e B1+2c
CR B1ab(iii)
Rapa
Strobilus brevis brevis
CR B1ab(iii)
Rapa
Opanara depasoapicata
CR A2e B1+2c
CR B1ab(iii)
Rapa
Strobilus brevis pumilus
CR B1ab(iii)
Rapa
Opanara duplicidentata
CR A2e
CR B1ab(iii)
Rapa
Strobilus brevis subsimilis
CR B1ab(iii)
Rapa
Opanara fosbergi
CR A2e B1+2c
CR B1ab(iii)
Rapa
Strobilus opeas
CR B1ab(iii)
Rapa
Opanara megomphala
CR A2e B1+2c
CR B1ab(iii)
Rapa
Strobilus opeas intermedius
CR B1ab(iii)
Rapa
Opanara megomphala megomphala
CR B1ab(iii)
Rapa
Strobilus opeas opeas
CR B1ab(iii)
Rapa
Opanara megomphala tepiahuensis
CR B1ab(iii)
Rapa
Strobilus perfragilis
CR B1ab(iii)
Rapa
Opanara perahuensis
CR A2e B1+2c
CR B1ab(iii)
Rapa
Strobilus subtilis
CR B1ab(iii)
Rapa
Orangia cookei
EN A2e B1+2c
CR B1ab(iii)
Rapa
Strobilus subtilis similaris
CR B1ab(iii)
Rapa
Orangia cookei cookei
CR B1ab(iii)
Rapa
Strobilus subtilis subtilis
CR B1ab(iii)
Rapa
Orangia cookei montana
CR B1ab(iii)
Rapa
Strobilus turritus
CR B1ab(iii)
Rapa
CR B1ab(iii)
Rapa
Strobilus turritus basalis
CR B1ab(iii)
Rapa
Orangia maituatensis
CR A2e B1+2c
CR B1ab(iii)
Rapa
Strobilus turritus turritus
CR B1ab(iii)
Rapa
Orangia sporadica
EN A2e B1+2c
CR B1ab(iii)
Rapa
Tornatellina bilamellata
CR B1ab(iii)
Rapa
Perahua bakeri
CR B1ab(iii)
Rapa
Tornatellinops concolorans
CR B1ab(iii)
Rapa
Perahua grandis
CR B1ab(iii)
Rapa
Tubuaia cremnobates
CR B1ab(iii)
Rapa
Orangia cookei tautautuensis
...
90
.......
Proposed
IUCN
status
Island
Tubuaia cylindrata
CR B1ab(iii)
Rapa
Tubuaia cylindrata cylindrata
CR B1ab(iii)
Rapa
Tubuaia cylindrata philolichen
CR B1ab(iii)
Rapa
Tubuaia inconstans
CR B1ab(iii)
Name
Current
IUCN
status
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Proposed
IUCN
status
Island
Lamprocystis vitrinella vitrinella
DD
Rurutu
Omphalotropis subimperforata
DD
Rimatara,
Rurutu
Rapa
Punctum polynesicum
DD
Tubuai,
Raivavae
Name
Current
IUCN
status
Tubuaia voyana rapaensis
CR B1ab(iii)
Rapa
Helicina minuta
DD
Rurutu
Tubuaia voyana teutuensis
CR B1ab(iii)
Rapa
Taitaa arauana
DD
Tubuai
VU D2
Rurutu
Taitaa dacryma
DD
Tubuai
Australdonta radiella
VU D2
Rurutu,
Tubuai
Taitaa neanica
DD
Raivavae
Australdonta radiella radiella
VU D2
Tubuai
Fluviopupa raivavaeensis
VU D2
Raivavae
Fluviopupa rurutua
VU D2
Rurutu
Microcystis aspera
VU D2
Raivavae
Microcystis lenticula
VU D2
Raivavae
Omphalotropis curta
VU D2
Rurutu
Helicina villosa
VU D2
Rapa
Australdonta tapina
DD
Rurutu
Celticola anatonuensis
DD
Raivavae
Diastole rurutui
DD
Rurutu,
Raivavae
Elasmias amphodon
DD
Rurutu
Elasmias simplicinum
DD
Raivavae,
Rapa
Lamprocystis punctifera
DD
Rurutu
DD
Rurutu,
Rapa
Australdonta pseudplanulata
Lamprocystis vitrinella
91
Taitaa striatula
DD
Rurutu
Taitaa terebriformis
DD
Raivavae
Taitaa zimmermani
DD
Tubuai
Tubuaia affinis
DD
Rurutu
Tubuaia amoebodonta
DD
Rurutu
Tubuaia bakerorum
DD
Rurutu
Tubuaia coprophora
DD
Rurutu
Tubuaia coprophora coprophora
DD
Rurutu
Tubuaia coprophora diminuta
DD
Rurutu
Tubuaia hygrobia
DD
Raivavae
Tubuaia myojinae
DD
Raivavae
Tubuaia saintjohni
DD
Raivavae
Tubuaia voyana manurevae
DD
Rurutu
Tubuaia voyana matonaaensis
DD
Rurutu
Tubuaia voyana turivaoensis
DD
Raivavae
Tubuaia voyana vaiaunanae
DD
Raivavae
...
Rhyncogonus sp., Raivavae, March 2008 (Photo J.-Y. Meyer).
...
92
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Insects
and Spiders
Elin M. Claridge, Jessica E. Garb, Rosemary G. Gillespie & Diana M. Percy
Here we examine patterns of terrestrial arthropod diversity in the Austral
Islands. This group of isolated volcanic islands, in the southeastern
Pacific, represents one of the most
remote archipelagos in the world. The
islands formed as the result of midplate volcanism and have no historical
connections with continental landmasses, thus all elements of the fauna
must have colonized these islands by
long distance dispersal from one of the neighboring
island chains or continental regions.
Such extreme isolation means that the rate of
immigration is frequently much lower than the
rate of species generation by evolutionary processes, this effect, combined with the availability
of ecological space on these islands can promote
adaptive radiation. Despite this apparent potential for adaptive radiation, the Austral Islands are
not widely regarded as a crucible of biodiversity
and evolutionary novelty, as compared with the
Hawaiian Islands, for instance. There are several
reasons why this may be the case:
• The Austral Islands are much smaller and
have a lower relief than the Hawaiian chain
— the collective area of the archipelago is just
146.8 km2, less than one seventieth of the area
of the Big Island of Hawaii alone; the highest
peak is Mt Perau on Rapa which is just 650 m,
Mauna Kea on Hawaii is a lofty 4 169 m, by comparison. Both area and elevation have long been
understood to limit the absolute diversity of
organisms that can occur on any given landmass
(Macarthur & Wilson 1963; Peck et al. 1999).
• The Austral Islands have been little studied in comparison to the Hawaiian Islands.
Collecting expeditions and systematic studies
on terrestrial arthropods are patchy. The Pacific
Entomology Survey, sponsored by the Bernice
P. Bishop Museum, Hawaii, the California
Academy of Sciences, San Francisco and the
University of California, Berkeley, visited the
Austral Islands in 1934 and the St. George
Expedition sponsored by the British Museum,
London, also visited the island of Rapa in the
Australs during its time in French Polynesia in
1925. These expeditions did collect a substantial number of insects and spiders, but were by
no means exhaustive and it is clear that some
taxonomic groups were largely overlooked. The
major systematic works on Austral Islands taxa
all focus largely on the island of Rapa and
include those of Zimmerman (1938) and later
Paulay (1985)'s work on cryptorhychine weevils, Clarke (1971)'s extensive study of the
Lepidoptera, and Berland (1934, 1942) and
more recently Ledoux & Hallé (1995)'s work
on the spider fauna.
• Lastly, the islands have been profoundly
impacted by human-disturbance. Despite the
fact that early Polynesians only colonized these
islands within the last several hundred years, this
has been sufficient time for their vegetation to
be radically modified by habitat destruction for
agriculture, grazing and the introduction of nonindigenous species. Anthropogenic impacts may
be particularly pronounced in this archipelago
due to its small size and low elevation.
Each of these factors likely contributes to the
apparent depauperacy of the Austral Islands terrestrial arthropod fauna.
Terrestrial arthropod groups from the Austral Islands
can be categorized as indigenous and non-indigenous. The latter represents introduced species that
were transported to the islands by humans, intentionally or otherwise, and includes several notable
agricultural pests. Undoubtedly there are other species that were introduced by early Polynesian settlers, but these may not be as easily identified as
recently introduced species. Within the indigenous
species category there are widespread species, which
occur more broadly across the Pacific and endemic
species, which may be endemic to island groups, a
single island or even just a single mountain-top or
valley. This latter category, termed narrow endemics
hereafter, is of greatest interest to evolutionary biologists, as their study allows insights into the processes
driving lineage diversification on these islands.
INtroduced species
The Austral Islands are host to a suite of nonindigenous, recently introduced species that are
­agricultural pests or are highly invasive. Introduced
93
species may pose a significant threat to indigenous
species in the Austral Islands: many prefer disturbed habitats, and occupy these in preference
...
Insects and Spiders
.. .....
is present in the Austral Islands, and it seems likely
that this will effectively control the sharpshooter
population there.
……Pantomorus cervinus (Coleoptera,
Homalodisca vitripennis (Photo J. Grandgirard).
to indigenous species; some may even displace
natives directly through competition or predation
as has been found in Hawaii (Krushelnycky et
al. 2005). The following is not an exhaustive list
of introduced species which occur in the Austral
Islands, but it does outline some of the major
groups of concern that were found to have reached
significant densities and therefore are considered to
be potentially problematic.
……Homalodisca vitripennis (Hemiptera,
Cicadellidae)
The Glassy-winged sharpshooter, Homalodisca vitripennis (senior synonym of Homalodisca coagulata,
Takiya et al. 2006) is among one of the most recent
documented introductions to the Austral Islands.
It was first recorded in French Polynesia in July
1999 (SPC 2002) and more recently arrived in
both Rurutu and Tubuai (official records date from
January 2005, but population densities suggest that
the species has been present in Rurutu for longer,
Petit et al. 2008). In continental America the species poses a serious economic threat to wine-growing regions because it is a vector of Pierce's disease
(Xyllella fastidiosa) a pathogen of grapevines. In
French Polynesia, it is unclear that H. vitripennis is
anything more than a nuisance due to the quantities of "honeydew" that it produces and its remarkably high population densities (Grandgirard et al.
2006). There is no evidence, as yet, to suggest that
it is a vector of plant disease in French Polynesia
nor that it is able to displace indigenous cicadellids,
though there is some suggestion that the species
may be toxic to spiders (Suttle & Hoddle 2006).
A recent biocontrol program has been extremely
efficient at controlling population densities in the
Society Islands, with as much as 95 % reduction in
population densities in the Australs, Societies and
Marquesas (Grandgirard et al. 2009). The biocontrol agent Gonatocerus ashmeadi, an egg parasitoid,
...
Curculionidae)
Fuller's rose weevil, Pantomorus cervinus (also
widely known by its junior synonym Asynonychus
godmani) was collected from Rapa in the Austral
Islands, the only other records from French
Polynesia being from Mt Marau in Tahiti. This weevil species, which originates from South America, is
an economic pest of citrus in continental America.
It was first recorded as a pest in California in 1879
and has subsequently spread throughout Europe,
Africa, Asia and Australasia (Chadwick 1965). In
the Pacific it has been recorded from Hawaii and
Easter Island (Woodruff & Bullock 1979). It may
have been introduced to French Polynesia on the
root-stocks of domestic roses or more likely citrus — oranges are grown both on Rapa and in the
Punaruu valley below Mt Marau, Tahiti.
……Bactrocera xanthodes (Diptera,
Tephritidae)
In French Polynesia there are four introduced species of tephritid fruit flies that are of economic
importance. One of these, the Pacific fruit fly
Bactrocera xanthodes, is restricted to the Austral
Islands (SPC 2002). Its presence has had an impact
on the local economy because of the restriction of
untreated citrus fruit exports from infested islands
to Tahiti. Eradication programs are in place to control this pest as well as the other Bactrocera species
found in French Polynesia, but as yet, they have
been unsuccessful in achieving complete eradication (SPC 2000, 2002).
Kallitaxila sinica (Photo J. Grandgirard).
94
.......
……Kallitaxila sinica (Hemiptera,
Tropiduchidae)
The tropiduchid planthopper, Kallitaxila sinica,
was recorded from Tubuai, Rurutu and Rimatara
at high densities feeding on a wide variety of host
plants including taro (Aracaceae) and Hibiscus tiliaceus (Malvaceae).
……Sophonia orientalis (Hemiptera,
Cicadellidae)
The Two-spotted leafhopper Sophonia orientalis (also
widely known by its synonym Sophonia rufofascia,
Webb & Viraktamath 2004) is an agricultural pest that
occurs in the Society, Marquesas and Austral Islands.
It was collected in Rurutu, Tubuai and Rimatara during the survey. The species is highly polyphagous
and in Hawaii feeds on a wide range of agriculturally
important and indigenous plant species. Feeding
damage can cause chlorosis, browning and has been
implicated in the dieback of Metrosideros polymorpha
(Myrtaceae) in Hawaii (Lenz & Taylor 2001).
……Nezara viridula (Hemiptera,
Pentatomidae)
The Southern green stinkbug Nezara viridula is a
highly polyphagous agricultural pest that is broadly
distributed across the globe, including Hawaii, New
Zealand and Australia in the Pacific. The species is
believed to have originated in Ethiopia and it is a
major pest of crops such as cotton and soybean. In
Hawaii, it is estimated that this species causes more
than US$ 6 million of damage to Macadamia nut crops
annually (Golden et al. 2006). Consequently, the species is a focus of numerous biocontrol programs.
Nezara viridula (Photo J. Grandgirard).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
R. Englund recorded the species from Rurutu in 2003,
but not elsewhere in the Australs. It does not appear
to be a major threat to the local agroeconomy, but it
should be treated as a species of concern. Biocontrol
measures targeted at this species should only be
approached with care as it has been demonstrated
that parasitoids introduced to control Nezara viridula
in Hawaii have also been targeting an endemic species, Coletichus blackburniae, the Koa bug (Hemiptera,
Scutellaridae) (Johnson & Follett 2005). This is particularly pertinent as R. Englund also collected specimens of a new endemic species of Coletichus from
Rurutu and Raivavae, further endemic species are also
known to occur in Tahiti and the Marquesas.
……Cheiracanthium mordax (Araneae,
Miturgidae)
The Long-legged sac spider Cheiracanthium mordax,
a native of Australia (Dondale 1966) was found to
occur throughout the Austral Islands and is also
known to have recently invaded Hawaii (Nishida
2002), and much of the insular Pacific. It is considered to be an agricultural pest when it infests
agricultural crops in high densities in the US, primarily because it limits the export value of these
crops. The species has also been shown to feed on
indigenous arthropod species in Hawaii (Louda et
al. 2003; R. Gillespie unpublished data).
……Heteropsylla cubana (Hemiptera,
Psyllidae)
The Leucaena psyllid, Heteropsylla cubana, native to
Central and South America, occurs throughout the
Pacific where it is found on the introduced legume,
Leucaena leucocephala (Mimosoidea). In the Austral
Islands both introduced legume and psyllid are
present, and the psyllid reaches high densities in
some locations. Of some concern on Rurutu is that
the Leucaena psyllid can also be found on a native
legume closely related to Leucaena, Schleinitzia
insularum, and where this native legume grows
in proximity to Leucaena numbers of H. cubana
were found to be high (D. Percy pers. obs. 2003).
The presence of this species is considered problematic where Leucaena is valued for agroforestry
(e.g. Indonesia, and Africa), but in areas where the
host plant is considered invasive, H. cubana may be
effective as a biological control agent. The Leucaena
psyllid can cause severe damage to the host plant,
but initially the extent of the infestation may not be
apparent because during early stages young shoots
rather than mature leaves are worst affected.
widespread indigenous species
There are many widely distributed terrestrial arthropod species that occur broadly across the Pacific.
These species are sufficiently dispersive to have
been able to colonize the Austral Islands without
95
the aid of humans and do not appear to have diversified within islands. Lack of diversification could
be explained as the result of:
• continued gene flow between islands,
...
.. .....
Insects and Spiders
Table 16: Pairwise genetic distances between islands of
the Australs for Tangaroa tahitiensis based on COI mtDNA
sequence data.
Moorea
Rurutu
Rurutu
Raivavae
Rapa
7 %
8-9 %
8 %
7 %
5-6 %
Raivavae
6RapaVaVai
1RapaPer
4Rapa23Mg1
5Rapa23Mg2
13RapaMaung
Rapa
10Raivavae
14Raivavae
Raivavae
2RurutuMoe
3RurutuMoe
9RaivavaeHiro
4 %
Rurutu
Moorea7.txt
Moorea8.txt
Moorea
UlobTubTam6B
UlobTubuai6B
• constraints maintaining morphological stasis,
• recent colonization.
Each of these scenarios is testable, given some
molecular phylogenetic data. In the first case, populations on islands should show genetic variation
that is shared between islands, so there should be
genetic variation but no geographic structure. In
the second case we would expect to see variation
and geographic structure in genetic data. In the
third case there may have been insufficient time for
diversification, in which case there should be no or
very little genetic variation between populations.
Here we present three examples of widespread species, for which some molecular data exists.
……Tangaroa tahitiensis (Araneae,
Uloboridae)
This species is endemic to the Austral and Society
Islands. Other species in the genus Tangaroa are
T. dissimilis from New Caledonia and Vanuatu
UlobVLAbaca30m A07
UlobVLAbaca30 A08
Tangaoa
tahitiensisSociety &
Austral Islands
Tubuai
Viti Levu
Daramuliana
tenellaFiji Islands
Hyptiotes gertchi
5 changes
Figure 16: Molecular phylogenetic tree for Tangaroa tahitiensis.
See Table 16 for distance estimates.
and T. beattyi from the Caroline Islands (Opell
1983). The affinities of Tangaroa species outside
the Pacific region (or between the islands of the
Pacific) are unknown. However, Tangaroa species each occur broadly across islands within the
region where they are found. Molecular analysis
using mitochondrial COI gene sequences demonstrates that specimens of T. tahitensis from three
different islands in the Australs group are highly
differentiated genetically from each other, populations from Rapa being separated by large distance
Figure 17: Phylogenetic analysis of Misumenops rapaensis.
A - Strict consensus of 36 equally parsimonious trees retained from a parsimony tree search based on additional COI data
(738 base pairs). Numbers above nodes refer to bootstrap support values from 1 000 replicates, numbers below nodes refer to
decay index values.
B - One of three trees retained from ML analysis of COI data, numbers above branches refer bootstrap values from 100 replicates.
...
96
.......
from those on Rurutu and Raivavae (Fig. 16,
Table 17). There appears to have been a geographic progression in how the islands have been
colonized, from the oldest island of Rurutu, to
the youngest island of Rapa (Fig. 16). However,
divergence times between different island lineages
estimated using the universal rate of arthropod
mtDNA pairwise divergence, 2.3 % per million
years (Brower 1994), suggests that this progression does not fit the geological ages of the islands
and implies a more recent colonization of the
islands from west to east. Lack of morphological
diversification here does not appear to be a result
of continued gene flow or a recent colonization of
the Austral Islands.
……Misumenops rapaensis (Araneae:
Thomisidae)
Thomisids in the Austral Islands are also represented by a single endemic, but widespread, species, Misumenops rapaensis. This species occurs
throughout the archipelago (Berland 1934, 1942)
and, despite the separation of the islands, Berland
(1942) stated that across the different islands,
M. rapaensis possesses no discernable morphological differences. A more recent taxonomic treatment by Ledoux & Hallé (1995) concluded that
the species represented an endemic element of
the archipelago with no differentiation between
the islands, possibly due to inter-island migration. In addition to occurring widely across the
islands, M. rapaensis appears common at both
low and high elevation collecting sites. Molecular
analysis of mitochondrial sequence data (Garb &
Gillespie 2006) indicate that despite their lack of
observable morphological differentiation, populations of M. rapaensis occurring on different islands
are genetically distinct and likely represent an
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
indigenous component of each island's terrestrial
fauna (Fig. 17). Again scaling the level of genetic
distance exhibited between these two islands to
Brower's (1994) rate of arthropod mitochondrial
pairwise sequence divergence (2.3 % per million
years), would suggest that the lineages restricted
to Rurutu and Tubuai diverged approximately 3.7
million years ago. Thus, rather than current gene
flow or recent colonization, the apparent lack
of morphological differences between these two
islands could be attributed to constraints maintaining morphological stasis across these islands,
or simply lack of ecological opportunity for diversification.
In the examples above, there is evidence of geographic structure between different islands, which
is a little unexpected in taxa that do not exhibit any
notable morphological differentiation. It would be
interesting to extend the study of broad endemics to include highly dispersive taxa, such as the
­dragonfly Pantala flavescens (Odonata: family),
which has a very broad distribution and is an active
flier, to establish whether some species undergo
significant gene flow between islands in the Pacific.
Another interesting example of a broadly dispersed species is the psyllid, Mesohomotoma hibisci
(Carsidaridae). This species occurs throughout the
Pacific, including the Austral Islands, on its host
plant Hibiscus tiliaceus. There is some debate about
whether H. tiliaceus is naturally widespread — it
is a common element of low elevation forests in
the Austral and other Pacific islands — or whether
Polynesians introduced or augmented the distribution range of this plant and thereby in the process
increased the distribution of the psyllid. Analysis of
molecular divergence in M. hibisci could be used to
test these scenarios.
Narrow endemics
The Austral Islands have been less studied than
many other Pacific archipelagos thus far, and
because of their small size and the heavy impacts
of human modification, they might not be expected
to host a substantial endemic arthropod fauna.
Nevertheless, levels of endemicity are extremely
high if the small island area is taken into account.
Here we discuss several groups that appear to
exhibit high levels of endemicity. Further groups of
interest that require further study and more rigorous collections are also identified.
……Miocalles spp. (Coleoptera,
Curculionidae, Cryptorhynchinae)
The cryptorhynchine genus Miocalles occurs throughout French Polynesia and across the western Pacific
to New Zealand and Australia. Astonishingly, however, the centre of diversity for this genus lies on the
97
island of Rapa, where there are currently 67 described
species (Paulay 1985) occurring on an island that is a
mere 40 km2, that is a species density of 1.67 species/
km2 (as compared with 0.06 species/km2 for the celebratedly diverse Hawaiian Drosophilidae, of which
there are an estimated 1 000 species in the Hawaiian
archipelago). Miocalles from Rapa was even proposed to be a possible example of adaptive radiation,
though preliminary molecular work appears to support Paulay (1985)'s assertion that the group could
represent multiple independent colonizations of the
island (E. Claridge unpublished data). Nevertheless,
there is evidence that each of the lineages on Rapa has
undergone dramatic morphological and ecological
shifts associated with adaptation to host-plant preference and oviposition site. Collectively, the genus
feeds on 24 genera of indigenous plants on the island,
which represents the vast majority of the indigenous
...
.. .....
Insects and Spiders
154°W
152°W
150°W
148°W
147°W
146°W
RURUTU (0.125)
MARIA
R. debilis
R. excavatus
R. hispidus
R. tenebrosus
RAIVAVAE (0.222)
R. nigerrimus
R. sp. 1
R. sp. 2
R. sp. 3
22°S
RIMATARA (0.069)
R. rufulus
Tropic of Capricorn
TUBUAI (0.067)
R. longulus
R. nodosus
R. obscurus
RAPA (0.275)
24°S
26°S
0
200 miles
0
200 kilometres
Pacific Ocean
R. aeneus
R. angustus
R. erebus
R. expansus
R. gracilis
R. interstitialis
R. omus
R. pleuralis
R. pubipennis
R. regularis
R. viridescens
R. sp. "tarakoi"
MAROTIRI (5.00)
R. variabilis
R. zimmermani
Figure 18: The distribution of Rhyncogonus species in the Austral Islands, including all described species and four previously
undescribed species. The density of species (sp / km2) is shown in parentheses for each island.
vegetation. There are also a further nine endemic species that have been described from other islands in
the Australs (Zimmerman 1938), not including a previously undescribed species collected on Allophyllus
rhomboidalis (Sapindaceae) by Elin Claridge during
the Austral Islands Biodiversity Survey of Rimatara in
2004 (Claridge 2006).
be ecological (Claridge 2006). These Broad-nosed
weevils are not host-specific to the same degree as
Miocalles. Molecular work also suggests that the
Austral Islands lineage has been present in the
……Rhyncogonus spp. (Coleoptera,
Curculionidae, Entiminae)
The Broad-nosed weevil genus Rhyncogonus has
also undergone considerable diversification in the
Austral Islands. There are a total of 20 species
described from the Australs (Van Dyke 1937), with
a further three new species collected on the island
of Raivavae in 2002 and another species collected
from Rapa by G. Paulay in 1980. The distribution
and density of species diversity across the Australs
is shown in figure 18. Rapa is host to the highest
species diversity in the archipelago, with 11 of
the described species endemic to the island and a
further two collected from Marotiri, a nearby uninhabited islet. Molecular phylogenetic work demonstrates that the Rapan species of Rhyncogonus
form a monophyletic unit with an age consistent
with the geological age of Rapa, suggesting that it
represents an island radiation, though the cause
of this radiation is not clear, it does not appear to
...
Rhyncogonus nigerrimus, Raivavae, March 2008
(Photo J.-Y. Meyer).
98
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
region for the last 10 Myr, at least. This is consistent with the known geological age of the Austral
Islands (Dickinson 1998).
…
…Paro spp. (Araneae: Linyphiidae)
The linyphiid spider genus Paro (which has been
proposed as a junior synonym of Laetesia, G.
Hormiga pers. comm.) is confined to the summit
area of Mt Perau on Rapa, where it builds flimsy
sheet webs low down in the vegetation. To date, the
only described species from Rapa has been P. simoni
(Ledoux & Hallé 1995). However, comparison of
the male palp among the specimens collected in
the field in 2002 show that there are only a few
specimens that match the morphology of P. simoni.
Others are quite distinct in palpal morphology,
coloration and leg spination. This may represent a
previously unknown case of radiation on the island
of Rapa. Little is known of the ecological habits of
these different morphotypes, but it will be the subject of future research.
A number of other groups have endemic species
that occur in the Australs, but in most cases the
group is not yet sufficiently well known, the systematic work has not yet been carried out, or they
may be represented by just a small number of species. These groups include hemipteran groups, such
as nabids, reduviids, scutellerids, and fulgoroid
hoppers in the Delphacidae and Issidae. Members
of the psyllid genus Trioza (Hemiptera: Triozidae)
that feed on the plant genus Metrosideros, which
is widely distributed in the Pacific, have undergone endemic island radiations in the Society and
Marquesas Islands, but only one endemic member
of this group, T. zimmermani, is currently known
from the Austral Islands, and it is only known
from Tubuai. Three other psyllid genera found in
Trioza zimmermani (Hemiptera, Triozidae)
nymphs are found in pit galls on leaves of
Metrosideros collina. This psyllid is currently
only known from Tubuai (Photo D.M. Percy).
the Australs are also each represented by a single
endemic species found on one island only, including a monotypic genus, Anomocephala, endemic to
Rapa (Tuthill 1942).
Narrow endemic species are also a conservation
priority, by definition, because of their uniqueness
and their narrow distribution — they are readily
threatened by habitat loss or by competition with,
or predation by, introduced species.
Discussion
Having outlined some of the terrestrial groups
that are present in the Australs we will now discuss some of the common biogeographic patterns
shown by the indigenous species that occur there.
…
…Western origins
A prevailing view concerning the biogeographic
origins of Polynesian biotas is that the vast majority of taxa have colonized these remote islands
from the west, using intermediate islands as stepping-stones (Gressitt 1956; Miller 1996). For the
Uloboridae, origins cannot be determined: The
small genus Tangaroa (three species) which was
established based on morphological criteria has
— outside French Polynesia — been found only
in New Caledonia and New Hebrides, and the
Caroline Islands (Opell 1983), suggesting origination from the west; however its relationships
99
to other genera in the family are unknown. For
the Thomisidae, Lehtinen (1993) argued that the
Polynesian fauna originated from two opposing
directions, one being from the New World, giving
rise to the Misumenops and Mecaphesa spiders of
Hawaii, the Society Islands, and the Marquesas,
and the other direction being from Melanesia, giving rise to the widespread Diaea found in Tonga,
Samoa and Fiji. Molecular work on the Pacific
Thomisidae (Fig. 19) shows that the Hawaiian
and Society Islands Thomisidae in the genus
Misumenops are allied, while Misumenops rapaensis
is nested within the genus Diaea (Garb & Gillespie
2006). Thus, an eastern origin is inferred for the
single (monophyletic) lineage found from Hawaii
to the Marquesas and Societies, while a western
origin is inferred for the widespread representative,
M. rapaensis, in the Austral Islands. Interestingly,
...
Insects and Spiders
.. .....
Figure 19: Phylogram of one of three retained ML trees for Pacific Thomisidae (Garb & Gillespie 2006). Additional trees only differ in
arrangement of taxa within the Hawaiian clade. Numbers above nodes indicate ML bootstrap replicate values from 100 replicates. M.
rapaensis outlined in gray box; letters after Hawaiian taxa indicate distribution of species as follows: N = Necker, K = Kauai, O = Oahu,
M = Maui, H = Hawaii.
the lineages do not overlap; rather, their ranges
abut between the Australs and Societies. In a similar manner, molecular data for the Pacific psyllids show that the Austral member of the genus
Trioza, together with members from the Societies
and Marquesas, have a western origin initiating
from Australasia. However, two other monotypic
psyllid species found in the Australs appear to
have sister taxa in either the Hawaiian Islands or
the neotropics (D. Percy unpublished data). For
Rhyncogonus weevils, both molecular and morphological work suggest that the genus is nested within
a sister tribe which occurs throughout the western Pacific and appears to represent the ancestral
lineage that pre-dates the origin of Rhyncogonus
(Claridge 2006). The distribution of diversity in
Miocalles is also consistent with western affinities,
though the centre of diversity is in fact on Rapa in
the Australs. The hypothesized western origins of
the Pacific biota appear to hold true for the Austral
Islands arthropods, as far as we know at this point,
though it has become increasingly apparent that
the Hawaiian Islands have received colonists from
continental America and that the same is probably
true — though to a much lesser extent — of the
Marquesas and the Societies.
……
Sequential colonization of islands
Colonization in the direction of younger islands has
been documented repeatedly in the Hawaiian Islands,
and is a general pattern seen in hotspot island chains.
It is explained as a consequence of the increased
success of establishment on younger islands, where
ecological opportunity is likely to be more readily
. . . 100
.......
available (Gillespie 2002). For the Austral Islands,
the progression rule and absolute geological ages
of islands would predict a pattern of phylogenetic
progression in the following order: Rimatara, Rurutu,
Tubuai, Raivavae, then Rapa. The topology of the
phylogenetic pattern consistent with this prediction is (Rurutu (Tubuai (Raivavae (Rapa)))), with
older islands appearing in successively more basal
positions relative to younger islands. However, geological evidence suggests that both Rimatara and
Rurutu have been secondarily uplifted within the last
1-2 Myr (see chapter by Maury et al., this volume),
and that the volcanic islands may in fact have been
entirely submerged prior to this secondary uplift
(Paulay & McEdward 1990). Thus, these two islands
may be home to younger lineages, than predicted by
absolute geological age. The results from molecular
phylogenetic of Rhyncogonus largely supports the second scenario, with evidence for back-colonization of
Rurutu and Rimatara from the younger Australs, then
a sequential colonization pattern down the chain
(Claridge 2006). The pattern seen in Misumenops
rapaensis is consistent with the first pattern, though
it is important to note that the island of Rimatara was
not sampled and that the estimated age of this species
is considerably younger than that expected for a species which was shadowing the geological formation
of islands, versus a more recent eastward expansion
across the Pacific, using the islands available.
…
…The uniqueness of Rapa
There appear to be a few groups of arthropods that
form small radiations of endemic species in the
Austral Islands, more particularly on the island
of Rapa. In each case, there is plenty of scope for
further investigation of these systems. Establishing
a robust phylogenetic framework for Miocalles, in
French Polynesia, in particular, would allow valu-
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
able insights into the geographic and geological
timing of the radiation on Rapa.
The unique and unusual nature of the terrestrial
biota of Rapa appears to be a recurring theme in this
book. It is unclear exactly why Rapa is so unusual,
though several hypotheses can be put forward.
• Isolation - Rapa is the most inaccessible island
in French Polynesia, and one of the most isolated landmasses in the world.
• Climate and topography - Rapa has a cool wet
subtropical climate, thus both wet and cloud forest
occur at lower elevations here than in the Society
Islands. It is also the only island in the Austral
group that has sufficient elevation to generate
its own climate and thus to support cloud forest.
Cloud forest is known to harbor a high diversity of
endemic species, elsewhere in the Pacific.
• Human Impact - Rapa is the most recently
colonized island in French Polynesia, the inaccessibility of this island may have saved it from
excessive human impact, and the island remains
fairly isolated, lacking an airport. However,
introduced ungulates have had a profound
impact on mid to low elevation habitats. This
may be less than that seen in the other Austral
Islands, but islands in the Societies, by grace of
their high elevation and rarely accessible ridges
are definitely more intact.
• Inherited diversity - The region near the
MacDonald seamount is geologically complex. Rapa sits on a large shallow plateau, and
Pleistocene sea-levels fluctuated by up to 120 m
over the past 1-2 Myr (Dickinson 1998), probably doubling the area of the island; G. Paulay
(1985) suggested that such sea-level changes
may have played a significant role in generating
species diversity in Miocalles.
ConclusionS
The terrestrial arthropod fauna of the Austral
Islands is clearly a mosaic of indigenous and introduced species. Despite the small size, low elevation
and intense human modification of the Austral
Islands there is still an important endemic element
present that represents a rich tapestry of diversity,
with the low islands in the north showing strong
biotic affinities, and in some cases the histories
of the biota parallel the geological histories of
the islands. The island of Rapa stands out as a
diversity hotspot in the region. The distinctive
history of the island may be related to a number
of factors including its isolation, topographical
diversity, and history (both geological and recent).
Endemic groups should be the focus of conservation efforts as well as continued scientific study.
The Austral Islands Biodiversity Surveys, organized
101
by the Délégation à la Recherche (French Polynesia
Government) in collaboration with the Institut
Louis Malardé (Tahiti), identified a number of previously undescribed terrestrial arthropod species,
primarily associated with the remnant patches
of native vegetation found on the islands, which
serves to emphasize the importance of conserving
these remaining habitat patches. Research is critical
at this point:
• To understand the histories of the different
components of the biota in the region, in order
to assess its future trajectory in the face of sustained or intensified habitat modification and
climate change.
• To distinguish between native and introduced
elements of the biota, and thus examine the
interactions between these elements.
...
Ischnura aurora, female and male (Photo R. Englund).
. . . 102
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Odonata
and Selected Aquatic Insect Taxa
Ronald A. Englund
Little was known about the aquatic
insect fauna of the Austral Islands,
prior to the 2002-2004 scientific expeditions, particularly the
Odonata (dragonflies and damselflies). Early insect collecting expeditions to French Polynesia focused
more on the Society and Marquesas
Islands (Kimmins 1929; Needham
1932, 1933, 1935a, 1935b; Mumford
1942), with few known historical
collections from the smaller and
more isolated Austral Islands. The
St. George Expedition, which stayed
on Rapa from April 10-25, 1925, was probably the
earliest insect collecting expedition in the Austral
Islands (Lieftinck 1966). Likely, because of the
steep topography of Rapa and the specialized
nature of making these collections, aquatic insect
collections from Rapa are unknown from the 1925
St. George Expedition. The 1934 Mangarevan
Expedition was the next major expedition to
visit the Austral Islands, with E.C. Zimmerman
making extensive collections of a wide range of
terrestrial beetles in the main Austral Islands,
and also in many of the smaller offshore islands
as well (Zimmerman 1936). Once again, aquatic
insects were not a focus of collections during this
expedition. The first collections of aquatic insects
(a new damselfly species) were made in Rapa, by
J.F. Gates Clarke in 1963 and even this was an
incidental collection, as Clarke was conducting
a Microlepidoptera study (Lieftinck 1966). This
almost complete lack of knowledge of the aquatic
insect fauna of these islands led to the current
investigation.
Extremely isolated and consisting of a series of
small islands, yet older geologically than the
Society Islands, the Austral Islands were found
to have a rich and diverse aquatic insect fauna,
despite their small size and mostly disturbed land
areas. This paper covers the results of the 20022004 biodiversity surveys, with particular emphasis on the Odonata and the location and type
of aquatic habitats found. Threats facing aquatic
insects in the Austral Islands will be examined and
suggestions will be provided to assist in the conservation of the diverse native aquatic insect fauna
remaining in the Austral Islands.
All three widely recognized types of tropical
island types (Mueller-Dombois & Fosberg 1998)
were sampled during the Austral Islands surveys: atoll and reef islands, such as the outlying
"motu" found on Tubuai, the elevated limestone
or "makatea" island portions of Rurutu and
the high volcanic inner portions of Rurutu and
Tubuai. The diversity of geological island types
sampled during these surveys allowed a variety
of ecological areas and varying plant and aquatic
systems to be assessed. Excluding the marine
insects, dragonflies were the only aquatic insects
observed in the makatea and "motu" (sandy or
rocky islet) areas. The Austral Islands have been
heavily inhabited and extensively disturbed for
nearly a thousand years, with only remnant native
forest vegetation remaining.
Aquatic insect sampling
The aquatic surveys concentrated on Odonata
(damselflies and dragonflies), as they have been
found to be sensitive to disturbance and are found
in a wide of range aquatic habitats, thus they are
good indicator species of environmental quality
(Englund et al. 2007; Allison & Englund 2008). In
the tropical insular Pacific, damselflies (Zygoptera)
(Polhemus & Asquith 1996) and certain aquatic
Heteroptera such as Veliidae (Polhemus &
Polhemus 2004) or Saldidae (Cobben 1980) are
also obvious indicator groups. Damselflies are also
charismatic enough to be easily observed and collected by amateurs, they are often known and
appreciated by indigenous peoples, making these
insects good "flagship species".
103
Entomologist Ron Englund collecting on Tamatoa
stream on Tubuai, the location of the new species of
aquatic beetle Rhantus englundi (Photo R. Englund).
...
Odonata and Selected Aquatic Insect Taxa
.. .....
Yellow pan traps, aerial nets, dip nets, selective
fogging of aquatic habitats with pyrethrins, and
benthic kick samples were used to collect larval
and mature stages of aquatic insects. Benthic sampling was conducted at aquatic sampling stations
by holding an aquatic dip net, while disturbing
the rock substrate upstream of the net. Immature
aquatic insects were collected from rocks found in
riffles by using a toothbrush and fine-point tweezers to extricate larvae from algae covering the
rocks. Visual observations of aquatic insects, especially of larger taxa such as Odonata ­(dragonflies
and damselflies), were made whilst hiking along
streambeds and in terrestrial habitats as well.
Sampling effort was focused on habitat suitable for
native aquatic insects such as splash-zones around
riffles and cascades, wet rock faces associated with
springs and seeps, waterfalls and wetland areas
near and along the stream corridor. General collecting was conducted in prime native aquatic
insect habitats with numerous aerial net sweeps
taken around riffle splash-zones, cascades, seeps,
and waterfall areas.
austral islands aquatic habitats
…
…Rapa
The second largest of the Austral Islands has a
wetter climate regime, especially in the summit
areas and a much greater quantity of stream habitats than the other Austral Islands. In contrast to
Raivavae and Rurutu, almost all streams on Rapa
are fully flowing, and not interrupted by a captage
Taro field, Rapa (Photo R. Englund)
Overgrazed stream habitat on the island of Rapa lacking
the damselfly Ischnura thelmae (Photo R. Englund).
or diversion. A large water storage tank exists
along the stream flowing into the main Haurei
village, but it was uncertain if this tank is fed by
a surface water diversion or groundwater wells,
and municipal water in Haurei village is available
only intermittently. However, the Haurei village
stream flows uninterrupted from its headwaters to
the ocean, where it is channelized. All streams in
the other currently uninhabited valleys on Rapa
flow uninterrupted to the ocean, although small
and occasional water diversions for taro (Colocasia
esculenta, Araceae) still occur in many valleys.
Extensive taro wetlands can be found both above
Haurei village, along the shores of Haurei bay, and
in the many currently uninhabited valleys such
as Hiri bay and elsewhere. Stream habitats can be
separated into two distinct classes in Rapa:
• Areas containing and lacking overtopping
riparian vegetation, with grazed areas containing
. . . 104
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Aquatic habitat for the new species of damselfly Ischnura
jeanyvesmeyeri on Raivavae (Photo R. Englund).
Waterfall habitat from the island of Rapa (Photo R. Englund).
only low grasses along the stream corridor. Most
lowland stream habitats have been severely overgrazed by cattle, goats, and horses, with the resultant effect of a complete loss of stream vegetation.
• The second major type of stream habitat is
a very small percentage of streams containing
riparian vegetation. An example is the stark
contrast between heavily overgrazed areas such
as that above Tumu waterfall, and a portion
of the stream flowing to Hiri bay where feral
ungulates have been excluded because taro is
still cultivated. These fenced areas exist to keep
out grazing animals where taro is currently still
grown, and some of the fenced riparian areas
include mixture of introduced Strawberry guava
(Psidium cattleianum, Myrtaceae), native ferns
and plants, with the alien plants appearing to
have little negative impacts on native aquatic
biota such as the large endemic Rapa damselfly. This includes areas around Haurei village
where a large wooden fence extends far out into
Haurei bay to keep cattle out of the village; this
fence also has the effect of keeping cattle out of
mountainous areas behind the village, and parts
of Hiri valley where taro is still grown.
105
……
Raivavae
Drainages on Raivavae are short, and all drainages
on the island are interrupted by a concrete captage
(drinking water diversion). The largest flowing
drainage on the island was an apparently unnamed
stream that drained into the extensive taro fields
between Mahanatoa and Rairua villages, and was
easily accessed at the concrete bridge crossing the
stream. Above the captage this stream was 1-2 m
wide, and contained some pools up to nearly 1.0 m
in depth, although most areas were much shallower and consisted of 3-10 cm shallow riffles and
runs. Many of the riffles were flowing over tree
roots, although this stream did contain a small
amount of gravel riffles.
Vaipa stream, located above Vaiuru village, one valley away from Tuarani, was extensively sampled and
was nearly as large as the Tuarani stream, but was
quite different in character. Vaipa stream, and the
streams draining into the Tuarani taro fields contained little to no loose gravel or cobble substrate,
and flowed through bedrock chutes and pools. Vaipa
stream was accessed by hiking above the water catchment at approximately 50 m elevation, and then
hiking through thick Hibiscus ­tiliaceus (Malvaceae).
