Trouble in Paradise: Paleoecology and extinction of island birds

Transcription

1 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

2 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

3 Moorea, French Polynesia 3

4 Endangered Pacific island birds 4

5 Barnosky et al. 2004, Science 5

6 Barnosky et al. 2004, Science 6

7 l Human colonization of Oceania Based on Kirch 2002, On the Road of the Winds 7

8 l Bird extinctions in Oceania 8

9 l Bird extinctions in Oceania 9

10 l Bird extinctions in Oceania 10

11 Holocene paleorecord of Pacific islands Fossil vertebrate localities: archaeological sites Makauwahi Cave, Kauai 11

12 Holocene paleorecord of Pacific islands Fossil vertebrate localities: archaeological sites natural traps Puu Makua Cave, Maui 12

13 Holocene paleorecord of Pacific islands Fossil vertebrate localities: archaeological sites natural traps bone accumulations by predators Me Aure Cave, New Caledonia 13

14 l Extinction Mechanisms overexploitation of populations introduction of exotic predators and diseases habitat destruction 14

15 l Extinction Mechanisms overexploitation of populations introduction of exotic predators and diseases habitat destruction These processes remain primary drivers of modern extinctions 15

16 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

17 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

18 Classic Mark-recapture estimates 18

19 Classic Mark-recapture estimates 19

20 Classic Mark-recapture estimates N = (M * T) / R = (3 * 3) / 1 = 9 20

21 Mark-recapture for fossils Marked Living species Historically observed Recaptured Living species Historically observed Known only from fossils 21

22 Number of extinctions Bayesian hierarchical mark-recapture model Duncan, Boyer & Blackburn, 2013, PNAS 22

23 Number of extinctions Bayesian hierarchical mark-recapture model Duncan, Boyer & Blackburn, 2013, PNAS 23

24 Number of undiscovered species Duncan, Boyer & Blackburn, 2013, PNAS 24

25 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

26 l New Caledonia 26

27 Mé Auré Cave site Me Aure Cave, New Caledonia 27

28 Mé Auré Cave record Cal BP

29 Mé Auré Cave Birds Boyer et al. 2010, Biodivers Conserv 29

30 Mé Auré Cave Birds Boyer et al. 2010, Biodivers Conserv 30

31 New Caledonia's dry forest The most threatened tropical dry forest in the world. -Conservation International Bouchet et al

32 Boa Cave site Boa cave 32

33 Boa Cave excavations

34 Boa Cave excavations

35 Boa Cave excavations

36 Boa Cave excavations

37 A giant extinct bird Sylviornis

38 Known extinctions in New Caledonia Sylviornis Meiolania Mekosuchus 38

39 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

40 The Hawaiian islands H. D. Pratt 40

41 The Hawaiian islands 41

42 The Hawaiian islands 42

43 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

44 Holocene paleorecord of Pacific islands 44

45 Extinctions 3500 ybp - present Random forest model Boyer 2010, Conservation Biology 45

46 Extinctions 3500 ybp - present Random forest model n = 1264 Accuracy: 87% False-negatives: 5.1% False-positives: 31% Boyer 2010, Conservation Biology 46

47 Extinction risk predictions Boyer 2010, Conservation Biology Hawaiian thrush Henderson island rail Cloven-feathered dove 47

48 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

49 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

50 Ecosystem services provided by birds Functional Diversity 50

51 Functional diversity of the bird community 51

52 Declining Functional Diversity with Extinctions Extinction (%) Boyer & Jetz, 2014, Global Ecology and Biogeography 52

53 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

54 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

55 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

56 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

57 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

58 Eradicate invasive predators 58

59 Eradicate invasive predators 59

60 Reintroduce birds to former range Rimatara Lorikeet reintroduced to Atiu, Cook Islands more than 200 years after 387 miles 60

61 Restore habitats Lepredour island, New Caledonia: eradication of deer, goats, cats dry forest restoration reintroduction of native birds 61

62 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

63 63