Alison`s presentation

Transcription

Alison`s presentation
Trouble in Paradise: Paleoecology and extinction
of island birds
Alison G. Boyer
Dept. Ecology and Evolutionary Biology
University of Tennessee
&
Climate Change Science Institute
Oak Ridge National Laboratory
Acknowledgements
Helen James (Smithsonian USNM)
Walter Jetz (Yale U.)
David Steadman (U. Florida)
Christophe Sand (IANCP, New Caledonia)
Jack Grant-Mackie (Auckland U, NZ)
Trevor Worthy (U New South Wales, Aus)
Richard Duncan (Lincoln U, NZ)
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Moorea, French Polynesia
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Endangered Pacific island birds
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Barnosky et al. 2004, Science
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Barnosky et al. 2004, Science
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Human colonization of Oceania
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Based on Kirch 2002, On the Road of the Winds
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Bird extinctions in Oceania
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Bird extinctions in Oceania
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Bird extinctions in Oceania
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Holocene paleorecord of Pacific islands
Fossil vertebrate localities:
archaeological sites
Makauwahi Cave, Kauai
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Holocene paleorecord of Pacific islands
Fossil vertebrate localities:
archaeological sites
natural traps
Puu Makua Cave, Maui
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Holocene paleorecord of Pacific islands
Fossil vertebrate localities:
archaeological sites
natural traps
bone accumulations by
predators
Me Aure Cave, New Caledonia
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Extinction Mechanisms
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overexploitation of populations
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introduction of exotic predators
and diseases
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habitat destruction
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Extinction Mechanisms
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–
overexploitation of populations
–
introduction of exotic predators
and diseases
–
habitat destruction
These processes remain primary
drivers of modern extinctions
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Island bird extinctions
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How many species were lost?
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Which species went extinct?
How did they change ecological
communities?
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How can they be prevented?
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How many species were lost?
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Islands differ in:
• collection effort
• number of sites
• taphonomy of sites
• traits and characteristics of
species
Low collection rate means
many extinct species
may remain to be
discovered
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Classic Mark-recapture estimates
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Classic Mark-recapture estimates
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Classic Mark-recapture estimates
N = (M * T) / R = (3 * 3) / 1 = 9
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Mark-recapture for fossils
Marked
Living species
Historically observed
Living species
Historically observed
Recaptured
Known only from fossils
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Number of extinctions
371
Bayesian hierarchical mark-recapture model
618
Duncan, Boyer & Blackburn, 2013, PNAS
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Number of extinctions
Bayesian hierarchical mark-recapture model
371 618
Duncan, Boyer & Blackburn, 2013, PNAS
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Number of undiscovered species
'J
TQF
SFT
JTMB
TVS
UIF
JOD
TQF
SFN
OPO
5I
FYU
PG U
TFB
Duncan, Boyer & Blackburn, 2013, PNAS
PG U
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Island bird extinctions
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How many species were lost?
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Which species went extinct?
How did they change ecological
communities?
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How can they be prevented?
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New Caledonia
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Mé Auré Cave site
Me Aure Cave, New Caledonia
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Mé Auré Cave record
Cal BP
200
1200
2400
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Mé Auré Cave Birds
Boyer et al. 2010, Biodivers Conserv
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Mé Auré Cave Birds
Boyer et al. 2010, Biodivers Conserv
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New Caledonia's dry forest
“The most threatened
tropical dry forest in the world.”
-Conservation International
Bouchet et al 1995
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Boa Cave site
Boa cave
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Boa Cave excavations 2011
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Boa Cave excavations 2011
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Boa Cave excavations 2011
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Boa Cave excavations 2011
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A giant extinct bird
Sylviornis
Known extinctions in New Caledonia
Sylviornis
Meiolania
Mekosuchus
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Which species went extinct?
Me Aure Cave:
interior forest spp. declined and
second-growth generalists increased
Boa Cave:
the largest vertebrate species
disappeared
Forest remains intact only on steep ridges
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The Hawaiian islands
H. D. Pratt
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The Hawaiian islands
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The Hawaiian islands
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Extinction selectivity
Why are some species more likely to be
threatened with extinction than others?
External threats
• hunting, predators, disease,
habitat loss
Intrinsic susceptibility
• body size, endemism,
flightlessness, trophic guild
Environmental correlates
• island area, isolation, climate
James & Olson 2003, Auk
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Holocene paleorecord of Pacific islands
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Extinctions 3500 ybp - present
Random forest model
Boyer 2010, Conservation Biology
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Extinctions 3500 ybp - present
Random forest model
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n = 1264
Accuracy: 87%
False-negatives: 5.1%
False-positives: 31%
Boyer 2010, Conservation Biology
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Extinction risk predictions
Boyer 2010, Conservation Biology
Hawaiian thrush
Henderson island rail
Cloven-feathered dove
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Which species went extinct?
Large species
Those found on only a few
islands
Diet of vegetation and seeds
Island characteristics and
deforestation were less
important
Giant Moa (Dinornis robustus), by Paul Martinson
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Island bird extinctions
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How many species were lost?
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Which species went extinct?
How did extinctions change ecological
communities?
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How can they be prevented?
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Ecosystem services provided by birds
Functional
Diversity
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Functional diversity of the bird community
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Declining Functional Diversity with Extinctions
Extinction (%)
Boyer & Jetz, 2014, Global Ecology and Biogeography
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Declining Functional Diversity with Extinctions
Guam:
Loss of birds led to dramatic increase in spiders
(Rogers et al. 2012)
Extinction (%)
Boyer & Jetz, 2014, Global Ecology and Biogeography
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Declining Functional Diversity with Extinctions
New Zealand:
Loss of bird pollinators led to reduced fitness of
trees (Anderson et al. 2011)
Extinction (%)
Boyer & Jetz, 2014, Global Ecology and Biogeography
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Declining Functional Diversity with Extinctions
Fiji:
Loss of frugivorous birds led to decline in native
trees (Meehan et al. 2002)
Extinction (%)
Boyer & Jetz, 2014, Global Ecology and Biogeography
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Island bird extinctions
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How many species were lost?
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Which species went extinct?
How did they change ecological
communities?
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How can extinctions be prevented?
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Modern biodiversity in crisis
Threatened with extinction
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12% of birds
25% of mammals
> 30% of amphibians
Nearly half of all threatened
bird species are found on
oceanic islands
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Eradicate invasive predators
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Eradicate invasive predators
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Reintroduce birds to former range
Rimatara Lorikeet
reintroduced to Atiu,
Cook Islands more than
200 years after
387
mil
es
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Restore habitats
Lepredour island, New
Caledonia:
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eradication of deer,
goats, cats
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dry forest restoration
reintroduction of native
birds
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Oceanic islands as global microcosms
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Islands are self-contained, replicated units with a long
record of coupled human-environmental history
We study past extinctions
to understand:
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baseline conditions
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causes of biodiversity loss
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predictability of extinctions
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consequences of
extinctions for societies &
ecosystems
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