...
Odonata and Selected Aquatic Insect Taxa
.. .....
Matavahi and Mihiura marshes, found on the western
side of the island. These two wetlands are undoubtedly the largest in the Austral Island chain, and one
of the larger wetland areas in all of French Polynesia.
Small taro fields within the Matavahi marsh, near
Piton Pahatu were sampled for aquatic insects, and
the adjacent marsh was also briefly sampled.
The two major watershed areas sampled included
an unnamed stream sampled from 18-150 m elevation and an unnamed tributary at the highest
reaches of the Vaiapu watershed, below the summit of Mt Panee. Tamatoa Stream was accessed
near the Tamatoa cemetery and the stream was
surveyed by hiking upstream. The stream was covered with a thick growth of Hibiscus tiliaceus and
Pandanus tectorius (Pandanaceae) in the lowest
reaches of this stream and had scattered cobbles
and larger rocks, but mostly the stream flowed
through soil and finer substrates. At 20 m elevation
the stream channel started to pick up gradient and
cobbles became more common, and small tributaries started to empty into Tamatoa Stream. Stream
flow was somewhat high and the water was turbid
from heavy rains the day before. At the end of the
survey at around 150 m elevation a few 1-2 m high
Taro field, Raivavae (Photo J.-C. Thibault).
At 122 m elevation the stream corridor opens up
into a series of spectacular cascades where taro is
semi-cultivated on a long series of vertical cascades.
Vaipa stream was then sampled until the stream
became completely overgrown by Dicranopteris linearis (Gleicheniaceae) at 207 m elevation.
One important observation is that virtually all
Raivavae streams still contained extensive riparian or streamside vegetation throughout most of
their lengths. Riparian vegetation in the lowland
areas consisted of secondary growths of Hibiscus
tiliaceus and other species, but became increasingly
more native as elevations increased. For example,
water flow first appeared in a drainage of Mt Araua
at 164 m elevation, in an area of relatively intact
native vegetation. Mt Hiro is the highest peak on
Raivavae, and water flow first appeared in the main
gulch here at 213 m elevation, in an area of native
ferns and plants. The highest permanent waterbody
on Raivavae was at 262 m elevation and started as a
perched spring and wetland that turns into a small
trickle, on the Anatonu village side of Mt Hiro.
The two largest taro-growing areas on Raivavae
were the Tuarani taro fields located north of Vaiuru
village, and the region between Mahanatoa and
Rairua. These areas were extensively sampled for
native and non-native aquatic biota.
…
…Tubuai
The watersheds of Tubuai are relatively short and
radiate out in a spoke-like arrangement from the central spine of the caldera. One of the most ­prominent
features of Tubuai is the large wetland complex of
. . . 106
Tamatoa stream on the island of Tubuai, and location where the
new species of aquatic beetle Rhantus englundi (Photo R. Englund).
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
plunge pools were observed, and stream gradient
began to pick up significantly.
The other major aquatic system surveyed was the
area below the Mt Panee summit, and at 250 m elevation was the highest elevation at which flowing
water was found on Tubuai. Water started flowing
here from a perched spring in a mixed Pandanus
tectorius and Strawberry guava (Psidium cattleianum) forest, flowing downstream over the smooth
rock face into a large pool, estimated at 10 x 12 m
in size, at around 170 m elevation. Several samples
were collected while climbing down the steep
madicolous rock wall. Madicolous or hygropetric
habitat is defined as an area of vertical rock faces,
over which a thin film of water flows permanently.
As this is probably the largest permanently wetted
rock face area on Tubuai the area was of great biological interest for aquatic insects, and should be
sampled more thoroughly in the future as a number of aquatic taxa, not collected during the brief
sampling period on Tubuai, could potentially be
found here. This large wetted rock wall and downstream cascade chutes contradicts the observation
by Craig (2003) that Tubuai lacks stream chute
habitat. Stream sampling on Tubuai was hindered
by poor water clarity resulting from very heavy
rains during the collection period.
…
…Rurutu
Aquatic wetland habitats are reduced in compari-
son to the vast wetlands found on Tubuai, even
so, Rurutu contains small but significant stream
systems with extensive aquatic habitats. Wetland
areas, mainly taro fields are not uncommon, and
those sampled included the Peva Iti marsh and
wetland area that was being used as pastureland,
several large taro fields near Moerai Village, and
in the Plateau Paparai limestone plateau basin.
Rurutu has a complex geological history and has
undergone submergence and also emerged from
the ocean Craig (2003). The streams in Rurutu
appear geomorphologically older as they mainly
flow over smooth chutes into shallow hard rock
pools with cascades having mostly been eroded
away, confiming Craig's (2003) observations.
Puputa stream, flowing behind the main village
of Moerai was the largest stream on Rurutu and
was diverted for domestic supplies (as were all
streams on Rurutu) at an elevation of 64 m. Water
temperature above the diversion was recorded at a
cool 20.5° C. The stream flowed for an estimated
400-500 m above the captage before the largest
waterfall observed on Rurutu was encountered at
82 m elevation. The free-flowing Puputa stream in
this area was heavily shaded, mainly by Hibiscus tiliaceus and Pandanus tectorius and was relatively high
gradient with ample riffle habitats and excellent
water clarity. Puputa stream was sampled intensively for aquatic biota on November 2003. Other
high quality stream habitats sampled on Rurutu
107
Puputa cascade on Rurutu, waterfall habitat for the new
species of damselfly Ischnura rurutana (Photo R. Englund).
included the smaller Uatoa Stream that fed the taro
fields of Narui Village. Above the taro fields this
beautiful stream flowed through a grove of Tahitian
chestnut (Inocarpus fagifer, Leguminosae) trees and
has a series of clear pools with very little vegetation
growing underneath these large trees.
One of the most unusual hydrogeological features
in French Polynesia was observed on Rurutu, just
south of the village of 'Auti, with a freshwater
stream disappearing directly into a makatea cliff.
This stream originated in a bowl-shaped depression
that supported taro fields in the Paparai limestone
plateau, and flowed in an easterly direction before
disappearing into the base of a 100 m tall makatea
cliff. The stream then discharges underground into
the ocean through the makatea somewhere along
the coast around Toarepe point. Native migratory
stream organisms are apparently able to penetrate
these underground caverns as crustaceans and fish
were observed in the stream prior to its disappearance into the makatea cliffs.
……
Rimatara
At only 9 km2 this low-lying island has a highest
elevation of only 106 m, and is circular in shape.
...
Odonata and Selected Aquatic Insect Taxa
.. .....
This island was sampled in October-November
2004, prior to the completion of the airport runway, when the island was only accessible by the
Tuha’a Pae cargo boat. Found at 22° S, Rimatara
is the smallest of the Austral Islands containing
permanent freshwater habitats (Maria atoll and
Marotiri islets lack permanent freshwater habitats). Only one small permanent stream (< 150 m
in length) was observed, but relatively large
amounts of wetlands were found on Rimatara.
Aquatic habitats sampled included several taro
fields, the large Maunutu wetlands near Anapoto
village, the Mururau taro fields and wetlands, and
the Haretii wetlands. Much of the islands "mato"
(raised limestone) habitat was destroyed during the
­construction of the airport in 2004, with this area
containing some of the best native forest habitat.
The Maunutu wetland complex near Anapoto was
bound on the north where the karst walls form the
wetland boundary. Taro is grown in small sections
of this wetland, but dominant plant is the giant
bulrush (Schoenoplectus subulatus subsp. subulatus,
Cyperaceae). Freshwater eels (Anguilla marmorata)
and eleotrid (Eleotris sp.) fish access the wetland
through the karst surrounding the Maunutu wetland. The Mururau wetland and taro field area
appeared to have been reduced in size by c. half,
due to the construction of the municipal stadium,
of the remaining wetland 60 % was covered with
taro and 40 % was covered with Schoenoplectus
rush. The only apparent flowing water on Rimatara
was observed at an unused water catchment that
was diverted at the Haretii wetland area. The
stream was small and flowed where an abandoned
water catchment no longer diverted the water. The
stream started at the head of a small valley growing taro and bananas, but flowed for only 150 m
Rimatara wetland habitat (Photo R. Englund).
in a muddy, shallow, 0.5 m wide channel, less than
3-5 cm deep, until disappearing into alluvium. No
fish were observed in this small stream.
odonata and aquatic insects of the Austral islands
These were the first comprehensive aquatic insect
surveys of the Austral Islands, and have provided
much useful information, recording many new
insect species. The native aquatic species found in
the Austral Islands are internationally important,
and preservation of this biodiversity is critical for
preserving the rich Polynesian culture, found here.
It is also necessary to preserve biodiversity to allow
a greater understanding of the natural biological
processes of dispersal and colonization of the fauna
to these remote and isolated island areas.
A total of 10 Odonata species were collected or
observed in the Austral Islands, with two new single-island endemic damselfly species collected from
Raivavae and Rurutu (Table 17). Voucher specimens were collected for all species to verify their
identifications, except for the large and fast Anax
species observed on Tubuai — from its coloration
and size this species appears to be Anax guttatus.­
. . . 108
A male Ischnura jeanyvesmeyeri, a new species of
damselfly collected on Raivavae (Photo R. Englund).
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Ischnura thelmae male, Rapa (Photo R. Englund).
Ischnura auroa female, Nuku Hiva (Photo R. Englund).
The total number of Odonata species on each island
ranged from a four on Rimatara to a six on Tubuai
and Rurutu. Rapa, Raivavae, and Rurutu had one
endemic damselfly, while the other Odonata species found throughout the Australs were widespread indigenous species. With the exception of
Tubuai, the Odonata species listed from the surveyed Austral Islands should be considered fairly
comprehensive, due to the good survey conditions
and adequate sampling time. Tubuai has the distinction of being the only island with flowing water in
French Polynesia sampled since 1999 to not have an
endemic damselfly species found on it, and this may
result from a very short visit and very poor sampling
conditions during our stay on Tubuai (rain and
high water levels). Further sampling is clearly warranted on Tubuai and initial observations indicate
that an endemic upland damselfly could potentially
be found in the Mt Panee summit waterfall area,
because this section of stream lacks invasive fish
species (see "invasive species" section below).
Adult male of the new damselfly species
Ischnura rurutana found at Puputa
cascade, Rurutu (Photo R. Englund).
Damselfly larvae of Ischnura rurutana, a
new species of damselfly collected from
Puputa cascade, Rurutu (Photo R. Englund).
109
...
Odonata and Selected Aquatic Insect Taxa
.. .....
Table 17: Odonata and selected aquatic insect taxa found in the Austral Islands.
X = native but Indigenous and naturally found on other islands. E = island endemic. New species = discovered during these Austral
Island expeditions and already described in literature.
Taxon
Rapa
Raivavae
Tubuai
Rurutu
X
X
Rimatara
Zygoptera (Dragonflies)
Aeschnidae
Anaciaeschna jaspidea
X
Anax prob. guttatus
X
Corduliidae
Hemicordulia sp.
E
Libellulidae
Diplacodes bipunctata
X
Pantala flavescens
X
Tholymis tillarga
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Anisoptera (Damselflies)
Coenagrionidae
Ischnura aurora
X
Ischnura jeanyvesmeyeri (new species)
E
Ischnura rurutana (new species)
Ischnura thelmae
E
E
Heteroptera (True Bugs)
Veliidae
Microvelia nr. prompta
Microvelia sp.
X
X
X
E?
Coleoptera (Beetles)
Rhantus englundi (new species)
E
Diptera (Flies)
Ceratopogonidae
Dasyhelea sp. 1
X
Dasyhelea sp. 2
X
Dolichopodidae (N.L. Evenhuis pers. comm.)
Campsicnemus sp. 1
E
Campsicnemus sp. 2
E
Teuchophorus sp.
E
Ephydridae
Scatella sp.
X
X
Scatella nr. sexpunctata
X
X
Zeros sp.
X
Simuliidae
Inselium rurutuense
E
Limoniidae sp. 1
X
Limoniidae sp. 2
X
. . . 110
X
X
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
The skating fly Campsicnemus found in puddles near
the summit of Mt Perau, Rapa (Photo R. Englund).
Diplacodes male, Rapa (Photo R. Englund).
Single-island endemic damselflies were found on
Rapa, Raivavae, and Rurutu, and are noteworthy
in that they are the largest and perhaps some of
the rarest species found in the worldwide genus
Ischnura (Englund & Polhemus 2010). Threats to
these species include water diversions and invasive
fish species. Virtually all the streams on Raivavae
and Rurutu are diverted for agricultural or domestic use, and streams are quite small (< 1 m wide,
3-15 cm deep in most cases) and abbreviated on
these islands. On the island of Raivavae Ischnura
jeanyvesmeyeri was collected at a wide range of elevations, from just above sea level at two locations,
the Tuarani River (6 m elevation), and 1 m elevation at an unnamed stream, between Mahanatoa
and Rairua villages. Both of these lower elevation
locations were heavily vegetated forested areas,
connecting taro fields. In low elevation areas
I. jeanyvesmeyeri preferred areas of the stream
around exposed rootwads, in the stream along
the main part of a forested stream channel. None
of the endemic Austral Islands damselflies were
observed in or around the large lowland taro fields
Hemicordulia from Raivavae (Photo R. Englund).
111
...
Odonata and Selected Aquatic Insect Taxa
.. .....
or w
­ etland areas where Ischnura aurora and other
dragonflies were abundant. The large endemic
Austral damselflies are unusual in that they appear
to be obligate forest-dwelling species. Although
both introduced and native plant species inhabit
these riparian areas, I. thelmae, I. jeanyvesmeyeri,
and I. rurutana have been only found around
riparian areas in forested stream habitats, usually
in a mixed canopy of lowland plants of Hibiscus
tiliaceus, guava (Psidium guajava), ferns, Tahitian
chestnut, and other plants.
While the damselfly species on Rapa (Ischnura
thelmae) was described in 1966 (Lieftinck 1966),
new species were found on Rurutu (Ischnura rurutana) and Raivavae (Ischnura jeanyvesmeyeri) during these expeditions. The endemic Austral Islands
damselflies are unique as they represent the largest
known species of the widespread Ischnura genus,
of which members are normally quite small.
……Other aquatic insect species of
interest
Although this chapter is focused on Odonata from
the Austral Islands, some of the other aquatic
insects collected during the surveys are also of
great interest. Because very little has been published on the fauna of these islands, most of the
groups shown in Table 17 and discussed below
were new archipelago records for the Austral
Islands. For example, a new species of aquatic
beetle diving beetle in the family Dytiscidae was
found on Tubuai (Rhantus englundi) (Balke &
Ramsdale, 2006). Three species of Rhantus have
been found in the Society Islands, but this was the
first record of an aquatic beetle from the Austral
Islands. Rhantus englundi was collected in slowmoving water at the lower elevations of Tamatoa
stream, in an area that was heavily shaded by
Hibiscus tiliaceus (Englund 2003).
An undescribed species of Microvelia, an aquatic
heteroptera (true bug), was collected on Rapa.
The Rapa Microvelia was quite distinct from
other species in the Microveila prompta group
that is found elsewhere in the Austral Islands
and in the Society Islands (J.T. Polhemus pers.
comm.); this new species awaits description. On
Rapa, two undescribed species of water skating
flies (Campsicnemus) and a third closely related
undescribed species (Teuchophorus) were found
in aquatic habitats (N.L. Evenhuis pers comm.).
The record for Campsicnemus is the most southerly yet for this genus, and combined with the
finding of the new species of Teuchophorus
flies, are of great biogeographic interest due to
Rapa being at the extreme ends of the known
range of these genera (N.L. Evenhuis pers.
comm.). Ephydrid flies were also quite common
in many of the Austral Island stream habitats,
and were particularly abundant in Rapa streams.
Further work is needed on these flies, and it is
unknown whether any new ephydrid species
were collected.
conclusions
……Conservation of native species in
Austral Islands aquatic habitats
Extensive research in Hawaii has shown the
devastating impacts of alien fish species on the
native stream fauna (Englund 1999; Englund &
Eldredge 2001). So far, the Hawaii findings seem
applicable to French Polynesia as well; island
endemic damselflies have never been found in the
presence of invasive fish species on the island of
Tahiti (R. Englund unpublished data) or Tubuai.
Every effort should be made to avoid additional
introductions of any non-native aquatic species to
the Austral Islands.
Significant findings of these surveys include a
pristine native freshwater fauna lacking introductions of nonindigenous fish, amphibians, or
aquatic reptiles in Rapa, Raivavae, Rurutu, and
Rimatara. Tubuai was the only island currently
having two harmful invasive fish species: guppies (Poecilia reticulata) and tilapia (Tilapia spp.).
Invasive fishes were found in all aquatic habitats
sampled on Tubuai, particularly the large wetland
complex of Matavahi and Mihiura marshes. The
only area lacking invasive fish species on Tubuai
was the large waterfall area below the Mt Panee
summit, which contained the highest known elevation area on the island with flowing water. This
waterfall flowed into a series of stair-step pools
and chutes that were too steep and high gradient for introduced fish to access, and this area
is a potential refuge area for native species, such
as endemic damselflies, that could be negatively
impacted by introduced fish.
It is quite possible that invasive fish species
have eliminated the native damselfly from lowelevation stream areas, as none were observed
during sampling. In contrast, endemic or native
stream damselflies have recently been collected
throughout areas of French Polynesia lacking
these alien fish species. Endemic species were
collected at low elevations on Raivavae (3-4 m
above sea level), and at elevations just above sea
level in the Marquesas and in Hawaii (Englund
2008). The widespread indigenous Odonata
found throughout the Austral Islands appear
to be more resistant to alien fish species, on
Tubuai the common species of native damselfly,
Ischnura aurora, was found in taro patches and
wetland areas, along with five widespread species
of ­dragonflies.
. . . 112
.......
…
…Future research prospects
The findings in this paper should be considered
preliminary, due to the rapid nature of the biological assessments conducted during this study. These
brief surveys found a rich taxonomic diversity in
aquatic habitats, and the findings illustrate the
need for additional research and monitoring of this
highly endemic fauna. Future surveys should focus
more effort on Tubuai because brief preliminary
surveys found endemic insects aquatic insects such
as Rhantus englundi and Tubuaivelia michaili, while
more extensive surveys may find an even greater
113
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
diversity of endemic species. Tubuai could provide a test case for the impacts of alien species on
freshwater ecosystems, as this was the only island
with two widely dispersed invasive fish species.
Collaborations with paleoecologists have uncovered the remains of aquatic insects such as black
flies (Simuliidae) in pre-human contact core samples (see chapter by Prebble, this volume) and will
likely lead to many new exciting findings. We have
only just started to examine the structure, function
and biodiversity of freshwater habitats in these
remote and isolated islands of French Polynesia.
...
Vegetation
.......
....
Cyrtandra elizabethae (Gesneriaceae), an endangered shrub
endemic to Raivavae and Rurutu (Photo J.-Y. Meyer).
. . . 116
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Vascular Flora
General Traits and Main Threats
Jean-Yves Meyer, Hervé Chevillotte & Timothy J. Motley *
The Austral Islands remained for a
long time outside shipping routes and
were ignored by naturalists despite
their proximity with the Society
Islands, in particular Tahiti where the
first plant collections were made by
J. Banks & D. Solander in 1769 during J. Cook’s first voyage. H. Cuming
performed the first collections on the
Austral Islands in 1828, representing
about 20 samples from Rurutu, Rapa,
and Tubuai that were deposited in Kew
(K). A the end of the 19th century, E.F.
Raoul spent some time in Rapa and
the few specimens he collected were
deposited at the herbarium of the
Muséum national d’Histoire naturelle in
Paris (P). It was only in the beginning
of the 20th century that the Bernice P.
Bishop Museum of Honolulu (BISH),
alone or in association with other
institutions, organized two expeditions between 1921 and 1923 covering almost the entire French Polynesia
and resulting in the first significant
collections on the Austral Islands.
During the Bayard Dominick Expedition between
1921 and 1922, ethnobotanists such as R.T. Aitken
in Tubuai and A.M. Stokes & J.F.G. Stokes collected
across the Austral Islands. The Whitney South Seas
Expedition took place between 1921 and 1923,
with E.H. Quayle as the main collector on the
Austral Islands. In 1934, the BISH organized the
Mangarevan Expedition, the greatest scientific expedition of the century in Eastern Polynesia, with F.R.
Fosberg & H. St John as the main collectors on the
Austral Islands, the Gambier, the Pitcairn, and the
majority of the Society Islands, adding over 5 000
new specimens. About 40 years passed before the
botanical surveys conducted by the Paris Muséum
national d'Histoire naturelle (M.N.H.N.) in 1979
(Tubuai), 1981 (Rurutu), and 1984 (Rapa). The
results were published by Hallé (1980, 1983), Hallé
& Florence (1986), and Florence & Hallé (1986).
The Bishop Museum harbors some plants from the
Austral Islands collected by J.P. Chapin in 1934, W.
Hambuechen in 1960, J.F.G. Clarke in 1963, S.H.
Sohmer in 1971, N.L.H. Krauss in 1977, and G.
Paulay in 1979. The M.N.H.N. and the Musée de
Tahiti et des îles (PAP) hosts some collections done
during the inventory of the flora of French Polynesia
by J. Florence in 1983 and 1991 (in particular with
W.R. Sykes in Raivavae, CHR, P and PAP). The
present study includes some samples from R. Graffe
and A. Varney, collected between 1982 and 1990 as
well as specimens accumulated between 2001 and
2004, including collections on Rapa by T.J. Motley,
S.P. Perlman & K.R.Wood funded by a National
Geographic grant, and by J.-F. Butaud, J. Florence,
J.-Y. Meyer during the program "Inventory of the
biodiversity of the Austral Islands" undertaken by the
government of French Polynesia in all islands.
Floristic Affinities of the Austral Islands within French Polynesia
Balgooy (1971) considered Eastern Polynesia (comprising the Cook Islands, French Polynesia, and the
Pitcairn Islands) as the province of Southeastern
Polynesia belonging to the Eastern Malaysia region.
Its geographic location places it at the extreme part
of the South Pacific islands characterized by an
impoverishment in a west-east gradient: there are
over 3 000 species in New Caledonia and about 900
species in Eastern Polynesia, which has however a
rate of endemism of about 50 %.
In the vicinity of the Tropic of Capricorn for the
northern group (Maria, Raivavae, Rimatara, Rurutu,
and Tubuai, near 23° S) and well beyond for the Rapa
group (Rapa and Marotiri, 27-28° S), the flora of the
Austral Islands presents some tropical to subtropical
or sub-temperate characteristics. In addition to the
geographic similarities among themselves or with
the Cook Islands (the nearest group), the islands of
the northern group present some similarities with
some tropical islands such as the Society Islands
(500 km away, at 15-17° S) while the Rapa group is
relatively isolated at over 1 200 km from Tahiti.
To determine the floristic affinities, the Kröber similarity index (Sk) will be applied. This index reduces
the impacts of number disparity compared to an
index such as the Sörensen. The Kröber similarity
index is computed as follows:
Sk = [(A+B) x C/2A x B]  x  100
• A = number of species from the first archipelago
• B = number of species from the second archipelago
• C = number of species common to both archipelagos.
* This paper was originally written in French with Jacques Florence (IRD, Paris) who declined co-authorship on this
revised English version.
117
...
.. .....
Vascular Flora, General Traits and Main Threats
Table 18: Floristic affinities (Angiosperms and Pteridophytes) among the archipelagos or the island groups of Eastern Polynesia.
The numbers of common species are above the diagonal and the values of the Sk index below. The highest Sk values involving the
Austral Islands and the Rapa Group are in bold, the lowest in bold italics. The floristic data were obtained from the botanical database
"Nadeaud" under ™Access, updated in September 2006.
Archipelago
Austral
Austral
Gambier
Rapa
Marquesas
Society Tuamotu
Cook
Pitcairn
Total
67
98
88
171
72
142
69
230
41
38
68
48
45
48
83
57
95
33
83
46
191
143
44
86
40
320
82
172
64
553
72
46
98
55
256
Gambier
55
Rapa
47
35
Marquesas
33
29
24
Society
53
47
33
35
Tuamotu
52
53
26
30
49
Cook
59
36
38
30
49
51
Pitcairn
48
52
34
25
37
46
The index will help characterize the floristic similarities among the various archipelagos and island
groups of Eastern Polynesia and indicate the status
of the Austral Islands within Eastern Polynesia.
Tables 18 and 19 summarize the data on vascular
plants (Angiosperms and Pteridophytes), of the
Angiosperms alone, and the values of the Kröber
index.
To characterize the floristic affinities of Eastern
Polynesia, a grouping can be made within an AustralCook-Society-Tuamotu-Gambier (ACSTG) polygon,
with indices close to or higher than 50 (Fig. 20).
The Pitcairn group is similar to the Gambier while
the archipelagos or islands
located far from this set present the lowest similarities
first among themselves, then
with the ACSTG polygon.
Based on Table 18, Rapa and
the Marquesas, with a distance of 2 000 km between
them have the lowest Sk
index (Sk = 24). Among
the other pairs including
the Marquesas, the value is
higher than 30 only with
the Society Islands (Sk = 35)
followed by the Austral
Islands (Sk = 33). Globally,
the floristic affinities are the
exact reflection of the relative geographic location of
the archipelagos: the greater
the distance, the lower the
floristic affinities. The most
extreme examples are the Marquesas-Rapa Group
or Marquesas-Pitcairn pairs. Brown (1935) ranked
each archipelago (Austral, Rapa, Society, Marquesas,
and Tuamotu) as a district, with the exception of the
37
104
Gambier and the Pitcairn, which were grouped in one
district. The Gambier Islands are virtually as similar
with the Tuamotu than the Pitcairn. The Pitcairn,
located further to the others except the Tuamotu,
could be integrated in the ACSTGP polygon on one
hand and opposed to the Marquesas and the Rapa
Group on the other hand. However, such in-depth
discussion is beyond the framework of this study.
For the islands included in the biogeographical
focus area, the highest Sk value corresponds to
the Austral-Cook pair. The Austral Islands present just slightly lower affinities with the Gambier,
the Society, and the Tuamotu, followed by the
Figure 20: Graphical representation of floristic affinities for
vascular plants among the archipelagos or island groups of
Eastern Polynesia, based on the Sk index values from Table 18;
the highest area values are in red for the northern group of the
Austral Islands and in blue for the Rapa group.
. . . 118
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 19: Floristic affinities for Angiosperms among the archipelagos or island groups of Eastern Polynesia. The numbers of common
species are above the diagonal and the values of the Sk index below. The highest Sk values involving the Austral Islands and the Rapa
Group are in bold, the lowest in bold italics The floristic data were obtained from the botanical database "Nadeaud" under ™Access,
updated in September 2006.
Archipelago
Austral
Gambier
Rapa
Marquesas
45
55
51
104
24
30
32
Austral
Society Tuamotu
Cook
Pitcairn
Total
60
88
48
156
48
40
38
34
62
46
24
45
29
125
73
34
46
28
224
71
93
43
372
60
37
85
38
151
Gambier
51
Rapa
40
29
Marquesas
28
31
20
Society
47
45
25
26
Tuamotu
54
56
24
28
51
Cook
57
43
33
25
43
55
Pitcairn
46
49
30
24
33
45
Pitcairn (48 %) and the Rapa Group (47 %). The
Rapa Group presents the highest index with the
Cook, the Pitcairn, and the Society, and the lowest index with the Marquesas, then the Tuamotu
(mainly due to very limited common coastal plants
with the former and few common inland plants
with the latter). These results highlight the remote-
37
78
ness of the Rapa Group, which justified its ranking
as a district of the Eastern Polynesia province by
Balgooy (op. cit.).
For Angiosperms only (Table 19), index values
are globally lower since ferns, including numerous
wide-ranging species found almost everywhere,
increase the values of indices
Inter-island Affinities within the Austral Archipelago
Table 20: Floristic affinities for vascular plants (Pteridophytes and Angiosperms) on the
Austral Islands. The floristic data were obtained from the botanical database "Nadeaud"
under ™Access, updated in September 2006.
Islands
Maria
Maria
Raivavae
21
Rimatara Rurutu Tubuai Rapa Total
18
19
19
5
23
65
116
124
76
162
71
66
36
84
120
71
152
82
172
Raivavae
52
Rimatara
50
59
Rurutu
48
74
66
Tubuai
47
74
58
74
Rapa
12
43
33
42
Similarly to the archipelagos, Tables 20 and 21 present the floristic affinities for
all plants and Angiosperms
only for each of the Austral
Islands
In Table 20, the values of the
similarity index correspond
to the geographic location
and physiographic factors of
the main islands (Raivavae,
Tubuai, and Rurutu) of
the northern group, which
present the strongest affinities among themselves with
45
v­alues exceeding 70. The
lowest affinities are with
Rapa, for which the highest
indices are with the same
islands. The similarity index
values for Angiosperms only
(Table 21), except for Maria
(with very few ferns) with
Rapa, are still slightly lower
than for the global flora.
191
Table 21: Floristic affinities for Angiosperms on the Austral Islands. The floristic data were
obtained from the botanical database "Nadeaud" under ™Access, updated in September 2006.
Islands
Maria
Raivavae
Maria
Rimatara Rurutu Tubuai Rapa Total
17
14
15
15
1
19
49
77
82
44
113
52
48
24
63
75
39
99
45
111
Raivavae
52
Rimatara
48
61
Rurutu
47
73
68
Tubuai
46
73
60
72
Rapa
3
37
29
35
119
...
37
125
.. .....
Vascular Flora, General Traits and Main Threats
Native and Endemic Flora on the Austral Islands
Floristic data for the Austral Islands are the most
recent in the botanical history of Polynesia. The
islands remained long unexplored and were not
included in the first inventory of the flora of the
region (Drake del Castillo 1893), which covered
the Society Islands and secondarily the Marquesas,
the Gambier, and the Tuamotu, as well as Wallis.
It was only in the 20th century with the works of
Brown (1931, 1935) and Brown & Brown (1931)
that the first collections and descriptions of new
species from these islands were published. About
one hundred taxa, considered to be endemic to
these islands, were described, only half of which
is maintained or combined to date. The works of
Copeland (1938) on ferns, of Hallé & Florence
(1986), and Florence (1997, 2004) on flowering
plants have added 25 new taxa.
Endemism will be presented at the genus and
species levels, with an overview of the native
flora of French Polynesia and the biogeographical focus area.
Charpentiera (Amaranthaceae) and Nesoluma
(Sapotaceae) are trans-equatorial and limited to
the eastern part of the Pacific:
• The former mainly extends to the Hawaii
Islands to the north and there is one species
common to the Austral Islands and the Cook
Islands in the south;
• The latter extends to the Hawaii Islands in
the north to Eastern Polynesia in the south
(Wagner et al. 1990).
Other genera such as Fitchia (Asteraceae) have 6
species endemic to Eastern Polynesia —Society
(3), Rapa (1), Gambier (1 extinct), and Cook
(1)—, Oparanthus (Asteraceae), and Apetahia
(Campanulaceae) are common in Rapa (2) and the
Marquesas (3) for the former and Rapa (1), Marquesas
(2) and the Society (1) for the latter. There are
other genera endemic to the Pacific such as Meryta
(Araliaceae) restricted to the South Pacific (with the
exception of one species in Micronesia), particularly one species common to the Cook, the Austral,
Rapa, and the Pitcairn and another one endemic
…
…Genus-level endemism
While endemic families are the exception for
the Pacific biome (five endemic families in New
Caledonia, Jaffré et al. 2004, only one in Fiji,
Balgooy op. cit.), genera that are endemic to an
archipelago characterize insular flora (104 endemic
genera in New Caledonia for example, Jaffré et al.
op. cit.). Table  22 provides the figures of genus-level
endemism for each archipelago in Polynesia, from
the island level to the scale of Eastern Polynesia.
While genus-level endemism appears marginal,
the peculiar status of Rapa is again confirmed as
it harbors seven genera endemic to the Eastern
Polynesia province, representing about 5 % of all
genera on the island, way ahead of the Marquesas
with about 2.5 %.
Table 23 presents the taxonomic distribution of
these genera, the genera with the wide distribution in the Pacific or those restricted to specific
archipelagos or islands and found in the biogeographical focus area.
Charpenteria australis (Amaranthaceae), an endangered shrub
endemic to Raivavae, Rurutu and Tubuai (Photo J.-Y. Meyer).
Table 22: Genus-level endemism in French Polynesia. EI: endemic to an island. EA: endemic to an archipelago. EPF: endemic to French
Polynesia. EPO: endemic to Eastern Polynesia. GE: endemic genera. The floristic data were obtained from the botanical database
"Nadeaud" under ™Access, updated in September 2006.
Austral
Rapa
Gambier
Marquesas
Society
Tuamotu
French Polynesia
EI
-
3
-
-
-
-
3
EA
-
-
-
2
-
-
2
EPF
1
3
-
2
1
-
3
EPO
-
1
1
-
3
-
3
Total GE
1
7
1
4
4
. . . 120
11
.......
Nesoluma polynesicum (Sapotaceae), a small
tree endemic to Raivavae, Rapa, and the Cook
and Hawaiian Islands (Photo J.-Y. Meyer).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Haroldiella rapaensis (Urticaceae), an erect
herb endemic to Rapa, only found on Mt Perau
(Photo J.-Y. Meyer).
Table 23: Distribution of several endemic genera of Polynesia or the Pacific (west to east). The extra-tropical islands of Lord Howe and
Norfolk are included for Australia. For distribution types: EI = island endemic. EA = endemic to the Austral archipelago. EPA = endemic
to the Pacific. EPAS = endemic to the South Pacific. EPF = endemic to French Polynesia. EPO = endemic to Eastern Polynesia.
EPT = endemic to trans-equatorial Polynesia. The most restricted distributions are in bold.
Austral
Charpentiera
(Amaranthaceae)
EPT
Meryta
(Araliaceae)
EPA
Rapa
EPA
Apostates
(Asteraceae)
EI
Fitchia
(Asteraceae)
EPO
Oparanthus
(Asteraceae)
EPF
Pacifigeron
(Asteraceae)
EI
Apetahia
(Campanulaceae)
EPF
Corokia
(Escalloniaceae)
EPAS
Exocarpos
(Santalaceae)
EPA
Nesoluma
(Sapotaceae)
EPT
Hebe
(Scrophulariaceae)
Haroldiella
(Urticaceae)
Metatrophis
(Urticaceae)
Marquesas
Society
EPA
Hawaii
EPT
EPT
EPA
EPA
EPO
EPO
NewZealand
Australia
EPA
EPA
EPAS
EPAS
EPA
EPA
EPF
EPF
EPF
EPA
EPT
EPT
EPAS
EA
Cook
EPT
EPT
EPAS
EA
EI
121
...
.. .....
Vascular Flora, General Traits and Main Threats
Pacifigeron rapensis (Asteraceae), a subshrub endemic to Rapa,
restricted to the highest ridges of Mt Perau(Photo J.-Y. Meyer).
to Rapa. Corokia (Escalloniaceae) is found in New
Zealand and the extra-tropical islands of Australia
(Lord Howe and Norfolk) and is represented by
one species in Rapa. Hebe (Scrophulariaceae) is
centered on New Zealand and has one endemic species in Rapa. Exocarpos (Santalaceae) ranges from
Southeast Asia, through Malaysia and the South
Pacific to Rapa (with one endemic species) and
Hawaii to the north. Other genera not cited here,
such as Eurya (Theaceae), an Asia-Pacific genus,
has a range that finds its Australian-Eastern limit in
Rapa; Astelia (Asteliaceae) is distributed from NewGuinea, New Zealand, through the summits of the
Pacific to Chile and has one endemic to Rapa.
Rapa clearly appears as the island harboring the
largest number of endemics: three genera endemic
to the island and virtually all the other endemic
genera to Eastern Polynesia and French Polynesia,
with the exception of Lebronnecia (Malvaceae) and
Plakothira (Loasaceae) known from the Marquesas
or Sclerotheca (Campanulaceae) from the Cook and
Society Islands.
……
Primary flora of French Polynesia
Table 24 presents the rate of endemic and native
flora at species level, for vascular plants on all
archipelagos of French Polynesia. The endemism
rate is computed as followst :
TE = 100 x FE/FEI
• FE is the number of endemic taxa
• FEI the sum of endemic taxa and non-endemic native taxa, i.e. the primary flora.
Only the island-level and archipelago-level endemics are taken into account; the higher-level endemics are considered native.
An impoverished flora in this region of the Pacific
is the main result of the various physiographic and
biogeographical factors since the emergence of volcanoes. French Polynesia harbors 884 species of
vascular plants, a far lower number than on other
archipelagos or islands: New Caledonia has over
4 000, the Fiji about 1 300, (Smith 1979-1991) and
the Hawaii Islands about 1 100 species (Wagner et
al. 1990). These low numbers conceal a real diversity
of endemic flora, with 477 endemic species or 54 %.
Table 24: Native and endemic vascular flora on the French Polynesia archipelagos. FE: endemic flora. FI: indigenous or native flora.
FEI: endemic and native flora. TE: rate of endemism. The floristic data were obtained from the botanical database "Nadeaud" under
™Access, updated in September 2006.
Austral
Rapa
Gambier
Marquesas
Society
Tuamotu
French Polynesia
FE
25
60
7
155
224
6
477
FI
205
131
76
166
329
92
407
FEI
230
191
83
321
553
98
884
TE
11 %
31 %
9 %
48 %
40 %
6 %
54 %
. . . 122
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Capparis cordifolia (Capparidaceae), a native vine found in
coastal areas in Rimatara, Rurutu and Rapa (Photo J.-Y. Meyer).
For native flora, the total for the archipelagos is
higher than the combined total for Polynesia as
many species are common to two or more archipelagos. The Marquesas have the highest rate of
endemism due to their isolation in the Pacific: they
are the most distant from the landmasses, at over
5 000 km from Central America or 7 000 km from
Australia, presenting an active speciation. The
Society Islands benefit from the mass effect and
the diversity of the ecological niches in Tahiti, the
largest island at 1 050 km2 with the highest summit at 2 241 m in Mt Orohena. Tahiti harbors 161
native species out of the 224 found in the archipelago, or 72 %. Rapa ranks first in the biogeographical focus area with an endemism rate of 31 %.
……
Primary flora of the Austral Islands
Table 25 presents the numbers for endemic flora
on the Austral Islands, at the (infra) species level.
Only island endemic species are included, the
higher-level endemics being considered native.
The main islands of the northern group have comparable rates even if Raivavae is the only one with
a rate reaching 4 %, due to comparable physiographic and anthropogenic conditions. The rate
does not exceed 5 % at Rimatara, the smallest
island with a maximum altitude of 100 m. Maria
has a "motu" flora including only coastal species
and no e­ ndemics.
……
Specific status of Rapa
Data on species endemism also confirm the distinctiveness of Rapa (Table 26). The limited floristic
Myoporum stokesii (Myoporaceae), a shrub endemic to
Raivavae, Rimatara, Rurutu and Tubuai (Photo J.-Y. Meyer).
123
...
.. .....
Vascular Flora, General Traits and Main Threats
Table 25: Distribution of native and endemic flora at island-level on the Austral Islands. FE: endemic flora. FI: indigenous or native
flora. FEI: endemic and native flora. TE: rate of endemism. The floristic data were obtained from the botanical database "Nadeaud"
under ™Access, updated in September 2006.
Islands
Maria
Raivavae
Rimatara
Rurutu
Tubuai
Rapa
FE
–
6
2
2
2
59
FI
23
145
79
143
158
135
FEI
23
162
84
152
172
191
TE
–
4 %
2 %
1 %
1 %
31 %
Table 26: Comparison of endemism rates for the floristically richest islands of French Polynesia. The floristic data were obtained from
the botanical database "Nadeaud" under ™Access, updated in September 2006.
Islands
Hiva Oa
Nuku Hiva
Raiatea
Tahiti
Rapa
9
14
14
18
31
Surface (km²)
315
340
171
1045
40
Max. elevation
1276
1224
1017
2241
650
% island endemism
affinities with the neighboring archipelagos and the
moderate endemism at genus-level (still the highest in the sub-region) highlight the isolation of this
island in Eastern Polynesia. With an endemism rate
of 31 % at the level of species, Rapa has the highest
rate in French Polynesia and Eastern Polynesia.
Sophora sp. (Fabaceae), a small shrub discovered on ridges below Mt Taitaa in Rurutu (Photo J.-Y. Meyer).
. . . 124
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Taxonomic Disharmony of Flora in French Polynesia
and the Austral Islands
The distance between the volcanic islands and the
continental landmasses or the nearest archipelagos, which are potential reservoirs of diaspores,
contributes to the selection of living organisms
based on their means of dispersal: among fauna,
large carnivores or herbivores are absent; among
plants, groups with voluminous fruits or seeds that
cannot be transported through a natural means of
dispersion or by ocean currents, air, or animals
cannot be found. Entire families such as Meliaceae,
Annonaceae or Ebenaceae are absent or poorly
represented in Eastern Polynesia while they can
be found in the Fijis. Conversely, some families
benefited from this first filter and are overrepresented compared to the continental masses. Ferns,
with spores that are easily dispersed by wind, are
the most vivid example: the Society Islands harbor
the highest rate of ferns among the oceanic islands
(Florence 1993).
Tables 27 and 28 present the data on the Austral
Islands and the Rapa group. As the flora is less
significant and the relevant families (eight in
total) less represented, the threshold was set at
six ­species.
For the Austral Islands, the figures are heterogeneous but low: two families are overrepresented,
the Urticaceae and the Convolvulaceae. While the
former is found at a comparable rate in French
Polynesia, the latter is absent at the Polynesian
level. Its presence might be due to the relative significance of open and coastal habitats compared to
forests but mainly to the low representation of large
families: the Convolvulaceae of the Austral Islands
for instance represent almost all those found in
Ixora brevipedunculata (Rubiaceae), a shrub
endemic to Tubuai and Raivavae in the
understorey of wet forests (Photo J.-Y. Meyer).
Polynesia. For the others, surpluses or deficits are
milder than for the entire Polynesia, which reflects
a more balanced flora for subtropical islands. It
should be noted that due to the low numbers, a
more rigorous interpretation is difficult.
The Rapa Group has partly the same elements as
the Austral Islands, with less heterogeneous numbers. Urticaceae are overrepresented but in low
Table 27: Importance of the eight most abundant families in the Austral Islands compared to worldwide abundance. The highest
surpluses are in bold, the highest deficits in bold italics. The Fabaceae family includes here the Caesalpiniaceae, Mimosaceae, and
Fabaceae sensu stricto. The Malvaceae includes Bombacaceae, Malvaceae sensu stricto, Sterculiaceae and Tiliaceae.
