Seed dispersal dynamics and the decline of Hawaii`s fruit

Seed dispersal dynamics and the decline of Hawaii`s fruit

Seed dispersal dynamics and the decline of
Hawaii’s fruit-eating birds
L. Pejchar1, S. Culliney1, M. Kaushik1, S. Bombaci1, L.
Crampton2, R. Switzer3, V. Ruiz-Gutierrez1
1Colorado
State University, 2Kauai Forest Bird Recovery Project, 3Keauhou
Bird Conservation Center
Photo: ZSSD
How are birds important for seed dispersal?
Distance
dispersal
Directed
dispersal
Photo: ZSSD
Fertilizing effects
Germination
benefits
50% of Hawaii’s native plants rely on seed
dispersal by birds
50% of Hawaii’s native plants rely on seed
dispersal by birds
The Alala, Omao and Puaiohi are Hawaii’s only extant
native frugivores
Drivers of Decline and Extinction
Predation
Habitat loss and
degradation
Competition and
disease
Captive population, future release?
Photo: ZSSD
Susan Culliney-ZSSD
Questions
1. What seed dispersal services are lost…and
restored, by the extinction and recovery of Alala?
2. Does the decline of Puaiohi in the presence of
exotic birds alter seed dispersal dynamics?
3. Are bird reintroductions restoring ecological
processes in New Zealand’s mainland sanctuaries?
Questions
1. What seed dispersal services are lost…and
restored, by the extinction and recovery of Alala?
2. Does the decline of Puaiohi in the presence of
exotic birds alter seed dispersal dynamics?
3. Are bird reintroductions restoring ecological
processes in New Zealand’s mainland sanctuaries?
´Alalā
Corvus hawaiiensis
Native - extinct
in wild
Ōma´o
Myadestes obscurus
Native – narrow range
Leothrix
Leiothrix lutea
Exotic - widespread
Japanese White-eye
Zosterops japonicus
Exotic - widespread
´Alalā
Corvus hawaiiensis
Native - extinct
in wild
Ōma´o
Myadestes obscurus
Native – narrow range
Leothrix
Leiothrix lutea
Exotic - widespread
Japanese White-eye
Zosterops japonicus
Exotic - widespread
Keauhou Bird Conservation Center (Volcano, HI)
Susan Culliney: ZSSD
Susan Culliney: ZSSD
Susan Culliney: ZSSD
Plants Included in Study
Methods: Dispersal Behavior
1) Gave each ´Alalā suite of berries, observed (Bird level)
Susan Culliney: ZSSD
Eat
Susan Culliney: ZSSD
Carry
Susan Culliney: ZSSD
Cache
2) Fate of seeds discovered next day (Flock level)
Susan Culliney: ZSSD
% seeds digested
% seeds plucked/moved
Results: Dispersal Behavior (EAT)
1.0
Old Alala (>3 yr)
Young Alala (0-3 yr)
0.6
0.4
0.2
Plant Species
N=
6
12-19
12-18
10-29
10-23
10-27
15-24
3
12-18
12-25
Loulu green
Loulu black
Halapepe
Hoawa
Ohe mauka
Pilo
Kolea
Naio
Pukiawe
Olapa
Kawau
Mamaki
Ohelo
0.0
Oha kepau
Probability of eating
0.8
t=? p=?
3-25
6-13
4-12
3-9
´Alalā flock consumed all plants in the study, a form of seed dispersal
Results: Dispersal Behavior (CARRY)
Flock carrying behavior
1.0
0.8
t=? p=?
0.6
0.4
0.2
Loulu green
Loulu black
Halapepe
Hoawa
Ohe mauka
Pilo
Kolea
Naio
Pukiawe
Olapa
Kawau
Mamaki
Ohelo
0.0
Oha kepau
Probability of observed carrying
Old Alala (>3 yr)
Young Alala (0-3 yr)
Plant Species
N=
6
12-19
12-18
10-29
10-23
10-27
15-24
3
12-18
12-25
3-25
6-13
4-12
´Alalā flock carried all plants, a form of seed dispersal
3-9
Halapepe
Loulu black
Loulu green
Pilo
Kolea
Naio
0.8
Pukiawe
0.6
Olapa
3.9
Kawau
2.9
Mamaki
Hoawa
% times
cached
Ohelo
1.2 2.2 0.7 1.1 0.5 0.2 1.2 3.6 2.4 1.5
Oha kepau
Ohe mauka
Results: Dispersal Behavior (CACHE)
´Alalā flock cached all plants, a form of seed dispersal
Methods: Germination Benefits
Compared germination success among four treatments:
Whole
Cleaned
Fecal
Pellet
Susan Culliney: ZSSD
Results: Germination Success (%)
Oha kepau
Ohelo
a
60
40
20
b
cl
fec
Clean
60
40
b
20
b
fec
Clean
20
b
10
Mean % Germination
30
pell
wh
Pellet Whole
t=3.24, p=0.0604, n=5
wh
Whole
t= 7.87, p=0.0411, n=3
Hoawa
80
a
a
60
40
b
20
a
80
60
a
a
40
b
20
0
0
0
fec
Fecal
100
a
a
Clean Fecal
cl
Clean
Pilo
a
fec
10
Whole
100
cl
b
20
t= 7.24, p=0.0087, n=5
Olapa
50
ab
ab
30
wh
Fecal
t= 16.52, p=0.0014, n=5
40
40
0
cl
Whole
a
50
0
wh
Fecal
Mean % Germination
a
Mean % Germination
