The Status of the Worldls Land and Marine Mammals: Diversity, Threat
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RESEARCH ARTICLES nized species, including marine mammals, were not covered in previously published analyses. Here, we present the results of the most com- The Status of the World’s Land prehensive assessment to date of the conservation status and distribution of the world’s mammals, covering all 5487 wild species recognized as and Marine Mammals: Diversity, extant since 1500. This 5-year, IUCN-led col- laborative effort of more than 1700 experts in Threat, and Knowledge 130 countries compiled detailed information on species’ taxonomy, distribution, habitats, and pop- 1,2 1,2 3 1,2 1,2 Jan Schipper, * Janice S. Chanson, Federica Chiozza, Neil A. Cox, Michael Hoffmann, ulation trends, as well as the threats to, human 1 1,4 5,6 1,2 7 Vineet Katariya, John Lamoreux, AnaS.L.Rodrigues, Simon N. Stuart, Helen J. Temple, use of, ecology of, and conservation measures for 8 3 2,4 2 Jonathan Baillie, Luigi Boitani, Thomas E. Lacher Jr., Russell A. Mittermeier, these species. All data are freely available for 9 10 2,4 11 2,12 Andrew T. Smith, Daniel Absolon, John M. Aguiar, Giovanni Amori, Noura Bakkour, consultation and downloading (11). 13,14 15 8,16 17 18 Ricardo Baldi, Richard J. Berridge, Jon Bielby, Patricia Ann Black, J. Julian Blanc, Diversity. Mammals occupy most of the 2,19,20 21,22 23,24 25 Thomas M. Brooks, James A. Burton, Thomas M. Butynski, Gianluca Catullo, Earth’s habitats. As in previous studies (8, 12), 26 8 8 27 28 Roselle Chapman, Zoe Cokeliss, Ben Collen, Jim Conroy, Justin G. Cooke, we found that land species (i.e., terrestrial, 29,30 31 32 33 Gustavo A. B. da Fonseca, Andrew E. Derocher, Holly T. Dublin, J. W. Duckworth, including volant, and freshwater) have particularly 34 35 36 2 37 Louise Emmons, Richard H. Emslie, Marco Festa-Bianchet, Matt Foster, Sabrina Foster, high levels of species richness in the Andes and 38 39 40 41 David L. Garshelis, Cormack Gates, Mariano Gimenez-Dixon, Susana Gonzalez, in Afromontane regions in Africa, such as the 42 43 44 Jose Fernando Gonzalez-Maya, Tatjana C. Good, Geoffrey Hammerson, Albertine Rift. We also found high species 45 46 46 47 48 Philip S. Hammond, David Happold, Meredith Happold, John Hare, Richard B. Harris, richness in Asia, most noticeably in the 49,50 51 52 33 Clare E. Hawkins, Mandy Haywood, Lawrence R. Heaney, Simon Hedges, Hengduan mountains of southwestern China, 34 7 53 54 Kristofer M. Helgen, Craig Hilton-Taylor, Syed Ainul Hussain, Nobuo Ishii, peninsular Malaysia, and Borneo (Fig. 1A). The 55 56,57 9 58 Thomas A. Jefferson, Richard K. B. Jenkins, Charlotte H. Johnston, Mark Keith, ranges of many large mammals have recently 59 60 61,62 9 63 Jonathan Kingdon, David H. Knox, Kit M. Kovacs, Penny Langhammer, Kristin Leus, contracted substantially in tropical Asia (13), so on August 21, 2009 64 65 66 16 Rebecca Lewison, Gabriela Lichtenstein, Lloyd F. Lowry, Zoe Macavoy, local diversity was once undoubtedly even 16 67 25 68 Georgina M. Mace, David P. Mallon, Monica Masi, Meghan W. McKnight, higher. Overall, the species richness pattern for 69 70,71 72 73 Rodrigo A. Medellín, Patricia Medici, Gus Mills, Patricia D. Moehlman, land mammals is similar to that found for birds 74,75 76 77 78 79 Sanjay Molur, Arturo Mora, Kristin Nowell, John F. Oates, Wanda Olech, and amphibians (12), which suggests that 80 34 52 55 William R. L. Oliver, Monik Oprea, Bruce D. Patterson, William F. Perrin, diversity is similarly driven by energy avail- 1 7 81 82 56 Beth A. Polidoro, Caroline Pollock, Abigail Powel, Yelizaveta Protas, Paul Racey, ability and topographic complexity (14, 15). 