Austral Islands
Surplus/Deficit
Worldwide
Family
Species
% (1)
(1)/(2)
Species
% (2)
Fabaceae
14
6,1 %
0,8 %
18 000
7,5 %
Rubiaceae
14
6,1 %
1,4 %
10 200
4,2 %
Orchidaceae
12
5,2 %
0,7 %
18 500
7,7 %
Cyperaceae
7
3 %
1,7 %
4 350
1,8 %
Convolvulaceae
6
2,6 %
3,7 %
1 600
0,7 %
Euphorbiaceae
6
2,6 %
0,8 %
8 100
3,4 %
Malvaceae
6
2,6 %
1,3 %
4 800
2 %
Urticaceae
6
2,6 %
6,5 %
1 050
0,4 %
All families
230
240 000
125
...
Vascular Flora, General Traits and Main Threats
.. .....
numbers; Cyperaceae are the other only family in
excess, with a factor higher than 2. Other families
such as Euphorbiaceae, Poaceae, and Rubiaceae
are roughly balanced while Asteraceae, Fabaceae
or Orchidaceae present the same deficit as on the
global level.
Cirrhopetalum umbellatum (syn. Bulbophyllum longiflorum,
Orchidaceae), a small epiphytic native orchid often growing
on mossy branches in Tubuai and Rurutu (Photo J.-Y. Meyer).
Pilea bisepala (Urticaceae), an erect herb
endemic to Raivavae, Rapa and extirpated in
Rarotonga (Cook Islands) (Photo J.-Y. Meyer).
. . . 126
Parapteroceras papuanum (syn. Tuberolabium papuanum,
Trachoma societatis, Orchidaceae), a rare native epiphytic
orchid found in Tubuai and Rapa (Photo J.-Y. Meyer).
Cladium mariscus (Cyperaceae), a large erect
native sedge commonly found in wetlands of
Rimatara, Raivavae and Tubuai (Photo J.-Y. Meyer).
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 28: Importance of the eight most abundant families in the Rapa group compared to worldwide abundance. The highest
surpluses are in bold, the highest deficits are in bold italics.
Rapa Group
Surplus/Deficit
Worldwide
Species
% (1)
(1)/(2)
Species
% (2)
Asteraceae
9
4,7 %
0,5
22 750
9,5 %
Cyperaceae
9
4,7 %
2,6
4 350
1,8 %
Poaceae
7
3,7 %
0,9
9 500
4 %
Rubiaceae
7
3,7 %
0,9
10 200
4,2 %
Urticaceae
7
3,7 %
9,2
1 050
0,4 %
Euphorbiaceae
6
3,1 %
0,9
8 100
3,4 %
Fabaceae.
6
3,1 %
0,4
18 000
7,5 %
Orchidaceae
6
3,1 %
0,4
18 500
7,7 %
Family
All families
191
240 000
Main threats
…
…Secondary flora of French polynesia
Due to the human presence since the arrival of the
at first, centralized on the Society Islands and
Tahiti, the unavoidable points of passage in the
19th century, then spread to the other archipelagos in the 20th century due to the increase
of sea, then air trade. The European introduction ratio, in terms of area, is about 3.5 for the
Austral Islands while it is about 2 for Rapa,
located further from the air and sea routes and
where the penetration of European species is
less significant.
• Islands or archipelagos with an IS < 100 harbor
more introduced species than native species, in
descending order, the Tuamotu, the Gambier,
and the Austral Islands. The converse ranking
includes the Marquesas, the Society, and Rapa. In
the former case, a pool of trivial secondary species rapidly invades the "coastal" islands where
floristic diversity is low; conversely, high flora
richness counterbalances its importance. Finally,
Rapa continues to benefit from its isolation.
Polynesians, around 500 AD and the settlement of
Europeans at the end of the 18th century, the indigenous flora had to compete with species introduced
accidentally or intentionallywith the different
waves of human colonization in the Pacific. Species
introduced by the Polynesians came mainly from
the West while those brought by the Europeans are
more cosmopolitan. Table 29 presents the breakdown of secondary flora for each archipelago. The
secondarization index IS is computed as follows:
IS = 100 x FP/FS
• FP = primary flora
• FS = secondary flora.
This table highlights some general traits of the secondary flora:
• The Polynesian contribution is always inferior
to the European contribution, which is about
five-fold. European introductions were constant
Table 29: Introduced flora in French Polynesia and secondarization index. IP: Polynesian introductions. IE: European introductions. FS:
secondary flora. FP: primary flora. IS: secondarization index (Florence 1993). Adv.: weeds. Nat.: naturalized species.
Austral
Gambier
Rapa Group
Marquesas
Society
Tuamotu
38
24
24
16
23
12
37
28
48
28
18
16
62
40
35
65
76
34
107
110
59
31
49
21
105
103
178
190
76
63
Sub-total
217
90
70
208
368
139
FS
279
130
105
273
444
173
FP
230
83
191
320
553
98
IS
82
64
181
117
125
57
IP
Adv.
Nat.
Sub-total
IE
Adv.
Nat.
127
...
Vascular Flora, General Traits and Main Threats
.. .....
……Invasive species on the Austral
Islands
Raivavae
The main invasive alien plants on Raivavae include,
in order of importance: the thimbleberry Rubus rosifolius (Rosaceae), forming dense thorny scrubs in
the understory of remnant altitude rainforests; the
shrub Eugenia uniflora (Myrtaceae) forming almost
impenetrable dense scrubs in low and medium altitude mesophilous communities; the grass Melinis
minutiflora (Poaceae) forming dense mats in open
areas following fires and overgrazing; the small tree
or shrub Psidium guajava (Myrtaceae) found on dry
ridges up to higher elevations; the plant Kalanchoe
pinnata (Crassulaceae) forming dense colonies in
the understory of low altitude mesophilous and
hygrophilous forests; the sub-shrub Ocimum gratissimum (Lamiaceae) and the tall grass Miscanthus
floridulus (Poaceae) in dry and open areas; the
vine Passiflora maliformis (Passifloraceae) entirely
covering some areas of secondary mesophilous vegetation; and the herbaceous plant Commelina diffusa (Commelinaceae) particularly abundant in low
to high altitude wetlands, mixed with the small
herbaceous vine Pilea microphylla (Urticaceae).
Naturalized alien plants that are potentially invasive include Leucaena leucocephala (Fabaceae),
Tecoma stans (Bignoniaceae), Hedychium flavescens
(Zingiberaceae), still relatively uncommon, but also
recently planted trees such as Falcataria moluccana
(syn. Paraserianthes falcataria, Fabaceae) and Pinus
caribaea (Pinaceae), quickly naturalizing in open
areas. The vine Solanum seaforthianum (Solanaceae)
observed in low altitude secondary vegetation, and
Psidium cattleianum (Myrtaceae) planted in some
gardens in Anatonu are not yet naturalized. Lantana
camara (Verbenaceae) is still absent on Raivavae.
Rapa
The vegetation on Rapa is highly threatened by
repeated fires, accidental or voluntary, (for cultivation or to facilitate the hunting of wild pigs), overgrazing by herbivores (feral goats, cows, horses,
pigs), and invasive plants (including Psidium cattleianum, Rubus rosifolius, and Hedychium flavescens).
There are many potentially invasive species such
as Falcataria moluccana or Syzygium cumini, and
ornamentals such as Passiflora ligularis, Sambucus
sp. that should be carefully monitored or even
controlled.
Contrary to what Hallé (1987: 102) wrote following the 1986 mission that the altitude forest was
not under the threats of fires, men, or goats, we
observed signs and damages by goats up to the
summit of Mt Perau at an altitude of about 600 m,
and signs of fires on summits higher than 450 m
(at Mt Karere). Already in 1934, it was reported
that the people of Rapa burnt their lands, that only
some areas of undisturbed natural forest remained
and "hardly a quarter of the original forest cover now
exists" (Zimmerman 1938: 6). Paulay estimated in
1980 that "only one-fifth of Rapa is covered by native
forest" (1985: 99). Altitude rainforests remain the
most preserved habitat on the island due to their
relative remoteness.
Invasion of native mesic forest by the small alien tree Eugenia
uniflora (Myrtaceae) on Raivavae (Photo J.-Y. Meyer).
. . . 128
.......
Wild horses in Rapa (Photo R. Englund).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Intentional fire in Pandanus plantation on Rimatara (Photo J.-Y. Meyer).
Among the first recommendations, the rapid eradication of goats on Karapoo Rahi and the elimination
of rats would protect one of the last remnants of
semi-dry forests on Rapa and one of the last two
populations of the endemic variety of sandalwood
(Santalum insulare var. margaretae). Building fences
would also protect some fragments of semi-dry forests of floristic (presence of rare endemic species) and
faunal (presence of endemic Samoana snails) interest, such as those located above Pariati bay under
Mt Erepau and above Anarua bay under Mt Motu.
These conservation measures must be combined with
a strict ban of fires, a limitation of the wandering
of horses and cows, already recommended in 1986
during a public meeting at the village of Haurei and
potentially done by building exclosures.
Rimatara
Deforestation and clearing of the coastal plains, valleys, hills, and interior plateaus for cultivation and
plantation (coconut, pandanus, coffee, banana, citrus, potato, nono, etc.) resulted in the near-extinction of native plant formations, with the exception
of limestone plateaus or "mato" that are difficult to
reach (due to the sharp edges of "feo" and crevasses)
and poorly suited to cultivation, even if dolines are
cultivated or serve as pens for pigs or plantations for
Cannabis sativa. Repeated fires to clear the understory of plantations (including Pandanus tectorius,
pers. obs. 2004) also contributed to the local loss
of native plants, particularly ferns. Construction on
beaches (concrete benches and tables) and plantations of strands of "riri" (Crinum asiaticum) or
"aito" (Casuarina equisetifolia)­had a significant
impact on the native coastal vegetation. Natural
vegetation on some islets such as Motu Ura and
Motu Rama south of the island (facing the village
of Mutuaura) has been almost entirely destroyed
by fires and wandering pigs. The impact of freeroaming pigs and feral goats has been observed in
129
the "mato" and swamp areas: grazed native plants,
destroyed ferns, churned-up earth, and dissemination of invasive introduced plants.
The construction of 1 500 m-long and 150 m-wide
airplane runway (started in 2000) on the largest
limestone plateau in the north to accommodate ATR
72 planes was done without a proper environmental
impacts assessment (Meyer et al. 2004) and caused
severe damage on the natural forest of this limestone
plateau (deforestation, fires, filling of caves with
stumps of native trees, weed colonization). The
deforested area represents 65 ha (a 2 250 m-long
strip of 400 m at its widest part) or about 40 % of
the limestone plateau area of the island.
Feral pigs in Rimatara (Photo J.-Y. Meyer).
...
Vascular Flora, General Traits and Main Threats
.. .....
Airport construction in Rimatara, November 2004 (Photo J.-Y. Meyer).
Rurutu
Hallé and lower island compared to Tubuai and
where the main crests are more accessible due to
their soft terrain, suffered from a strong degradation of its primitive flora (Hallé 1983: 147). The
natural forests of Rurutu are now restricted to small
fragments of vegetation and their surface gradually
decreases due to the impacts of past and current
human activities, the growing threats of invasive
introduced plants (including Melinis minutiflora,
Tecoma stans, Lantana camara) and overgrazing
by large herbivores (semi-feral goats and horses).
Several endemic plants such as Cyrtandra elizabethae
(Gesneriaceae) or Coprosma velutina (Rubiaceae)
which are restricted to these forest remnants are
now critically endangered (Meyer 2004).
With the presence of herbivores, voluntary or accidental fires constitute one of the main factors of
Remnants of native wet forest with Cyathea tree ferns
below Mt Taatioe, Rurutu (Photo J.-Y. Meyer).
. . . 130
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Dense thickets of Strawberry guava Psidium cattleianum
(Myrtaceae) on Mt Taitaa, Tubuai (Photo J.-Y. Meyer).
disturbance and change for the natural vegetation.
They contribute to the destruction of the forest cover
and the understory (rich in native and endemic
ferns), its replacement by heaths dominated by
"anu’e" Dicranopteris linearis (Gleicheniacea) ferns
or invasive grasses such as Melinis minutiflora,
"ae’o" (Miscanthus floridulus, Poaceae) savannas or
"miri" Ocimum gratissimum (Lamiaceae) bushes,
leading to soil depletion, intensification of erosion
on steep slopes, and reduction of water resources
for the island and its inhabitants.
Tubuai
Natural vegetation is reduced to small fragments
of rainforests between 300 and 420 m on the crests
and slopes of Mts Taitaa and Panee in the northeast
and on the crest between Mts Mareura, Hanareho,
Tavaetu, and Tonarotu in the south. The main
threats on these vegetation formations include
clearing and deforestation for cultivation and plantation, as well as quarries, accidental or voluntary
fires, and invasion by the Strawberry guava Psidium
cattleianum. According to Hallé (1983), the choice
of natural areas to be protected corresponds to the
richest areas in orchids. We believe that the loss of
native orchids is directly linked to the massive invasion of Strawberry guava, closing completely the
canopy and causing the disappearance of terrestrial
orchids and support plants for epiphyte orchids.
In a letter dated February 3, 1997 (pers. comm.),
G. Paulay of Guam University suggested that "an
intense manual eradication effort could probably stop
this advance and save the numerous endemic species
threatened". Given the current extent of the invasion, we believe that a complete eradication of this
"plant pest" is impossible in Tubuai. Only a manual
control, by uprooting the seedlings and cutting the
trees, associated with chemical efforts to treat cut
stumps on small areas of floristic interest (fragments
of natural forests) seems feasible and would protect
the most threatened and legally protected endemic
species in French Polynesia such as Acalypha raivavensis (Euphorbiaceae), Charpentiera australis
(Polygonaceae), Meryta brachypoda (Araliaceae),
or Psychotria tubuaiensis (Rubiaceae).
CONCLUSION
Despite levels of species diversity and endemism
that are lower than on the Society and Marquesas
archipelagos, the primary vascular flora on the
Austral Islands, and particularly on the remote
island of Rapa, represents an exceptional natural
heritage in French Polynesia. Given the intensi-
131
fication of anthropogenic threats (overgrazing by
herbivore ungulates, accidental or intentional fires,
invasive alien plants, construction of airfields),
conservation efforts combined with an increased
awareness of local authorities and populations constitute a priority.
...
Haurei village and bay from Mt Perau, Rapa (Photo R. Englund).
. . . 132
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Vegetation
Types and Map of Rapa
Timothy J. Motley, Alfred Luongo & Jean-Yves Meyer
Oceanic islands are fragile ecosystems that are easily modified by
human disturbance (Carlquist 1965;
Kirch & Hunt 1997; Greimler et al.
2002). Islands make up more than
one third (36 %) of the World’s biological hotspots (Myers et al. 2000)
and Polynesia/Micronesia (which also
includes Hawaii and the western part
of Melanesia) is categorized as one
of the 34 world biodiversity hotspots
(www.biodiversityhotspots.org). The
flora and fauna of each island or archipelago are highly susceptible to degradation and extinction (Sakai et al.
2002); however, by continuing research
efforts and examining biological and
geological patterns we can perhaps
focus conservation efforts. The criteria
for determining biodiversity hotspots include the
size of the area, degree of isolation, levels of species
endemism, habitat loss, future threats to habitat, and
number of extinct or threatened species.
Table 30: The 16 extremely rare vascular plant species occurring
on Rapa. Population size estimated in 2002.
Taxon
Family
Figure  21: Topographic map of Rapa indicating the main mountain
peaks along the crest of the former caldera. © Pacific-image.
Estimated
population Size
(Nb. individuals)
Status
Apostates rapae
Asteraceae
2
endemic genus
Astelia rapensis
Asteliaceae
5-10
endemic species
Bidens meyeri
Asteraceae
20
endemic species
Coprosma cookei
Rubiaceae
10-20
endemic species
Haloragis stokesii
Haloragaceae
5-10
endemic species
Hernandia ovigera subsp. stokesii Hernandiaceae
5
endemic subspecies
Liparis clypeolum
Orchidaceae
9
indigenous species
Malaxis resupinata
Orchidaceae
5
indigenous species
Marattia stokesii
Marratiaceae
3-10
endemic species
Metatrophis margaretae
Urticaceae
1
endemic genus
Pacifigeron rapensis
Asteraceae
10-20
endemic genus
Pilea bisepala
Urticaceae
10-15
indigenous species
Pilea occulta
Urticaceae
3
endemic species
Pisonia coronata
Nyctaginaceae
21
endemic species
9
endemic variety
5
indigenous species
Santalum insulare var. margaretae Santalaceae
Zanthoxylum nadeaudii
Rutaceae
133
...
Rapa, a small high volcanic island (Fig. 21) fits the
hotspot criteria very well.
Until recently, little current
botanical information was
available for the island,
other than the specimens
and data collected on
short exploratory excursions during the Whitney
South Seas Expedition
in 1921 by E.H. Quayle,
the Bayard Dominick
Expedition in 1921-1922
by A.M. Stokes, the St.
George Expedition by
L.A.M. Riley in 1925, the
Mangarevan Expedition in
1934 by F.R. Fosberg and
H. St. John, and the Flore
de la Polynésie Française
project in 1983-1984 by
J. Florence (IRD) and N.
Hallé (Muséum national
d'Histoire naturelle, Paris).
Vascular plant endemism
Vegetation Types and Map of Rapa
.. .....
Pacifigeron rapensis on summital ridge,
Mt Perau (Photo J.-Y. Meyer).
on Rapa was estimated to be 59 % by F.B.H. Brown
(1935), Florence (1987) calculated 37.8 % endemism on Rapa and the Marotiri islet, and Motley
et al. (2002) estimated between 38-40 % endemism for Rapa. These are relatively high levels of
endemism for such a small island. The island is
also host to three monospecific endemic genera;
Apostates, Pacifigeron, (Asteraceae) and Metatrophis
(Urticaceae). Each of these endemic genera is
threatened. Apostates rapae is known from only two
individuals, Metatrophis margaretae is known from a
single individual and Pacifigeron rapensis is known
from less than 20 individuals in two populations
in the cloud forest. Thirteen other taxa of vascular
plants on Rapa have been reduced to less than 25
individuals (Table 30).
Rapa is a distinctive island and so is its vegetation. Part of what makes the vegetation of Rapa
different from the rest of Southeastern Polynesia
is its location­at 27º 37’ S latitude. Due to this
southern position, temperatures can reach lows
of 8.5º C and many species like coconuts, mangos, and breadfruit which are common on the
other tropical islands do not thrive, or are absent
(Brousse & Gelugne 1986). Mueller-Dombois &
Fosberg (1998) described the vegetation of Rapa
as moist to wet, broadleaf, evergreen forest. In the
phytogeographic analyses of Rapa based on shared
geographic affinities of genera from each Pacific
island or continent, Van Balgooy (1971) found
Rapa a difficult island to classify. Rapa not only
shared affinities with Southeastern Polynesia like
the other Austral Islands, but it also had strong
affinities with New Zealand, Lord Howe, Norfolk,
and Chatham islands in the southern hemisphere
and with the Hawaiian islands to the north. Van
Balgooy (1971) considered in fact Rapa as difficult
to classify as New Caledonia, and in the end he
resolved to place it in the Southeastern Polynesian
Province, but as an anomalous district.
Humans have most likely inhabited Rapa since
the 14th or 15th century. Goats were introduced
by Europeans, after the discovery of the island by
George Vancouver, captain of the HMS Discovery
in 1791. Human impacts on the flora of Rapa were
profound, even prior to European contact, and this
human modification was only accelerated by the
introduction of feral animals such as goats, cats,
rats, horses, cattle, and rabbits (Zimmerman 1938),
which are still present on Rapa today. Many early
accounts of the islands mention the Polynesianintroduced Aleurites moluccana (Candlenut tree)
as a common component of the lowland forest
(Riley 1926; Collenette 1926; Mueller-Dombois
& Fosberg 1998). It is no longer such a common tree; we observed only occasional individuals
of this species during our surveys. Furthermore,
large ferns such as Marattia (Mueller-Dombois &
Fosberg 1998) are mentioned as being a common
native component of the rain forest, but only a
single individual was discovered during the recent
botanical explorations. The Hawaiian species of
Marattia are highly susceptible to feral pig disturbance (Palmer 2003) and this may explain its
decline in Rapa.
Because the vegetation of Rapa Island is unique,
threatened and dynamic, we have strived to document and delineate the present vegetation with an
emphasis on the native components. Vegetation
mapping, using satellite imaging with GIS technology, has allowed us to get a better estimate of the
types and extent of the vegetation of Rapa. The
vegetation map is used here to define broad vegetation classes and types, to calculate area and cover
values of vegetation categories, to map distribution (GPS localities) and habitats of rare species,
as a benchmark to study vegetation change over
time, and to aid in making conservation decisions
and policies.
. . . 134
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
MATERIALS AND METHODS
A vascular plant checklist of Rapa was compiled
from existing floras (Riley 1926; Brown 1931, 1935;
Brown & Brown 1931; Copeland 1932; Florence
1997, 2004), botanical literature (Florence & Hallé
1986; Hallé & Florence 1986), the field notes of
H. St. John and R. Fosberg (deposited at the B. P.
Bishop Museum, Botany Department Archives), the
B. P. Bishop Museum Herbarium type collection
and herbarium specimens (BISH, NY, PAP, UC)
and updated. Species were categorized as native or
non-native. Native species were divided into indigenous (species naturally occurring on Rapa, but also
occuring elsewhere) or endemic (species occurring
only on Rapa). The non-native species category
was divided into Polynesian introductions (species
brought by Polynesians) and modern introductions
(species that arrived after European contact).
The island vegetation was divided into three broad
classes (Table 31):
• Native;
• Introduced (both modern and Polynesian);
• Mixed.
An area of vegetation was considered native if ≥ 60 %
of the vegetation cover was composed of native species. An area was placed in the introduced class if
≤ 10 % of the vegetation was composed of native
species. The mixed class applies to areas where the
native component of the vegetation was approximately < 60 % and > 10 % (in most cases dominated
by introduced species with small patches of scattered
native species) or if the satellite resolution made the
delineation among these categories unclear. Each
vegetation class was then subdivided into vegetation types. The types were designated to reflect species composition using indicator species to define
boundaries. In addition to species composition,
……Introduced vegetation
Table 31: Vegetation classes and estimated area.
Category
Area (km2)
Percent cover (%)
Introduced
24.5
64
Native
5.0
13
Mixed
4.0
11
Unexplored
4.6
12
38.1
100
TOTAL
climate,­geography, elevation, and human land use
were also factored into type classifications.
Field surveys carried out during March 18-May 11,
2002 sampled and vouchered vegetation (NY, P,
PTBG, PAP, BISH, US) across 88.2 % the island’s
surface (leaving 11.8 % unexplored). Supplementary
field surveys were conducted by the third author
in December 2002 (Meyer 2002b). During these
surveys detailed notes and records of forest species
and composition were recorded along with elevation and GPS coordinates in most situations. The
extent and ranges of vegetation types were delineated on a topological map with the aid of an aerial
photograph. Subsequent to the field survey a georeferenced IKONOS natural color Satellite image
(0.82 m resolution) was obtained of Rapa. By using
the satellite image and ArcView GIS 3.2 software
(ESRI, Redlands, CA, USA) we were able to delineate boundaries of vegetation types accurately. Once
the vegetation layer was complete the resulting map
could be used to visualize the extent of vegetation
and calculate land area of different vegetation classes
and types. Using GPS co-ordinates, rare species (species with fewer than 20 individuals or known from
a single population) were overlaid on the vegetation
map to identify locations of conservation interest.
VEGETATION TYPES
Pine plantation
Dating from approximately 1980 (J.-F. Butaud,
Service du Développement rural, pers. comm.), the
evergreen coniferous species were planted in rows
on the slopes near the villages and above Anatakuri
bay. Presently the pine plantations have a closed
canopy 10-15 m in height. The dominant planting
is Pinus caribaea var. hondurensis with P. caribaea var.
caribaea­ (Caribbean pines) and Agathis lanceolata.­
There is little ground cover beneath the canopy,
but some native remnants (e.g. Metrosideros collina,
Vaccinium rapae, Glochidion longfieldiae, Boehmeria
virgata and Dicranopteris linearis) remain on the plantation periphery and in gulches and gaps at higher
elevations. Pinus caribaea is becoming naturalized in
the Dicranopteris heath fernlands of the island.
135
Pine plantations around the Haurei village (Photo J.-Y. Meyer).
...
Vegetation Types and Map of Rapa
.. .....
Pinus caribaea naturalized in fernlands (Photo J.-Y. Meyer).
Active agriculture
This vegetation type refers mainly to the flooded taro
(Colocasia esculenta) patches. These areas are often
surrounded by other cultivated fruits and vegetables
like banana, oranges, yams, guava, coffee, or carrots.
Inactive agriculture
This vegetation type consists of inactive taro fields
and the surrounding vegetation that often still contains fruit trees and other cultivated species found in
the active agricultural sites. Taro cultivation was once
quite extensive on the islands with historic human
populations estimated at over 2 000 individuals (estimate of the Missionary Davies in 1826; Buck 1938)
as compared to the 470 residents in 2002 (Institut
de la Statistique de Polynésie française, www.ispf.pf).
Vancouver noted the extensive taro fields in the lowland areas during his visit to Rapa (Vancouver 1798;
Beck 1922), many of which are now abandoned.
Taro patches (Photo T. Motley).
Human habitation
All permanent habitation presently exists along the
coast of Haurei bay. There are two villages situated
across from one another near the mouth of the bay.
Area, the smaller of the two villages, is on the north
shore and Haurei (Ahurei) village is on the south.
There are also a few homes near the back of the bay,
which do not appear in this vegetation type; these
isolated homesteads are included in the active or
inactive agricultural types. Additionally, the 14
archeological sites consisting of terraced fort-like
structures ("pa"), which are on the summits of
fourteen of the high peaks, and may also have been
areas of human habitation, are not included in this
vegetation type. These sites make up only 0.03 km2
of the land area of the island and are included in
the introduced grass-shrub vegetation type, which
now envelops these abandoned structures.
Alien grass/shrub
This vegetation type is most common in the drier
to mesic areas of the island, it is found from just
above sea level to nearly 400 m elevation. In most of
these savanna-like areas the dominant component
is the grass Miscanthus floridulus accompanied by
secondary grass species, such as Melinis minutiflora
(Molasses grass), Paspalum spp., Sporobolus spp. and
Panicum maximum. Miscanthus floridulus can grow
up to 3 m in height and forms dense, almost impenetrable stands due to the buildup of plant material
from the previous years of growth. When dry, this
tangle of old growth makes excellent fodder for
natural and anthropogenic fires which maintain this
habitat and help it encroach on native vegetation
. . . 136
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
types. Burning has been practiced on the island for a
long time (Zimmerman 1938), for clearing land and
easing human movement, it also encourages new
growth of grasses as forage for the feral goat, cattle,
and horse populations. In burnt and grazed areas
broadleaf herbs such as Emilia fosbergii, E. sonchifolia,
Conyza bonariensis, Gnaphalium luteo-album,
Pseudelephantopus spicatus, and Verbena litoralis are
common. The shrub component is made up almost
entirely of stunted Strawberry guava (Psidium cattleianum). Lantana camara and Leucaena leucocephala,­
two invasive species in this type of habitat on other
Pacifc Islands, are not currently a problem on Rapa.
Only a single individual of Leucaena leucocephala,
which forms pure stands below 200 m in some of the
Society Islands (Fosberg 1992) and the Marquesas,
was seen next to the road west of Area village, and
was destroyed.
Secondary forest
Secondary forest on Rapa is primarily composed
of Strawberry guava (Psidium cattleianum) which
grows from sea level up to > 600 m in elevation. In
places this species forms dense monospecific thickets, with stems < 40 cm apart, shading out the entire
understory. The canopy of these thickets can be as
Oparanthus coriacea on montane ridge
above Haurei village (Photo J.-Y. Meyer).
Alien grass- and shrublands (Photo R. Englund).
137
...
Vegetation Types and Map of Rapa
.. .....
low as 1 m or up to 5 m, depending on the topology and habitat. Other invasive myrtaceous trees
on Rapa include Psidium guajava, Syzygium cumini
(Java plum), and S. jambos (Rose apple). A thicket
of Syzygium jambos was seen growing near the summit of Mt Perau near 600 m. The other two species
(Common guava and Java plum) are presently found
only in the lower elevations and valleys near areas
of human habitation or cultivation. Other trees
making up the secondary forest type include Citrus
aurantium (orange tree), Coffea arabica (coffee),
Melia azedarach, Erythrina variegata, Ficus tinctoria, Aleurites moluccana (Candlenut), and Casuarina
equisetifolia. In forest gaps and gulches the vine
and shrub species Ipomoea spp., Ricinus communis,
Triumfetta rhomboidea, Musa spp. (banana trees),
Rubus rosifolius, Hedychium flavescens, and Zingiber
zerumbet commonly occur.
……Native vegetation
Cloud forest
Cloud forest vegetation is found at elevations of
590-650 m, the summit regions of Mt Perau. As
its name implies, this region is draped in clouds
on most days. Mt Pukumaru (605 m), and the
Corokia collenettei on summital ridge,
Mt Maugaoa (Photo J.-Y. Meyer).
summits­behind Haurei village are also often under
cloud cover, but this region was not designated
cloud forest because of the absence of some characteristic species. Indicator species for this vegetation type include Carex stokesii, Geniostoma
rapense, Pilea occulta, Pacifigeron rapensis, Plantago
rupicola, Elaphoglossum rapense, and Blechnum
venosum. Cloud forest vegetation consists of
stunted Metrosideros collina, Corokia collenettei,
Oparanthus coriaceus, O. rapensis, Eurya japonica
and Weinmannia rapensis trees (2-3 m in height),
and thick tangles of Freycinetia rapensis. The trees
and ground are covered with a heavy growth of
bryophytes, small epiphytic filmy ferns, and large
foliose lichens. Understory and/or epiphytic species which are only found here or in higher elevation rain forest vegetation include Haroldiella
rapensis, Marattia stokesii, Astelia rapensis, and
Liparis clypeolum.
Cloud forest on Mt Perau (Photo J.-Y. Meyer).
Rain forest
This vegetation type is restricted to higher elevations on Rapa, found in hanging valleys, on steep
slopes and ridges. There are remnant patches of
this vegetation type in lower elevation areas, suggesting that this vegetation type may once have
extended from near sea level up to around 600 m
elevation. On the lower slopes and in valleys and
. . . 138
.......
gulches between 150-400 m the dominant forest species is Metrosideros collina. Other canopy
species are Corokia collenettei and Weinmannia
rapensis. Secondary canopy species include Eurya
japonica, Meryta brachypoda, Fitchia rapensis, Celtis
pacifica, Oparanthus rapensis, Homalanthus stokesii,
Sophora rapaensis, Fagraea berteroana, Melicope
margaretae, the large ferns Angiopteris rapensis and
several tree fern species (Sphaeropteris (Cyathea)
tahitensis, Cyathea medullaris,­ and C. stokesii).
Common understudy species include Freycinetia
rapensis, Streblus anthropophagorum, Apetahia margaretae, Acalypha polynesiaca, Claoxylon collenettei
and Macropiper puberulum. Metrosideros, Fitchia,
Boehmeria virgata and the tree ferns are the common
component in the hanging valleys. On the drier,
exposed ridge tops, dense tangles of Freycinetia
give way to Dicranopteris, and other ferns and species such as Dodonaea viscosa, Vaccinium rapae,
Glochidion spp., Myrsine rapensis, Styphelia rapae,
Alyxia stellata, Dianella intermedia, Coprosma
rapensis, Hedyotis rapensis, and Pipturus australium. On the higher, wetter slopes from 400-600 m,
the pteridophyte flora becomes richer, as does
the epiphyte cover on the branches of the canopy
trees. Metrosideros is still the dominant tree species
in the high elevation rain forest and Freycinetia
forms thick stands between the trees. Other species
restricted to or more common in this high moist
rainforest include Geniostoma rapense, Meryta
chlorisantha, Coriaria ruscifolia, Haloragis stokesii, Astelia rapensis, Plantago rapensis, Peperomia
spp., Coprosma cookei, Psychotria rapensis, Hebe
rapensis, Haroldiella rapensis, Pittosporum rapense,
Hedyotis rapensis var. taverana and several fern
species in the genera Blechnum, Elaphoglossum,
Asplenium, Davallia and Trichomanes. Hebe and
Hedyotis are usually on the windswept cliffs. Much
of the native rainforest remains here only because
it is on inaccessible, almost vertical slopes and
because Freycinetia forms dense thickets, which act
as a barrier to feral ungulates.
Dry-Mesic forest
Dry-mesic forest is becoming rare due to the heavy
impact of fires and invasive animals (cattle, goats).
Remnants of this forest type occur from 40-400 m.
The forest canopy can reach heights of 7-8 m,
with a semi-open canopy. One remaining remnant of this forest type occurs on Karapoo Rahi
islet and is the location of species uncommon
on the main island. Endemic indicator species
include: Santalum insulare var. margaretae, Pisonia
coronata, Nesoluma polynesicum, Hernandia ovigera,
and Zanthoxylum tahitense. Dominant trees include
Metrosideros collina, Corokia collenettei, associated
with Allophyllus rapensis, Celtis pacifica, Maytenus
pertinax, Pittosporum rapense, Psydrax odorata,
Melicope margaretae, Sophora rapaensis, and
Streblus pendulinus (on boulders). The understory­
139
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Inflorescence of Fitchia rapensis, Mt Namuere
(Photo J.-Y. Meyer).
Fruits of Pittosporum rapense, Mt Maugaoa
(Photo J.-Y. Meyer).
Flowers of Hedyotis rapensis, Mt Maugaoa
(Photo J.-Y. Meyer).
...
Vegetation Types and Map of Rapa
.. .....
Dry-Mesic forest remnant, Mt Erepau (Photo J.-Y. Meyer).
consists of Dicranopteris fern heath with scattered
shrub ­species Glochidion longfieldiae, G. rapaense,
Dodonaea viscosa, and Coprosma rapensis and
Macropiper puberulum. A remnant of native shrub
land, untouched by grazing mammals, was found
on the summit of Mt Tepiahu, with a dense cover
of Metrosideros collina, Hedyotis rapensis, and the
native vines Cocculus orbiculatus and Morinda myrtifolia (Meyer 2002b).
Coastal forest
Coastal forest is principally composed of Pandanus
tectorius with Myoporum rapense and Tournefortia
argentea and occurs on rocky beaches and coastal
shelves. In the swampy interior coast of Haurei
bay are areas of Hibiscus tiliaceus forest. These
forest types exist from sea level to 20 m in elevation and have canopies 4-6 m in height. The
understory is composed of salt-tolerant grasses,
sedges, and a few herbs and vines. Species of
special interest in these areas include the rare
species Hibiscus australensis, which is found in
wet seeps and ditches and is also known from
Raivavae, Rurutu, Tubuai (Meyer 2002a,b), the
Cook Islands (http:// cookislands.bishopmuseum.
org/species.asp?id=6228) and Pitcairn Island
(Waldren et al. 1998), as well as the recently discovered (Florence & Hallé 1986), though widely
distributed species, Triglochin striatum, a tiny herb
(3 cm) that grows in seeps where fresh water
meets the sea.
Flower of Hibiscus australensis, Haurei village
(Photo J.-Y. Meyer).
Strand vegetation
On Rapa this low vegetation type occurs on rocky
shores, or more rarely on sandy shores along the
coast and in bays, with Pandanus tectorius, Myoporum
rapense and rare Heliotropium foertherianum­
. . . 140
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Pandanus tectorius coastal forest (Photo T. Laitame).
(syn. Tournefortia argentea), and most often on cliff
faces. It can occur from sea level to up to 200 m
elevation. It is a mixed community of species consisting of Lycium sandwicense, Sesuvium portulacastrum, Plantago rapensis, Portulaca lutea, Melanthera
(Wollastonia) biflora, Apium prostratum, Peperomia
spp., and Ischaemum byrone. Other less common
species associated with this vegetation type include
on sea-cliffs Capparis cordifolia, Chamaesyce sparrmanni, Lobelia anceps, Eugenia reinwardtiana,
Hedyotis rapensis, and Tetragonia tetragonioides.
……Mixed vegetation
Introduced and native grass-shrub
This vegetation type is principally made up of the
alien grass/shrub vegetation, but contains small
patches of native vegetation. The resolution of
the satellite image was not high enough to separate the small areas of native vegetation from the
i­ntroduced vegetation in some areas. The native
patches consist of Dicranopteris fern heath with
scattered Lycopodiella cernua and the shrub species
Dodonaea viscosa, Vaccinium rapae and Glochidion
longfieldiae. More than 80 % of the area designated with this vegetation type is introduced alien
species.­Continued burning of the grasslands favors
the introduced vegetation occurring in these areas.
Introduced and native forest
Ninety-five percent of this vegetation type is composed of Psidium cattleianum. The 5 % made up
of native rain forest occurs in transition zones
between delineations of native rain forest and
introduced forest regions and in gulches or on
steep cliffs and in valleys where our notes were not
detailed enough and the satellite resolution was
too low to distinguish the myrtaceous forests of the
native Metrosideros patches from the P. cattleianum
dominated introduced vegetation.
VEGETATION ANALYSIS AND PERCENT COVER
…
…Vegetation classes
Analysis of the vegetation classes (Fig.  22, Table  31)
revealed that only 13 % of intact native vegetation
remains on Rapa. Most of these areas are steep
cliffs or ridges, over one-third of the remaining
native vegetation is in the form of coastal strand
141
that clings to vertical sea-cliffs. Introduced vegetation makes up 64 % of the island vegetation. This
figure is likely an under-estimate as the remaining 23 % of the vegetation is classified as either
"mixed" or "unexplored". As noted above, the
mixed forest and mixed grass/shrub vegetation are
...
Vegetation Types and Map of Rapa
.. .....
Figure 22: Map of vegetation classes.
predominantly composed of introduced vegetation.
In no area that was surveyed in 2002 did we see
any evidence that native vegetation was encroaching on introduced vegetation. Indeed, it was quite
the opposite. Freycinetia thickets seem to be some
deterrent to feral unugulates, acting as a protective
barrier for the rainforest vegetation; however, there
are areas where the goat populations are even consuming the tough Freycinetia thickets.
…
…Native vegetation
The native vegetation was divided into five types
(Fig. 23, Table 32). Rain forest accounts for just
over half of the native vegetation. The coastal
strand, which occurs primarily on the sea cliffs,
comprises 35 % of the native vegetation. The
other three vegetation types (cloud, dry-mesic and
coastal forests) make up less than 2 % of the total
island cover. The coastal forest still exists in bays
along the periphery of the island. It was likely
more extensive in these areas and also present in
Haurei bay, where it no longer exists. This vegetation type is composed mostly of common widespread Pacific Island species, with the exception
of the endemic species Myoporum rapense. On the
other hand, the cloud and the dry-mesic forests
contain much higher l­ evels of endemism. Based on
. . . 142
Freycinetia arborea thickets,
Mt Hiri, Rapa (Photo J.-Y. Meyer).
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Figure 23: Map of native vegetation types.
the 1934 notes of St. John and Forsberg, it is likely
that the dry-mesic forest was much more extensive in the recent past. Dry-mesic forest is heavily
impacted by anthropogenic burning and grazing
by feral ungulates. The cloud forest region may
always have been restricted to the highest peaks
of Mt Perau, although some peaks such as Mt
Pukumaru may have in the past been high enough
to support cloud forest habitat.
……
Introduced vegetation
The introduced vegetation was divided into six
types (Fig. 24, Table 33). Grass/shrub vegetation
makes up 75 % of the introduced vegetation and
covers nearly half of the entire island. This vegetation type is very susceptible to erosion. During the
heavy rains which are common on Rapa the soil
runoff containing the iron-rich volcanic soil is very
apparent in the ocean and bays. Nine percent of the
Table 33: Types of introduced vegetation.
Table 32: Types of native vegetation.
Type
Percent of
Percent cover
Area
vegetation class
of island
2
(km )
(%)
(%)
Type
Percent of
Percent cover
Area
vegetation
class
of island
(km2)
(%)
(%)
Forest
3.4
14
9
Grass-Shrub
18.4
75
48
Cloud forest
0.06
1
< 1
Rain forest
2.68
54
7
Pine plantation
0.8
3
2
Dry-Mesic forest
0.37
7
1
Active agriculture
0.3
1
< 0.5
Coastal forest
0.16
3
< 1
Inactive agriculture
0.6
3
1.5
Coastal strand
1.73
35
5.0
Human habitation
1.0
4
3
TOTAL
5.00
100
13
TOTAL
24.5
100
64
143
...
.. .....
Vegetation Types and Map of Rapa
Figure 24: Map of introduced vegetation types.
……
island is comprised of introduced forest and 2 % is
planted in pines. The remaining 5 % of the island is
used for human habitation and agriculture (either
active or inactive taro fields).
Mixed and unexplored vegetation
The mixed vegetation is divided into two types
(Table 34). This vegetation is a 60-40 % split of forest
and grass/shrub habitat, respectively. The unexplored
vegetation (Table 35), which covers 12 % of the
island, is 80 % forest and 20 % grass/shrub vegetation.
Table 34: Types of mixed vegetation.
Table 35: Types of unexplored vegetation.
Type
Percent of
Percent cover
Area
vegetation class
of island
2
(km )
(%)
(%)
Type
Percent of
Percent cover
Area
vegetation class
of island
2
(km )
(%)
(%)
Forest
2.4
60
6.5
Forest
3.7
80
10
Grass-Shrub
1.6
40
4.5
Grass-Shrub
0.9
20
2.0
4.00
100
11
TOTAL
4.6
100
12
TOTAL
CONSERVATION
Insular populations and fragmented ecosystems
make the unique species on islands vulnerable to
extinction (Paulay 1994; Laurance & Bierregaard
1997). Rapa, with only 13 % of its intact native
vegetation remaining, has many endemic species
and habitats that need protection.
The cloud forest and dry-mesic forest types are obvious candidates for conservation, based on the small
proportion of the island they now occupy (< 2%)
and the high number of endemics they harbor, however, their transitions to threatened habitats have
taken very different pathways. Cloud forest (< 1 % of
. . . 144
.......
Psidium cattleianum thickets on ridge,
Mt Namuere, Rapa (Photo J.-Y. Meyer).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Feral cattle damages on forest,
Mt Namuere, Rapa (Photo J.-Y. Meyer).
island cover) has probably never been widespread
because it is limited by elevation, it is restricted to
one contiguous area (6 ha), but in the past may have
existed in a second region on Mt Pukumaru. Major
concerns for this forest type are competition by
introduced plants (mainly Strawberry guava Psidium
cattleianum) and its destruction by feral animal
populations. Dry-mesic forest (1 % of island vegetation), on the other hand, was much more extensive
in the past. Presently the dry-mesic forest consists
of 16 small fragments (of an average size of 2 ha)
of forest totaling less than 1 km2 (only 36.8 ha).
