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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) 2 Moorea, French Polynesia 3 Endangered Pacific island birds 4 Barnosky et al. 2004, Science 5 Barnosky et al. 2004, Science 6 Human colonization of Oceania l Based on Kirch 2002, On the Road of the Winds 7 Bird extinctions in Oceania l 8 Bird extinctions in Oceania l 9 Bird extinctions in Oceania l 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 Extinction Mechanisms l – overexploitation of populations – introduction of exotic predators and diseases – habitat destruction 14 Extinction Mechanisms l – overexploitation of populations – introduction of exotic predators and diseases – habitat destruction These processes remain primary drivers of modern extinctions 15 Island bird extinctions l How many species were lost? l Which species went extinct? How did they change ecological communities? l l How can they be prevented? 16 How many species were lost? l 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 Living species Historically observed Recaptured Known only from fossils 21 Number of extinctions 371 Bayesian hierarchical mark-recapture model 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 'J TQF SFT JTMB TVS UIF JOD TQF SFN OPO 5I FYU PG U TFB Duncan, Boyer & Blackburn, 2013, PNAS PG U 24 Island bird extinctions l How many species were lost? l Which species went extinct? How did they change ecological communities? l l How can they be prevented? 25 New Caledonia l 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 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 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 How many species were lost? l Which species went extinct? How did extinctions change ecological communities? l 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 How many species were lost? l Which species went extinct? How did they change ecological communities? l 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 mil es 60 Restore habitats Lepredour island, New Caledonia: – eradication of deer, goats, cats – dry forest restoration reintroduction of native birds – 61 Oceanic islands as global microcosms l l l Islands are self-contained, replicated units with a long record of coupled human-environmental history We study past extinctions to understand: – baseline conditions – causes of biodiversity loss – predictability of extinctions – consequences of extinctions for societies & ecosystems 62 63