a
80
0
Mean % Germination
Mamaki
60
80
Mean % Germination
Mean % Germination
100
cl
fec
Clean Fecal
pell
wh
Pellet Whole
t= 10.78, p=0.0010, n=5
cl
fec
Clean Fecal
pell
wh
Pellet Whole
t= 5.41, p=0.0171, n=5
For most plant species ´Alalā digestion increased germination
success probably by removing fruit pulp from seeds
Hoawa (Pittosporum hosmeri)
% Germination
Mean % Germination
100
a
80
60
a
a
40
b
20
0
cl
fec
Clean Fecal
pell
wh
Pellet Whole
t= 5.41, p=0.0171
Summary
´Alalā:
• Dispersed seeds of all plants
• Dispersed seeds via multiple mechanisms
• Increased germination success for some
species
: ZSSD
Culliney et al. 2012 Ecological Applications
Summary
´Alalā:
• Dispersed seeds of all plants
• Dispersed seeds via multiple mechanisms
• Increased germination success for some
species
1. Feed Alala native fruit prior to release
: ZSSD
2. Select/restore reintroduction sites with
popular fruiting plant species
3. Alala may be critically important for
some large-fruited species…yet another
reason to invest in recovery efforts
Culliney et al. 2012 Ecological Applications
Questions
1. What seed dispersal services are lost…and
restored, by the extinction and recovery of Alala?
2. Does the decline of Puaiohi in the presence of
exotic birds alter seed dispersal dynamics?
3. Are bird reintroductions restoring ecological
processes in New Zealand’s mainland sanctuaries?
How does the decline of Kauai’s last native
frugivore impact seed dispersal dynamics?
Are introduced birds filling the gap?
Kawaikoi
Mohihi
Kawaikoi
Mohihi
Exotic frugivores
37.15 birds/ha
43.22 birds/ha
Puaiohi
1-2 territories
17-19 territories
s
1. Does seed rain differ in the absence of
Puaiohi?
2. How similar is the diet of Puaiohi and
Japanese White-eye?
% of samples with seeds
Composition of seeds in fecal samples
80
70
60
50
40
30
20
10
0
Japanese
Series1
White-eye
n = 33
Puaiohi
Series2
n = 66
% of samples with seeds
Composition of seeds in fecal samples
80
70
60
50
40
30
20
10
0
Japanese
Series1
White-eye
n = 33
Puaiohi
Series2
n = 66
Questions
1. What seed dispersal services are lost…and
restored, by the extinction and recovery of Alala?
2. Does the decline of Puaiohi in the presence of
exotic birds alter seed dispersal dynamics?
3. Are bird reintroductions restoring ecological
processes in New Zealand’s mainland sanctuaries?
Research Questions
1. How does bird density and diversity in and out of sanctuaries affect the
rate and pattern of seed dispersal?
2. What is the relationship between sanctuary size, bird diversity and seed
dispersal dynamics?
3. Do sanctuaries have “spillover effects”, thus altering seed dispersal
dynamics beyond the fence?
Conclusion
• ´Alalā disperse a wide variety of
native plants, and enhance
germination for many
• In the absence of Puaiohi, we
predict a shift towards smallerseeded & exotic plants
• New Zealand’s mainland islands
and the ecological
consequences of bird
reintroductions…stay posted!
Acknowledgements
Keauhou Bird Conservation Center &
The Zoological Society of San Diego
Alan Lieberman, Richard Switzer, Jeremy
Hodges, Robby Kohley, Blake Jones,
Sarah Bebus, Rachel Kingsley, Lynne
Neibar, Pete Bibeault, Lisa Komarczek,
Jen Holler, Kyle Parsons, Kara
Kneubuhler, Angie Sewell, Rebecca
Espinoza, & numerous interns.
Funding Sources
CSU Warner College of Natural
Resources
Hawaii Division of Forestry and Wildlife
CSU Office of International Programs
National Science Foundation
Fulbright Foundation
Sigma XI
Field Assistants
Jen Holler, Kyle Parsons, Jeremy
Hodges, Kasha Malling and the staff of
KFBRP
Image Sources
ZSSD, Jack Jeffrey, Patrick Ching,
Google Image Search, Susan Culliney,
Monica Kaushik, KFBRP, Sara Bombaci
Plant Collection
Jon Price, Rhonda Loh, Sierra
McDaniels, Peter Van Dyke, Linda Pratt,
Thane Pratt, Jack Jeffrey
Thank you!
Liba Pejchar
Dept. of Fish, Wildlife and
Conservation Biology
Colorado State University
[email protected]
http://warnercnr.colostate.edu/~liba/
Lab twitter: @TheLibaLab