These forest fragments have been created by human
activities such as burning, clearing, and harvesting
(e.g. sandalwood and firewood) in the drier vegetation zones. Competition from introduced grasses
and feral animals continues to impact, alter, and
fragment the dry-mesic forest. The fragments are
quite heterogeneous with quite different species
compositions. For instance, Butaud et al. (2005;
145
this volume) were able to locate Rapan sandalwood
(Santalum insulare var. margaretae) in only two of
the remaining dry forest regions. Based on reports
from local residents, sandalwood was once more
widespread, occurring in additional populations.
Therefore, choosing the appropriate regions for conservation are most critical for the dry-mesic forest,
than for the intact cloud forest example.
One approach for selecting habitats and areas to
preserve is to use the vegetation map with GPS
coordinates of the rare and endemic species of a
vegetation type to focus conservation efforts and
select sites (Fig. 25). Using the vegetation map and
satellite image it is also possible to monitor changes
in the extent of native vegetation over time, using
the present map as a benchmark. This approach
has been used in the past in other islands using
historical aerial photos and satellite images (e.g.
Hawaiian Islands: University of Hawaii Department
of Geography 1983).
...
Vegetation Types and Map of Rapa
.. .....
Hernandia ovigera subsp. stokesii leaves
(Photo J.-Y. Meyer).
Figure 25: GPS points for individuals of two extremely rare
species in native dry-mesic forest vegetation.
CONCLUSION
The vegetation map of Rapa was created as a best
estimate of the native and introduced vegetation
present on the island in 2002. Creating an interactive vegetation map was not the primary goal of
our field surveys so the delineations and descriptions of the vegetation types were done based on
field observations and in conjunction with close
examination of satellite imagery. The map is subjective because no plots were sampled or relevés
made, and therefore no statistical calculations of
coverage and abundance are available. In spite of
these limitations, this is the best data that exists
regarding the current vegetation of Rapa, and it
can be improved upon in later studies by vegetation ecologists using more statistically rigorous
methods. Because the map was made using GIS
technology and overlaying the satellite image with
data layers, we were able to make more precise
calculations of the existing vegetation types. The
remaining 13 % intact native vegetation calculated
here is less than the estimates (15-20 %) made by
the botanist visiting the island in 2002, and also
those of previous scientists (20 %: Paulay 1985).
This map was made to produce a better understanding of the vegetation of Rapa and the remaining native plant component, to locate regions
where rare and vulnerable forest remnants and
species exist, to better direct and focus future biological surveys on Rapa, and to provide information for future conservation efforts by the French
Polynesian Government.
We have established that Rapa fits all the criteria
for a biological hotspot and contains one of the
most unusual floras in the islands of Southeastern
Polynesia, sharing affinities with other regions of
the southern hemisphere (New Zealand, Pitcairn
Islands and Juan Fernandez Islands) and with the
Hawaiian Islands to the north (perhaps due to
their shared subtropical climates). Phylogenetic
studies are now being conducted on several plant
lineages that confirm Rapa as a unique flora,
important for understanding Pacific biogeography (Hoggard et al. 2003; Dempewolf et al. 2005;
Motley 2005a,b; Rouhan et al. 2005; Tronchet et
al. 2005). In our discussions of conservation we
focused on the two rarest native vegetation types;
however, this does not diminish the value of more
intact areas like the native rain forest. Rain forest is an important component of the watershed
of any island group (Wood 1982), it can also
help reduce erosion, particularly since the loss
of dry-mesic forest at low elevations. Presently,
after heavy rains the iron-rich volcanic soil turns
the ocean and Haurei bay red. This is detrimental
. . . 146
.......
to the coral growth and to fishing in the region,
which is the protein staple for the human population of Rapa. It is our hope that conservation of
the native vegetation will be a consideration in
future construction and developments on Rapa
(e.g. airports and roads), with a focus on preventing further fragmentation of the forests and protecting the unique species and ecosystem of Rapa.
Cloud forest in gulch below Mt Perau (Photo J.-Y. Meyer).
147
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
...
Haurei village and bay from Mt Perau, Rapa (Photo R. Englund).
. . . 148
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
The Paleobotanical
Record of Rapa: Indications for the Phytogeography
Matthew Prebble
The most enduring subject of interest in the phytogeography of the
Pacific region is the process of
speciation, specifically the timing
of island radiations and the ecological controls on speciation (e.g.
Carlquist 1974). The pattern of floral diversity on islands is thought
to be determined by the timing of
island orogeny, the vagility (dispersal ability) of species and the
propensity for increased genetic isolation and/or divergence from parent populations after establishment
on an island (Carlquist 1974, 1996;
Grant 1981). Along geological time
scales (over millions of years), it is
thought that centres of geological
diversity and tectonic activity may
provide a good indication of floral diversity and rates of endemism.
Balgooy et al. (1996) examined a
limited phytogeographical dataset
of the Malesian flora (a continental
island), comparing the distribution
of endemic plants with regional geological variation, and found that a
correlation exists between areas of
Miocene plate tectonic activity and
the proportion of endemic taxa in
that area. They suggest that the collision of more than thirty tectonic
plates in northern New Guinea probably initiated intensive speciation.
The geologically diverse islands of
New Caledonia, as another example,
have the most (~100) endemic genera and the highest rate of endemicity anywhere
in the Pacific (Jaffré 1993; Morat 1993). By comparison, the relatively uniform geology of the
neighbouring Vanuatu and the Santa Cruz Islands
(Solomon Islands) is represented by only one
endemic genus (Balgooy et al. 1996).
Current explanations for the endemic character of
island floras that have developed since the Miocene
are often based on the assumption of a stable geological, biological and climatic environment (Hope
1996). On the contrary, palaeoenvironmental data
for the Pleistocene and Holocene suggest disturbance processes prior to human arrival were more
pronounced on oceanic Pacific islands, than on
the adjacent continents (Enright & Gosden 1992).
149
Exposure to tectonic activity, fluctuating sea levels,
tsunamis, cyclones and volcanic ash fallout have
produced an uneven array of geomorphic signatures
across many islands, some indicating entire removal
of habitats suitable for particular vegetation types.
The relationship between disturbance processes
and endemism, however, remains uncertain.
Within geological timescales, one of the most critical
forms of evidence that attest to the endemic character
of island floras is the fossil record. MacPhail (1997)
has outlined some compelling cases as to why endemism in island floras at the generic or family level is
not necessarily evidence for long-term isolation or
local speciation. Lactoris fernandeziana is the sole
representative of the Lactoridaceae and is a shrub
confined to cloud forest above 500 m on Masatierra
island (33° 50’ S - 80° 00’ E) in the Juan Fernandez
archipelago of Chile (Sampson 1995). The location
of fossil pollen of Lactoridaceae (Lactoripollenites)
in Cretaceous deposits of Southern Africa (Zevada
& Benson 1987), India, Australia and Antarctica
(M.K. Macphail pers. comm.) suggests that this
family may have been a common element in the
Cretaceous Gondwana flora. Only L. fernandeziana
has survived, as one of many highly restricted
endemics on this volcanic oceanic island formed
~4 Ma (Stuessy et al. 1984). Other cases include
the Norfolk Island (28° 58’ S - 168° 03’ E) endemic
and monospecific tree genus Ungeria floribunda
(Malvaceae) in the Sterculiaceae. This species is
partially synonymous with the extant Asian genus
Reevesia (Malcaeae) known from Cretaceous deposits from Australia and New Zealand as the fossil pollen type Reevesiapollis reticulatus (Couper)
Krutzsch. Norfolk Island formed between 3 and
2.3 Ma (Jones & McDougall 1973) pinpointing the
maximum time at which the genus became extinct
in Australia and New Zealand.
What can be gathered from first-time appearances
in Cretaceous fossil pollen records, as Pole (1994,
after Martin (1982) and MacPhail (1997) have
suggested for the flora of New Zealand, is that the
endemic character of Pacific Island floras probably
owes much to selective extinctions of formerly
more widespread lineages, but little to physical
barriers to dispersal, as proposed by Carlquist
(1996). MacPhail (1997) suggests that the New
Zealand flora, as is the case for the oceanic islands
of the Pacific, is entirely derived from long distance dispersal and the key to understanding the
importance of endemic taxa is identifying the timing of extinction of parent populations.
...
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
.. .....
Another key interest for phytogeography of the
Pacific has been the extent of environmental
change following human arrival on islands during the Holocene. Colonisation of the Austral
Islands formed part of a wider oceanic movement
of Austronesian speaking people that came out of
the Western Pacific around 3 500 cal. yr B.P. culminating in the settlement of Easter Island (e.g. Hunt
& Lipo 2006) and New Zealand (Anderson 2003;
Wilmshurst et al. 2008) by 850 cal. yr B.P. Relevant
to this paper are radiocarbon ages from archaeological sites on Rurutu (Vérin 1969; Bollt 2005; Weisler
et al. 2006) and Tubuai (R. Bollt unpublished data)
indicating that the Austral Islands was first colonised within this same period. Based on the largest,
best-preserved and earliest archaeological sequence
located on Rapa, colonisation of the Austral Islands
was probably complete by around  cal. yr B.P.
(Kennett et al. 2006). Palaeoecological records from
lowland swamp deposits from Rimatara (Prebble
& Wilmshurst 2009), Tubuai and Raivavae (M.
Prebble & Porch unpublished data) reveal that ecological impacts were initiated synchronously with
human colonisation
Late Holocene palaeobotanical records from many
Pacific Islands indicate that vegetation change has
primarily been a consequence of human activity.
Indications of extensive ecological impacts come
from evidence of human-induced terrestrial avifauna and snail extinctions from the fossil record
(e.g. Solem 1991; Steadman 1995; Tennyson &
Anderson 2012; see chapter by Gargominy &
Fontaine, this volume). Abrupt changes in vegetation during the Pleistocene and Holocene have
been defined from palaeoenvironmental research
undertaken on several Pacific islands (e.g. Flenley
et al. 1991; Athens & Ward 1995, 2001; Stevenson
et al. 2001; Haberle 2003; Fall 2005; Prebble &
Dowe 2008). For many of these islands, human
impact has been inferred from palynological signatures, but the timing and processes of the respective
changes have been contested given the uncertainties involved with absolute chronometric controls
on dated archaeological material (e.g. Spriggs &
Anderson 1993; Kirch & Ellison 1994; Anderson
1995), or with the influence of climate and sealevel change (e.g. Flenley et al. 1991; Hunter-
Anderson 1993; Nunn 1997; Dickinson 2001).
In this paper, palaeobotanical records from Rapa
are examined in the context of the modern flora of
Rapa and phytogeography of the Austral Islands. An
overview is provided of the phytogeography of the
late Miocene-Pliocene (12-1.8 Ma) and Pleistocene
(between 1.8 Ma and 10 000 years), examining the different plant lineages that migrated into
Oceania following extensive island formation. The
maximum first-time appearance of fossil pollen on
Rapa is delimited by the island’s Pliocene orogeny
(< 4.8 Ma). The Pleistocene is examined in the context of the available palaeobotanical records and
environmental proxies for processes (e.g. glaciation
and sea level fluctuation) that may influence vegetation change and plant migration to the islands
and the propensity for speciation. I also examine
the phylogeographic (the study of the distribution of genetic diversity) evidence for the derivation of oceanic floras based on the recent research
on taxa represented in the Austral Islands flora.
Secondly, I present a summary of Holocene-aged
(< 10 000 cal. yr B.P.) palaeobotanical records from
the coastal lowlands of Rapa, providing an outline of
vegetation change and differing floral representation
of indigenous taxa during the three major regional
environmental transitions: the post-glacial marine
transgression, the mid-Holocene sea-level highstand
and the late Holocene human impact period.
Coring in a wetland (Photo J.-Y. Meyer).
PHYTOGEOGRAPHIC IMPLICATIONS OF THE PALAEOBOTANICAL RECORD
……Late
Miocene and Pliocene (~12 -1.8 Ma)
phytogeography of the Pacific
For a prolonged period during the Miocene, the
largest southern Pacific-rim continents (South
America, Australia and New Zealand) moved northwards. New Zealand entered the warm-temperate
zone shifting over 20° C northwards while Australia
had moved into the warm-temperate and tropical
climatic zones by the mid-Miocene (Markgraf et al.
1995). This northward drift allowed for the expansion of warm-temperate and tropical floras from the
north. Fossil evidence for Australian genera such
as Eucalyptus in New Zealand during early to midMiocene attests to this warm-temperate expansion
(Pole 1993). The northward drift also provided a
greater floral source area of potential colonists for
the mid-Miocene-aged or older Pacific Islands (e.g.
Fijian archipelago).
. . . 150
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
The climate of the late Table 36: List of taxa identified from the Arahu lignite deposit, Rapa, French Polynesia.
Miocene (~12-5.3 Ma) was
characteristically cooler and
Biogeographic
Palynologist
Family
Species
more variable than the earlyaffinity
mid Miocene as a function of Arecaceae/Liliaceae
unknown
L. Cranwell
the increasing periodicity of
Wind dispersed exotic
sea level fluctuations driven Cupressaceae
L. Cranwell
Dacrydium sp.
from
the Western Pacific
by an intensified succession
of glacial periods extending Cyatheaceae
Cyathea spp.
Pacific
L. Cranwell
the polar ice shelves. These
unknown
Cosmopolitan
L. Cranwell
fluctuations are thought to Cyperaceae
have altered species dis- Piperaceae
unknown
Pacific
L. Cranwell
tributions by hindering or
Myrtaceae
unknown
L. Cranwell
enhancing speciation or
cf. Coprosma rapensis
New Zealand/Pacific
L. Cranwell
ultimately causing extinc- Rubiaceae
tion (Macphail et al. 1993). Sapindaceae
cf. Dodonaea viscosa
Pacific
M. Prebble
Winkworth et al. (2002)
unknown
L. Cranwell
suggest that this environ- Taccaceae
mental instability led to the Zingiberaceae
unknown
L. Cranwell
development of more open
habitats that allowed more
Austral Islands is a shallow (< 2 m thick) lignite
opportunities for the establishment of a number of
seam located at Arahu at the northeast head of
Pacific plant lineages.
Unlike in New Zealand, where debate over the oriHaurei harbour on Rapa at around 180 m in elevagin of the flora has involved long-distance dispersal
tion (Fig. 29). As Maury et al. (see chapter by
mechanisms (Pole 1994) and the widely discredited
Maury et al., this volume) have discussed, the prespanbiogeography theory (McGlone et al. 2001),
ence of palagonite suggests the lignite was deposthe indigenous floras of the Austral Islands had to
ited into a small lake or swamp, possibly within
arrive across the Pacific Ocean by long distance disa previous lava lake (Brousse & Gelugne 1986).
persal (Carlquist 1974, 1996). The 40K/40Ar chroThis lignite represents one of
1 - The earliest description of this
nologies for island orogeny reviewed by Maury et
only two deposits in the remote deposit dates to 1865 when John
al. (see chapter by Maury et al., this volume) supisland Pacific, the other located
Vine Hall on the S.S. Ruahine
travelling from New Zealand to
port the hypothesis that the original floral colonists
at Babeldaob in Palau (Federated
Panama stopped on the island in
probably migrated from adjacent, older seamount
States of Micronesia). The Arahu light of it being a suitable prospect
islands "downstream". Given that all islands in the
deposit formed prior to the ero- for a steam ship depot. Hall (1869:
Austral Islands are of late Miocene to Pliocene age
sional dissection of a former lake 132-133) noted that "Coal of a very
inferior quality, has been found
but derived from two different hotspots, the direccaldera that now forms the harin the interior; the natives use it
tion of plant dispersal is unclear but can generally
bour on the southeast side of the occasionally for cooking etc., but it is
useless for steam [ship] purposes".
be assumed to follow a northwest (Rimatara and
island 1.
Rurutu are the oldest islands) to southeast direction (Rapa and Marotiri are the youngest islands).
If this interpretation holds, island orogeny and age
may only have minor consequences for phytogeography, except that these islands have had, at a
minimum, only 3.8 Ma (based on the 40K/40Ar ages
of Marotiri) of above sea-level terrestrial exposure
to accumulate and evolve endemic floras. The question remains whether the Austral Islands flora,
including endemic species, arose during the late
Miocene or later epochs.
……Palaeobotanical evidence and late
Miocene-Pliocene phytogeography
Fossil data that provide an unambiguous signal
marine transgressions and regressions are difficult
to obtain given the paucity of coastal or marine
fossil records from the late Miocene-Pliocene
(Jablonski 1980), especially in the Pacific region.
The only probable Pliocene (< 4.8 Ma) deposit of
value for a palaeobotanical interpretation on the
151
Dodonea viscosa (Sapindaceae) (Photo J.-Y. Meyer).
...
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
.. .....
Chubb (1927) collected some material whilst on
the St. George Pacific Expedition of 1924-25 and
submitted some samples to the Natural History
Museum (London). He described the deposit as
lignite, 'intercalated between lava flows' and at
points a few metres thick. He found an outcrop
immediately below Mt Taga overlying parent rock
consisting of clays interbedded with fine laminae
of lignite. In 1939, Cranwell (1964) examined
some Arahu lignite collected by Raymond Fosberg
in1934 as part of the Bernice P. Bishop Museum
Mangareva Expedition. She suggests from J.F.G.
Stokes earlier description of the lignite outcrop
that 'it can be inferred that the deposit lay partly in
a calderon which was emptied when later breached
by the sea' (Cranwell 1964: 45-46).
A list of pollen and spore types identified from
the Arahu desposit is presented in Table 36.
Cranwell located Cyathea tree fern type and other
ferns spores, algal (e.g. Phycopeltis) and fungal
(Microthryriaceae) fruiting bodies and a range of
pollen types. Characteristic of the pollen assemblages examined are high proportions of sedges
(Cyperaceae) indicative of "nutrient-rich waters".
Other Monocotyledon taxa include: Zingiberaceae,
Taccaceae and some "palmoid" grains (probably of
Arecaceae or Liliaceae type). Of the Dicotyledon
taxa identified, the following are represented:
Myrtaceae, Piperaceae, Sapindaceae, and Rubiaceae
of a type comparable to the endemic species
Coprosma rapensis. Cranwell also identified a few
grains of the Gymnosperm genus Dacrydium, distinct from the New Zealand species D. cupressinum initially considered to be a contaminant. This
could also have been derived from a wind blown
dispersal during the late Miocene following the
Coprosma cookei (Photo J.-Y. Meyer).
pacific expansion of Dacrydium into areas such as
New Zealand (Pole 2001) and potentially the Fijian
archipelago or islands further west (M.K. Macphail
pers. comm.).
The presence of a Coprosma type pollen grain within
the pollen sample examined by Cranwell (1964)
suggests that the floral affinity of Rapa with New
Zealand ascribed for the modern flora of the island
may have a late Miocene/Pliocene origin. Coprosma
is regarded as one of a number of New Zealand genera that make up the flora of Rapa including Veronica
(Scrophulariaceae), Olearia (Asteraceae) and Corokia
(Corokiaceae), not found on any of the other islands
in the Austral Islands or in the tropical Pacific.
In August of 2002, the author collected some material from the Arahu lignite deposit with the intention of processing some material for pollen analysis.
The site is heavily eroded across the whole outcrop
and is only exposed in a few places below the
Taga ridgeline. In a number of places the lignite
is overlain by recently eroded clay. The banded
clay that Chubb described was not
2 - A collection of this
located. Some lignite 2 was processed
lignite and reference
at the Australian National University
pollen slides are held
by the Department of
for palynomorphs with a similar, but
less diverse assemblage consisting of Archaeology and Natural
history, The Australian
Cyperaceae, Poaceae, Cyathea tree
National University.
fern type and monolete fern spores,
Dodonaea (Sapindaceae) and Rubiaceae type grains
(see Table 36 for list). Like Cranwell, Macphail
(pers. comm.) and the author did not identify
any pre-Pleistocene fossil taxa, that may specify
further the likely age of the deposit, although the
40K/40Ar ages provided in Maury et al. (see chapter
by Maury et al., this volume) confine the age of this
deposit to < 4.8 Ma or younger.
……Phylogeographic evidence and late
Miocene-Pliocene phytogeography
Fossil data only provide a partial representation of
the palaeoflora and thus do not always allow for
a precise or complete interpretation of phytogeographical patterns. The preserved pollen and fern
spore assemblages of the Arahu lignite deposit,
from Rapa, tend to be biased towards wind pollinated and swamp species. Previously, the absence
of late Miocene-Pliocene sub-fossil deposits from
Oceania has limited phytogeographical interpretation to molecular evidence. The recent application of phylogenetic and phylogeographic methods
allows the inference of the timing of genetic differentiation. These inferences are established on
the basis that the geological age of island orogeny
provides the upper boundary on the time available for a newly established population to become
genetically isolated from their parent populations
(Avise 2000). For many Pacific plant lineages, phylogenetic studies have confirmed the importance
of an eastward dispersal route in which western
Pacific species are basal to eastern species.
. . . 152
.......
The timing of dispersal events can also be inferred
from phylogenetic data using the first fossil appearance of a taxon as an upper boundary. There are,
however, a number of problems that may arise
in interpreting molecular evidence, including the
genetic influence of multiple colonisation events,
hybridisation and polyphyly. Despite these pitfalls, molecular data from many Austral Islands
floral lineages suggests that most dispersal events
took place during the late Miocene-Pliocene with
extant island taxa derived from this diversification.
Most taxa are derived from the tropical west-east
dispersal routes (see examples below) with some
taxa following a southerly route from New Zealand
(e.g. Sophora tomentosa and Veronica rapensis)
and American lineages (e.g. two Plantago species
(Plantaginaceae) from Rapa after Hoggard et al.
2003 and T. Motley (unpublished data).
Tronchet et al. (2005; T. Motley unpublished data)
used two nuclear-encoder spacer regions from
ribosomal RNA sequences to resolve the genetic
relationships between the Pacific populations of
the Araliaceae genus Meryta, of which two extant
species (M. chloristantha and M. brachypoda) are
found in the Austral Islands. The spacer region
data showed that the Austral Islands populations
are derived from the diverse New Caledonian lineages. The ancestral New Caledonian species may
be derived from populations from either Fiji (M.
tenuifolia) or New Zealand (M. sinclairii), although
this relationship remains unclear. Tronchet et al.
(2005) suggest that the east Pacific populations,
including those from the Austral Islands would
Meryta chloristantha (Araliaceae), Rapa (Photo J.-Y. Meyer).
153
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Sophora tomentosa (Fabaceae) (Photo J.-Y. Meyer).
have arisen after the late Miocene-Pliocene island
orogeny, from long-distance dispersal events.
The phylogenetic relationship of some Austral
Islands taxa to late Miocene-Pliocene dispersals
from New Zealand has received more attention.
Using sequences from an intergene region (atpBrbcL) of chloroplast DNA, Hurr et al. (1999) found
that the Edwardsia section of the genus Sophora,
found across the southern Pacific from New Zealand
to Chile, is monophyletic but from a distant nonEdwardsia lineage from the northwest Pacific. These
data suggest that this section of Sophora initially
dispersed to New Zealand from the northwest
Pacific along an Antarctic route by the late Miocene,
then dispersed across the South Pacific and to the
Austral Islands. Based on molecular clock estimates
and fossil pollen dates from ancestral New Zealand
species, the derived S. tomentosa, represented on all
islands in the Austral Islands (J.-Y. Meyer unpublished data) and S. toromiro, found only on Easter
Island (Zizka 1991), are late Miocene to Pliocene in
age. Dispersal of the buoyant Sophora seeds to these
islands from New Zealand is seen as the most likely
explanation for this distribution.
Nuclear ribosomal internal transcribed spacers
(nrITS) from species in the genus Hebe, represented
on Rapa by V. rapensis, indicate dispersal eastward
from New Zealand to South America probably during the late Miocene (Wagstaff & Garnock-Jones
2000; Winkworth et al. 2002; M. Bayly and P.
Garnock-Jones unpublished data). Winkworth et
al. (2002) suggest that the Sub-Antarctic Islands
and the Antarctic may have provided a steppingstone for dispersal from New Zealand to South
...
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
.. .....
America. It is possible that Rapa may have also
served as a stepping-stone for dispersal.
Few other high-resolution phylogeographic studies have been completed for representatives of the
Austral Islands flora. Florence (1997) analysed
the floral affinities the flora of subtropical Rapa
withrespect to that of other Pacific regions, and
found that over 45 % of the genera present were
shared with the tropical Western Pacific. The other
islands in the Austral Islands showed a higher affinity, unsurprising given their more tropical position.
Limited phylogeographic studies are also available for a number of pan-tropical genera including
Scaevola (Goodeniaceae; S. taccada is found on
most of the islands in the Austral Islands; Howarth
et al. 2003), Hibiscus (Malvaceae: Hibisceae;
including Talipariti tiliaceum syn. Hibiscus tiliaceus
represented on most islands; Pfeil et al. 2002) and
Erythrina (Fabaceae represented by E. variegata on
most of the islands; Bruneau 1996) each known
to display some long-distance dispersal capacities.
These phylogenetic analyses suggest that most pantropical taxa had arrived in the Pacific region prior
to the orogeny of the Austral Islands.
……Pleistocene
(last 1.8 Ma - 10 000 yr B.P.)
phytogeography of the Australs
Little is known of the dynamics of Pleistocene vegetation change for Pacific Islands. The configuration
of islands in the Pacific Basin was essentially the
same as today and the geology has remained tectonically stable throughout this period, compared to the
regions lying along the continental plate boundaries to the west. Few terrestrial catchments in the
region have accumulated Pleistocene-aged sediment
deposits. The lack of large sedimentary basins in this
region dictates that continuous terrestrial records of
an age exceeding the Holocene will remain elusive
(Hope 1996). Inferences of vegetation change for
the Pleistocene in Oceania tend to rely on indirect
proxies such as glacial or sea level signatures to
determine constraints on vegetation.
The influence of Pleistocene sea level fluctuations on
vegetation change in the Pacific can be inferred from
sea-level proxies found in marine (e.g. coral reefs and
marine sediments) and coastal sedimentary deposits
(e.g. mangrove sediments) and other geomorphological indicators (e.g. coastal caves and uplifted
coral terraces). Eustatic sea levels in the last 1.8 Ma
have fluctuated by up to 140 m on a time scale of
about 100 000 years. The time spent at the lowest
levels is similar to that spent at their highest, about
10-15 000 years or 10 % of the time with intermediate levels achieved at other times (Shackleton 2000).
Bathymetric data from much of the Pacific indicates
that almost all existing island groups remained separated during glacial low-stand sea levels.
Estimates of interglacial and glacial sea levels are
known for the late Pleistocene Pacific from a series of
dated uplifted-coral terraces in the Huon Peninsula,
Papua New Guinea (Chappell & Polach 1991).
The closest series of uplifted terraces to the Austral
Islands that provide any indication of Pleistocene
sea levels come from the Fijian archipelago (e.g.
Nunn & Omura 1999). Uplifted Pleistocene reefs
are found on Rurutu (Stoddart & Spencer 1987;
Pirazzoli & Salvat 1992) and Tubuai (Pirazzoli &
Salvat 1992) where emergence by volcanic loading
of the Arago Seamount (Bonneville et al. 2002) has
left Last Interglacial shoreline signatures from a time
when sea level was approximately 5 m above present level (e.g. Chappell & Shackleton 1986).
Lower sea levels during glacial periods had the
effect of increasing land area and therefore reducing migration distances between islands. For the
Austral Islands this would have resulted in a marginal reduction in the distances between islands.
Based on limited bathymetric data and with the
estimated sea level decline for the Last Glacial
period, Rapa potentially expanded its terrestrial
area up to around 200 km2. The ocean floor immediately surrounding these islands lies at a depth
varying between 2 and 4.7 km. All of the surrounding satellite islets off the coast would have been
joined with the main island allowed continuous
tracts of vegetation to form between them. Given
the rise in altitude of the island with lowering
sea-level, orographic precipitation concentrated on
windward flanks of the island may have increased
leading to increasing valley dissection and sediment erosion, as has been proposed for most
Pacific high islands (e.g. Gavenda 1992). Paulay
(1985) suggests that the montane cloud forest of
Rapa would have extended down in elevation to
encompass a greater area, potentially connecting
the previously disjunct forest tracts.
Lower sea levels also had the effect of creating erosion dominated fluvial systems by increasing river
gradients. This increased valley incision and sediment mobilisation limiting accommodation space
for sediment deposition and organic accumulation
and subsequently sub-fossil preservation. Vegetation
development particular at the outlets of rivers and
in coastal areas was likely to have been greatly
restricted. Coastal swamp forest or mangrove environments would have been restricted to small refugia, or, were entirely absent during these periods.
……Palaeobotanical evidence and
Pleistocene phytogeography
Lyon (1930) identified Pleistocene-aged macrobotanical remains of fifteen tree species from a tuff
deposited in a salt lake at Moanalua, Oahu in the
Hawaiian Islands. Amongst the species identified
were the endemic Pritchardia spp. (Arecaceae),
Metrosideros polymorpha (Myrtaceae) and Acacia
koa (Fabaceae), all indicative of a mesic interglacial environment (Ruhe 1964 in Gavenda 1992).
By contrast, Hay & Iijima (1968 in Gavenda 1992)
later examined the geomorphology of the site and
. . . 154
.......
interpreted the deposit to be from a glacial period
at ~350 000 yr B.P. providing evidence for the longterm presence of at least three endemic species.
Some near-continuous Pleistocene palynological records are available from continental sites in
Oceania including the Grande Terre, New Caledonia
(Stevenson et al. 2001; Stevenson & Hope 2005)
and in New Zealand where there are numerous
records (Vandergoes et al. 2005). Only one record
has been located from the Fijian archipelago at
Lake Tagimaucia on Taveuni (Southern 1986; Hope
1996). Discrete Pleistocene units have also been
located along the Plaine des Lacs, New Caledonia
(Hope & Pask 1998), Nadrau Plateau on Viti Levu,
Fiji (Southern 1986) and from several sites in New
Zealand (e.g. Moar & Suggate 1996). Only three
island groups in Oceania have provided palynological records extending back to the Pleistocene,
including Easter Island (Rano Kao, Rano Raraku and
Rano Aroi in Flenley et al. 1991), Oahu, Hawaiian
Islands (Selling 1948; Athens 1997; Hotchkiss &
Juvik 1999) and San Cristobal, Galápagos Islands
(Colinvaux 1972; Colinvaux & Schofield 1976).
All of these sites are located in either high elevation
bogs (Hawaiian sites) or remnant volcanic caldera
lakes, but are rare in the region. Most interpretations
of these records imply cooler and drier conditions
during glacial periods with an increase in montane
and herbaceous taxa in lowland areas in response to
a decrease in forested environments.
Pleistocene-aged palaeobotanical material may
be retrievable from the moat-swamp deposits of
Rimatara. Maunutu moat-swamp on the northeast side of Rimatara has been cored to a depth of
14.5 m in two different locations both not reaching
basal parent rock. Material has yet to be submitted
for radiocarbon dating, but it is anticipated that
this material may yield late glacial ages. It has been
found that such moat swamp deposits on other
"makatea" islands in the Cook Islands may reach
depths of more than 16 m below the sedimentary
surface, but the depths of these deposits may be
much greater, potentially below 20 m in depth.
……Phylogeographic evidence for
Pleistocene phytogeography
From phylogenetic evidence it seems probable that
most plant dispersals to the Austral Islands took
place soon after island orogeny in the late Miocene/
Pliocene. Additional plant migration to the archipelago probably occurred via long-distance dispersal
mechanisms, including avian dispersal and floating
propagules, but most of these recent arrivals were
probably taxa already established on the islands.
Little evidence, molecular or otherwise, has been
made available confirming any Pleistocene plant
arrivals of taxa new to the Austral Islands. Wright et
al. (2000) examined the nuclear ribosomal DNA of
the Metrosideros subgenus Metrosideros that includes
~26 anemophilous (wind-dispersed pollen) species
155
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Metrosideros collina (Myrtaceae) (Photo J.-Y. Meyer).
found throughout the Pacific. They identified three
monophyletic clades, two of Miocene age with one
thought to be derived from a Pleistocene dispersal of a species identical to the New Zealand species Metrosideros excelsa, only separated by a single
nucleotide change. Wright et al. (2000) attribute this
late dispersal to a change in late Pleistocene wind
patterns, namely an intensification of the southeast
trades. Using several molecular calibration methods,
Percy et al. (2008) estimate the colonization of the
Hawaiian Islands by Metrosideros to be potentially as
old as 3.9 Myr with an ancestral position on Kauai.
This clearly represents a more ancient arrival of
Metrosideros to the islands than suggested by Wright
et al. (2000). Percy et al. (2008) do agree with the
direction of dispersal from New Zealand indicated
by Wright et al. (2000) and suggest that the Austral
Islands was probably the first stepping-stone.
Two varieties of M. collina are now found throughout Oceania and are found on all of the populated
islands of the Austral Islands, except Rimatara,
although fossil pollen has recently been identified
from that island (M. Prebble unpublished data).
Metrosideros may also have been extirpated on
Easter Island since human colonisation as indicated by fossil Myrtaceae pollen characteristic of
Metrosideros (Flenley et al. 1991).
……Holocene phytogeography of the
Austral Islands
Compared to Pleistocene phytogeography, the
Holocene is relatively well understood from
numerous records (Hope et al. 1999). Holocene
...
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
.. .....
­ hytogeography, prior to human colonization, is
p
primarily controlled by geodynamic processes,
influenced by eustatic and hydro-isostatic sealevel fluctuations. The post-glacial marine transgression of the early Holocene had the regional
effect of enhancing the sediment budget, especially behind accreting river levees, boulder beachridges, and coral reef systems. This increase in
sediment accumulation allowed formerly restricted
coastal vegetation to establish. On most islands
in the Pacific this usually did not take place until
eustatic sea level reached near modern levels by
~8 000 cal. yr B.P.when coastal sediment accumulation reached its peak behind reef bound lagoons
that restricted wave-induced sediment erosion.
Palynological sequences obtained from anaerobic,
organic rich depositional contexts, that have accumulated since the post-glacial marine transgression
in the early Holocene are available in most Pacific
island archipelagos, including the Austral Islands.
Suitable contexts for pollen preservation, such as
large closed lake basins or Sphagnum peat deposits,
are rare in the Pacific Islands and are absent in the
Austral Islands. The lack of closed volcanic lake
calderas and peat bogs in the Austral Islands has
meant that most sedimentary catchments preserving Holocene palaeobotanical remains are located
on levee-backed marshlands (Rapa and Raivavae),
beach-backed swamps (Rapa, Raivavae, Tubuai,
Rurutu) and "makatea" moat swamps (Rurutu and
Rimatara). Deep upland sedimentary deposits are
absent from the Austral Islands, although some
shallow deposits have been located with cores
retrieved, but these have yet to be analysed.
Coastal marshland deposits on the islands can be
characterised on the basis of sedimentary basin
size and morphology, structure of the alluvial/
marine interface and the morphology of offshore
reefs. The largest coastal sedimentary catchments
in the Austral Islands with organic rich marshland
deposits, are found on Tubuai. Cores retrieved
from these sites have yet to be analysed, but preliminary results from Mihiura swamp reveal a
substantial coastal swamp forest dominated by
Pandanus and palm trees including Pritchardia and
Cocos nucifera (Prebble & Dowe 2008). Other trees
growing in abundance within or adjacent to these
swamp forests included a number of extirpated
(e.g. Macaranga) or rare (e.g. Charpentiera) tree
or shrub taxa. Similar records have been retrieved
from Raivavae at Rairua, the largest coastal sedimentary catchment on the island. The largest
coastal sedimentary catchment on Rapa is found at
the head of Haurei (see below). Smaller sedimentary catchments are located at the base of windward
boulder and leeward sandy beach embayments
of the island (Fig. 26). The more deeply incised
windward embayments are characterised by higher
energy fluvial/alluvial systems, but highly organic
fine-grained sediment deposits preserving botanical
Figure 26: Satellite image of Rapa showing the main windward boulder beach and leeward sandy beach embayments. The position
of Tukou and the highest mountain peak are also indicated.
. . . 156
.......
remains tend to be of late Holocene age and often
directly associated with human-induced sedimentation following agricultural expansion (Kennett et
al. 2006; Prebble & Dowe 2008).
A unique characteristic of "makatea" islands, like
Rimatara and Rurutu is the extensive sedimentfilled and waterlogged depressions that extend out
like a moat, between the inner rim of the annular
limestone and the base of the inland volcanic core.
Most of these "moat deposits" are covered with
swamp vegetation. Small ponds are also found
in some locations on Rimatara, lying adjacent to
the "makatea" cliff edge. A series of palaeobotanical records have been retrieved from the most
intact moat-swamp deposits located on Rimatara,
described by Prebble and Wilmshurst (2009). The
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
pre-human record from Maunutu Swamp is dominated by Pandanus and palm swamp forest with
an understorey of Acrostichum fern. Other trees
growing in abundance within or adjacent to these
swamp forests included a number of extirpated
(e.g. Terminalia) or rare (e.g. Homalium) tree or
shrub taxa. This swamp forest was rapidly cleared
after around 800 yr BP during human colonisation
at which time Colocasia esculenta raised fields were
established.
The moat deposits located on Rurutu may yield
significant palaeoecological information, but now
appear to be buried under thick layers of sterile
overburden. Estuarine or lagoon deposits on the
south side of the island may reveal some fossil
material, but this has yet to be established.
PALAEOBOTANICAL EXAMINATION OF TUKOU MARSH, RAPA
……Study site: geography, climate and
vegetation
Haurei harbour on Rapa represents the remnant of
one of the original volcanic calderas formed during
island orogeny and opened to the sea sometime in
the Pliocene. The shallow bathymetry of the harbour
suggests that the entire area was exposed during glacial lowstand sea levels. The exposed reef at the harbour entrance, backed by calcareous reef shoals along
the interior, currently restricts wave-action from the
sea, to the degree that the harbour can be described
as a lagoon. At low tide fine-grained sediments of a
mixture of alluvial sediments, shell and coral detritus
are exposed to reveal three prominent birds-foot river
deltas and tidal flats extending out from the hightide shoreline. Water depth surrounding the Tapuki
("Tapu'i") basaltic islet in the centre of harbour is no
more than 1.5 m below low tide level.
Figure 27: Section of a sketched map of the head of Haurei harbour, Rapa by John Vine Hall (1869a) showing the location of the main
marsh systems ("Taro patches") including Tukou.
157
...
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
.. .....
Shoreward of the exposed deltaic sediments are
a series of levee-backed marshes positioned at
Tukou, Matataa and Aitoke (Fig. 27). All of these
sites have been heavily modified by human activity
and grazing by cattle, horses and goats. A map of
Haurei harbour sketched in 1864 by Captain John
Vine Hall (1869) shows the position of a number
of coastal pondfield systems that were used for
Colocasia esculenta cultivation (Fig. 27). Remnant
dry stonewall terrace features are now interspersed
within many of the levee-backed marshes, along
the margins of riverbeds or situated along the
present shoreline. At certain points, these marshlands extend over 100 m inland and rise to an
elevation of over 3 m above sea-level. On the most
inland side, these marshes are bound either by
river levees or steeply rising embankments of the
surrounding hill slopes that appear to have been
cut by a previous, probably mid-Holocene, sealevel high stand (Fig. 28).
Tukou marsh lies on the south side of the broadest river delta and associated tidal flats of Haurei
harbour. The marsh is banked and divided by
two smaller prograding river channels forming
two waterlogged depressions. The central most
marsh depression was chosen for palaeoenvironmental analysis (Fig. 29) and sediment cores were
taken in 2002 (June-August). The modern marsh
appears to have developed behind the southern
levee of the main river and the northern levee of
the smaller river bounded the marsh to the south.
The marsh extends from the estuarine shoreline,
marked at high tide (~0.4 m above mean sea level)
by driftwood and estuarine detritus, ~135 m to the
embankment of the surrounding hill slope. Below
Figure 28: Approximate position of mid-Holocene highstand
maximum marine incursion after sea-level stabilization at
Tukou (blue line). Up to ~3 m of organic rich sediment has
been accommodated at the site above present high tide/
spring tide line marked by the interface between the marsh
and the tidal flats.
Colocasia esculenta cultivation (Photo J.-Y. Meyer).
the embankment the marsh reaches a maximum
elevation, based on laser transit measurements,
of 3 m above the high tide mark.
The topography of the remnant
agricultural terrace features lie an
additional 50 cm or more above the
marsh surface.
Tukou receives around 2 5003 000 mm annual rainfall based on
measurements taken from Haurei
village, also at sea-level (Rapa Meteo
unpublished data). Tukou is fed by
two permanent streams that drain
the eastern catchment of the PerauNamuere range with water flow
gradients averaging above 30° C.
Hydrological data are unavailable for
this catchment. From readings taken
in 2002, both rainfall and wind are
greatest from June to August with
the average temperature minimums
fluctuating around 15° C reaching as low as 10° C
in August 2002 (Rapa Meteo unpublished data).
Thunder and lightning occur infrequently at any
time of the year with only two storms recorded
from February to March 2002.
. . . 158
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Figure 29: Satellite image of Tukou showing the position of Core 1 (red dot), the multiple profile transect (red line) and the position
of the upper, central and lower marshes and other surrounding features..
The vegetation of the waterlogged marsh surface
is currently dominated by introduced agricultural
grasses (e.g. Paspalum subjugatum) and adventive
herbs (e.g. Commelina diffusa and Ludwigia octovalvis) with some indigenous sedges (e.g. Carex spp.)
and rushes (e.g. Schoenoplectus subulatus subsp. subulatus; some authors suggest that this may have been
introduced to French Polynesia). The embankment
on the periphery of the marsh is largely open grass
with some naturalised Syzgium jambos and Psidium
spp. trees (both in the Myrtaceae). Some indigenous
tree taxa are found at the site including Talipariti tiliacea (Malvaceae) and Metrosideros collina (Myrtaceae).
Hall’s (1868) sketch of the site indicates that stonewall terraces lined the upper portion of the marsh
and were focused along the banks of the adjacent river
channels. Some of these terrace features remain but in
a degraded state. Only one feral C. esculenta specimen
was located at Tukou with no other cultigens identified. The marsh is currently left for cattle grazing.
