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) 2
Moorea, French Polynesia 3
Endangered Pacific island birds 4
Barnosky et al. 2004, Science 5
Barnosky et al. 2004, Science 6
l Human colonization of Oceania Based on Kirch 2002, On the Road of the Winds 7
l Bird extinctions in Oceania 8
l Bird extinctions in Oceania 9
l Bird extinctions in Oceania 10
Holocene paleorecord of Pacific islands Fossil vertebrate localities: archaeological sites Makauwahi Cave, Kauai 11
Holocene paleorecord of Pacific islands Fossil vertebrate localities: archaeological sites natural traps Puu Makua Cave, Maui 12
Holocene paleorecord of Pacific islands Fossil vertebrate localities: archaeological sites natural traps bone accumulations by predators Me Aure Cave, New Caledonia 13
l Extinction Mechanisms overexploitation of populations introduction of exotic predators and diseases habitat destruction 14
l Extinction Mechanisms overexploitation of populations introduction of exotic predators and diseases habitat destruction These processes remain primary drivers of modern extinctions 15
Island bird extinctions l l l How many species were lost? Which species went extinct? How did they change ecological communities? l How can they be prevented? 16
l How many species were lost? 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 17
Classic Mark-recapture estimates 18
Classic Mark-recapture estimates 19
Classic Mark-recapture estimates N = (M * T) / R = (3 * 3) / 1 = 9 20
Mark-recapture for fossils Marked Living species Historically observed Recaptured Living species Historically observed Known only from fossils 21
Number of extinctions Bayesian hierarchical mark-recapture model 371 618 Duncan, Boyer & Blackburn, 2013, PNAS 22
Number of extinctions Bayesian hierarchical mark-recapture model 371 618 Duncan, Boyer & Blackburn, 2013, PNAS 23
Number of undiscovered species Duncan, Boyer & Blackburn, 2013, PNAS 24
Island bird extinctions l l l How many species were lost? Which species went extinct? How did they change ecological communities? l How can they be prevented? 25
l New Caledonia 26
Mé Auré Cave site Me Aure Cave, New Caledonia 27
Mé Auré Cave record Cal BP 200 1200 2400 28
Mé Auré Cave Birds Boyer et al. 2010, Biodivers Conserv 29
Mé Auré Cave Birds Boyer et al. 2010, Biodivers Conserv 30
New Caledonia's dry forest The most threatened tropical dry forest in the world. -Conservation International Bouchet et al 1995 31
Boa Cave site Boa cave 32
Boa Cave excavations 2011 33
Boa Cave excavations 2011 34
Boa Cave excavations 2011 35
Boa Cave excavations 2011 36
A giant extinct bird Sylviornis
Known extinctions in New Caledonia Sylviornis Meiolania Mekosuchus 38
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 39
The Hawaiian islands H. D. Pratt 40
The Hawaiian islands 41
The Hawaiian islands 42
Extinction selectivity External threats hunting, predators, disease, habitat loss Intrinsic susceptibility Why are some species more likely to be threatened with extinction than others? body size, endemism, flightlessness, trophic guild Environmental correlates island area, isolation, climate James & Olson 2003, Auk 43
Holocene paleorecord of Pacific islands 44
Extinctions 3500 ybp - present Random forest model Boyer 2010, Conservation Biology 45
Extinctions 3500 ybp - present Random forest model n = 1264 Accuracy: 87% False-negatives: 5.1% False-positives: 31% Boyer 2010, Conservation Biology 46
Extinction risk predictions Boyer 2010, Conservation Biology Hawaiian thrush Henderson island rail Cloven-feathered dove 47
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 48
Island bird extinctions l l l How many species were lost? Which species went extinct? How did extinctions change ecological communities? l How can they be prevented? 49
Ecosystem services provided by birds Functional Diversity 50
Functional diversity of the bird community 51
Declining Functional Diversity with Extinctions Extinction (%) Boyer & Jetz, 2014, Global Ecology and Biogeography 52
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 53
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 54
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 55
Island bird extinctions l l l How many species were lost? Which species went extinct? How did they change ecological communities? l How can extinctions be prevented? 56
Modern biodiversity in crisis Threatened with extinction 12% of birds 25% of mammals > 30% of amphibians Nearly half of all threatened bird species are found on oceanic islands 57
Eradicate invasive predators 58
Eradicate invasive predators 59
Reintroduce birds to former range Rimatara Lorikeet reintroduced to Atiu, Cook Islands more than 200 years after 387 miles 60
Restore habitats Lepredour island, New Caledonia: eradication of deer, goats, cats dry forest restoration reintroduction of native birds 61
l Oceanic islands as global microcosms l Islands are self-contained, replicated units with a long record of coupled human-environmental history l We study past extinctions to understand: baseline conditions causes of biodiversity loss predictability of extinctions consequences of extinctions for societies & ecosystems 62
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