…
…Field methodology
The vegetation history of Rapa, as inferred from
Tukou marsh, was examined for three main
­purposes. Firstly, to outline the extent of Holocene
vegetation on Rapa; secondly to assess the influence
of fluctuating Holocene sea levels on vegetation
and coastal sedimentation; and lastly the site was
159
Ipomea obscura & Ludwigia octovalvis (Photo J.-Y. Meyer).
...
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
.. .....
Schoenoplectus littoralis (Cyperaceae), Rapa (Photo T. Laitame).
examined for human impact signatures as discussed
in Kennett et al. (2006). In order to assess changes
in vegetation throughout the Holocene, an attempt
was made to obtain the oldest and most continuous section from the marsh. Cores were attempted
in the Haurei lagoon at different intervals between
Tukou marsh and Tapuki islet, using both Russian
D-Section and Livingston corers. The texture of
sediments in the lagoon was such that no core was
retained with sufficient integrity for palynological
analysis. After initial probing, the longest profile
was located at the marsh/lagoon interface (Tukou
Core 1, Fig. 29). This 6.5 m sediment profile was
taken 5 m inland of the shoreline using a 50 mm
Russian D-Section corer down to 5 m below the
marsh surface, with the remaining 1.5 m extracted
using a 35 mm diameter Livingston piston corer.
…
…Laboratory and numerical methods
Each extracted core was taken back to the laboratory
for further analyses including radiocarbon dating, sedimentary, faunal and palynological analyses. Five samples were submitted for Accelerator Mass Spectrometry
(AMS) radiocarbon dating, listed in Table 37. The
calibrations provided were calculated using the OxCal
program version 3.10 with the IntCal04 calibration
data set (Bronk Ramsey 2005). Of these radiocarbon
samples, one leaf sample was submitted along with
three macro-charcoal particles. The remaining sample
was submitted as a pre-treated pollen concentrate,
processed using standard pollen protocols without the
addition of carbon-based acids.
One cubic centimetre (cm3) samples in volume were
taken at approximately 0.10 m intervals throughout each core. Pollen analysis of sediment samples
was conducted using the standard preparation techniques. To enable the calculation of pollen concentrations, Lycopodium clavatum marker spores of a
known number were added. Palynomorph counts
generally amounted to 300. Microscopic charcoal
fragments were also counted for each sample using
the point count method (Clark 1982). Foraminifera
(rotalids indicative of estuarine/intertidal conditions;
J. Reeves pers. comm.) and calcareous dinoflagellates
(indicative of estuarine conditions; M. Young pers.
comm. 2004) within the pollen concentrates were
counted as broad indicators of estuarine/intertidal
environments, but were not identified to taxa due to
dissolution during pollen processing.
Pollen and spore identification was assisted by
reference material collected in the field by the
author and regional reference collections held at
the Australian National University. All pollen taxa
names refer to the family or genera of extant plant
taxa, with the exception of the fossil classification Arecaceae: Iguanurinae type (Prebble & Dowe
2008) derived from an extinct palm of that subtribe. Mineral magnetic susceptibility analysis was
used to detect coarse changes in mineralogy down
the cores. Each core was scanned using a MS/2
Bartington Susceptibility Meter and core loop at
2 cm intervals, in order to identify peaks in magnetic mineral concentration.
All pollen and spores were counted as a ratio to
added exotic Lycopodium spores (per cm3). The
concentration (per cm3) data for pollen, spores
and microcharcoal particles, foraminifera and dinoflagellate counts as well as percentage pollen and
spore data were placed into stratigraphic diagrams
(Figs 30A,B) using the program C2 Data Analysis
version 1.4 (Juggins 2005). Radiocarbon ages, linear age models and magnetic susceptibility data
were also placed in these diagrams. This program
was also used to numerically examine the relationship between samples using correspondence
analysis (CA).
. . . 160
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 37: List of AMS radiocarbon dates obtained from the Tukou Cop1 sediment profiles. Presented are the sample depths,
radiocarbon laboratory (ANU = Australian National University. California = University of California, Irvine. ANSTO = Australian
Nuclear Science and Technology Organisation), material dated, pollen concentrations/cc, laboratory sample codes, uncalibrated
determinations and calibrated ages to 2σ and 2σ central point estimates. Dates from two samples were replicated at 240-242 cm
(Core 3) and 210-212 cm (Core 6) and calibrated using the combine algorithm in the OxCal program version 3.10.
Sample
180-182 cm (California)
232-234 cm (ANU)
Material
dated
Pollen
conc/cc
Leaf
Pollen
39 556
Lab Code
C14
Error
Age (uncal.)
2σ
2 σ central
Error
point estimates
UCIAMS 2196
1 845
30
1870-1700
1785
85
ANU 11921
3 650
190
4550-3450
4000
550
516-518 cm (California)
Charcoal
UCIAMS 2283
5 150
25
5990-5760
5875
115
562-564 cm (California)
Charcoal
UCIAMS 2195
6 700
45
7670-7470
7570
100
582-584 cm (ANU)
Charcoal
ANU 11928
6 520
190
7750-6950
7350
400
624-626 cm (ANU)
Pollen
ANU 11922
7 020
200
8300-7450
7875
425
14 240
PALAEOBOTANICAL RESULTS
……Core stratigraphy, chronology and
eustatic sea levels
The basal sediments (650-600 cm) of the core consist primarily of compacted reddish-brown basaltic
clays with minimal organic content (< 10 %). Above
these clays, a large unit (600-120 cm) encompassing much of the core consists of fine to coarse estuarine sands, silts and differing proportions of shell
and coral debris and other calcareous material.
Magnetic susceptibility measurements (K units)
correspond to increasing proportions of inorganic
(basaltic) mineral sands. Above this unit lies a predominantly organic unit (120-0 cm) with differing
degrees of silt and clay, but lacking any calcareous
material. The upper 22 cm of the core lie above the
high-tide line and consist of sedge (Cyperaceae)
and grass (Paspalum conjugatum) roots.
Five AMS dates were obtained for Tukou Core 1 at
different intervals throughout the core (Table 37)
and these are presented as linear-age models in
stratigraphic diagrams (Figs 30A,B). The most basal
sample submitted for dating located at 624 cm in
depth obtained an age of 8 300-7 450 cal. yr B.P.
(Table 37). Dated from pollen concentrates this
sample represents the most basal age for the Tukou
deposit, but may as discussed below stem from
reworked material. The estuarine sedimentary unit
with calcareous material was dated to between
~8 000 and 2 000 cal. yr B.P. No radiocarbon dates
were obtained from the upper organic unit, thus
the chronology remains uncertain and is discussed
below in the context of palynological markers.
The most detailed chronological measurements
for eustatic sea level change in OIRO come from
an analysis of barrier reef coral cores from coastal
Tahiti (Bard et al. 1996). These have provided
comparable rates of sea level change for the late
Glacial-Holocene period and a linear age model of
this record is presented alongside the age model for
161
the Tukou Core 1 sequence (Figs 30A,B). The three
most basal ages dating from 7 450-8 300 cal. yr B.P.
are all situated at depths deemed to lie above
eustatic sea level at that time. All of these ages have
been taken from depths associated with counts of
foraminifera and dinoflagellates representative of
intertidal or estuarine conditions. From the Tahiti
coral record, Bard et al. (1996) estimates the level
of eustatic sea level to lie at this time between
around -20 and -12 m below current mean sea
level, at least 6 m below the Tukou levels. Either sea
level rose more rapidly on Rapa, or older organic
material at the base of Tukou Core 1 have been
reworked. The later explanation is followed here.
By 6 500 cal. yr B.P., the Tahiti record indicates that
sea levels reached levels represented at the Tukou
Core 1 site. Ages obtained from this core that are
younger than 6 500 cal. yr B.P are assumed to be
consistent with the timing of sediment deposition
and not a product of post-depositional processes.
Direct indications of estuarine or littoral conditions are available from the shell macro-remains of
bivalves, gastropods and other fauna (e.g. crabs).
The highest concentrations (10-15 %) of shell
remains are found at differing depths between
250-150 cm along with whole pieces of coral
debris. Taxa recorded in this section of the core
include bivalves in the Veneridae (Galrarium pectinatum; Clypeomorus sp.) and Mytilidae (Saccostrea
sp.), Tellinidae (Tellina cf. staurella) families (K.
Szabo pers. comm.). In the basal sediments of the
core between 540-250 cm shell concentrations lie
below 5 % with all of the above taxa recorded in
different sections. Saccostrea sp. and crab remains
were recorded throughout this section. Until further analyses of these bivalve remains including
isotopic analyses are undertaken, no definitive
interpretation of the littoral or estuarine environment can be made.
...
.. .....
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
Pollen taxa
Family
Present
in
Tertiary
Present in
early – mid
Holocene
Present in
last 2000
years
Indigenous
representatives
in modern flora
Biogeographic
affinity
Acalypha1
Euphorbiaceae
N
Y
Y
Acalypha spp.
Possible extinct species
Indo-Pacific/Endemic?
Angiopteris
Angiopteridaceae
N
Y
Y
Angiopteris rapensis, A. longifolia
Indo-Pacific/Endemic
Arecaceae: Iguanurinae Type
Arecaceae,
Subfamily Arecoideae,
Tribe Iguanurinae
Y?
Y
Y
Extinct
?
Asteraceae-Tubuliflorae
Asteraceae
N
Y
Y
2
numerous species
?
Asteraceae-Liguliflorae
Asteraceae
N
Y
Y
2
numerous species
?
Casuarina2
Casuarinaceae
N
Y
Y
1
Casuarina equisetifolia
Celtis
Ulmaceae
N
Y
Y
Celtis pacifica
Coprosma
Rubiaceae
Y
Y
Y
Coprosma cookei, C. rapensis
Coprosma spp.
Possible extinct species
Pacific/Endemic
Cyathea
Cyatheaceae
Y
Y
Y
Cyathea affinis, C. medullaris,
C. rapensis, C. stokesii
Indo-Pacific/Endemic
Cyperaceae
Cyperaceae
Y
Y
Y
Numerous species
Pan-tropical,
cosmopolitan
Davallia/Histiopteris
Davalliaceae/
Dennstaedtiaceae
N
Y
Y
Numerous species
Pan-tropical,
cosmopolitan
Dryopteridaceae
Dryopteridaceae
N
Y
Y
Numerous species
Pan-tropical
Euphorbiaceae
Euphorbiaceae
N
Y
Y
Numerous species
?
Freycinetia
Pandanaceae
N
Y
Y
Freycinetia arborea
Indo-Pacific
Glochidion
Euphorbiaceae
N
Y
Y
Glochidion longfieldiae,
G. rapaense, G. societatis
Haloragaceae
Haloragaceae
N
Y
N
Haloragis stokesii
Indo-Pacific/Endemic
Hebe rapensis
Scrophulariaceae
N
Y
Y
Hebe rapensis
New Zealand/Endemic
Hibiscus tiliaceus
Malvaceae
N
Y
Y
Hibiscus tiliaceus
Hypolepis
Dennstaedtiaceae
N
Y
Y
Hypolepis punctata, H. tenuifolia
Lycopodium sp.
Lycopodiaceae
N
Y
Y
Numerous species
?
Malvaceae undifferentiated
Malvaceae
N
Y
Y
Numerous species
?
Meryta
Araliaceae
N
Y
Y
M. chloristantha, M. brachypoda
Monolete Psilate
?
N
Y
Y
Numerous species
?
Monolete undiff.
?
N
Y
Y
Numerous species
?
Myrtaceae undiff.
Myrtaceae
N
Y
Y
Numerous species
?
Omalanthus
Euphorbiaceae
Y
Y
N
Omalanthus nutans, O. stokesii
Indo-Pacific/Endemic
Pandanus cf. tectorius
Pandanus
N
Y
Y
Pandanus tectorius
Indo-Pacific/Endemic?
Poaceae
Poaceae
Y
Y
Y
Numerous species
?
Pteris
Pteridaceae
N
Y
Y
Numerous species
?
Polypodiaceae
Polypodiaceae
Y
Y
Y
Numerous species
?
Rubiaceae
Rubiaceae
Y
Y
Y
Numerous species
?
Sophora
Fabaceae
N
Y
Y
Sophora tomentosa
Pacific
Trilete Psilate
?
Y
Y
Y
Numerous species
?
Trilete undiff.
?
Y
Y
Y
Numerous species
?
Triumfetta comp.
Malvaceae
N
Y
Y
Triumfetta procumbens
Urticaceae/Moraceae
Urticaceae/Moraceae
N
Y
Y
Numerous species
. . . 162
Indo-Pacific, probably
exotic/contamination
Indo-Pacific
?
Indo-Pacific
Indo-Pacific/Pan-tropical
Indo-Pacific
Indo-Pacific
?
.......
Table 38: Palynomorphs from Tukou Core 1. Listed are the
presence or absence of palynomorphs in Tertiary and midHolocene sediments or from sediments < 2 000 cal. yr B.P.
in age. Also listed are the possible representatives of the
palynomorphs found in the modern flora and the biogeographic
affinity of taxa.
1Pollen or spore type wind blown. 2Pollen or spore type capable
of long distance dispersal (after Close et al. 1978).
…
…Palynological analysis
The different palynomorphs identified from Tukou
Core 1 are listed in Table 38, along with their presence or absence in Tertiary, mid-Holocene and
< 2000 cal. yr B.P. aged sediments and their biogeographic affinity. Proportional palynological data are
also presented in stratigraphic diagrams according to
the occurrence of taxa throughout the core in proportions of either > 5 (Fig. 30A) or < 5 % (Fig. 30B).
Taxa are grouped from left to right according trees
and shrub, herb, fern and fern ally groups. Taxa are
sorted within these groups in stratigraphic succession
using the sort function in C2 Data Analysis program
(Juggins 2005). The core is divided into four palynological zones on the basis of major vegetation changes.
Zone I (650 to 245 cm; ~6 500 - 4 000 cal. yr B.P.)
Trilete fern spores including Cyathea tree fern and
Angiopteris types dominate this Zone. Palynomorph
concentrations remain low until ~6 500 cal. yr B.P.
after which time concentrations reach their highest
in the early Holocene until 5 000 cal. yr B.P. Tree and
shrub taxa are only preserved in low percentages or
trace counts or percentages. Pandanus cf. tectorius type
pollen does not enter the record in percentages > 5 %
until after 6 000 cal. yr B.P. Triumfetta (probably T.
procumbens), Euphorbiaceae and Myrtaceae pollen are
the most consistently represented tree and shrub taxa
found in this Zone. Both foraminifera and dinoflagellates are found in trace counts at the base of this Zone
but were not located after around 5 000 cal. yr B.P.
From 6 500 cal. yr B.P. the Arecaceae: Iguanurinae
type pollen appears in the record.
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Iguanurinae type pollen become more consistently
represented in this Zone.
Zone IV (85 to 0 cm; ~1 000 cal. yr B.P. to present)
Apart from Myrtaceae (undifferentiated to species)
pollen, all tree and shrub taxa and trilete type fern
spores decline or are absent in this Zone. Charcoal
particles first appear in high concentrations at
the base of this zone. Pandanus cf. tectorius type
peaks to its highest recorded levels at the base of
this Zone. Charcoal concentrations and Pandanus
proportions decline to low levels in association
with a sedimentary change at around 50 cm below
the marsh surface. Cyperaceae and Poaceae (both
< 40 μm and > 40 μm size classes) and palynomorph concentrations increase to their highest
levels at the top of this Zone.
……
Correspondence analysis (CA)
Correspondence analysis was performed on the percentage data all pollen and spore taxa identified in
Tukou Core 1. Eigenvalues (Axis 1) generated for
each sample are presented as proportions of the total
variation in the dataset in each of the two stratigraphic diagrams (Fig. 30A and 30B). These values
account for 36 % of the variation in the entire dataset.
These values are primarily controlled by the proportions of Pandanus cf. tectorius type pollen within
each sample. The greatest variation that exhibited in
this core occurs in the basal section of Zone I from
~6 500 - 6 000 μm cal. yr B.P. and in Zones II and IV.
Zone II (255 to 145 cm; ~4 000 - 1 500 cal. yr B.P.)
Fern spores continue to dominate the early part
of this Zone but in fluctuating proportions and
decrease by 3 000 cal. yr B.P. in response to increasing Pandanus cf. tectorius and Cyperaceae pollen. Palynomorph concentrations decline from the
base of this Zone to the lowest recorded concentrations recorded at the top of the zone from
3 000 - 2 000 cal. yr B.P. Both foraminifera and dinoflagellates reappear in the early part of this Zone
from 4 000 to 3 000 cal. yr B.P.
Zone III (145 to 85 cm; ~1 500 - 1 000 cal. yr B.P.)
Pandanus cf. tectorius pollen along with palynomorph concentrations increase from the base of
this Zone. Trilete fern spores including Cyathea
tree fern and Angiopteris types decline in this
Zone. Celtis (probably C. pacifica) and Arecaceae:
163
Pandanus tectorius (Photo J.-Y. Meyer).
...
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
.. .....
Figure 30A: Percentage
pollen diagram for Tukou
Core 1 (total of 6.55 m).
The following are presented
in the diagram from left
to right: Core lithology
(> 0 = increasingly coarse),
magnetic susceptibility values
(k), calibrated radiocarbon
ages (line and ticks with the
Tahitian sea-level curved
overlayed in green after Bard
et al. 1996), taxa (pollen
and spores: taxa with ≥ 5 %
of total palynomorph sum
are presented as colour
coded bars; samples with
proportions < 5 % are
presented as triangle symbols)
and total palynomorph
concentrations (per cm3),
microcharcoal particle
concentrations (per cm3),
foraminifera and dinoflagellate
counts, palynomorph
richness (number of taxa),
Correspondence Analysis
scores (CA score 1) and
palynological zones.
Four palynological zones
(Early Holocene Marine
Transgression Zone I; MidHolocene highstand Zone II;
Late Holocene swamp forest
Zone III; Human impact
Zone IV) are presented. The
dashed black line indicates
the position of the high
tide line. The horizontal
transparent red bar indicates
the section of the core
where the sedimentary unit
associated with palynological
signatures of human impact
(namely micro-charcoal
particles) are poorly
constrained by radiocarbon ages.
. . . 164
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Figure 30B: Percentage
pollen diagram for Tukou
Core 1 (total of 6.55 m).
The following are presented
in the diagram from left
to right: Core lithology
(> 0 = increasingly coarse),
magnetic susceptibility values
(k), calibrated radiocarbon
ages (line and ticks with the
Tahitian sea-level curved
overlayed in green after
Bard et al. 1996), (pollen
and spores: taxa with
< 5 % are presented as
coloured triangle symbols)
and total palynomorph
concentrations (per cm3),
microcharcoal particle
concentrations (per cm3),
foraminifera and dinoflagellate
counts, palynomorph
richness (number of taxa),
Correspondence Analysis
scores (CA score 1) and
palynological zones.
Four palynological zones
(Early Holocene Marine
Transgression Zone I; MidHolocene highstand Zone II;
Late Holocene swamp forest
Zone III; Human impact
Zone IV) are presented. The
dashed black line indicates
the position of the high
tide line. The horizontal
transparent red bar indicates
the section of the core
where the sedimentary unit
associated with palynological
signatures of human impact
(namely micro-charcoal
particles) are poorly
constrained by radiocarbon
ages as shown in Figure 30A.
165
...
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
.. .....
SUMMARY OF TUKOU CORE 1
……Early Holocene marine transgression
Zone I (~6 500 - 4 000 cal. yr B.P.)
The dominance of ferns (e.g. Angiopteris) and
Cyathea tree ferns from ~6 500 cal. yr B.P. indicate a waterlogged swamp setting characterised by
prominent alluvial sedimentation infilling an intertidal embayment indicated by the presence of foraminifera, dinoflagellates and littoral/intertidal shell
remains. Some tree and shrubs including Pandanus
and Triumfetta (a coastal strand taxon) were located
along the coastal surrounding the throughout this
Zone. The extinct Arecaceae: Iguanurinae type
palm became prominent on the coastline after
around 6 500 cal. yr B.P.
……Mid-Holocene highstand Zone II
(~4 000 - 1 500 cal. yr B.P.)
Fluctuation in the estuarine hydrology of the waterlogged fern swamp from 4 000 - 3 000 cal. yr B.P. is
indicated by traces of both foraminifera and dinoflagellates as well as differing proportions of littoral/intertidal shell remains at irregular depths. A
coastal Pandanus forest with a sedge (Cyperaceae)
understorey is represented but is restricted to the
brackish/freshwater periphery of the fern swamp
and estuary after 3 000 cal. yr B.P. This swamp forest is restricted from expanding by high sediment
mobility from both transgressive and regressive
hydrological influences inferred from extremely
low palynomorph concentrations (see below for
further discussion).
……Late Holocene swamp forest Zone III
(~1 500 to 1 000 cal. yr B.P.)
After around 1 500 cal. yr B.P. the Pandanus coastal
forest expanded behind a prograding tidal-river
levee indicated by a magnetic susceptibility peak
(high mineral sedimentation) and the absence of
calcareous shell remains. This restricted any tidal
influence on the site and allowed the predominantly freshwater swamp to develop. Other taxa
including Celtis and the Arecaceae: Iguanurinae
type palm become established within this developing swamp forest.
……Human impact ZonetoIVpresent)
(< 1 000 cal. yr B.P.
This Zone, divided into two parts, is characterised
by palaeoenvironmental human impact signatures
including swamp forest decline in response to
burning indicated by peaks in microcharcoal particles. From the presence of charcoal particles radiocarbon dated from Zone I it is clear that burning
was part of the pre-human island ecosystem. An
interpretation of charcoal particles present in Zone
IV may therefore remain equivocal in the absence
of other human impact indicators. This problem is
illustrated by the peaks in charcoal particles in the
first part of this Zone (highlighted in Figs 30A,B)
that are followed by an increase in Pandanus cf.
tectorius representation. Peaks in Pandanus pollen may be representative of one of the following:
sediment compaction in the early part of this Zone
allowing for pollen to accumulate and become
more concentrated with depth; the opening of forest conditions allowing for more pollen deposition;
or the possibility that Pandanus responds to burning by increased flowering and pollen production.
The abrupt decline in Pandanus in the later part
of this Zone (above 50 cm below marsh surface)
appears to represent a more precise indication of
human activity. This palynological signature of
coastal swamp forest clearance appears similar in
extent to that represented by the modern marsh at
Tukou. The decline in charcoal signals in this later
part may represent a decreased in the amount of
available fuel available for burning at Tukou after
an initial peak in human-induced fires.
EARLY HOLOCENE MARINE TRANSGRESSION AND VEGETATION CHANGE
The prominence of long-dispersal ability, as a feature of the Austral Islands flora (see chapter by
Meyer et al., this volume), has led to selective
immigration, and is responsible for many characteristic features of tropical/sub-tropical island floras,
particularly during periods of lowered sea-level and
consequent land expansion. The early Holocene
sea-level transgression must have restricted the
retention of coastal taxa, but its effect on the range
of endemic taxa remains difficult to assess. Disjunct
patterns of representation of endemic taxa in the
Austral Islands may be directly caused by repeated
sea-transgressions/inundation. As Paulay (1985)
has suggested, on the highest islands montane
cloud forests may have extended down in elevation
to encompass a greater area during sea-level low
stands. However, during the post-glacial marine
transgression, genetically isolated populations may
have been created within each of the main valleys,
that were formerly connected along the now inundated coastal margins. Some tree and shrubs including Pandanus and Triumfetta may have been more
prominent on the coast of Rapa prior to inundation.
……Mid-Holocene sea-level and
vegetation change
The most pronounced feature of the mid-Holocene
record at Tukou is the development of coastal
. . . 166
.......
swamp forest vegetation. Records of swamp forest
development elsewhere in the Pacific following
mid-Holocene sea level change are available from
mangrove pollen studies in Micronesia (e.g. Ward
1988; Kawana et al. 1995) and Tonga (Ellison
1989, 1991). No "true" mangrove taxa are presently known from the Austral Islands or in the subfossil record, but some of the specialised growth
forms and life-histories that characterises the mangrove habit, namely aerial prop or stilt root growth
phases, are found in a few coastal strand species
(e.g. Ficus and Pandanus species). Prop roots are
found in many species of Pandanus (Pandanaceae),
notably on the most widespread species, P. tectorius (Stone 1976, 1988; St. John 1979). Tomlinson
(1986) regards them as a stabilising feature of older
trunked trees. P. tectorius is found throughout the
tropical and subtropical Indian and Pacific Oceans
in substrates ranging from freshwater swamps
to coastal rocky beaches and seasonally brackish periphery of the tidal zone. For their ability
to establish on these wide-ranging environments
some Pandanus species have been described as
"freshwater mangroves".
Pandanus tectorius is a common swamp and dry
land forest tree found throughout the Austral
Islands and on other islands in the region, it commonly forms monospecific stands with a sedge/
herb dominated understorey (Ash & Ash 1984).
As no "true" mangrove species occur in the Austral
Islands, P. tectorius appears to assume the role of
the mangrove type habit, forming dense stands
along the few margins of tidal flats where human
activity has not been prominent.
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Other Pandanus species may be indigenous to
the Austral Islands, for example Harold St. John
recorded 13 species of Pandanus on Rapa in 1934
and made a similar number of Pandanus species
determinations for many Pacific Islands (e.g. Fiji,
St. John 1976). Stone (1988) and Smith (1981)
suggest many of these are simply varieties of P.
tectorius. In examining the genus on Tahiti, Stone
(1988) could not discount the human introduction of additional of Pandanus species or P. tectorius
varieties.
The tree has an unusual life history rarely found in
perennial plants (Hallé et al. 1978) that may be an
adaptation to coastal strand environments. From a
study of Fijian populations, Ash (1987) found that P.
tectorius prop roots usually do not develop until 5-12
years after a semi-prostrate growth and trunk growth
phase. Prop root growths coincide with a flowering
phase that may last for up to 40 years. Like "true"
mangrove species this growth form allows these trees
to adjust to mobile sediment regimes, but also to
accrete sediment immediately behind the prop roots,
creating an autogenic environment suitable for P.
tectorius but also pollen preservation.
P. tectorius is a species which produces vast amounts
of pollen, a strategy not often exhibited in perennial
dioecious taxa. Pandanus pollen grains are generally
dispersed by wind (anemophily) or small invertebrates (entomophily) (Meilleur et al. 1997). Modern
pollen studies of Pandanus suggest it is only locally
dispersed, though one case of long distance dispersal,
presumably by river transport, to deep-sea sediments
has been recorded by Van der Kaars (1991). One
study from a series of lowland swamp forest sites in
Table 39: Additional palynomorphs recorded from Tukou Cores 2-6 not recorded in Core 1. Listed are the presence or absence
of palynomorphs in Tertiary sediment (after Cranwell 1964), early to mid-Holocene sediments (Zones II and III) and in Zone IV
sediments aged < 1 000 cal. yr BP, the botanical status and biogeographic affinity of taxa.
Pollen taxa
Amaranthaceae
Family
Amaranthaceae
Arecaceae/Liliaceae Arecaceae/Liliaceae
Present in Present in Present in Present in
Tertiary
Zone II
Zone III
Zone IV
Indigenous
representatives in
modern flora
Biogeographic
affinity
N
Y
N
Y
?
Pan-tropical/Endemic?
N
Y
Y
Y
?
?
Canavalia
Fabaceae
N
N
N
Y
Canavalia sericea
Canavalia spp.
Possible extinct species
Indo-Pacific/Endemic?
cf. Psychotria
Rubiaceae
N
N
Y
N
Psychotria rapensis
Endemic
Dicranopteris
Gleicheniaceae
N
Y
Y
Y
Dicranopteris linearis
Indo-Pacific
Dodonaea viscosa
Sapindaceae
Y?
Y
Y
Y
Dodonaea viscosa
Indo-Pacific
Geniostoma
Loganiaceae
N
Y
Y
Y
G. quadrangulare,
Indo-Pacific/Endemic
G. rapense,
G. rupestre var. micranthum
Myoporum
Myoporaceae
N
Y
Y
N
Myoporum rapense
Santalaceae
Santalaceae
N
Y
N
N
Exocarpos psilitiformis,
Santalum insulare var. Indo-Pacific/Endemic
margaretae
Scaevola taccada
Goodeniaceae
N
N
Y
N
Scaevola taccada
167
...
Indo-Pacific/Endemic
Indo-Pacific
.. .....
The Paleobotanical Record of Rapa:
Indications for the Phytogeography
Canavalia sericea (Fabaceae) (Photo J.-Y. Meyer).
Southeast Asia (Anderson & Muller 1975) found that
pollen representation may be poor from sites dominant in Pandanus, but this may be due to differential
pollen production of species other than P. tectorius.
The Tukou Core 1 palynological record (Figs 30A,B)
outlines the coastal significance of P. tectorius from
the early Holocene. The morphological variability of
pollen located in this core and other cores from Rapa
and Rimatara (see below) is such that P. tectorius
seems the most likely species ascribed to this pollen.
It is likely that for this reason no other species will
be discernable with any certainty. From Zone III of
the Tukou Core 1 sequence I suggest that Pandanus
tectorius swamp forest expanded behind a prograding tidal-river levee after around 2 000 cal. yr B.P.
This levee probably appeared due to accreting sediments built up behind developing Pandanus prop
roots during a period of stable sea level. This autogenic process acted to restrict any tidal influence on
the site and allowed the predominantly freshwater
swamp to develop. Other taxa including Celtis and
the Arecaceae: Iguanurinae type palm become established within this developing swamp forest. The
mid-Holocene swamp forest expansion described
may have allowed many plant taxa to establish on
the island in a formerly restricted or unavailable
environment.
Palynological data from five other mid-Holocene
aged cores obtained from Tukou along a 100 m
transect, extending inland from the Core 1 location, reveal a number of additional taxa not identified in Core 1 (Table 39). Important amongst these
taxa are Santalaceae (either Exocarpos psilitiformis, or
Santalum insulare var. margaretae) discussed in regard
to historical exploitation by Butaud et al. (2005) and
Butaud et al. (see chapter by Butaud et al., this volume), Myoporum and Geniostoma which have endemic
representatives in the modern flora. Macrobotanical
remains identified from these same five other cores,
mostly in the form of seeds (Table 40), provides evidence of local presence of Celtis pacifica, Meryta and
Pandanus tectorius with some tentative identifications
of Astelia, Zanthoxylum, Apocynaceae and possibly an
extinct Lepidium.
Table 40: Macrobotanical remains recorded from Tukou Cores 1-6. Listed are the presence or absence of material in pre-human
Holocene sediments (Zones I, II and III) and in Zone IV sediments aged < 1 000 cal. yr B.P., the botanical status and biogeographic
affinity of taxa.
Pollen taxa
cf. Apocynaceae
Family
Apocynaceae
Material
Present in
pre-human
zones
Material present
in human impact
Zone IV
seed
Y
N
Indigenous
representatives
in modern flora
Biogeographic
affinity
Indo-Pacific?
seed
Y
N
M. chloristantha,
M. brachypoda
Brassicaceae
N
Y
N
EXTINCT
Indo-Pacific
Liliaceae
N
Y
N
Astelia rapensis
Endemic
Indo-Pacific
Meryta
Araliaceae
cf. Lepidium
cf. Astelia
Pandanus cf. tectorius Pandanaceae
Y
Y
N
Pandanus cf.
tectorius
Austral Islands endemic
cf. Zanthoxylum
Rutaceae
seed
Y
N
Zanthoxylum
Indo-Pacific
Celtis pacifica
Ulmaceae
seed
Y
N
Celtis pacifica
Indo-Pacific
. . . 168
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
HUMAN IMPACT AND VEGETATION CHANGE
Palaeoenvironmental research in the Pacific Islands
has focused on the issue of whether vegetation
change in late Holocene records can be used as a
proxy of human impact and initial colonization,
especially in situations where the archaeological
record remains ambiguous (Flenley et al. 1991;
Spriggs & Anderson 1993; Kirch & Ellison 1994;
Parkes 1997; Dodson & Intoh 1999; Stevenson
et al. 2001; Athens et al. 2002; Anderson 2003).
Palaeobotanical records now provide a robust
proxy for human activity, particularly in remote
archipelagos like the Austral Islands, as human colonisation was late on these islands. Palaeobotanical
research conducted on Rapa (Kennett et al. 2006)
by the author on Haurei sediments recorded the
introduction of agriculture signaled by the appearance in sedimentary sequences of introduced plant
cultigen pollen (e.g. Colocasia esculenta). Such
evidence provides an unequivocal human introduction and its appearance parallels evidence for
burning as indicated by increasing charcoal concentrations in the same records and the decline in
arboreal pollen types. The rise of pollen and spores
of seral taxa are also found to increase in conjunction with more colluvial sedimentation.
The human colonisation sequence on Rapa, evident in the palaeobotanical record and familiar to
most remote Pacific islands settled within the last
1 500 cal. yr B.P., involved the substantial alteration of the environment in the form of lowland
deforestation and the establishment of extensive
agricultural systems. The decline of a Pandanus/
palm tree swamp forest is a feature of this record,
although several other taxa identified in pre-human
aged sediments are not found after 800 cal. yr B.P.
(Omalanthus, Myoporum, Santalaceae, Lepidium,
Amaranthaceae and Haloragis). Decline in these
taxa may reflect a direct response to humaninduced forest clearance, but may also represent
the environmental impact of rat (Rattus exulans)
introduction , or a response to the extinction of key
bird dispersers including cf. Ducula, Gallirallus and
Cyanoramphus (Tennyson & Anderson 2012).
CONCLUSIONS
From the palaeobotanical research conducted on
Rapa, the diversity and endemic character of the
flora, with its high representation of sub-tropical
Pacific lineages, is a fragmented relict of a formerly more diverse flora. Many of the endemic
genera represented on the island probably did
not evolve as endemics in situ but became extinct
on other island groups either from preceding
climatic or geological events (namely sea-level
fluctuations) or through extensive environmental impact associated with human impact. The
169
relative floral richness of Rapa compared with
the other islands in the Austral Islands, discussed
by Meyer et al. (see chapter by Meyer et al., this
volume) is intriguing. I suggest that the island’s
elevation and geographic/geomorphic diversity,
including the size of the eroded volcanic calderas
and disjunct valley systems, may have maintained
greater habitat heterogeneity, allowing endemic
species to survive despite the intense and continuing environmental degradation, following
human settlement evident on the Austral Islands.
...
Sandalwood (Santalum insulare) formerly planted on Tubuai Island, May 2012 (Photo J.-F. Butaud).
. . . 170
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Sandalwood
Current State of Knowledge
Butaud, Jean-Pierre Bianchini,
and Implications Jean-François
Jean-Marc Bouvet, Vincent Gaydou,
Émeline Lhuillier,
for Conservation
Phila Raharivelomanana & Fanny Rives
and Enhancement
Sandalwood is a small, root hemiparasitic tree, prized worldwide for
the distinctive fragrance of its heartwood (its sapwood has no scent).
Sandalwood essential oil, extracted
by distillation of the wood, is used
in perfumery and aromatherapy. In
India and China, sandalwood has
been used in religious ceremonies
for thousands of years, particulary as temple incense (Ehrhart &
Nasi1996).
There are 16 species of sandalwood,
exclusively distributed in the IndoPacific region (Barrett & Fox 1995).
The most commonly known species,
the white sandalwood (due to the
pale color of its heartwood) or Indian
sandalwood (Santalum album), grows
naturally and is cultivated in India, Indonesia, and
Australia, but has also been introduced into many
countries including French Polynesia. Other known
species are the yellow sandalwoods (with a yellowish heartwood) from New Caledonia (Santalum
austrocaledonicum) and Fiji (Santalum yasi).
Marotiri), despite several indications on Tubuai
(Aitken 1930; Sam Tahuhuterani pers. comm.
2002). Furthermore, surveys done under the present scientific program did not identify any introduced species of sandalwoods. However, it is likely
that the Indian sandalwood is present in gardens
on Tubuai and Rurutu, the most populated islands.
……History
of the discovery
and exploitation of sandalwood
…
…The sandalwood in French Polynesia
There is only one native species of sandalwood
from the Austral Islands
In 1896, Jean Nadeaud was the first botanist to
obtain the information on the Austral Islands sandalwood, in this case that of Raivavae (Nadeaud
1896). However, these sandalwood populations
had been made known to the western world some
70 years earlier, at the time of the sandalwood traders and the triangular trade between the AngloSaxon sailors, China, and the Pacific islanders. The
latter supplied wood to the sailors in exchange for
metal objects, fabric, whaleboats, weapons and
liquor. Sandalwood traders used the wood as an
exchange currency with China, mainly for tea
(Shineberg 1967; Dening 1980).
The stock of sandalwoods on the two (or three)
islands must have been low compared to Fiji, the
Marquesas, Hawaii, or New Caledonia as there are
very few traces left of this exploitation.
in French Polynesia, the eastern Polynesian sandalwood (Santalum insulare). This species is also
found on the Cook Islands (Mitiaro only) and on
the Pitcairn Islands (Henderson only), hence it is
endemic to eastern Polynesia. In contrast, the Indian,
New Caledonian, and Fijian sandalwoods were introduced relatively recently to French Polynesia for
timber. Among these three species, the Indian sandalwood is now a naturalized species on the semidry hills of the northwestern coast of Tahiti, on
Moorea and Hiva Oa (Butaud & Defranoux 2007).
Botanists have divided Santalum insulare into
nine varieties restricted to the different archipelagos, based on their anatomy (flowers, fruits, and
leaves) (Fosberg & Sachet 1985). Of these nine
varieties, two are found on the Austral Islands: the
first is endemic to Raivavae (var. raivavense) and
the second to Rapa (var. margaretae). Botanists
and foresters have never been able to demonstrate
the presence of sandalwood on the other Austral
Islands (Maria, Rimatara, Rurutu, Tubuai, and
Raivavae
According to Edwards (2003, partially quoting
Maude 1968): "Sandalwood traders were coming to
Raivavae in the 19th century. Captain Fodger convinced the locals to supply 1.5 tons of sandalwood in
1812 (Maude 1968: 196) and in 1819, Captain Lewis
agreed with the Tahitian King Pomare II to take him to
Tubuai and Raivavae in exchange of sandalwood from
Raivavae. There are very few records of visits of sandalwood traders on Raivavae but sandalwood was as
at the time the main commodity in eastern Polynesia.
It is therefore likely that other traders came. Oral
tradition confirms this allegation as the top of the
Taamaa peninsula (probably Taamora, the summit
of Vaianaua peninsula) was allegedly covered with
sandalwood forest. Today, it is mainly grasslands.
(…) In 1817, sandalwood was the main commodity of
the eastern Pacific but trade was declining due to the
depletion of sandalwood resources on many islands.
In addition, the Australian government imposed a tax
171
...
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
.. .....
of 2.10 pounds per ton of sandalwood (and motherof-pearl) (Maude 1968: 200). An important reserve
of sandalwood remained on Raivavae and Tubuai, but
high demographic pressure on limited resources caused
frequent tribal wars which sidelined the trade and the
flow of highly desirable European goods".
Maude & Crocombe (1962) further mentioned
that Captain Michael Fodger of the Daphne
obtained 1.5 tons of sandalwood as ransom for the
release of a Raivavae chief he held hostage. This is
more proof of the brutality of sandalwood traders
throughout Polynesia.
Fodger was the first to mention the presence of
sandalwoods on Raivavae. Captain Lewis of The
Arab was persuaded by Pomare II to take him to
the island in exchange for sandalwood, following
the information provided by Fodger (Massal 1973).
Rapa
Hanson (1973) recounts: "In 1825, taking advantage
of a stopover on Rapa, the galley Snapper loaded several tons of sandalwood. In 1826, an English trader
settled on the island for the exploitation of resources,
including sandalwood, a commodity highly-prized by
the Chinese at the time". Shineberg (1967) notes that
sandalwood had been found on the Austral Islands
in the 1820s: "Captain Ebrill brought back 40 tons
from his 1826 voyage, and 28 tons in his 50-ton
schooner the year after”. However, she questions
the veracity of the statements made by sandalwood
traders who might have wanted to conceal a more
important source of sandalwood (New Hebrides).
Given that these two sources are concordant, it is
highly likely that part of the sandalwood exploitation
on Rapa (and, similarly, on Raivavae) occurred in the
mid-1820s. These dates and information are reported
in the Encyclopédie de la Polynésie (Toullelan 1986).
Based on an average weight of 50 kg of heartwood
per tree, the 70 tons of sandalwood harvested on
Rapa represented about 1 750 individual trees.
Assessement
Sandalwood was occasionally exploited on the Austral
Islands over two decades (from 1812 to 1827). This
consisted of uprooting the trees, stripping them
of their sapwood on the spot and transporting the
logs to the seashore. Tree populations were thus
overexploited. J. Nadeaud (1896) noted that sandalwood used to be abundant on Raivavae, but that the
populations were plundered for sale (or bartering).
However, Edwards (2003) indicated that tribal wars
interrupted the sandalwood trade on Raivavae and
that much wood remained during the first quarter of
the 19th century. Nevertheless, it is possible that the
remaining populations were exploited between 1830
and the end of the 19th century.
TRADITIONAL AND CONTEMPORARY USES OF SANDALWOOD
ON THE AUSTRAL ISLANDS
The Polynesian name for sandalwood on the
Austral Islands is the same on Raivavae and Rapa:
"ahi". Early botanists sometimes spelled it "eahi",
including the "e" meaning "the" or "this". In comparison, sandalwood is called "ahi" on the Society
Islands, "puahi" on the Marquesas Islands, and
"a'i" on the Cook Islands.
As elsewhere in the Pacific (Brown 1935; Shineberg
1967), the inhabitants of the Austral Islands, in
particular those of Raivavae (Nadeaud 1896), identified several varieties of sandalwood based on the
qualities of the heartwood (scent, color, hardness).
It appears that regardless of the species, there are
roughly three varieties:
• a high-quality dark sandalwood often called red,
• a relatively high-quality sandalwood called yellow,
• a low-quality sandalwood called white.
These names have led to some confusion between the
high-quality Indian white sandalwood and the lowquality variety (white) of Polynesian red sandalwood.
As far as Raivavae is concerned, J. Nadeaud noted in
1896, from the account of one of his acquaintances,
a native of the island, the different varieties recognized by the islanders:
• The "ahi mara aito" with hard and dark wood;
• The "ahi popouru" with soft and very fragrant
wood, the real "ahi";
• The "ahi tiare", called "ahi marea" by the
Tahitians, with a pale yellow wood.
While the inhabitants of Raivavae distinguished
the different varieties, we have no record of any
traditional use from the island even if it is likely
that many uses existed. An ethnobotanical study
of the island should help collect more information
even if some knowledge has been lost.
On Rapa, sandalwood was only used as fuel wood
due to its pleasant smell. It is likely that it was also
appreciated for its insect repellent properties.
Aitken, an ethnologist who studied life on Tubuai
in the 1920s (Aitken 1930), reported several uses
of sandalwood on the island. Unfortunately, it cannot be determined whether these applied to the
local sandalwood or to that from Raivavae. Nor is it
known whether the inhabitants practicing such uses
were those who originally came from other islands.
Indeed, Aitken’s inventory of the plants of the island
does not include the sandalwood or "ahi/eahi/iahi".
The reported uses included the following:
• Flowers and pieces of sandalwood or rosewood
are placed in the box used to store clean laundry.
• Sandalwood was used to perfume the tapa.
• "Raau vari": cure for painful periods or lack of
menstruation. Mix the water of four green coconuts with a handful of dried sandalwood pow-
. . . 172
.......
der. Dosage: half a glass of the warmed liquid
followed by the same quantity cold. Repeat
three times a day until healed.
• "Raau taria mai": cure for ear pains or ear abscess. Crush six red leaves and six green leaves of
"tou" (Cordia subcordata); add a small quantity
of "monoi ahi" (coconut oil with sandalwood).
Pour a small quantity of juice directly in the ear,
several times a day. The mixture can be slightly
warmed before application.
It is interesting to note that both medicinal recipes
are very similar to Marquesan recipes.
There is clearly an imbalance of available information
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
between Tubuai, where there is little or no sandalwood left, and Raivavae and Rapa, where natural populations remain. It suggests that some
knowledge on the Raivavae and Rapa sandalwoods
must have been overlooked or lost. Ethnobotanical
­studies of both islands are highly desirable in order
to preserve any remaining knowledge.
During the past ten years or so, a demand for sandalwood has arisen on Raivavae (no commercial
prospect for sandalwood exists on Rapa, where there
are only relict populations). Sandalwood is transformed and sold as hairpins, powder to perfume the
monoi or even as raw wood on Raivavae or Tahiti.
BOTANICAL DESCRIPTION OF THE SANDALWOOD
FROM THE AUSTRAL ISLANDS
…
… Botanical history
The first samples of sandalwood from the Austral
Islands were collected in 1921 by a couple of
American ethnologists, the Stokes, who spent several months on both islands (mainly on Rapa). In
1935, the American botanist F.B.H. Brown used the
two samples to describe two new taxa:
• Santalum insulare var. raivavense for the
Raivavae sandalwood, considering the variety
to be very close to the Tahitian one (Santalum
insulare var. insulare),
• Santalum margaretae for the Rapa sandalwood, considering that the anatomical differences from the Tahitian variety were significant
enough to describe it as a different species.
In 1938, C. Skottsberg, using the samples collected
by H. St John and F.R. Fosberg during the 1934
Mangarevan Expedition, validated Santalum insulare
var. raivavense and reduced the Rapa sandalwood
to a simple variety of the Polynesian sandalwood,
Santalum insulare var. margaretae, considering that
the observed variation did not justify its naming as
a distinct species (Skottsberg 1938).
The lastest study, by Fosberg & Sachet in 1985,
maintained and repositioned both varieties within
the nine botanical varieties of Santalum insulare of
eastern Polynesia and considered the species as a
variable complex.
…
…Recent morphological data
The botanical descriptions by Fosberg & Sachet
(1985) can be amended with our own observations
and collections of fruits (N = 36), seeds (N = 206),
and leaves (N = 520). While hundreds of measures
of seeds and leaves were taken during the different
missions, the former descriptions were based only
on three collections for the Rapa variety and eight
for the Raivavae variety. In addition, no description of the mature fruit was available for either
variety; the fruit described from Rapa was clearly
immature. The newly acquired data are presented
in Tables 41 and 42.
173
Fruits and Seeds
During the various expeditions, fruits, seeds (shell and
kernel), and shell pieces (endocarp) were collected
from the various populations. Sometimes, the only
parts available were leftover seeds gnawed by rats. The
figures in Table 41 relate to mature fruits and fully
developed seeds except the fruit collected on Rapa.
Only one green fruit, shaped as a double pear (narrowed at the apex and base) was observed on Rapa
on a tree in the Karapoo Rahi population. Three old
nuts damaged by rats were found on the ground in
Anatakuri Nako and a single one in Karapoo Rahi. The
green fruit was close to maturity as its seed was well
developed and hard. However, it is likely that a mature
fruit would have been 1 or 2 mm bigger than the green
fruit, making it 28 mm long and 19 mm wide. The
dimensions and shapes of the fruits and seeds were
recorded. Average, maximum, and minimum values
for each population are noted in Table 41. Sandalwood
seeds have a more or less pointed apex and a more or
less developed excrescence at the base. These parameters were estimated, along with the roughness of the
seeds. Seeds have lines of weakness or ridges where
the shell cracks open upon germination; the number
of ridges, mainly between two and four, was recorded.
Raivavae fruits are round to oval, averaging about
25 mm in length and width while the only fruit
from Rapa is more oval and slender, reaching an
estimated length of 28 mm and an estimated width
of 19 mm at maturity. Based on these unbalanced
data, a net differentiating criterion would be the
length/ width ratio, which is higher than 1.4 on
Rapa and lower than 1.2 on Raivavae.
On Raivavae, seeds are oval, obtuse, and rough.
Most often, they have three dehiscence lines and
very little excrescence at the base. They have an
average­length of 17.2 mm and an average width
of 15.7 mm with a length/width ratio lower than
1.2. The limited data available from Rapa indicate
a length of 19 mm and a width of 13.1 mm, with a
ratio higher than 1.3. The length/width ratio is also
a distinctive criterion between both varieties.
...
.. .....
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
Table 41: Morphological data of fruits and seeds of Santalum insulare from the Austral Islands (dimensions in mm, max-average-min).
Population
Island
Raivavae
Shape
Fruit
Fruit
Nb.
Nb.
Seed
Seed
Length
Width
Seed
Ridge
Length
Width
Apex
Fairly
Excrescence
Roughness
None to little
Very rough
None
Fairly rough
Anatonu-Mouatapu area
2
Round
23
22-21.5-21
13
3.1
21-18.1-16
18-16.5-15
Mahanatoa-Pahonu area
0
Round
-
-
3
3
18-17.3-17
18-17-16
Motu Araoo
4
Oval
27-22.8-15
25-20.5-10
4
3.8
19-15-9
17-13.8-7
Motu Haha
0
-
-
-
1
3
15
13
Motu Mano Iti
1
Round
27
27
1
3
20
19
Motu Numiri Rahi
1
Oval
34
31
28
3.4
24-21.1-19
20-18.2-16
Motu Rani
24
32-25.2-23
29-25.9-24
87
3.3
21-17.4-15
19-15.4-13
Motu Tahaupaetoru
1
Oval
30
26
2
3
19-18.5-18
17-16.5-16
Motu Vaiamanu
1
Oval
31
27
2
3
22-20-18
20-19-18
Vaianaua peninsula
1
Round
22
22
48
3.1
20-15.8-13
18-14.6-12
35
Oval
34-25.3-15
31-25.1-10
201
3.2
24-17.2-9
20-15.7-7
Karapoo Rahi
1
Double
Pear
26
18
2
2
19
14
Pointed
A lot
Rough
Anatakuri Nako
0
-
-
-
3
-
-
12.5
-
-
-
Total
1
26
18
5
2
19
14-13.1-12.5
Pointed
A lot
Rough
Total
Rapa
Nb.
Fruit
Flattened
Oval
Double
Pear
pointed
Not very
pointed
Not very
pointed
Not very
pointed
Not very
pointed
Pointed
Not very
pointed
Fairly
pointed
Pointed
Not very
pointed
Not very
pointed
It should be noted that the dimensions of these
apparently viable fruits and grains can vary by a
factor of two within the same population. Seeds
from "motus" on Raivavae appear to be slightly
larger than those from the main island.
Leaves
The sample size was 10 adult leaves per tree.
Table 42 presents the average, maximum, and minimum values for each population and each island
of the length and width of the limb, the length of
the petiole, the nervation, and the angles of the
apex and limb base.
Measurements show that the leaves of Raivavae sandalwoods are elliptical to oval, with a petiole of (13)-8(4) mm long. The limb is acute to obtuse, 79 mm long
and 42 mm wide on average and has 6 to 14 pairs of
veins. Leaves of Rapa sandalwoods have similar characteristics, but are more frequently oval, with an obtuse
apex on the limb. On average, the limb is 66 mm long
and 32 mm with 6 to 11 pairs of veins and the petiole
is (10)-7.4-(5) mm. The limb is smaller on average on
Rapa (which could be due to more restrictive weather
. . . 174
Ripe sandalwood fruit on Motu Araoo, Raivavae,
January 2005 (Photo J.-F. Butaud).
Fairly
Not very
rough
None
Fairly smooth
None
Fairly rough
Little
Fairly smooth
Little
Fairly rough
Little
Fairly rough
None to little
Fairly rough
None to little
Little
Fairly to very
rough
Fairly to
very rough
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 42: Morphological data of leaves of Santalum insulare from the Austral Islands (dimensions in mm and angles in grads, maxaverage-min).
Island
Raivavae
Nb.
trees
Shape
(E = Elliptical,
O = Oval)
Pétiole
Lenth
Width
Apex
(A = Acute,
O = Obtuse)
Nervation
Apex
angle
Base
angle
Anatonu-Mouatapu area
3
E > O
7-5.8-5
88-71-60
50-40-31
A
11-9-7
130-95-70
150-120-100
Anatonu temple
3
E > O
12-9.4-6
123-83-62
50-39-29
O > A
12-9-6
100-75-60
150-110-70
Hotuatua islet
3
E = O
11-6.7-5
109-81-65
52-45-34
A
12-9.5-8
120-85-60
150-120-90
Mahanatoa-Pahonu area
1
E > O
8-7.1-6
58-52-43
32-29-26
O = A
9-7.5-6
130-90-70
130-100-90
Anatonu-Mahanatoa area
1
E
11-9.8-8
87-76-72
50-40-30
O
8-7-7
120-85-70
100-90-80
Mouatapu
1
E = O
8-6.4-6
58-53-47
31-27-20
A
8-6.5-6
100-70-60
130-115-90
Tapioi
1
E
12-11.3-10
72-63-57
47-38-32
A
10-8.5-7
120-95-80
120-100-80
Vaianaua peninsula
8
E > O
12-8-5
100-70-50
61-39-22
A > O
12-9-6
160-105-60
160-105-70
Motu Araoo
3
E
13-9.6-6
131-98-79
74-51-43
O
13-9.5-6
110-90-70
120-95-80
Motu Haha
2
E = O
11-8.3-5
91-77-66
58-49-31
O > A
11-9-7
120-90-70
150-125-80
Motu Mano Iti
2
E
9-6.3-4
100-90-71
48-40-31
O
13-12-10
90-80-60
120-100-80
Motu Mano Rahi
3
E
9-7.6-6
94-83-40
63-44-35
O > A
14-11-10
130-95-70
120-110-80
Motu Niupapa Rahi
1
E
9-7.3-6
94-84-72
45-38-31
A
10-9-8
100-80-70
160-120-100
Motu Numiri Rahi
3
E
11-7.7-4
99-83-66
57-45-30
O > A
13-10-7
140-105-70
150-115-80
Motu Rani
3
E
11-8.3-5
113-87-66
54-47-30
O > A
12-9.5-8
120-90-70
120-100-80
Motu Vaiamanu
5
E = O
12-8.5-4
107-85-64
58-43-31
O = A
14-10.5-8
130-85-50
140-110-80
43
E > O
13-8.0-4
131-79-40
74-42-20
A = O
14-9.5-6
160-90-50
160-110-70
Karapoo Rahi
7
O > E
8-6.5-5
91-67-46
50-33-22
O
11-8-6
100-65-40
130-95-70
Anatakuri Nako
2
O > E
10-7.8-5
78-64-50
37-31-22
O
12-8.5-6
80-60-50
120-90-60
Total
9
O > E
10-7.4-5
91-66-46
50-32-22
O
11-8-6
100-65-40
130-95-60
Population
Total
Rapa
conditions on Rapa). In addition, the angles of the
apex and limb base help distinguish the two varieties:
the leaves on Rapa are more triangular or slender at
the apex (65 grads on Rapa and 90 on Raivavae) and
slightly less rounded at the base (95 grads on Rapa and
110 on Raivavae).
There was no significant variation between the populations of the high island and those of the "motus"
on Raivavae. However, the leaves from the low-altitude sheltered populations appear to be larger than
those from the exposed populations at higher altitude.
Thus populations at Mouatapu (high altitude cliff),
Mahanatoa Pahonu (exposed rocky area at medium
altitude), and Tapioi (boulder at mid-altitude) have
smaller limbs. These observations indicate the existence
of ecotypes by adaptation to site-specific conditions.
Assessement
More information is now available, allowing a better
characterization of these two varieties. Differentiating
criteria are clearer for seeds and leaves but there is an
important variability within each variety and population. In addition, these variations could be correlated
with ecological conditions such as altitude and climate,
showing that the sandalwood adapts to its habitat.
175
Inflorescence of sandalwood on Motu Numiri Rahi,
Raivavae, November 2002 (Photo J.-F. Butaud).
...
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
.. .....
STATE OF THE RESOURCE
This assessment is based on information from
herbarium samples, inhabitants of the islands of
Tubuai, Rapa, and Raivavae, and recent surveys.
…
…Tubuai
As mentioned above, no botanist has ever found
any sandalwood on Tubuai. The locals simply
recall that "previously", sandalwood was present
on the island (Butaud 2006). Recently, only one
person could attest the presence of sandalwood
ten years earlier on Tubuai (S. Tahuhuterani pers.
comm. 2002). It seems reasonable to assume that
sandalwood still exists on the island based on
this account and the configuration of the island.
The area mentioned includes Mt Tavaetu and Mt
Hanareho, their western slopes, and their eastern foothills where a tree supposedly used to be
exploited near the old "tou" (Cordia subcordata)
or "miro" (Thespesia populnea). In 2003, a one-day
survey focused on the area but there was no sign of
sandalwood. If there are any sandalwoods remaining on Tubuai, it is likely that there are fewer than
ten relict individuals. However, it is likely that a
few trees were recently introduced from Raivavae
and grow on Tubuai near settlements.
…
…Rapa
Before our surveys, sandalwood populations on
Rapa Island were known to botanists from two
sites: the historical site of Mt Tanga, where the first
two samples were collected in 1921 and 1934, and
Anatakuri Nako bay, near the pass leading to Akao
bay, discovered in 1984. Our surveys focused on
these sites, as well as on two other sites mentioned
by islanders, in particular by Benjamin Pukoki,
the local SDR manager. The latter sites are located
respectively on the left side of Anarua valley and
on Karapoo Rahi islet. The findings of the surveys
are presented in Figure 31 and in the following
paragraphs (Butaud 2006).
The summit of Mt Tepiahu to Mt Tanga east of
Haurei (Ahurei) was surveyed, as well as the slopes
northwest of the pass between these two mounts. No
sandalwood tree was found. The vegetation is very
degraded today, consisting only of a bush of Cattley
guavas (Psidium cattleianum), ferns (Dicranopteris
linearis), and "reeds" (Miscanthus floridulus). This
degradation is probably due to fires and overgrazing by goats. In addition, the site is relatively visible
and accessible from the current quay from which
the inhabitants or possibly visitors could have easily
spotted any sandalwood. Another Mt Tanga exists
north of Area and was visited. The vegetation there is
very low and again no sandalwood tree was observed.
Anatakuri Nako bay
The islanders, in particular B. Pukoki, know this
sandalwood site. The botanists J. Florence and
N. Hallé also visited the site in 1984. According to
J. Florence, it contained about 30 trees in 1984; 10
years ago (around 1992), only about 15 trees were
known from the site, according to B. Pukoki. The
survey shows that this historical population now
includes only three live trees and 13 dead trees, still
standing or washed away by a landslide. The site is
exposed to the north and has a slope of 70 %.
This stand is located in Anatakuri Nako bay, under
the pass to Akao bay. The main tree was found at
an altitude of 205 m and had a diameter at breast
height of 13 cm (stump diameter of 24 cm) for a
height of 4.5 m. The two other trees had a stump
diameter of respectively 13 and 26 cm. On the
observation date, March 26, 2002, the leaves just
came out, with a pale to soft green color and were
visible from far away. Only a few flower buds
were observed. No fruit was found. Three old nuts
damaged by rats were found on the ground: the
width of the shells was measured and was close to
12.5 mm.
The surrounding vegetation was very poor as
Freycinetia and Macropiper were the only semiwoody plants directly found near the sandalwoods.
What appeared to be a Sophora had been dead for
several years and a little further, a few Cyathea and
Metrosideros were observed.
Several assumptions can be made to explain the
extremely rapid decline of this population. First,
no regeneration is possible due to the presence of
Figure 31: Status of Santalum insulare populations on Rapa.
© Pacific-image - From Saquet ill.
. . . 176
.......
rats and their predation on fruits, as well as the
presence of goats and their predation on any plantlets and suckers. Mature trees are constantly under
the attack of goats (and maybe cows) that eat the
leaves. This is obvious as no leaf was found below
one meter fifty from the ground. Furthermore,
goats are causing the disappearance of host plants,
leading to a nutritional stress for the sandalwoods.
And last, it can be reasonably assumed that soil
compaction due to the presence of herbivores has
a negative impact on sandalwoods (root asphyxia)
and that, associated with the loss of neighboring
trees, contributes to landslides on steep slopes as
observed for this population. The landslide has
washed at least three sandalwoods and four other
live or dead trees are located at its edge. It is
remarkable that anthropogenic exploitation of sandalwood has played no role in the decline of this
population. There was no sign of exploitation on
this site well known by the islanders.
A potential conservation effort for this very precarious stand would be to build a fence impassable to
herbivores and to plant native trees near the sandalwoods and the landslide.
Anarua bay
Thirty years ago, B. Pukoki noticed at least three
sandalwoods on the southern side of Anarua bay,
above Akaeke point. The survey area is located
at an altitude of 150 m, with a northern exposure and an average slope of 80 %. This site is
a relict semi-dry forest including the following
woody species: Metrosideros collina, Nesoluma polynesicum, Streblus anthropophagorum, Psydrax odorata, Cyclophyllum barbatum, Myrsine sp., Meryta
sp., Myoporum rapense, Boehmeria virgata, Celtis
pacifica, Maytenus pertinax, Allophyllus rapensis,
Scirpus sp., and Freycinetia sp. No sandalwood,
dead or live, was found. The forest was highly
degraded due to overgrazing by goats and cows.
Several trees were observed, particularly on the
lower part. The sandalwoods observed 30 years ago
might have been exploited and thrown to the ocean
from the neighboring cliff.
Karapoo Rahi islet
B. Pukoki and several other inhabitants knew this
population of sandalwoods. It is found on an islet
located south of the island, separated by a stretch
of shallow water of about thirty meters wide. The
side where the sandalwoods are found has a western and northwestern exposure, an altitude of 80 to
110 m and a slope of 80 %.
This population comprised 11 distinct adult trees
and four dead trees. There was no sign of regeneration and no indication of exploitation by man. The
sapwood was still intact on the dry trees, which
means that they died not long ago. Dry leaves
were even present on one of the dead trees. Goats
(about thirty) have devastated this islet. Rats were
177
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Dead sandalwood on Karapoo Rahi islet,
Rapa, due to the loss of shrubby host plants
and overgrazing by herbivores, April 2002
(Photo J.-F. Butaud).
also present as indicated by an old eaten nut on
the ground.
On March 26, 2002, the trees had recent leaves of
light to soft green color. Some trees seemed to have
been affected by the sea spray. The phenological
stage was more advanced than on Anatakuri Nako
as most trees were in full bloom. A single fruit was
observed; a large double-pear shaped green fruit of
a length of 26 mm and a width of 18 mm, with a
19 mm long and 14 mm wide seed. The nut found
on the ground had the same dimensions. The
largest tree was 4 m tall with a diameter at breast
height of 17 cm.
The surrounding vegetation was very degraded and
poor due to overgrazing by goats. It was primarily
herbaceous layer including Paspalum conjugatum,
Commelina diffusa, Bidens pilosa, Ageratum conyzoides, Macropiper sp. and Gahnia sp. There were several scattered shrubs and trees, including Cyathea
medullaris (many dead individuals), Pandanus sp.,
Xylosma sp., and Celtis pacifica.
This population is likely the most important on
Rapa and apparently the only hope for safeguarding this endemic variety if conservation measures
are taken. It is crucial to eradicate the goats from
this island of high value for flora (J.-F. Butaud
pers. obs.) and fauna. The second step would be to
eradicate the rats for the benefit of birds, insects,
and the regeneration of some plant species.
Assessement
There are very few data available on the original
range of the Rapa sandalwood. Therefore, it is
difficult to assess the extent of the populations of
sandalwood before the arrival of sandalwood traders or herbivores about 200 years ago. However,
several assumptions can be made:
...
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
.. .....
• The exposure is significantly similar for the
four sites visited: west, northwest to north. It
appears that the sandalwoods on Rapa prefer the
sites most exposed to the sun and heat, with the
driest conditions. This confirms the observations
made on the Society Islands (Butaud 2004).
• The altitude range is also relatively restricted
for the various sites (between 80 and 250 m).
The sandalwood seems to grow at a lower altitude, with a lower level of precipitations.
• Sandalwood populations were observed on
steep slopes (70 to 80 %), which are common on
Rapa. This does not preclude the growth of sandalwoods on gentler slopes (< 50 %). However,
populations on gentle slopes are easier to access
and exploit, which might have led to their loss
on such sites and their restriction to steeper
slopes today.
• Finally, while highly degraded, the vegetation
on theses sites could be considered as a low
altitude mesophilous vegetation, but not supralittoral. Most tree species found on these sites
do not grow at higher altitudes (above 300 m)
where the vegetation varies from hygrophilous
to ombrophilous.
It is highly likely that the original range of the Rapa
sandalwood covered areas of mesophilous vegetation, at an altitude between 10 and 300 m, with a
slope higher than 50 %, and facing west, northwest
and north. Potential surveys should focus on this
type of habitat to search for new populations of
sandalwood. The chances are very small as neither
the local inhabitants, nor the Hawaiian botanists
who visited the area for a month during the first
half of 2002 were able to find other trees.
The 14 trees found in 2002 should be compared to
the estimated 1 750 trees exploited by sandalwood
traders in the beginning of the 19th century. This
clearly shows that exploitation by man was the
main factor leading to the depletion of sandalwood
on the island of Rapa.
……
Raivavae
Before our various surveys, seven populations of
sandalwood were known through herbarium samples. Three populations were from coral "motus"
(Vaiamanu, Tahaupaetoru, and Haamu), one from a
volcanic islet (Hotuatua), and the three others from
the high island itself (Vaianaua, northern slopes of
Mt Hiro and south side of Mt Hiro). Samples highlighted one of the characteristics of the Raivavae
sandalwood: it grows both on limestone on "motus"
and on the volcanic soils of the high island. Among
the seven populations, six were found during our
recent surveys. The population on the southern side
of Mt Hiro was not located but is not necessarily
lost as the survey in the area was limited. In addition, 13 new populations were found. All sites were
surveyed and studied (Fig. 32) with the exception
of Anatonu stadium — the population was observed
through binoculars —, the south side of Mt Hiro,
and Motu Haamu, which was not surveyed during
the expeditions but still has many sandalwoods (W.
Tetuanui, SDR pers. comm.). Table 43 presents the
altitude and population size for each site.
Figure 32: Status of Santalum insulare populations on Raivavae. © Pacific-image - From Saquet ill.
. . . 178
.......
In addition to the "motus" in
the aforementioned table, the
Papararuu, Ruahune, Arae,
Ruahota Rahi, Ruahota Iti,
Opunui, Numiri Iti, Tou,
Otaha 4, and Otaha 3 "motus"
were visited but no sandalwood
was observed. It appears that
the size of the "motu" might
affect the presence or absence
of sandalwood. Below a certain
surface threshold, sandalwoods
are not present. Small "motus"
are often submerged by the sea,
which could impede the growth
or germination of sandalwoods.
Larger "motus" are higher and
often protected against sea rise.
The originality of Raivavae
compared to the other islands
where sandalwood can be
found in French Polynesia lies
in the diversity of its soils. The
Raivavae sandalwood can be
found both on the "motu" coral
soils and on the volcanic soils
of the high island. Sandalwoods
on "motus" are peculiar, as
are some other plant species
(Myoporum stokesii, Nesoluma
polynesicum) unusual for this
type of habitat. Precipitations
might be a factor as they are
well distributed throughout the
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 43: Description of the populations of Santalum insulare on Raivavae.
Location
Altitude
(m)
Size
(nb. individuals)
40-80
20
100
20
Border Mahanatoa-Anatonu
50-80
70
Anatonu temple
50-125
80
Anatonu stadium
70
> 10
30-90
90
Mouatapu
235
1
Mt Hiro
400
< 10 ?
Mt Tapioi
120
1
Hotuatua islet
3-45
15
Motu Vaiamanu
4
1 000
Motu Numiri Rahi
2
45
Motu Rani
1
60
Motu Tahaupaetoru
2
50
Motu Araoo
3
250
Motu Niupapa Rahi
2
300
Motu Haamu
4
> 100
Motu Mano Rahi
2
150
Motu Mano Iti
2
17
Motu Haha
2
50
1-400
> 2 340
Population
Vaianaua peninsula
Mahanatoa-Pahonu area
Volcanic high island
Coral "motu"
Anatonu-Mouatapu area
Total
year and might wash out the salt from the sols
(150 mm per month on average with a minimum
of 108 mm in September).
Therefore, there are two main types of populations
(Butaud 2006).
Populations on "motus"
"Motus" are flat limestone areas, varying from
sand to gravel with more or less organic matter. The surrounding vegetation is rather sparse
with a grass cover. The main trees found near
sandalwoods include the "tafano" (Guettarda speciosa), the "fara" (Pandanus tectorius), the coconut tree (Cocos nucifera), the "pu'atea" (Pisonia
grandis), and the "'aito" (Casuarina equisetifolia).
It should be noted that no other species, including the sandalwood, is found on the pure stands
of "'aito", "pu'atea", and "fara". The shrub layer
can contain the "pohotura'aua" (Sophora tomentosa), the "nanie" (Suriana maritima), the "ouru"
(Scaevola sericea), Hedyotis romanzoffiensis and the
"miki miki" (Pemphis acidula). The herbaceous
layer includes the "naveoveo" (Lepturus repens),
the "tonene" (Cassytha filiformis), Psilotum nudum,
Chamaesyce fosbergii, Boerhavia tetrandra, the
The only natural plantlet of sandalwood
observed in all of Polynesia on Motu Rani,
Raivavae, November 2002 (Photo J.-F. Butaud).
179
...
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
.. .....
"metuapua'a" (Microsorum grossum), Achyranthes
aspera var. velutina, the "pia" (Tacca leontopetaloides), Davallia solida, and Nephrolepis sp.
Regenerated sandalwoods were only observed on
the Motu Rani. Most trees are from root or stump
suckers, following harvest but mainly due to accidental or deliberate (clearing) fires that regularly
devastate some islets such as Motu Mano Rahi. The
biggest sandalwoods are 6 m tall with a diameter of
15 cm at the base. On average, they are about 3 m
tall with a diameter of 8 cm. The heartwood is only
formed in the roots when they are not unearthed
for sale or for monoi.
Populations on the high island
They are found mainly on dry crests with a northern exposure (populations from Anatonu to
Mahanatoa) as well as near rocky areas (Tapioi,
Mouatapu, Vaianaua Peninsula, and Hotuatua
islet). These topographical conditions match those
of the sandalwoods found on the other islands
of French Polynesia. The slope is not necessarily
steep and some trees can even be found on a flat
terrain (Mt Taamora on the Vaianaua peninsula).
The surrounding vegetation is usually low (less
than 5 m), open, and degraded by fires or feral
goats. The tree and shrub layers include "purau"
(Hibiscus tiliaceus), "fara" (Pandanus tectorius),
Xylosma suaveolens, Celtis pacifica, Premna obtusifolia, Glochidion raivavense, Psidium guajava, and
even Serianthes rurutensis. The herbaceous layer
consists of Microsorum grossum, Ocimum gratissimum, Miscanthus floridulus, Elephantopus mollis,
Dianella intermedia, Nephrolepis sp., Dioscorea sp.,
Davallia solida, and Dicranopteris linearis. The lower
Sandalwood from a root sucker on Motu Mano Iti,
Raivavae, November 2002 (Photo J.-F. Butaud).
Shrubby sandalwood on low coastal vegetation on
Motu Rani, Raivavae, January 2005 (Photo J.-F. Butaud).
. . . 180
.......
part of the "Anatonu temple" stand is located on an
unusual raised limestone area, where some more
calcicolous species such as the "tafano" (Guettarda
speciosa) are found. The sandalwoods on the high
island are generally shorter than 5 m, including the
numerous suckers from the Anatonu populations.
Assessement
The original range of the Raivavae sandalwood was
very broad. Given its good dynamics (suckers and
natural regenerations) on coral "motus", it is certain that its presence is natural and not due to man.
The original range was likely restricted to the edge
of the "motu", on the seaside, on rocky sols among
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Scaevola or on the lagoon side on sandy soils among
Sophora, as well as in areas cleared by storms. The
extension of the range was due to the presence of
men and the anthropogenic clearing on the "motus"
since the Polynesian period. Today, recurrent fires
contribute to its vegetative propagation through
root and stump suckers. On the northern coast of
the high island, sandalwoods probably grew on
most medium-to-steep slopes of ridges and sides, on
rocky soils or scree, with the driest exposure, from
sea level to the summit. Its presence on the more
humid southern coast must have been limited to the
steepest slopes. It was likely absent from the coastal
plains and the large valleys with gentler slopes.
DYNAMICS AND THREATS
The sandalwood from the Austral Islands is faced
with a contrasting situation on the two islands
where it is still found. On Rapa, the remaining
populations are relict, quite old, in a moderately
anthropized environment. On Raivavae, the populations consist essentially of numerous young trees
surviving in a highly anthropized and modified
habitat. Regeneration, both seed-propagated and
vegetative, has not happened for dozens of years on
Rapa. On Raivavae, vegetative propagation through
root and stump suckers is intense and seed-propagated reproduction, although marginal, still exists.
These dynamics are related to relatively similar
but slightly different ecological and anthropogenic
conditions among the islands. These conditions
are presented below and are not fundamentally
different from the other archipelagos (Butaud &
Tetuanui 2005).
…
…Poaching
While direct human impact is not the main cause
for the diminishing numbers of sandalwoods in
the Austral Islands today, it was in the case in
the past and some populations did not recover
from the abusive harvests of the past centuries.
Poaching is still effective today and continues to
decrease the populations and to limit the growth
of large fruit-bearing trees. Focusing on the best
trees, the harvest contributes to a negative selection among varieties and limits the enhancement
opportunities under a production plantation program. Human exploitation is particularly visible
on Raivavae due to a recent demand for sandalwood, arising partly from the regular meetings
in Tahiti, during craft shows, of craftsmen from
all over French Polynesia. On these occasions,
Marquesans, who are large users of sandalwoods,
were able to engage with the Raivavae and buy
sandalwood at a lower price than in the Marquesas
Islands. The Raivavae realized the importance of
the available resource and the potential revenues.
In "handicraft fare" from Rairua to Raivavae, sev-
181
eral sandalwood objects can be found including
hairpins (between 1 000 XPF and 1 300 XPF),
pieces of sandalwood more or less stripped of sapwood (2 000 XPF for a 60 cm long by 5 cm wide
branch or 3 000 XPF for a hollow branch of 80 cm
in length and 10 in width), and sandalwood powder (2 000 XPF for a 150 ml jar), which is often of
low quality as it includes the sapwood or is mixed
with "ngaio" (Myoporum stokesii), another fragrant
wood. In Tahiti, the "craftsmen’ Heiva" offered in
2001 some sandalwood powder at 1 100 XPF per
bag (20 cm long, 5 cm wide) and in 2002 a noncarved piece of sandalwood from Raivavae (30 cm
by 12 cm) at 50 000 XPF. At the 2005 agricultural
fair in Tahiti, a 35 cm piece with a 10 cm diameter was offered at 3 000 XPF and a 35 cm piece
with an 8 cm diameter was sold at 2 500 XPF. Due
to the growing demand, we have observed many
trees stripped of their branches (particularly on
"motus") and others that are totally uprooted and
exploited (Anatonu, Vaianaua). While the sandalwood variety from Raivavae is not protected
through the regulations on nature protection, harvesting is regulated under the Polynesian Forest
Code, which requires felling permits.
……
Fire-induced degradation
Fire represents the second major threat on Raivavae.
Burning is deliberate on "motus" for clearing and
accidental on the heights of Anatonu. Land clearing by fire is forbidden by the Polynesian forest
regulations but is still practiced. It leads to the loss
of populations of fruit-bearing sandalwoods, creating, in the best cases, numerous suckers from the
scars on the roots.
……
Predation of seeds by rats
The main limiting factor of the seed-propagated
reproduction on both islands is the predation of most
seeds by rats feasting on their kernel. Caused by
the Polynesian rat (Rattus exulans) on both islands
and by the Black rat (Rattus rattus) on Rapa, many
...
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
.. .....
gnawed and open shells were found. Unlike in the
Society Islands and the Marquesas Islands (except
in Tahuata), predation is not absolute on Raivavae
where several dozens of mature seeds were found.
This could be explained by the absence or scarcity of Black rats on Raivavae (J.-C. Thibault pers.
comm. 2002). The Polynesian rat is less arboreal and
only eats a portion of the seeds, probably the most
accessible ones. The near lack of seed reproduction is mainly due to the successive introductions
(Polynesian and modern) of rats on the islands.
…
…Extinction of disseminators
In the same vein, the likely extinction of several
avian disseminators such as the Imperial pigeons
and Fruit doves (except the "koko" Ptilinopus huttoni on Rapa) on the Austral Islands (Steadman
1997) would have also limited the chances of germination of sandalwood seeds. The uneaten ripe
fruits fall and rot quickly on the ground, resulting
in the rotting of the kernel (J.-F. Butaud pers. obs.).
…
…Overgrazing by herbivores
The current main threat on the Rapa sandalwood is
overgrazing by introduced herbivores, principally
goats but also cows. The feral goat populations on
Rapa are only restricted by the available food. Their
size is increasing every year, as they are not hunted
enough, leading to the loss of natural forest. Goats
are highly present on both populations of sandalwoods on Rapa. Leaves are only found at the top of
trees and no sucker bigger than 20 cm was found.
The surrounding vegetation has been grazed and
replaced by unpalatable weeds. Therefore, very
few host plants remain, soils are compacted due to
grazing, and sandalwoods decline at an accelerated
rate. Both seed-propagated and vegetative regenerations are impossible due to the pressure from
herbivores. While there are other reasons for the
scarcity of the Rapa sandalwood, goats will hasten
its loss. Goats are less abundant on Raivavae but
still present on the altitude stands and on Vaianaua
Peninsula where the absence of suckers is the first
impact of their presence.
Sandalwood branch debarked by rats on Mahanatoa,
Raivavae, December 2002 (Photo J.-F. Butaud).
……
Growth of invasive plants
Natural habitat changes due to more or less invasive naturalized plants are also a concern on both
islands. Currently, there is no plant considered as
invasive in the sandalwood populations on both
islands but it is likely that in a near future, Psidium
cattleianum (Myrtaceae) on Rapa and Leucaena
leucocephala (Mimosaceae) on Raivavae will grow
and suffocate the mature trees, the suckers, and the
potential plantlets. In addition, many naturalized
grasses form the understory of sandalwoods and
certainly impair the germination of falling seeds.
The dynamics of sandalwood on the Austral Islands
has largely diverged from its natural path. While on
Raivavae the sandalwood seems to adapt to changing
conditions through a significant vegetative propagation, it might disappear soon from Rapa without any
voluntary effort. Threats are varied and accumulative. Sandalwood is a good example of the challenges
faced by most natural habitats in French Polynesia.
CHEMICAL CHARACTERISTICS OF THE SANDALWOOD
FROM THE AUSTRAL ISLANDS
…
…Background, sampling and methods
The chemical study was based on a 37 samples of
wood (Table 44). Dead trees were sampled on both
islands. Therefore, the total number of samples can
be higher than the number of known individuals
(in particular for Anatakuri Nako on Rapa). The
data presented below were produced by Gaydou
(2004) in addition to new samples in 2005.
The chemical studies aim at characterizing the
essential oil of the Austral Islands sandalwood
and estimating its variability based on geographic
(islands, populations) and site-specific (type of
soil) criteria (Butaud et al. 2004).
Wood samples were collected mainly on dead wood
to prevent any injury to the rare trees remaining in some populations. As most individuals, in
particular on Raivavae, are small, the high quality heartwood could not be collected. Often, only
false heartwood (duraminization due to injury) or
wood with many impurities were collected. While
experience has shown that in most cases the composition of false heartwood is very similar to actual
. . . 182
.......
­ uramen, the nature and the
d
state of the wood were taken
into account in the result.
Wood extracts were analyzed by gas chromatography. Concrete was obtained
through solvent extraction
from a small quantity of
wood and the essential oil
or essence by hydrodistillation of a larger quantity. In
practice, solvent extracts less
volatile (heavier) molecules
compared to hydrodistillation: the heavy fraction of the
concrete will not be found
(and no traces either) in the
essence. The proportion of
key molecules in the concrete
will be lower than in the
essence. Therefore, it is not
possible to accurately calculate the yield of essential oil
as well as the proportion of
the most important essence
molecules on an olfactory
point of view.
The identification of molecules represented by chromatogram peaks was based
on the calculation of Kovats
indices (using retention
times) and on the coupling
with the mass spectrometry and comparison with
the existing spectra database. Twenty-six peaks or
groups of peaks could be
individualized. Some peaks
were grouped, as they could
not be separated in a sufficient number of individuals.
They generally included one
majority compound and several minority compounds.
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Table 44: Sampling of Santalum insulare on the Austral Islands for chemical and genetic
studies.
Island
Raivavae
Known
numbers
Leaf
samples
Wood
samples
Vaianaua peninsula
20
8
3
Mahanatoa-Pahonu area
20
4
1
Border Mahanatoa-Anatonu
70
5
Anatonu temple
80
3
3
Anatonu stadium
> 10
Anatonu Mouatapu
90
4
1
Mouatapu
1
1
Location
Mt Hiro
< 10?
Mt Tapioi
1
1
Hotuatua islet
15
3
2
1 000
8
7
Motu Numiri Rahi
45
3
1
Motu Rani
60
5
4
Motu Tahaupaetoru
50
3
Motu Araoo
250
5
3
Motu Niupapa Rahi
300
3
1
Motu Haamu
> 100
Motu Vaiamanu
Motu Mano Rahi
150
3
1
Motu Mano Iti
17
2
1
Motu Haha
50
3
At least
2 340
64 (< 3 %)
80
Anatakuri Nako
3
3 (100 %)
4
Karapoo Rahi
11
11 (100 %)
5
14
14 (100 %)
9
Over
2 350
78 (3 %)
37
Total
Raivavae
Rapa
Total
Rapa
Total
Australs
…
…Chemical composition of the concrete
Table 45 presents the results of the chemical analyses of the Austral Islands sandalwood. For each
island, data are presented for all samples and for
samples of heartwood with no or few impurities (false heartwoods and impure duramens were
removed).
The molecules producing the characteristic smell
of sandalwood are mainly the (+)-(Z)-α-santalol
(α-santalol) and the (-)-(Z)-β-santalol (β-santalol),
on the dark green of the table. They form the main
compounds of the Austral Islands sandalwood concrete, ranging from over 35 % on average for all samples from Raivavae to about 60 % for q
­ uality samples
183
from Rapa. Important variations were observed
among the various samples but most variations
seemed to be explained by the poor quality of the
heartwood collected. When only the purest samples
are considered (duramens with no or few impurities), the proportion of both molecules is about 49 %
on Raivavae and 59 % on Rapa.
The Rapa sandalwood appears to be of better quality than on Raivavae with a higher content in
α- and β-santalol. This needs to be put into perspective as the number of samples is relatively
low, in particular from Rapa, and the structure
of sandalwoods on Rapa is significantly different
than on Raivavae. Sampled trees on Rapa had a
...
.. .....
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
Table 45: Composition of the Concrete of Santalum insulare on Rapa and Raivavae.
Island*
Raivavae (%)
Samples
Indices
All (28)
Rapa (%)
Pure heartwood (10)
All (9)
Pure heartwood (5)
Avg.
Stand. dev.
Avg.
Stand. dev.
Avg.
Stand. dev.
Avg.
Stand. dev.
Concrete yield
7.74
5.06
10.62
3.86
7.95
3.03
8.76
2.92
α-santalene
1.10
0.60
1.08
0.42
0.96
0.33
0.93
0.31
(Z)-α-trans-bergamotene
1.52
0.94
1.42
0.49
0.96
0.49
0.92
0.29
(+)-(Z)-α-santalol
26.58
11.69
35.18
7.33
33.19
14.96
40.60
12.52
(-)-(Z)-α-trans-bergamotol
4.69
1.87
5.80
1.46
4.64
0.81
4.92
0.46
(+)-(Z)-epi-β-santalol
2.04
0.82
2.55
0.57
2.86
1.19
3.53
1.06
(-)-(Z)-β-santalol
9.90
5.01
13.77
3.47
14.48
7.51
18.33
6.65
(Z)-nuciferol
8.07
8.49
5.37
3.32
4.26
5.41
4.02
6.74
(-)-(E)-β-santalol
2.82
1.33
2.97
1.54
2.53
1.34
2.22
0.82
(E)-nuciferol
2.53
1.46
2.47
1.90
2.68
2.34
2.17
3.12
(Z)-α-santalyl acetate
4.09
4.21
3.86
4.90
1.63
2.24
1.68
2.89
Dihydroxy-bisabolene
4.22
3.67
3.90
3.05
3.34
2.75
2.83
2.52
α-santaldiol
0.94
0.70
0.87
0.32
1.24
0.72
1.14
0.33
well-developed trunk, with an average diameter of
10 to 20 cm, and formed heartwood in branches,
trunks, and roots. On Raivavae, most individuals
were stump and root suckers, with a shrub or bush
structure, reaching less than 10 cm in diameter and
with heartwood formation only near the stump or
the root. The difference of quality should be related
to the age as well as to the location of the sampled
trees. Also, the difference of climate between both
islands (chillier and more humid on Rapa) has certainly an impact.
Compared to the Indian sandalwood (Santalum
album), the world reference in terms of heartwood
quality, the Austral Islands sandalwood is of good
quality. Standards for the essential oil of Indian sandalwood indicated α- and β-santalol contents respectively between 41 and 55 % and between 16 and 24 %
(ISO 2002). As the data available are only for the
concrete in the case of the Austral Islands sandalwood (between 35 and 41 % for the α-santalol and
between 14 and 18 % for the β-santalol), the proportion in the essential oil can only be roughly estimated
at 38-43 % for the α-santalol and 16-19 % for the
β-santalol. At first sight, the quality of the essential
oil from the Austral Islands sandalwood seems to be
slightly lower than the Indian sandalwood. For the
latter, extraction is done from trunks, branches, and
roots of large trees. On the contrary, for the Austral
Islands sandalwood, only small pieces of wood from
branches or trunks could be used. There is presumably a high potential for the local varieties.
The extraction yield by hydrodistillation for
the essence of Indian sandalwood reaches 3 to
6 % (Alpha 1997) and about 2.5 % for the New
Caledonian sandalwood (Butaud 2006). The laboratory extraction protocol using solvent has a yield
of 8 to 10 % of concrete for the Austral Islands
sandalwood. The solvent extraction technique produces a higher yield in α- and β-santalol compared
to hydrodistillation. Furthermore, several molecules (heavy fraction) not extracted by hydrodistillation are only present in the concrete. The yields
obtained are not directly comparable but suggest a
good yield (likely to be higher than 4 %) of essential
oil under a long-term enhancement program (from
plantations) of the Austral Islands sandalwood
……
Variability of the concrete
To assess the chemical composition variability
of the concrete of Austral Islands sandalwood,
a Discriminant Factor Analysis (DFA) was performed on all samples grouped in four populations
(the two from "Rapa" and a group each for the
"high island" and the "motu" on Raivavae), based
on the 12 molecules presented in Table 45. The
analysis maximizes the differences among groups.
Figure 33 illustrates the DFA.
The DFA highlights group segregation for α-, β- and
epi-β- santalol (positive F1 axis) and bergamotene
(negative F2 axis) and α-santaldiol (positive F2 axis).
The Rapa populations are relatively distinct with
higher concentrations of α- and β-santalol. There
is an apparent distinction between the two groups
from Raivavae, mainly based on the type of soil.
Individuals growing on the coral "motu" have lower
concentrations of α- and β-santalol compared to trees
on the volcanic high island. The tree marked with an
arrow on the graph also illustrates this statement: the
. . . 184
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Individuals (F1and F2 axes: 92.48 %)
5
4
-- F2 axis (16.15 %) -->
3
On coral
2
1
Anatakuri Nako
High island
0
Karapoo Rahi
Motu
-1
-2
-3
-4
-5
-5
-4
-3
-2
-1
0
1
2
3
4
5
-- F1 axis (76.33 %) -->
Figure 33: Graphical representation of the Discriminant Factor Analysis of the chemical composition of the concrete of Santalum
insulare from the Austral Islands, by population group.
tree is from the high island but its profile corresponds
more to the "motu" as it grows on raised coral on the
main island (Anatonu temple population).
The various surveyed populations present variable
chemical characteristics, some considered to be an
adaptation to the habitat, as demonstrated by the
slight differences in composition according to the
type of soil for the same botanical variety.
GENETIC CHARACTERISTICS OF THE AUSTRAL ISLANDS SANDALWOOD
Two genetic studies were successively carried out
based on leaf samples collected on islands where
sandalwoods grow, in French Polynesia and on
the Cook Islands (Mitiaro). The studies used chloroplast microsatellite (Butaud et al. 2005) and
nuclear (Lhuillier et al. 2006) markers and were
performed in the laboratory of genetics of CIRADforêt in Montpellier. The results from these studies
for the Austral Islands are summarized here.
Table 44 describes the sampling for both studies.
In addition to the samples collected in the Austral
Archipelago, two samples from Mitiaro, Cook Islands
(collected by Lex Thomson, CSIRO) were added to
the analysis using chloroplast microsatellites.
The evaluation of genetic diversity was only done
at the level of the archipelago and the islands, but
note at the population level to assess population
dynamics. Exhaustive sampling of a population
(except for the two relict populations on Rapa)
was not possible and priority was given to cover a
maximum number of populations.
……
Chloroplast microsatellites
Throughout French Polynesia, 17 different chlorotypes were found on about 500 collected samples
185
from 10 islands where sandalwoods are found, in
addition to Mitiaro, Cook Islands. No chlorotype
was shared among the archipelagos. In the CookAustral Archipelago, only three chlorotypes were
identified: one specific to Rapa, one specific to
Raivavae, and one shared between Raivavae and
Mitiaro. There is no diversity on Rapa and Mitiaro
and an average diversity on Raivavae (Table 46),
compared to the existing data from the other
Polynesian islands. Values can be explained by the
small size of the islands and the associated small
number of habitats but also by the relict nature of
sandalwood populations due to exploitation, fires,
and introduced animals. In addition, the archipelago has a strong genetic structure (69 % of the total
molecular variation observed among islands and
31 % within the islands) due to the high differentiation between Raivavae and Rapa from the absence
of a shared chlorotype. Differentiation is likely due
to the distance (over 500 km) between the two
islands, which restricts the exchange of seeds.
The main finding is the notable differentiation
among the sandalwoods of each archipelago, with
distinctive chlorotypes. Within the Cook-Austral
archipelago, Rapa is well isolated by its specific
...
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
.. .....
chlorotype, corroborating its Table 46: Parameters of genetic diversity for the Austral archipelago. He: heterozygosis.
botanical (several endemic
Effective nb.
Diversity
genera) and geological (very
Islands
Nb. samples Nb. chlorotypes
chlorotypes
(He)
old age of the islets neighboring Marotiri) characteristics Raivavae
48
2
1.65
0.40
(Florence 1997; Clouard &
14
1
1
0
Bonneville 2001). The fact Rapa
that the Mitiaro chlorotype is Mitiaro
2
1
1
0
shared with Raivavae might
64
3
2.42
0.59
suggest a same origin as well Archipelago
as preferential movements
8 locus or 16 alleles). Considering the significant
within a same geological archipelago rather than
multiplication in situ of sandalwoods through suckbetween two islands that are close but belong to two
ers, trees sampled as distinct individuals ("ramets"),
different archipelagos. In order to refine the recently
but with the same multilocus genotype, are predeveloped conservation strategy for the Mitiaro
sumed to be from the same genetic individual
sandalwood (Tangianau et al. 2004), a last resort
("ortet") and form a clone. Diversity is calculated
hybridization, with the introduction of seeds from
based on allele frequencies as well as genetic structhe genetically closer Raivavae sandalwood, should
ture indices. Genetic distances between genotypes
be considered rather than from the geographically
are calculated based on allele composition.
closer Raiatea (as initially planned).
It appears from the study that a little over 50 %
However, as shown by the minimum dissimilarity
of sampled sandalwood trees are clones, with the
network among the chlorotypes (Fig. 34), one of
same genetic heritage as all tested microsatellites
the two populations studied at Raiatea (black solid
(Table 47). This is particularly surprising as care
circle under Society) has a chlorotype that is relatively close to the one from Mitiaro and Raivavae,
was taken during sampling at Raivavae to focus on
which suggests a past gene flow in the archipelago
scattered trees in order to limit the selection of root
that does not seem to exist anymore.
suckers from the same parent plant. This means
The network reveals three series of chlorotypes,
that the actual number of individuals (genetic indithe ones from the Cook-Austral archipelago falling
viduals) is at maximum half of the estimated trees
between the Marquesas and the Society chloroor a little less than 1 200 on Raivavae.
types. This is surprising from a geographic point
On Rapa, the same genetic individual ("genet")
of view (as the Marquesas are closer to the Society
constitutes both known populations in which all
than the Austral Islands) but is a reflection of the
trees were sampled. The situation appears to be
important influence of geology and the distinct
more critical than what was assumed by conserages and histories of the various archipelagos on
vationists. The situation on Raivavae is relatively
sandalwood colonization. The likely routes of
colonization are established but neither the direction (Marquesas-Austral-Society or the opposite,
or Austral-Marquesas and Austral-Society) nor the
origin (even if the Hawaiian Archipelago is the most
likely from a taxonomic point of view (Fosberg &
Sachet 1985; Harbaugh & Baldwin 2005)).
At the population level, the distribution of chlorotypes is not very structured on Raivavae. The two
Society
chlorotypes are rather mixed on the "motu" and
only one seems to be present on the high island.
The lack of structure might be due to the small
size of the island and to the good dynamics of sandalwood, probably due to the scarcity or absence
of Black rats and the high number of individuals.
…
…Nuclear microsatellites
Nuclear microsatellites are more polymorphic than
chloroplast microsatellites as they are subject to
random recombination of the genome during sexual
reproduction. Nuclear microsatellites help detect
diversity at a finer scale, down to the subpopulation
level, if used in sufficient numbers. In the present
case, eight markers were applied and were able to
define multilocus genotypes (allele combination of
Raivavae
Society
Marquesas
Rapa
Raivavae
Mitiaro
Figure 34: Minimum dissimilarity network among the chlorotypes
of Santalum insulare in Eastern Polynesia (Circle sizes are
proportional to the number of individuals - Branch lengths are
proportional to the genetic distance).
. . . 186
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Genetic structure is very important
among the various archipelagos (Fst
of clones of 0.4 between the Marquesas and the
Austral Islands and 0.5 between the
Society and the Austral Islands), which
57
corresponds to the results of the prec62
edent study. Within the archipelagos, the
12
most important differentiation among
islands is between Raivavae and Rapa
38
(Fst = 0.648), confirming the recogni37
tion of the two botanical varieties even
if the markers used only measure neu50
tral diversity (Fig. 35). The Rapa gen50
otypes are very clearly distinguished
42
from those of Raivavae (100 % bootstrap). Furthermore, the populations of
67
Raivavae present a significant differen91
tiation (Fst = 0.162; P < 0.001). This cor86
roborates the grouping of the population
genotypes from Vaianaua and the South
53
West Motu observed in figure 35.
Figure 36 indicates that the Austral Archipelago
has an intermediate position compared to the other
archipelagos in terms of variability of nuclear microsatellites, confirming the findings of chloroplast
microsatellites. Bootstrap values (the probability of
observing a branch at a given spot on a tree) are
low due to the small sampling on Rapa and other
islands outside of the archipelago but the structure
of the tree is well established.
Table 47: Genotypes and clones of Santalum insulare from the Austral Islands.
Populations
Samples
Nb. génotypes %
Anatonu East
7
3
Anatonu West
13
5
Motu East
8
7
Motu South-West
8
5
Motu Vaiamanu
8
5
Petits Motu
10
5
Vaianaua
8
4
62
34
Anatakuri Nako
3
1
Karapoo Rahi
11
1
Total Rapa
14
2
Total Australs
76
36
Total Raivavae
­ ifferent as there are not many clones (less than
d
40 %) on the big "motus" and more frequent ones
(over 50 %) in the more concentrated populations of
the high island or the small "motus". The dynamics
of the sandalwood is therefore likely to be important
on the "motu" than on the high island.
This clonality is due to the capacity of the sandalwood to grow some suckers from stumps (after
exploitation) or roots (after a fire), all the more so
because of the slow or inexistent seed reproduction
caused by predation by rats and the extinction of
avian disseminators, thwarting all chances of seed
germination and dissemination.
……
Assessement
The situation is contrasted between both islands
with a significant differentiation between the two
varieties. Diversity is very limited on Rapa with
Figure 35: Neighbor-Joining tree of genotypes in the Austral archipelago.
187
...
Sandalwood, Current State of Knowledge and
Implications for Conservation and Enhancement
.. .....
only two "genets" and richer on Raivavae where
many populations do not have a defined structure. Diversity indices for the Austral archipelago
are significantly lower than on other archipelagos
(Expected heterozygosis (He) of 0.33 compared
to 0.51 on the Society and 0.55 on the Marquesas,
average number of alleles per locus (nA) of 3.25
compared to 6.50 on the Society and 6.13 on the
Marquesas). This means that diversity is lower
due to the degradation of the natural environment and the populations as well as the small
size of the islands compared to the other archipelagos. Therefore, the sandalwood populations
on the Austral Islands are more sensitive to new
disturbances and require preferred and early conservation efforts.
On the biogeographical level, the Austral Islands
sandalwood could constitute a link between the
Marquesas and the Society sandalwoods.
Figure 36: Neighbor-Joining tree of the islands of French
Polynesia.
REPRODUCTION EFFORTS AND CONSERVATION
AND ENHANCEMENT STRATEGY
……Reproduction efforts
Rapa
On Rapa, the only known experiment on the germination of the Rapa sandalwood by local SDR agents
used very few seeds and was a relative failure: two
seeds sprouted, then quickly rotted. However, this
demonstrates the possibility of collecting viable
seeds and getting to the germination stage.
Raivavae
In May 1985, seeds of Raivavae sandalwoods were
sent to Tahiti by the Rural Economy Services (SER)
but we do not have any subsequent information.
In March and April 2002, an SDR agent sent about
200 sandalwood fruits from Raivavae, from Motu
Rani to the 3rd agricultural sector on Tubuai. The
fruits were pulped upon arrival on Tubuai. They
were put to germinate at the Mataura nursery after
scarification (complete removal of the shell). No
preliminary treatment using gibberellic acid was
performed as advised by the management technique for the production of sandalwood plants in
nurseries (Butaud 2001). The results of this germination were deceiving: some seeds sprouted but no
seedling was produced due to a lack of monitoring
at the nursery (rotten kernels and damping-off).
The local staff performed a similar germination, which
produced several seedlings, scattered here and there
on Tubuai. None of these seedlings was recently found.
It seems that some inhabitants on Raivavae succeeded
in reproducing the local sandalwood as several trees
observed in private homes or in the SDR nurseries on
Tahiti and Raiatea presumably came from Raivavae. A
pastor on the island was presumed to have developed
his own germination technique, applied today by the
SDR agents in Moorea (non scarified seeds are put to
germinate in moss collected from trees and the kernel
is manually released from the shell after germination). While no private plantations of sandalwoods
were found on Raivavae, this information shows that
the population is willing to cultivate and plant sandalwoods and that the seeds can be easily accessed.
The lack of a real nursery on the island also hinders
the efforts to develop this species.
……Conservation and enhancement
strategies
Rapa
The situation of the Rapa sandalwood is very simple. There are only two populations left, in visible
decline, composed of a unique clone each and
presenting therefore major risks of inbreeding and
genetic depression. Trees bear very few fruits and
are directly threatened by grazing by feral goats.
Wood from this variety seems to of very high quality. The Rapa sandalwood variety is very differentiated from the varieties from Raivavae and other
Polynesian islands. Conservation of Santalum insulare var. margaretae is therefore a priority as it has
an original part of the genetic diversity of the species, is at the verge of extinction, and constitutes a
high quality natural resource for the future.
. . . 188
.......
The proposed strategy would be to start with the
mandatory preservation of both populations (at
least one tree for each population) and the search
of new populations on favorable sites.
The Anatakuri Nako population should be fenced
(wire fence) in order to mitigate the impacts of grazing by goats and to restore the surrounding vegetation.
The minimal area to be fenced should be 2 500 m2 (or
a 50 m by 50 m square and 200 m of wire fence),
centered on the three remaining trees and including the higher and lower parts of the population.
This technique could help restore the adult trees and
obtain root suckers. The genetic diversity would not
be enhanced but the clone will have better chances of
preservation. In a second phase, local shrubs or trees
could be planted in the enclosure to restore the stock
of host plants. The trunk could be wrapped (without
any nails or perforating devices) with metal bands (as
used on coconuts) to prevent the destruction of seeds
by rats. This would allow the harvest of potential
fruits and germination experiments ex situ.
Goats should be eradicated (culling or capture) on
the islet of Karapoo Rahi. This eradication would
benefit both the sandalwoods and the overgrazed
vegetation of interest. The sandalwood population
could be restored in a similar way than in Anatakuri
Nako. Host plants can also be replanted. Regarding
rats (probably Black rats), metal bands could be used
but it seems more interesting to perform a complete
eradication of rats on the islet to restore the entire
ecosystem (seabirds, endemic insects, vegetation).
In both populations, the seed harvest should be
done on a regular basis (every two weeks) so that
the mature fruits do not fall on the ground (and
risk rat predation or rot). The maturation duration
is between five and six months (J.-F. Butaud pers.
obs.). The maturity stage of the fruit should be estimated to determine when to visit the populations
that are far from the main village.
If the production and germination of seeds prove
successful, the seedlings can be used first to
enhance the existing populations and mainly to
diversify the gene pool. One tree from Anatakuri
Nako could be planted in Karapoo Rahi and vice
Arboreal sandalwood in coastal vegetation on Motu Vaiamanu,
Raivavae, November 2002 (Photo J.-F. Butaud).
189
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
versa. In this way, tree fertility (reduction of consanguinity) could be enhanced in case of a selfincompatibility system.
Raivavae
The Raivavae sandalwood is not threatened by
extinction in the short run. The number of genetic
or apparent individuals is still important and genetic
diversity is relatively high. The priority is to establish a conservation plantation (seed orchard) and
to conserve in situ isolated or original populations.
There are two of the latter: the population of the
Vaianaua peninsula, which only has old trees and
is grazed by goats, and the altitude population(s)
near Mt Mouatapu and Mt Hiro, comprising very
isolated trees in areas inaccessible to goats. The
strategy is the same for these populations and
involves eradication or control of the goat populations. On the Vaianaua peninsula, sandalwoods are
easy to access and subject to poaching. Awareness
should be raised among the population or at least
the owner(s) of the area.
A conservation plantation requires the establishment
of an equipped nursery (fridge, automatic watering
system, protected germination area) and the training of
future nursery workers. This project is being developed
by SDR for fruit-bearing species. Sandalwood could be
included. The second step is to collect seeds from the
maximum number of different populations, as genetic
studies did not highlight any significant differentiation
among the various areas. Collections could be done
without using rat poison, in particular on "motus"
where rats are not abundant. Otherwise, rat eradication could be performed on some small "motus", welldeveloped trees could be wrapped with metal bands, or
rats could be eliminated in some populations (use of
rat poison every two weeks at least). Harvested fruits
can be pulped, separated by origin, and stored in a cold
place. Germination could follow the protocol developed for the Marquesas (Butaud 2001). The conservation plantation will include at least 200 individuals
from a dozen of origins, or twenty some trees for each
population. In situ enrichment planting can be derived
eventually from the ex situ conservation plantation.
...
Tukou marsh and taro pondfields, Rapa (Photo R. Englund).
. . . 190
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
"Mikaka Rapa"
Taro Cultivars of Rapa
Timothy J. Motley & Roland Fenstemacher
Rapa, or Oparo as it was originally
named, is the southernmost inhabited
island of the Austral Islands (" Tuha'a
pae "). Rapa is isolated, being about a
day and a half by boat away (550 km)
from its closest neighbor, Raivavae.
Scientific estimates date Polynesian
habitation beginning in the 14th or
15th centuries (Kirch & Hunt 1997).
Captain George Vancouver was the first
European to discover Rapa in December
1791. Due to its isolation, missionaries
from Tahiti did not arrive to stay until
1826 (Davies & Newberry 1961).
At 27° S latitude, Rapa is outside the
tropics. The resulting near-temperate
climate must have presented particular
challenges to its original Polynesian
settlers, because many of their common food staples don’t flourish this
far south. For instance, breadfruit
(Artocarpus altilis, Moraceae) doesn’t
grow, and while coconut palms
(Cocos nucifera, Arecaeae) grow, they
do not set fruit. Bananas (Musa spp.,
Musaceae), or " tautau ", grow either
as dooryard plants, as scattered garden plantings, or
in small groves in damp forest areas, but they do not
flourish with enough luxuriance to become a staple.
As in many places in the Pacific, sweet potatoes
(Ipomea batatas, Convolvulaceae), or " kumara ", do
grow, but are not generally relished.
In Rapa, taro (Colocasia esculenta, Araceae), or
" mikaka ", is the staple crop. It is grown either
dry or wet, in extensive systems of shallow ponds
called " roki ", reminiscent of bygone taro culture
in Hawaii, where taro also once grew in extensive
systems of ponds, or " lo'i ". Even though dry taro
cultivated on Rapa can grow shoulder high, most
taro is cultivated wet, and most wetland taro grows
only knee high. The most common taros found in
" roki " are by far, the " 'ara'ara " and " ma'areva "
cultivars. It is remarkable how many of Rapa's taro
cultivars are the branching type, with corms that
branch at the apex.
As elsewhere, taro is vegetatively propagated
using slips or cuttings, termed " 'uli " in Rapa.
Farmers prepare slips by nicking a taro corm with
their thumbnail at the very base of the stalk, then
smartly snapping the stalk from the corm. The slip
is deliberately separated as closely as possible to
the corm, to insure none of the starchy corm is left
Taro Colocasia esculenta pondfield, Hiri bay, Rapa (Photo J.-Y. Meyer)
191
...
"Mikaka Rapa": Taro Cultivars of Rapa
.. .....
on the " 'uli " to cause rot. The slips are immediately replanted in the " roki ". Leaves are left on, but
folded over under the water. This is done so newly
planted " 'uli " are not felled easily by the wind.
As with " poi " in Hawaii, in Rapa taro is pounded
into a paste called " popoi ". The consistency of
Rapa's " popoi " however, is stiffer than " poi " is
in Hawaii. It corresponds to Hawaiian " pa'i'ai ", or
the stage after taro is pounded smooth, but before
enough water is added to make " poi ". In Rapa,
when asked about diluting " popoi " to as thin as
Hawaiian " poi " an informant (T. Flores) made
the humorous remark, "kapeke te popoi", which
invokes Kapeke, a Marquesan, who preferred his
" popoi " much too thin for Rapan sensibility!
The process of pounding taro into paste differs in
other notable ways between Rapa and Hawaii. In Rapa,
women work in the " roki ", cook the taro, and pound
the " popoi ", though this may not have been the case
in ancient times. Alternatively, in Hawaii, men usually
did the cultivating, cooking, and pounding of taro.
For a good description of taro culture in Hawaii, see
Pukui's article (1967) Poi Making in Hawaii.
Once a week in Rapa, usually on Saturdays, women
gather to prepare the coming week’s " popoi ", while
the men go fishing. Before, taro was cooked in the
" ko'otu ", or underground oven, but presently, boiling is the preferred method. Once cooked, the taro is
peeled, " 'oni ", and pounded on a large flat stone, the
" tuki ", using another stone, the " karā ", that evokes
the size and shape of half a red brick. Once the corms
are pounded smooth, the whole mass of " popoi " is
then repeatedly tossed forward on the " tuki " with a
resounding " whump ", in a process called " nane ".
This is done to both aerate the large mass of " popoi "
and to mix in a small packet of sour " popoi " saved
over from the previous week. This packet, called " te
'āno'i ", is intentionally added to the freshly made
" popoi " so it ferments quickly, because of the preference for the pleasant, tangy taste of sour " popoi "
at mealtimes. Both of these terms, " nane " and " te
'āno'i ", are Tahitian, the original Rapan terms are
" taviri " and " 'akama'u ", respectively. Like souring
enhances its taste according to the Rapan palate,
aerating the " popoi " enhances its consistency. This
process of aeration is a uniquely Rapan invention.
The next step is to take appropriately sized portions
(c.1-2 liters) of just-made " popoi " and transfer them
to " ti " (Cordyline fruticosa, Asparagaceae), or " karokaro ", leaf parcels for storage. These parcels are tied
at the top,
to form teardrop-shaped
bundles called
" penu ", that
are hung up,
away from
harm or nowPounding taro into " popoi "
adays, put in
(Photo R. Fenstemacher).
the ubiquitous
covered plastic bowl, and left to ferment. At mealtime,
" penu " are opened, their contents partially consumed,
and then wrapped up again for future meals.
Besides " popoi ", another unique way taro is c­ onsumed
in Rapa is in " takae " or " takai ". " Takae " is made by
wrapping small, cooked taros tightly together and
then beating or pressing the bundle with enough force
to exclude air, so that the individual small taros consolidate into one large loaf. This resulting loaf is then
sliced and eaten as is, like a single large taro.
Another taro dish in Rapa, a preparation of taro
leaves and pork called " fafapuaka ", is only eaten
on special occasions. This uncommon use of taro
leaves in the daily diet of Rapa is quite in contrast
with their ubiquity in Hawaiian culinary tradition.
Also in contrast with Hawaii, in Rapa there are
no particular taro cultivars especially identified as
being grown for their leaves.
The above description of how taro is used in Rapa at
present differs markedly from historical practice as
recounted by Stokes (1930), who did extensive fieldwork on Rapa from 14 April 1921 to 25 January 1922
(Stokes 1923). In an unpublished manuscript housed
at the Bishop Museum, Stokes (1930) reported that
the ancient way in Rapa of using taro for food was
not by making " popoi ", but by storing it in a pit, or
" rua ", to ferment, and then, usually baking it before
eating. Taro treated in this way was termed " tio'o "
or " ma'i ". Indeed, large pits that may have served
this purpose can still be seen even today, beside
the ancient hilltop forts, or " pa ", for which Rapa is
renowned.
The merchant Lucette's (1851) eyewitness account
from Rapa in February 1843 describes " tio'o " taro
preparation: "The tarro [sic] is first washed and
scraped free of all fibres of the outer coating, and it
is laid up in pits lined with leaves and grass, and
well covered with stones. In this manner it becomes
consolidated into a paste-like mass and will keep for
a year or two. It has to me a sour and very unpleasant flavour, being something like that of turned cream
cheese, and its smell is like that of a strong cheese.
The natives are passionately fond of it, and will eat
three or four pounds weight of it at a meal if they can
get it". Although the " tio'o " method of preparing
taro was abandoned by about the middle of the
nineteenth century, Stokes reported that it was still
commonly remembered in the early 1920's.
Storing seasonal crops underground to ferment was
a common practice in other Pacific islands like the
Marquesas, Mangareva, Samoa, Fiji, etc. In fact,
according to Teiura Henry of Tahiti, breadfruit fermented in this manner was also actually called " ti'o'o
or mahi " (Henry 1928). The unique aspect about this
underground storage method being used so extensively on Rapa is that taro is not a seasonal crop, but
can be harvested all year round. Stokes concludes
from this that in Rapa there is a strong cultural preference for the taste of fermented food. This preference is self-evident even today, because the universal
. . . 192
.......
staple of every meal is deliberately soured " popoi ".
Stokes (1930) makes a convincing case that
" popoi " was actually introduced from Tahiti,
around the time when Tahitian missionaries first
permanently came to Rapa in 1826. He points
out that the word " popoi " (written sometimes as
" poipoi ") is a Tahitian word imported to Rapa, and
he speculates that by the mid-1870s it had completely supplanted the original Rapan term, " poi ".
Stokes (1930) records another remarkable observation about the evolving use of taro in Rapa: "The
commonly related account of the introduction of the
" taviri " (aeration process) describes it as an accident,
resulting from the play of two young girls. The survivor of these, when interviewed in Mangareva, stated
that she and her companion were making " poi " at
" Tupuaki " (a village on Rapa) about 1870 or 1875 and
(as may frequently be observed today) they began to
play. One of them kneaded the " poi ", lifted and dropped
it. The resulting drum-like noise probably amused her
companion, who imitated her, and the play continued
until they were tired. The " poi " was found to have
been much improved, and the process was subsequently
repeated. Other people in " Tupuaki " took it up, and
later those in " Aurei " and other parts of the island."
Stokes noted that other parts of the taro, besides
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
the corm, were used for food. In ancient times, taro
stems, or " 'urī ", were cooked and eaten, though by
the time of Stokes’ visit, stems were only an ­animal
feed. Interestingly, he found a dish called " rū "
was made with taro leaves, by cooking together
pounded, unfurled taro leaves with the edible seaweed " limu papa " (Ulva fasciata, Ulvaceae).
During a two month period (March-May 2002) author
Fenstemacher conducted interviews of local residents
to compile Rapan taro cultivar names, morphological
descriptors for the varieties, uses and cultivation methods. We compared these data with records and herbarium vouchers from earlier scientists, and with photos
taken by author Motley during the interview process.
R. Fenstemacher interviewing informants in the taro fields
(Photo T. Motley).
MATERIALS AND METHODS
The Rapa Island taro cultivar descriptions, given
below, are taken from field observations and interviews made between 18 March and 11 May 2002,
and supplemented with unpublished and published
material from Stokes (1930, 1955), his herbarium
collections from 1921 (deposited at the B.P. Bishop
Museum, Botany Department Herbarium), the 1934
field notebooks and herbarium collections of St.
John (deposited at the B. P. Bishop Museum, Botany
Department Archives and Herbarium), and a Rapa
language word list compiled and housed in the
administrative offices on Rapa (Anonymous 2001).
Interview informants that provided significant data
consisted of ten residents. Other people were interviewed, but said they did not know too much about
the topic or told us to talk to the informants in this
study (i.e., identified these individuals as the most
knowledgeable about taro culture). They included
three women and seven men. Their names and estimated age ranges at the time of study are:
• Women: Mama Fa'atu (mid-60s), Mama Luita
(early 60s), and Mate Vahine (mid-40s);
• Men: Benjamin Pukoki (late 30s), Cerdan
Faraire (mid-40s), Papa Fa'atu (mid-60s), Papa
Teri'i (mid-late 60s), Papa Teura (early 50s),
Raymond Barsinas (late 20s-early 30s), and
Tetua Flores (mid-50s).
The cultivar descriptions that follow are admittedly open to criticism from many standpoints.
Two month’s worth of field observation is hardly
193
s­ ufficient to fully describe taro cultivars completely,
since taro has a distinctly cyclic growth pattern.
For instance, taro flowers are not described below
because none were seen. Furthermore, the choice of
color descriptors is somewhat subjective, no standard
color chart was used as reference to determine them.
However, color images were taken when possible.
Some cultivars have several forms and no systematic
attempts were made to describe each form. Some
well-known cultivars from earlier times have disappeared and their descriptions are from what little
could be recalled by informants or gleaned from the
literature. Such regrettable imperfections are not just
limited to descriptions of taro, but occur whenever
one attempts to describe from observations limited
by time, plants with a large number of cultivars and
forms that have arisen through vegetative propagation. Many other plants fall into this category, most
notably banana, sweet potato, kava, and sugar cane
to name a few. Despite these obvious limitations of
the present treatment, it is believed that the descriptions presented below are at least, a solid first step
toward cataloging Rapa's different taro cultivars.
The following descriptions of each taro cultivar are
arranged as follows: The nomenclature used in the
descriptions maintains Rapan sensibility whenever
possible. The most common cultivar names are in
italics, parenthetically followed by alternate, less
common names for the same taro cultivar. Listed
subsequently are some general characteristics of
­
...
"Mikaka Rapa": Taro Cultivars of Rapa
.. .....
the cultivars and forms, consisting of the overall
impressions and distinguishing features that one
might summarily use to categorize a taro from field
observations. The description details that follow
include petiole, leaf blade, and corm characteristics
as well as distribution, use, and additional remarks.
The concluding remarks section includes any historical observations that were recorded for that
particular cultivar by Stokes in 1930, by St. John
in 1934, and by any information on the herbarium
vouchers that were collected by Stokes in 1921
and by St. John in 1934. In the interests of presenting as complete and accurate record as possible of
these largely unpublished results, these historical
observations are presented as found, no attempts
were made to correlate the occasional conflicts in
the cultivar descriptions.
Finally, although " 'uo'uo ", " 'ere'ere ", and
" 'ute'ute " are formally used in the descriptions
below as white, black and red, respectively, it may
be useful in the field to also consider them informally in terms of light, dark and bronzed, respectively. Two common Hawaiian terms are repeatedly
used in the following cultivar descriptions: " 'ohā "
to mean taro suckers or lateral shoots, and " piko "
to mean the spot on the upper surface of a peltate
taro leaf, where the petiole is attached underneath.
Rapa taro names and descriptions
…
…" 'Apura " (" Matoe ", " Matae ")
General characteristics: Wild (naturalized), self-
green taro with long, slender rhizomes.
Petiole: Uniformly self-green (whitish green),
occasionally may slightly darken right at apex, just
below attachment to leaf blade; edges of petiole
sinus reddish; base is light green to greenish white.
Leaf Blade: Green with a light green to occasionally pinkish " piko ".
Corm: Small; white with yellow fibers; long, thin
rhizomes.
Distribution: Not cultivated, but commonly found
scattered along streams and seeps
Uses: None seen.
Remarks: Stokes (1921; Stokes 341 BISH, 1930,
1955) recorded " matoe " in 1921 as a two-foot tall
"mountain taro", that grew "between ferns and under
trees". In 1930 he records it was a wild taro "which
grew on the cliff faces… now known by its Tahitian
name " apura ", is commonly referred to as ancestral
food". Our informants in 2002 still recognized
" matoe " or " matae " as synonyms for " 'apura ",
and as the original Rapan names for this cultivar.
Both of these original names were recorded on the
Rapa language list (Anonymous 2001).
This taro was not cultivated in 2002, yet it was
still very common to find scattered along streams
and seeps. It is one of the two cultivars commonly
found in the wild, the other being " kapu'ue ". The
two are readily distinguished by their different coloration and different rhizome habit.
This cultivar is known in Hawaii as " 'aweu ", where
it too is also the most commonly found wild taro
(Whitney et al. 1939).
Taro cultivar " 'Apura ": young corm and petiole base
(Photo T. Motley).
Leaf Blade: Green with yellow " piko ".
Corm: White; branching, sometimes a lot; many
" 'ohā " (> 10); tough to pound.
Distribution: Common, very widely planted in
" roki ".
Use: As " popoi ".
Remarks: By far, one of the two most common taro
cultivars in " roki ", the other being " ma'areva ".
Informants say there are two forms, " 'ute'ute ", red
or reddish, and " 'uo'uo ", white or light-colored.
……" 'Ara'ara " (" Ara'ara ", " Araara ", " Ara
ala ", " Ara ara ", " Poitere ")
General characteristics: Light yellow, thin petioles
that droop to give a widely spreading appearance;
many " 'ohā ".
Petiole: Yellowish turning whitish at apex; edges of
petiole sinus red; pink base.
Taro cultivar " 'Ara'ara "
(Photo T. Motley).
. . . 194
Taro cultivar " Hamoa " leaf and " piko "
(spot opposite petiole attachment on
upper surface of peltate leaf)
(Photo T. Motley).
.......
In 1921, Stokes (1921; Stokes 433 BISH, 1930,
1955) collected this wetland cultivar originally
under the name " poitere ". In 1930 he recorded
that this native cultivar was called either " araara "
or " poitere ". By 1955 he listed " araara " and " poitere " separately, without mentioning their synonymy. Informants from Rapa today confirm Stokes'
original 1930 record, by saying that " poitere " is
definitely not its own taro cultivar per se, but rather
describes any kind of taro with lots of " 'ohā ",
a description that aptly fits this cultivar! Both
" 'ara'ara " and " poitere " appear as taro cultivars
separately in the Rapa language list (2001) without explaining this relationship. The herbarium
voucher from 1921 (Stokes 1921; Stokes 433 BISH)
appears to have a light stem and a leaf with a dark
line on its underside that runs from the base of the
leaf sinus to the " piko ".
St. John (1934; St. John 15753 BISH) records this
cultivar as " ara ala " and that it was much cultivated,
leaves pale green above, whitish green beneath, and
petioles violet. Corm white and " popoi " whitish, and
that this cultivar "makes one of the best " popoi "."
…
…" Hamoa "
General characteristics: Dark petiole with color
going into veins beneath leaf blade, black " piko ".
Petiole: White at base, then dusky blackish into
maroon at apex, color goes into veins on underside
of leaf; edge of petiole sinus is very narrowly a
dusky reddish color.
Leaf Blade: Green, prominent black " piko ".
Corm: White; 5-6 " 'ohā ".
Distribution: Only occasionally seen, planted dry.
Use: Not seen.
Remarks: Stokes (1930, 1955) does not record this
taro name.
Thirteen years after Stokes, St. John (1934;
St. John 15755 BISH) noted that this cultivar was
a fairly common dryland taro, recently imported
from Samoa via Raivavae, with leaf veins light
brownish, petiole blackish grey, and corm whitish
with many fibers.
Informants in 2002 also say this is an introduced
taro from Samoa via Raivavae.
This cultivar does not appear on the Rapa language
list (2001).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Petiole: White at base then
dusky red into whitish at
apex; youngest petiole has
greenish cast before new
leaf unfolds; edge of petiole
sinus black.
Leaf Blade: Green; dark red
to purple " piko ".
Corm: White with yellow
fibers; short, thick rhizomes
(c. 20 cm), 5-7 " 'ohā ".
Distribution: Not cultivated,
found wild, scattered along
streams and seeps, common,
although not found as often
as " 'apura ".
Use: None seen
Remarks: Said to spread
Taro cultivar " Kapu'ue ", petiole
base (Photo T. Motley).
rapidly and cook fast. This
name was recorded by Stokes
(1930, 1955) and the Rapa
language list (2001). Interestingly, Stokes identified
this cultivar in 1930 as a "mountain taro" but in
1955 as a "cultivated variety of taro".
St. John (1934; St. John 15362 BISH) recorded
finding this cultivar by a trail in the woods and
identifies it as indigenous, with erect, purplish-red
petioles.
……
" Kaupapa " (" Kopapa ", " Ruri ")
General characteristics: Very light color, almost
white petioles striped midway with darker green;
leaf has a distinct, red " piko ".
Petiole: Bright red ring at base then pink above,
grading into very light greenish-white with green
stripes midway, into light pinkish just at apex; edge
of petiole sinus red with dark blotches adjacent;
young petioles light pinkish.
Leaf Blade: Green, long; distinct, red " piko ".
…
…" Kaota "
This cultivar was not found on Rapa in 2002.
Stokes (1930, 1955) includes this name in his 1930
cultivar list, saying it was a wetland variety of taro
that was "cultivated in early days", but that it had
disappeared. It appears on the Rapa language list
(2001) and is recognized by informants as a name
for a lost taro cultivar, but otherwise unknown.
…
…" Kapu'ue " (" Kapue ")
General characteristics: Wild (naturalized), red-
Taro cultivar " Kaupapa " plant
(Photo T. Motley).
dish taro with short, thick rhizomes.
195
...
" Kaupapa " petiole
(Photo T. Motley).
"Mikaka Rapa": Taro Cultivars of Rapa
.. .....
Corm: Pink; said to become dark when cooked and
taste like " veo " cultivar.
Distribution: Rare, only found growing wild in
a stream above the renowned taro growing area,
" Tukou ". Not seen cultivated.
Use: None seen.
Remarks: Informants on Rapa in 2002 recognized
" ruri " as a synonym for this cultivar and say it has
three forms: " 'ute'ute " or red, " 'uo'uo " or white,
and " toretore " or striped. The description above is
taken from a wild-collected " toretore " form. The
other two forms were not seen and may be lost.
Informants said the " 'uo'uo " form has red sap and
a petiole sinus with a dark red edge.
Stokes (1921; Stokes 133 BISH, 1930, 1955) wrote
on the herbarium sheet of this collection from
1921, that this cultivar was a "mountain taro"
that grew two feet tall, with creamy white flowers and that both the leaves and corm were eaten.
Interestingly, he identified it as a cultivated taro in
1930 but again called it a "mountain taro" in 1955.
St. John (1934; St. John 15754 BISH) records this
cultivar was a little-cultivated wet or dry taro of
mediocre quality, leaves pale green above, paler
green beneath, edge of leaf sheath brown, petiole
base pinkish, and whitish above. Corm light rose.
This cultivar is on the Rapa language list
(Anonymous 2001).
…
…" Kokura "
This cultivar was not found in 2002. It is rec-
ognized by informants as a name for a lost taro
cultivar, but otherwise unknown. Stokes (1930,
1955) included this name in his 1930 cultivar list,
saying that it was a wetland variety of taro that
was "cultivated in early days", but that it had disappeared. This cultivar is on the Rapa language list
(Anonymous 2001).
……" Kororoinako " (" Kororoinaku ",
Petiole: Base white in both forms, then transitions
to a dusky, dark green in the " 'ere'ere " form or into
just dark green in " 'uo'uo " form; both forms transition gradually to a reddish-maroon, beginning
about halfway toward apex in " 'ere'ere " or nearer
the apex, and about two-thirds of the way up in
" 'uo'uo " form, both forms have an indistinctly
whitish edge of the petiole sinus.
Leaf Blade: Dark green; " piko " distinct and
y-shaped, its reddish-maroon color goes into the
leaf midrib and primary veins of the lobes or the
leaf base; the lower leaf blade has a dark line running from base of sinus to " piko ".
Corm: White; branching, sometimes a lot (up to
7 times).
Distribution: Very common, widely planted in
" roki ".
Use: As " popoi ".
Remarks: One of the two most common taro cultivars on Rapa, the other being " 'ara'ara ". Both
forms of this cultivar were seen in 2002, " 'uo'uo "
or white and " 'ere'ere " or black. These forms are
quite similar; their only apparent difference being
that one was decidedly lighter than the other.
Known as " ti'iti'i " on Raivavae, Rapa's nearest
neighbor. An informant notes that when the purple
" piko " of " ma'areva " yellows, that means it is ripe.
St. John (1934; St. John 15752 BISH) noted this
cultivar was "the taro of Mangareva", an ancient
introduction to Rapa, a much-cultivated wet
taro, leaf blades bluish green above and whitish
beneath, and reddish purple at point of attachment
to the green petiole. Its white corm makes brown
" popoi " of good quality. Curiously, St. John makes
no mention of this cultivar’s distinctly y-shaped
" piko " and the voucher specimen made from his
collection "15752" has no evidence of this characteristic either.
" Tororoinako ")
General characteristics: In 2002, informants on
Rapa say this cultivar only grows at the mouth of a
cave near the ocean at a place called " Tegaire ". It
was not collected in 2002.
Remarks: Said to have dark red petioles and a
white corm. Stokes (1930, 1955) includes this
name in his 1930 cultivar list, saying that it was a
wetland variety of taro that was "cultivated in early
days", but that it had disappeared. This cultivar is
on the Rapa language list (Anonymous 2001).
…
…" Ma'areva " (" Mareva ")
General characteristics: Dark leaf with a distinct,
y-shaped " piko " (caused by pigment going into
the leaf veins). Two forms of this cultivar were
seen, " 'uo'uo " or white and " 'ere'ere " or black.
These forms are quite similar; the only apparent
difference between cultivar forms is that " 'uo'uo ",
is decidedly lighter overall than " 'ere'ere ".
. . . 196
Taro cultivar " Ma'areva " leaf
and " piko " (Photo T. Motley).
" Ma'areva " petiole and lower
leaf surface (Photo T. Motley).
.......
Also quite curiously, and
quite in contrast to St. John’s
identification of this cultivar
as an ancient introduction to
Rapa, Stokes (1930, 1955)
definitely does not include
this as a separate cultivar
on lists from 1930 or 1955,
nor did he collect a voucher
of it in 1921. (See however,
" maiapa mareva " discussion below)
This cultivar name is on
the Rapa language list
(Anonymous 2001).
There are two cultivars
from Hawaii that, although
" Ma'areva " corm and " kumu "
they lack corms that
(base of petiole) (Photo T. Motley).
branch, nonetheless have
very similar appearances
to " ma'areva ". These two Hawaiian cultivars are
named " manapiko " and " Tahitian " (Whitney et al.
1939). While the first, " manapiko ", is an ancient
cultivar from Hawaii, the second, " Tahitian ",
was "introduced by Wilder from Tahiti" early in the
last century. Coincidentally, the main difference
between these two Hawaiian cultivars parallels
the main difference between the two forms of
" ma'areva " as cataloged above, i.e. " manapiko " is
decidedly darker than " Tahitian ".
……" Maiapa " (" Mai'iapa wowo ",
" Maiapa white ", " Maiapa mareva ",
" Maiapa mangareva ")
This cultivar was not found in our 2002 survey.
Informants say that around 2000, this cultivar
vanished in Rapa from an introduced disease. It
was said to have a corm that branched and that it
was "all white", similar to " 'ara'ara " in appearance.
Three forms of " maiapa " were recorded: " 'uo'uo "
or white, " 'ere'ere " or black, and " mangareva ".
Stokes (1921; Stokes 423[" maiapa "], 434[" maiapa
white "], 435[" maiapa mareva "]  BISH, 1930,
1955) collected all three forms of this wetland
cultivar in 1921 and noted in 1930 that while the
"light and dark varieties" of " maiapa " were native,
" maiapa mangareva ", (" maiapa mareva ") was a
recent introduction.
He described " maiapa " (" maiapa dark ") (Stokes
1921; Stokes 423 BISH) as a native wetland cultivar that was a foot and a half tall (46 cm), with
yellow flowers, a red " piko ", red leaf veins, and red
on the upper part of the stems.
He described " maiapa white " (" maiapa 'uo'uo ")
(Stokes 1921; Stokes 434 BISH) also as a native
wetland cultivar that was a foot and a half tall
(46 cm), but that it had white stems and a branching corm, with "two or more tops to one root". On
the herbarium sheet for this cultivar, it looks as
though its leaves have a distinct but ­
delicate,
197
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
y-shaped " piko ", with streaks of color going
rather far along the leaf veins, almost reaching
the edge of the leaf. Underneath the leaf, there
appears to be a dark line running from the base of
the leaf sinus to the " piko ".
He described " maiapa mareva " (" maiapa mangareva ") (Stokes 1921; Stokes 435 BISH) as a wetland
cultivar that was two feet tall (61 cm), with dark
purple stems, veins, and " piko ", and that its yellow
flowers also had purple stems. From the herbarium
sheet, it looks as though this cultivar's y-shaped
" piko " went along the leaf veins rather far, with
streaks going almost to the edge of the leaf, akin
to but darker and more robustly than the " maiapa
white " form does. Underneath the leaf there also
appears to be a dark line running from the base of
the leaf sinus to the " piko ", again somewhat akin
to, but more robustly than " maiapa white " does.
Unlike the " maiapa white " form however, this cultivar has some small dark purple area on the face of
its leaf at the base of the leaf sinus.
St. John (1934; St. John 15748 BISH) listed
" mai'iapa wowo " (" maiapa 'uo'uo ") as indigenous and commonly cultivated, leaf blades pale
green above, whitish green beneath, with whitish
petioles, corm and " popoi " white. He noted this
cultivar is "especially eaten as " takai " — steamed,
pounded into a mass, sliced and eaten".
This cultivar is on the Rapa language list
(Anonymous 2001).
…
…" Manaura "
General characteristics: Petiole is practically uni-
form green, leaf has no distinct " piko ".
Petiole: Whitish green towards base transiting to
uniformly plain, dark green that lightens again
toward apex, light brown just under leaf blade;
slightly whitish-green edge of petiole sinus.
Taro cultivar " Manaura " leaf
and " piko " (Photo T. Motley).
...
" Manaura " petiole
(Photo T. Motley).
"Mikaka Rapa": Taro Cultivars of Rapa
.. .....
Leaf Blade: green, slightly wavy edges; indistinct
" piko ".
Corm: pink; > 7 " 'ohā ".
Distribution: Uncommon, planted dry.
Use: None seen.
Remarks: This cultivar was only found once in
2002, growing dry. The grower, Benjamin Pukoki,
said it was from Raivavae. It appears to be a quite
recent introduction, as neither Stokes (1930, 1955)
nor St. John (1934) mentions finding this cultivar
on Rapa. In unpublished material about Raivavae
however, Stokes (1930) listed " manaura " taro as
an "ancient food" from Raivavae, Rapa's nearest
island neighbor. This cultivar is not found on the
Rapa language list (Anonymous 2001) either.
…
…" Matoro "
This cultivar was not found in 2002. Informants
describe it as having dark red petioles with a
pink base and a red corm. There were two forms,
" 'uo'uo " or white and " 'ere'ere " or black. In 1930,
Stokes (1930, 1955) included this cultivar name
on a list of taros that were being actively cultivated
at the time of his visit in 1921, saying that it was
a wetland variety of taro that was "cultivated in
early days", but did not collect a voucher of it.
This cultivar is not found on the Rapa language list
(Anonymous 2001).
…
…" Matuku "
General characteristics: Petioles slightly striped
toward base then turn purple two-thirds of the way
up towards leaf; distinct broad pink to white edge
of petiole sinus.
Petiole: Dark red ring at base, then pink into dark
green with a few light green stripes at base, grading
into dusky purple two-thirds of the way to apex;
broad pink to white edge of petiole sinus.
Leaf Blade: Green.
Corm: Pink; soft, easy to pound.
Distribution: Uncommon, planted dry.
Use: Not seen
Remarks: Informants say this cultivar has two
forms, " 'uo'uo " or white, and " 'ute'ute " or red.
Stokes (1921; Stokes 425, 432 BISH, 1930, 1955)
described " matuku " in 1921 as a native wetland
cultivar that was three feet tall (91 cm), with red
stems and yellow flowers. He noted that it could
grow to five to six feet tall (1.5 cm to 1.8 cm).
Although Stokes makes no mention of this cultivar having different forms, he still collected
it twice, Stokes 425 on 15 November 1921 and
Stokes 432 on 1 December 1921. The herbarium sheet of the first field collection Stokes 425
however, only consists of a single flower, which
although it lacks a tip, appears to have had a
spathe ~ 38 cm long!
St. John on the other hand, collected two forms
of this cultivar in 1934. He recorded " matuku "
(1934; St. John 15750 BISH) as an indigenous,
much cultivated, well-liked wet taro, leaf blades
dull green above, pale green beneath, petioles violet
at base, clear green above. Corm and " popoi " rose
colored. " Matuku 'uo'uo " (St. John 15746 BISH)
he described as an indigenous, much cultivated,
well-liked wet taro, leaf blades dull green above,
pale green beneath, petioles white at base, violet
at middle and upper parts. Corm and " popoi "
white. (Note: The summary checklist for H. St.
John's fieldwork in Rapa lists " 'matuleu 'uo'uo "
as the cultivar name for St. John 15746. However,
from the actual field notes for St. John 15746,
his handwriting reads " 'matuku 'uo'uo' ". Thus,
" 'matuleu' " is not considered to be a valid cultivar
name). This cultivar is on the Rapa language list
(Anonymous 2001).
……
Taro cultivar " Matuku " corm
and petiole (Photo T. Motley).
" Paka " (" Laupaka ", " Raupaka ")
A taro by this name was not found during our survey in 2002 and local informants said that " paka "
is definitely not a taro cultivar name, but instead
means "the skin of a young taro" or "to skin a young
taro". Thus, it appears that " paka " is not a valid
cultivar name. Neither Stokes (1930) nor St. John
(St. John 1934 BISH) reported finding a taro cultivar named " paka ". " Paka " in fact, does not appear
on any listing of taro cultivars until 1955, when
Stokes includes it on his list of words from Rapa
(1955). It was subsequently included on the Rapa
language list (Anonymous 2001).
Just how " paka " became a cryptocultivar remains
obscure, but it may be linked to the very first two
taros that Stokes ever collected on Rapa (1921;
Stokes 47 & 133 BISH). Having arrived on Rapa
on 14 April 1921, he made his first collection of
taro on 10 June. The herbarium sheet of this first
. . . 198
.......
­collection (1921; Stokes 47 BISH) consists of just
one large leaf with a dark purplish cast. On the
sheet, Stokes originally recorded the name as " laupaka ", then crossed this out and wrote " raupaka ".
The taro came from Maitua at 183 m elevation,
where it grew three feet tall (91 cm). He noted that
the leaves and blossom were cooked as greens, the
root as food, and that its flowers were white.
Two months later, on 15 August 1921, he collected his
second taro, " kaupapa " (1921; Stokes 133 BISH),
also from Maitua but at 168 m elevation. On its
herbarium sheet, this cultivar's leaves have a dark
purplish cast too. Stokes recorded it was a "mountain taro", that it grew two feet tall (61 cm), that
both the leaves and the corm were eaten, and that
it had creamy white flowers.
These two collections are similar enough that they
appear to be the same cultivar. Their leaves both
have a similar dark purplish cast, unlike any other
taros from Rapa in the herbarium. Both have quite
unusual white flowers; all other Rapa taros reportedly have yellow flowers. Both were collected just
two months apart from the upland area Maitua
within 15 m elevation of each other. Both are the
only two taro cultivars noted whose leaves were
eaten as greens. Most importantly, informants in
Rapa today define " raupaka " as "taro leaf", not as
the name of any particular taro cultivar.
Putting all this information together, it may just
be that in June 1921, when Stokes asked about
the name of the taro whose large leaf he had just
collected, informants simply told him that he had
collected a " raupaka " or a taro leaf. Two months
later, when he may have grown more adept at the
language, he collected this cultivar once again
from the same general area, and this time was able
to get its proper cultivar name, " kaupapa ". It is
plausible that the name " laupaka " or " raupaka "
was a case of mistaken identity in June 1921
and that thirty-four years later in 1955, Stokes
imperfectly recalled it as " paka ". In any event,
Stokes himself left these three particular names
off his 1930 listing of taro cultivars and St. John
(St. John 1934 BISH) never collected any cultivars
with these names either. Additionally, in 1955
even Stokes himself tentatively identified " raupaka " as "a leaf (of taro?)" in his list of words from
Rapa (Stokes 1955).
Since Stokes left " paka " off his original 1930
listing of taro cultivars and since it didn't show
up until 1955, 34 years after he left Rapa, and
since informants today say that " paka " is definitely not a taro cultivar, it appears fair to conclude that " paka " is not a valid taro cultivar
name. Likewise with " raupaka ", Stokes did not
put this name on any listing of taro cultivars and
informants today define " raupaka " as "taro leaf",
not as a taro cultivar, and so it appears fairly
certain that " raupaka " is also not a valid taro
cultivar name either.
199
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
" Rarotonga " (" Larotoa ", " Raratoa ")
This plant was not found, nor was any mention
made of it in 2002 by local informants. It currently
belongs in the genus Xanthosoma according to its
herbarium specimens. Thus, it appears that " rarotonga " is not a valid taro cultivar.
In 1921, Stokes (1921; Stokes 136 BISH, 1930,
1955) recorded this plant was "an introduced taro
now growing wild", in 1930 he wrote that it was
recently introduced to Rapa, calling it "a dryland
taro which is now growing without cultivation", and
in 1955 he listed " taro rarotonga " as "an introduced
variety of taro". On the herbarium sheet of his 1921
collection, Stokes included extensive explanatory
notes. He originally labeled it " larotoa ", but crossed
this out and wrote " rarotonga ". He recorded that it
was known in Rurutu and Rapa as Rarotongan taro.
It grew dryland, two to three feet high (61-91 cm)
on Rapa in the high, sheltered valley of Maitua.
Its primary stem was never eaten because it was
too coarse, only the lateral stems (or tubers) were
cooked underground and eaten, with the primary
stem being left alone to reproduce. Although he
noted that its tubers were very mealy when cooked
and never used for " popoi ", their advantage was
that they would keep well for six months or more,
whereas ordinary wetland taro rots within a week.
He recorded that its leaves were eaten too.
St. John however (1934; St. John 15756), identified " raratoa " as Alocasia macrorrhiza, which is
most definitely not a taro. His field notes record it
as introduced and cultivated dryland, leaves bright
green above and pale green beneath and that its
corms were baked in the " ko'otu ", not made into
" popoi ", with only side sprouts eaten and the main
one fed to pigs.
In 1981, it was determined from herbarium collections (Stokes 1921; Stokes 136 BISH & St. John
1934; St. John 15756 BISH) that " rarotonga " is a
species of Xanthosoma.
This name does not appear on the Rapa language
list (Anonymous 2001).
…
…" Rotere "
A taro by this name was not found during our survey
in 2002. In fact, " rotere " was tentatively identified
as a possible taro cultivar only on the Rapa language
list (Anonymous 2001) and not from any other
reference. When presented with this name, informants would correct " rotere " to " rotea ", and then
hesitantly offer that it might be a lost taro, but otherwise it was unknown. Stokes (1930, 1955) does not
identify " rotere " as a taro cultivar, but records that
" rotea " was the name of "a fern". Brown & Brown
(1931) documented " karotaa " (" ka rotea "?) was the
name of bird's-nest fern (Asplenium nidus) in Rapa.
St. John (St. John 1934 BISH) did not collect any taro
cultivar called either " rotere " or " rotea " during his
1934 visit. From this evidence, it appears likely that
" rotere " is not a valid taro cultivar name.
...
"Mikaka Rapa": Taro Cultivars of Rapa
.. .....
…
…" Taitika "
This cultivar was absent in 2002 and may be lost,
though it was noted on the Rapa language list
(Anonymous 2001). Informants describe it as
­having a white petiole, yellow corm, and lots of
" 'ohā ".
Stokes (1921; Stokes 424 BISH, 1930, 1955)
recorded " taitika " in 1921 as a native wetland cultivar that grew a foot and a half tall (46 cm), with
a red " piko " and a red root. In 1930 however, he
labeled " taitika " a wild taro, "which grew on the
cliff faces". By 1955, he listed " taitika " simply as "a
variety of taro" with no further explanation.
St. John (1934; St. John 15749 BISH) reported
" taitika " as indigenous and fairly commonly cultivated, leaf blades light green above with purplish
margin, whitish green beneath. Corm and " popoi "
are yellowish. His note that this cultivar has a
"sweeter flavor than most kinds", may indicate that
his sample was overripe.
…
…" 'Ue'ueine " (" Ueue'ine ", " Ulueine ")
Informant Benjamin Pukoki called his taro
" 'ue'ueine 'uo'uo ", or the white form of this cultivar, while Mama Luita called her taro " 'ue'ueine
'ute'ute " or the red form of this cultivar.
General characteristics: Reddish-green petioles
with light green stripes appearing towards base
and apex, solid color between; indistinct " piko ".
Petiole: The " 'uo'uo ", or white form, has a light
reddish base with a few indistinct green stripes,
grading into reddish-green with indistinct lighter
green stripes for about the first third, then becoming more or less solid green-light reddish for
the middle third, and changing to light reddishgreen with indistinct green stripes, lighter than
at base, for the top third; light reddish edge of
petiole sinus. The " 'ute'ute ", or red form, has a
Taro cultivar " 'Ue'ueine " leaves
(Photo T. Motley).
bright red petiole base going into red with green
stripes of the lower third, then more or less solid
reddish-green on the middle third, and then back
to red with green stripes, lighter than at base, for
the top third, (an informant says, sometimes this
form can be red with green stripes all along the
petiole, lightening toward apex); edge of petiole
sinus is red.
Leaf Blade: Green; indistinct " piko ".
Corm: White; soft, easy to pound.
Distribution: Occasional.
Use: For " popoi ".
Remarks: Two forms of this cultivar were seen, the
" 'uo'uo " or white and the " 'ute'ute " or red. These
forms are quite similar; their apparent difference is
that the white form, " 'uo'uo ", is generally lighter
red than the latter, with a light reddish petiole base,
while the red form, " 'ute'ute ", is darker red overall,
with a bright red petiole base.
Stokes (1930, 1955) does not list this cultivar name.
St. John (1934; St. John 15751 BISH) recorded this
was an indigenous taro, much cultivated wet or
dry, leaf light green above with paler veins, whitish green beneath. Corm pulp and good quality
" popoi " are both white.
This cultivar is on the Rapa language list
(Anonymous 2001).
……
" Veo "
General characteristics: Broad to narrow dark
green stripes on light green petiole; yellow corm.
Petiole: Base white, light green with broad to narrow dark green stripes on on bottom half, solid
light green on top portion.
Leaf Blade: Green; indistinct " piko ".
Corm: Yellow; c. 5 " 'ohā ".
Distribution: Occasionally seen planted dry.
Use: Not seen.
" 'Ue'ueine " petiole base
(Photo T. Motley).
. . . 200
" 'Ue'ueine " petiole and corm
(Photo T. Motley).
.......
Remarks: Informants say there are two forms of this
cultivar, " 'uo'uo " or white and " 'ute'ute " or red.
Stokes (1930, 1955) does not list this cultivar name.
St. John (1934; St. John 15747 BISH) listed a
cultivar named " veoveo " as indigenous, much
­
cultivated and well liked, leaf blades dull green
above and whitish green beneath, petioles purplish. Corm pulp and " popoi " white. This description however, does not match very well the taro
presently called " veo ".
This cultivar is on the Rapa language list
(Anonymous 2001).
" Veo " appears to be very similar, if not identical, to
a well-known cultivar in Hawaii, introduced from
American Samoa and known as " fai fa'ausi " (Lyon
Arboretum 1970).
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Taro cultivar " Veo ", lower petiole
(Photo T. Motley).
DISCUSSION AND CONCLUSIONS
Taro is the staple starch source on Rapa. It has been
estimated based on satellite imagery and GIS that
2 % of the island has been under taro cultivation at
some time (see chapter by Motley et al., this volume). This includes all of the suitable arable lands,
comprising most of the lower valleys and flat valley floors on the island. It has been hypothesized
that the Rapan Forts or " pa " were built to protect
limited food resources when the islands population was at a maximum capacity (Ferdon 1965).
Because of the importance of taro in the Rapan diet
over the past centuries, combined with the island’s
isolation and the human selection pressures on the
original cultivars brought to the island in colonizing canoes, over time many distinctive cultivars
have been selected for that are endemic to Rapa.
Our study recorded 19 possible cultivar names
of taro from Rapa. Three however, " Paka ",
" Rarotonga ", and " Rotere ", should not really be
considered as valid names for taro and should be
left off cultivar lists for the following reasons. None
of these three putative cultivars were found during
our survey in 2002. Historically, although Stokes
(1930, 1955) identified the first, " Paka ", as a taro
cultivar in 1955, he did not do so in earlier work
from 1930. He never collected any taro cultivar
by this name during his 1921 visit. St. John also
never collected any taro cultivar by this name during his 1934 visit. While " Paka " was included on
the Rapa language list (Anonymous 2001) as a taro
cultivar, informants from Rapa today definitely say
this is not a taro cultivar, but instead that " Paka "
means "the skin of a young taro" or "to skin a young
taro". The second cultivar, " Rarotonga ", is not a
taro according to its herbarium specimens, but
belongs in the genus Xanthosoma. The third questionable cultivar is " Rotere ", which appears as a
tentative taro cultivar only in the Rapa language list
(Anonymous 2001) and not in any other previous
references. When informants were presented with
201
" Rotere ", it was invariably corrected to " Rotea ",
which was then hesitantly recalled as maybe being
a lost taro. Stokes (1930, 1955) did not record
" Rotere " as the name of any taro cultivar however, but noted that " Rotea " was the name of "a
fern" instead. Brown & Brown (1931) recorded
" karotaa " (" ka rotea "?) as the name for bird’s-nest
fern (Asplenium nidus) in Rapa. St. John never collected any taro cultivar by either name in 1934, in
further support that " Rotere " is likely not a valid
taro cultivar. Thus, it appears reasonable to believe
that these three names, " Paka ", " Rarotonga ", and
" Rotere ", have been mistakenly identified as taro
cultivars in the recent past and will be so treated
here. These three invalid names will not be counted
as bona fide taro cultivars from Rapa.
Of the remaining 16 authentic cultivars of taro from
Rapa in Table 48, eight have several forms that are
widely recognized by local residents. The cultivars
" Kaupapa " and " Maiapa " each have three distinct forms and " 'Ara'ara ", " Ma'areva ", " Matoro ",
" Matuku ", " ‘Ue'ueine ", and " Veo " each have two
recognizable forms (Table 48). In total there are 26
distinct taros from Rapa, known either currently
or in the past. Three of these cultivars and one
form of a fourth cultivar are identified by informants or from records as "not Rapan." " Hamoa "
is identified as a Samoan cultivar. " Ma'areva " and
the " Mangareva " form of " Maiapa " are both introductions from Mangareva Island. " Manaura " was
introduced via Raivavae.
The diversity of Rapan taro is impressive for a
small island. Unfortunately, five cultivars and their
various forms no longer exist (Table 48). These
cultivars and their physical descriptions, although
sometimes vague, are still alive in the memories of
our informants. Therefore, some taro cultivars that
we recorded above we did not see during out visit.
Whether they still exist is unknown. For example,
" Kororoinako " is a cultivar known to grow only at
...
.. .....
"Mikaka Rapa": Taro Cultivars of Rapa
Table 48: The 16 confirmed taro cultivar names recorded on Rapa in 2002 and comparison with previous cultivar surveys. Numbers
in parentheses represent number of forms of cultivar.
Taro Cultivar Stokes St. John
(2002 survey) (1921) (1934)
'Apura
X
'Ara'ara (2)
X
Hamoa
Rapa language list
(2001)
Extirpated
cultivar
Recent
introduction
" Popoi "
cultivar
X
X
X
X
X
Samoa
Kaota
X
X
Kapu'ue
X
X
X
Kaupapa (3)
X
X
X
Kokura
X
Kororoinako
X
Ma`areva (2)
X
X
Maiapa (3)
X
X
X
X
X
?
X
Mangareva
X
Manaura
X
Mangarevan form
Raivavae
Matoro (2)
X
X
Matuku (2)
X
X
X
Taitika
X
X
X
'Ue'ueine (2)
X
X
Veo (2)
X
X
the mouth of a cave on the north side of the island;
we were unable to investigate this site. Many of the
cultivars may have just disappeared because of preference for other taros and disuse. Because population levels have dropped on Rapa, so has cultivation.
Only about one quarter of the taro fields identified
by satellite imagery are still actively planted (see
chapter by Motley et al., this volume). A more serious threat to taro comes from disease, which could
destroy the unique germplasm resources that may
exist in Rapan cultivars. An accidental introduction
of taro leaf blight into Samoa in 1993 nearly wiped
out most cultivars there (Caillon et al. 2006). The
recent loss on Rapa (in c. 2000) of the three forms
of " Maiapa " due to disease exemplifies the fragile
nature of these resources.
The erosion of genetic diversity of crop species
(Myers 1988) and cultural knowledge (Balick et
al. 2001) was the driving force behind this study.
When preparing to conduct this botanical expedition and research on Rapa it was apparent from
literature (Beck 1922) and from accounts in historical expeditions, that taro played an important role
in the survival of the Rapan people and that they
had developed unique culinary practices and culti-
X
X
X
X
vars. We have confirmed these historical accounts
and have given our best account of taro cultivars,
traditions, and uses in 2002.
Future studies should study the genetic diversity
that exists in the cultivars and forms of Rapan
taro, using molecular techniques. A germplasm
collection should be established because these
plants may harbor unique genetic material that
could be used to enhance disease resistance or
production. However, since taro is typically clonally propagated, seed storage is not an option;
long-term maintenance of such living collections
is fraught with difficulties (Motley 2006). The
best method is probably preservation through
tissue culture. Tissue culture efforts are underway at Lyon Arboretum in Honolulu, Hawaii to
preserve the remaining Hawaiian taro cultivars.
Using their methods and facilities may be a way
to start banking the germplasm resources of Rapa.
We also strongly suggest that support, both financial and technical, be given to the people of Rapa
to maintain a living collection of taro cultivars in
situ. Plans are underway to continue our studies
to include a genetic assessment of diversity of
Rapan taro.
. . . 202
.......
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
GLOSSARY OF TARO TERMINOLOGY*
a'apo'i – to cover an oven with plant material.
'akama'u – to make sour; by extension, the small packet of sour
popoi that's pounded into freshly made popoi, in order to
make it sour rapidly. Being replaced by Tahitian term 'ano'i
or te 'ano'i.
'akarapu – to mix.
'akatika – to level ground in roki by using water.
'akatoki – to separate twinned stalks of young branching taro.
'aka’ui – sheaf of plants.
'anavai – river, large stream.
'āno'i – see te ‘ano’i.
eaka – roots of taro plant.
'ere'ere – black, blackish, or dark-colored.
'eu – to cook food in oven; considered to be a Tahitian word,
Rapan term is tao.
fā – stem of taro plant.
fio – young taro spathe used by children as noisemaker; to
whistle.
fa'aruera'a kotae – small irrigation ditch between roki.
ha'apahura'a kotae – dam across watercourse that diverts water
into ditch that irrigates roki.
kai – food, to eat.
kaikai – food, to eat.
kao – unfurled young taro leaf.
karā – a very hard kind of stone; a brick-shaped pounder made
of such stone, pestle to pound popoi.
karokaro – Cordyline fruticosa, ti.
kauatu – oven.
kavake – taro suckers.
kavakevake – copiously suckering taro.
ko'a – general name for taro; cooked taro; taro food.
koaki te veoveo – perfectly ripe taro, just ready to eat.
kokura – a big roki.
ko'otu – oven.
koroara – when water leaks out a hole in a new taro pond.
kotae – water, fresh water.
kuanga – flowering taro.
kumara – Ipomoea batatas, sweet potato.
kumu – base of taro stem, up to about first 2 cm.
mai – overripe taro.
ma'i – ancient way of using taro, by fermenting in a pit and then
cooking (see also tio’o), a practice abandoned by about the
middle of the nineteenth century for popoi.
ma'u – fermented, soured.
mikaka – Colocasia esculenta, taro, generally small; general
Rapan term for taro.
nane – to vigorously aerate popoi with a resounding "whump."
Considered a Tahitian word, Rapan term is taviri.
ngutu’uvai – head of main ditch that diverts water to roki.
'ohā – Hawaiian term for taro suckers.
'oni – to peel cooked taro.
paka – skin of young taro or to skin young taro.
pa'u – edge of roki.
pē – soft rot of taro.
penu – teardrop-shaped; package of popoi in this shape,
fashioned from karokaro leaves or grass; old-style, similarly
teardrop-shaped pounding stone.
203
penuri – large package, fashioned from grass, used to transport
taro from the field, largely replaced in the 1960’s by sugar or
burlap bags introduced by the French military.
piko – Hawaiian term for area on upper surface of taro leaf,
where petiole is attached below to the peltate leaf, often
cited as a diagnostic characteristic of different taro cultivars;
bellybutton.
poitere – any freely suckering taro plant.
popoi – a stiff paste of pounded, cooked taro; the renowned
staple of Rapa, present at every meal and preferred well
soured. Considered a Tahitian word by J.F.G. Stokes (1930),
who hypothesized it replaced the original Rapan term poi, by
mid-1870s.
popoi ma'u – fermented popoi, the "staff of life" in Rapa, much
liked, present at every meal.
pua – flower.
raupaka – taro leaf.
roki – a shallow pond to grow taro, lo’i in Hawaiian.
rū– taro leaves cooked for food.
rua tio'o – pit to store tio’o or ma’i.
tanu – to plant.
tākae – a loaf of small taros, cooked whole (not grated) and
peeled, then pressed or pounded to consolidate, and baked
into a loaf that is sliced and eaten as is, as if it were one large
taro.
takai – see tākae.
tao – to place food in oven.
tapau mikaka – taro sap.
tapiri – stage in pounding popoi; paste of taro; to glue.
tarua – starchy.
tautau –  Musa spp., Musaceae, general Rapan term for banana.
taviri – to vigorously aerate popoi with a resounding "whump,"
now replaced by Tahitian word, nane.
te 'ano'i – small packet of sour popoi that’s pounded into
freshly made popoi, in order to make it sour rapidly.
Considered a Tahitian word, similar Rapan term is ‘akama’u.
teatea – white, whitish, light-colored.
tio'o – ancient way of using taro, by fermenting in a pit and then
cooking (see ma’i above), abandoned by about the middle of
the nineteenth century for popoi.
to'i – to separate leaves from the taro corm.
tuki – large, flat stone to pound popoi on; to pound food.
'uo'uo – white, whitish, light-colored; considered a loan word
from Tahiti, Rapan term is teatea.
'urī – taro slip to plant; stem of taro.
uru – to clean.
'ute'ute – red, reddish, bronzed.
'uvai – ditch that directs water to the roki.
va'iva'i – soft rot of taro.
varuvaru – to peel, to scrape.
veoveo – young taro flowers, which are edible.
* This glossary is a compilation of vocabulary words from Rapa that are
associated with taro culture and use. Besides terms that were collected in
2002, other sources of words for this glossary are Stokes (1930, 1955) and
Anonymous (2001).
...
.......
chapitre ou bien
d’une partie
Annexes
……
……
....
Taro pondfields, Rurutu (Photo J.-Y. Meyer).
. . . 206
Acknowledgements
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
All the authors and co-authors are
grateful to the Government of French
Polynesia for the funding support,
the Institut Louis Malardé for the
funds management and accountancy
(more particularly her former directors, François Laudon and Aurélie
Sunara), the Délégation à la Recherche
de la Polynésie française (Priscille Tea
Frogier) and the Délégation Régionale à
la Recherche et à la Technologie (Robert
Maurin) for providing the research
permits. Additional fundings were provided by the Comité français de l’UICN
to O. Gargominy and B. Fontaine, and
the Bernice Pauahi Bishop Museum
(Honolulu) to R. Englund.
We thank the Centre IRD in Tahiti
(and its former director Jacques
Iltis) for providing accommodation
for some expedition members; the
mayor’s­offices and the mayors of Rapa
(Tuanainai Narii), Raivavae (Teana
Teavatua), Rimatara (Georges Hatitio
and Damas Utia), Rurutu (Frédéric
Riveta), Tubuai (Chantal Tahiata);
the former Administrateur territorial
des Australes or "Tavana hau" (Gilles
Thuret); the Service du Développement
Rural (especially Pierre Atai and Itatoa
Teauroa on Rurutu, Teihotaata Mateau
on Tubuai, Jean-Jacques Teaurai and
André Ani on Raivavae, Benjamin
Pukoki on Rapa); the boat companies "SNA Tuhaa Pae" and the "Tahiti
Nui"and their crews; the military
ship La Railleuse of the French Navy
(Marine Nationale) and its crew; the
French authorities (Haut-Commissariat, COMSUP),
the gendarmes of Rimatara (Henri Fuentes and
Olivier Galan); the "Air Tahiti" flight company
(especially Hildegarde Olivain of the domestic
freight); the guesthouses (pensions de famille), Linda
and Nelson Tavaearii on Raivavae, Chantal Taharia
on Rimatara, Yves and Hélène Gentilhomme (Le
Manotel), and Tania and Landry Chung (pension
Temarama) on Rurutu, Sam (deceased) and Yolande
Tahuhuterani on Tubuai, Cerdan and Maite Teroro
Vahine Faraire on Rapa, and the local guides and
informants (including Viniura and Sylvie Goddart
on Tubuai, Albert Varney on Raivavae), the inhabitants and the land owners for permitting access
to their property (e.g. "motu" on Raivavae);
Philippe Paccou of the local newspaper La Dépêche
de Tahiti, Mirella Hauata of the local television
207
"TNTV", Elodie Lagouy who joined us in Rimatara.
We also acknowledge the speakers invited for the
"Austral Islands Biodiversity Conference" held in
2005: Benoît Stoll and Antoine N’Yeurt from the
Université de la Polynésie française, Timothy Motley
from the New York Botanical Garden (USA), Alice
Cibois from the Natural History Museum of Genève
(Switzerland), and René Galzin from the Université
de Perpignan (France) and CRIOBE-EPHE-CNRS
biological station (Mo’orea).
Some particular thanks from the authors and their
coauthors are given: J.-C. Thibault thanks Alain
Guillemont and Philippe Raust for their personal
communications and for sharing unpublished data
on the Australs birds, and to Alice Cibois for improving a first draft of the manuscript; O. Gargominy
and B. Fontaine thank Michel Charleux for showing
fossil deposits in Rurutu; R. Englund thanks Allen
Allison and Neal Evenhuis of the Bishop Museum
of Honolulu were also extremely helpful and supportive with Bishop Museum resources, as well as
Tracie MacKenzie who greatly assisted with logistics
throughout this project; the late T. Motley thanks
Steve Perlman, and Kenneth Wood, who were valuable
members of the March-May 2002 Rapa Expedition
funded by the National Geographic Society and the
Lewis B. & Dorothy Cullman Foundation, the New
York Botanical Garden and the staff at the Bishop
Museum Botany Department and Herbarium (BISH),
particularly Clyde Imada, the Musée de Tahiti et des
Iles and the (PAP) herbarium for assistance and use
of their collections; J.-F. Butaud and his coauthors
thank the research project on sandalwood genetics and evolution conducted by the Université de
la Polynésie française and funded by the program
"Ecosystèmes Tropicaux" of the Ministère de l'Écologie
et du Développement durable; R. Fenstemacher is
deeply indebted to Papa and Mama Fa’atu, Papa
Teri’i, Papa Teura, Mama Luita, Mate Vahine, Cerdan
Faraire, and Raymond Barsinas for graciously sharing
their profound knowledge of the different taros, their
culture, and their use, and he is also grateful to Tetua
Flores, whose openhearted friendship combined with
his energetic enthusiasm for this project, to make
gathering information about taro in Rapa that much
easier and so very enjoyable. Aronga nui e Rapa-ma!
The success of these field expeditions is largely attributed to the skills, complementarity and humour of
the teams lead by Jean-Yves Meyer (nicknamed "El
Commandante") who would like to dedicate this
book to Priscille Frogier, head of the Délégation à
la Recherche, and Ruth Leng-Tang, her secretaryaccountant, for their indefatigable moral support
during the past 12 years!
...
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.. .....
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. . . 218
Jean-Yves MEYER
Délégation à la Recherche
B.P. 20981
98713 Papeete
Tahiti - Polynésie française
[email protected]
Terrestrial Biodiversity of the Austral Islands,
French Polynesia
Benoît FONTAINE
Muséum national d’Histoire naturelle
Département Écologie et Gestion de la Biodiversité
UMR 7204 - CESCO - CP 51
57 rue Cuvier
75005 Paris - France
Paris - France
[email protected]
Elin M. CLARIDGE
B.P. 35 Moerai
98753 Rurutu
Polynésie française
[email protected]
Jessica E. GARB
Department of Biological Sciences,
University of Massachusetts Lowell
Olsen Hall 414
198 Riverside St
Lowell, MA 01854 - USA
[email protected]
René C. MAURY
UMR 6538 Domaines océaniques
Université de Bretagne Occidentale
29270 Plouzané - France
[email protected]
Rosemary G. GILLESPIE
Essig Museum of Entomology,
University of California, Berkeley
201 Wellman Hall #3112
Berkeley, CA 98720 - USA
[email protected]
Christelle LEGENDRE
UMR 6538 Domaines océaniques
Université de Bretagne Occidentale
29270 Plouzané - France
Catherine CHAUVEL
ISTerre, UMR 5025 LGCA
Université Grenoble Alpes
38041 Grenoble - France
Diana M. PERCY
Department of Botany
University of British Columbia
3529-6270 University Blvd.
Vancouver, BC V6T 1Z4 - Canada
Gérard GUILLE
Laboratoire de Géophysique
CEA/DAM/DIF
92197 Arpajon - France
current address:
Department of Life Sciences
Natural History Museum
Cromwell Road
London, SW7 5BD - UK
[email protected]
Sylvain BLAIS
UMR 6118 Géosciences Rennes
Université de Rennes 1
35042 Rennes - France
Ronald A. ENGLUND
Pacific Biological Survey
Bernice Pauahi Bishop Museum
1525 Bernice Street
Honolulu - Hawaii 96817 - USA
[email protected]
Hervé GUILLOU
UMR 8212 LSCE/CEA-CNRS
91118 Gif sur Yvette - France
Philippe ROSSI
Commission de la Carte Géologique du Monde
77 rue Claude Bernard
75005 Paris - France
Jean-François BUTAUD
UMR 241 EIO (Écosystèmes insulaires océaniens)
Université de la Polynésie française (UPF)
BP 6570
98702 Faa'a, Tahiti - Polynésie française
Jean-Claude THIBAULT
Muséum national d’Histoire naturelle
Département Systématique et Evolution
CP 51 - UMR 7205
57 rue CUVIER
75005 Paris - France
[email protected]
Consultant en foresterie et botanique polynésienne
BP 52832
98716 Pirae, Tahiti - Polynésie française
[email protected]
Timothy J. MOTLEY †
Stiffler Chair of Botany & Associate Professor
Old Dominion University
Department of Biological Sciences
110 Mills Godwin Bldg., 45th St.
Norfolk, VA 23529 - USA
Olivier GARGOMINY
Muséum national d’Histoire naturelle
Service du Patrimoine naturelle - CP 41
57 rue Cuvier
75005 Paris - France
[email protected]
219
...
Addresses of the Authors
.......
Addresses of the Authors
Addresses of the Authors
.. .....
Hervé CHEVILLOTE
IRD
32 avenue Henri Varagnat
93143 Bondy Cedex - France
[email protected]
Vincent GAYDOU
UMR 241 EIO (Écosystèmes insulaires océaniens)
Université de la Polynésie française (UPF)
BP 6570
98702 Faa'a, Tahiti - Polynésie française
[email protected]
Alfred LUONOGO
Uncle Owl Productions, Ltd.
New York - USA
Matthew PREBBLE
Department of Archaeology and Natural History
College of Asia and the Pacific
The Australian National University
Canberra
ACT 0200 - Australia
[email protected]
Jean-Pierre BIANCHINI
UMR 241 EIO (Écosystèmes insulaires océaniens)
Université de la Polynésie française (UPF)
BP 6570
98702 Faa'a, Tahiti - Polynésie française
[email protected]
Jean-Marc BOUVET
UPR 108 (Amélioration génétique et adaptation
des plantes méditerranéennes et tropicales)
Centre de recherche internationale en recherche
agronomique pour le développement (CIRAD)
Campus de Lavalette TA A-108/01
34398 Montpellier Cedex 5 - France
[email protected]
Émeline LHUILLIER
UPR 108 (Amélioration génétique et adaptation
des plantes méditerranéennes et tropicales)
Centre de recherche internationale en recherche
agronomique pour le développement (CIRAD)
Campus de Lavalette TA A-108/01
34398 Montpellier Cedex 5 - France
[email protected]
Phila RAHARIVELOMANANA
Laboratoire de Chimie des Substances Naturelles
Université de la Polynésie française
Tahiti - Polynésie française
[email protected]
Fanny RIVES
UPR 108 (Amélioration génétique et adaptation
des plantes méditerranéennes et tropicales)
Centre de recherche internationale en recherche
agronomique pour le développement (CIRAD)
Campus de Lavalette TA A-108/01
34398 Montpellier Cedex 5 - France
[email protected]
Ronald FENSTEMACHER
Ho'okahe Wai Ho'oulu 'Aina
45-622 Keaahala
Kaneohe, HI 96744-3320 - USA.
[email protected]
. . . 220
DERNIERS TITRES PARUS
cpn 71 : René Rosoux, Marie-des-Neiges de bellefroid, Jacques baillon & Annie moreau (Coords)
2011. – Lynx… le grand retour ? Actes du symposium d'Orléans 17, 18, 19 octobre 2008. 120 p.
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cpn 70 : Philippe bouchet, Hervé Le Guyader & Olivier Pascal (Eds) 2011. – The Natural History of
Santo. 572 p.
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cpn 69 : Dominique MONTI, Philippe KEITH & Érick VIGNEUX 2010. – Atlas des poissons et des crustacés de
la Guadeloupe. 128 p.
(ISBN : 978-2-85653-648-3) 23 $ TTC
cpn 68 : Loïc CHARPY (Coord.) 2009. – Clipperton environnement et biodiversité d’un microcosme océanique. 420 p.
(ISBN MNHN : 978-2-85653-612-4) (ISBN IRD : 978-2-7099-1660-8) 59 $ TTC
cpn 67 : Laurent CHIRIO & Matthew LEBRETON 2007. – Atlas des reptiles du Cameroun. 688 p.
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cpn 66 : Ludovic BOUDIN, Jordane CORDIER & Jacques MORET 2007. – Atlas de la flore remarquable du Val
de Loire entre le bec d’Allier et le bec de Vienne. 464 p.
(ISBN : 978-2-85653-602-5) 38 $ TTC
cpn 65 : Philippe KEITH, Gérard MARQUET, Pierre VALADE, Pierre BOSC & Érick VIGNEUX 2006. – Atlas
des poissons et des crustacés d’eau douce des Comores, Mascareignes et Seychelles. 250 p.
(ISBN: 2-85653-597-6, ISBN 13 : 978-2-85653-597-4) 26 $ TTC
cpn 64 : Catherine SOUTY-GROSSET, David M. HOLDICH, Pierre Y. NOËL, Julian D. REYNOLDS & Patrick
HAFFNER (Eds) 2006. – Atlas of Crayfish in Europe. 187 p.
(ISBN : 2-85653-579-8, ISBN 13 : 978-2-85653-579-0) 29 $ TTC
cpn 63 : Guy DUHAMEL, Nicolas GASCO & Patrick DAVAINE 2005. – Poissons des îles Kerguelen et Crozet.
Guide régional de l’océan Austral. 419 p.
(ISBN : 2-85653-578-X) 65 $ TTC
cpn 62 : Serge MULLER (Coord.) 2004. – Plantes invasives en France. 168 p.
(ISBN : 2-85653-570-4) 37 $ TTC
cpn 61 : Jacques BARDAT et al. 2004. – Prodrome des végétations de France. 171 p.
(ISBN : 2-85653-563-1) 21 $ (épuisé)
cpn 60 : Jean-François VOISIN (Coord.) 2003. – Atlas des Orthoptères et des Mantides de France. 104 p.
(ISBN : 2-85653-562-3) 18 $ (épuisé)
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