1 37 83 84 55 Jim Ragle, Pavithra Ramani, Galen Rathbun, Randall R. Reeves, Stephen B. Reilly, Marine mammals concentrate in tropical and 85 3 86 25 John E. Reynolds III, Carlo Rondinini, Ruth Grace Rosell-Ambal, Monica Rulli, temperate coastal platforms, as well as in off- 2 25 37 37 87 Anthony B. Rylands, Simona Savini, Cody J. Schank, Wes Sechrest, Caryn Self-Sullivan, shore areas in the Tasman and Caribbean seas, www.sciencemag.org 88 89 2 37 Alan Shoemaker, Claudio Sillero-Zubiri, Naamal De Silva, David E. Smith, east of Japan and New Zealand and west of Cen- 90 91 92 93 Chelmala Srinivasulu, Peter J. Stephenson, Nico van Strien, Bibhab Kumar Talukdar, tral America, and in the southern Indian Ocean. 55 94 95 96,97 Barbara L. Taylor, Rob Timmins, Diego G. Tirira, Marcelo F. Tognelli, As with land species, marine richness seems to 98 99 1 100 Katerina Tsytsulina, Liza M. Veiga, Jean-Christophe Vié, Elizabeth A. Williamson, be associated with primary productivity: Where- 2 101 44 Sarah A. Wyatt, Yan Xie, Bruce E. Young as land species’ richness peaks toward the equator, marine richness peaks at around 40° N Knowledge of mammalian diversity is still surprisingly disparate, both regionally and and S (16) (fig. S4), corresponding to belts of taxonomically. Here, we present a comprehensive assessment of the conservation status and high oceanic productivity (17). An interesting Downloaded from distribution of the world’s mammals. Data, compiled by 1700+ experts, cover all 5487 species, exception is the low species richness in the high- including marine mammals. Global macroecological patterns are very different for land and marine ly productive North Atlantic Ocean (17). Only species but suggest common mechanisms driving diversity and endemism across systems. one species’ extinction [Sea Mink, Neovison Compared with land species, threat levels are higher among marine mammals, driven by different macrodon (18)] and one extirpation [Gray Whale, processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct Eschrichtius robustus (19)] are recorded from (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also this region, yet evidence for many local extinc- disproportionately poorly known. These data are made freely available to support further scientific tions comes from historical records of species developments and conservation action. exploitation where they no longer occur ([e.g., Harp Seal, Phoca groenlandica, in the Baltic ammals play key roles in ecosystems traits associated with high extinction risk (3, 4), Sea (20); Bowhead Whale, Balaena mysticetus, (e.g., grazing, predation, and seed dis- and prioritization of species for conservation off Labrador (21); Walrus, Odobenus rosmarus, Mpersal) and provide important benefits action (5). However, the 1996 assessment was in Nova Scotia (22)]. Past human exploitation to humans (e.g., food, recreation, and income), based on categories and criteria that have now may therefore have depleted natural species yet our understanding of them is still surpris- been superseded, and the assessments are of- richness in the North Atlantic—as it probably ingly patchy (1). An assessment of the conser- ficially outdated for about 3300 mammals never did with land mammals in Australia (23) and vation status of all known mammals was last assessed since. Previously compiled global dis- the Caribbean (24). undertaken by the International Union for Con- tribution maps for terrestrial mammals (6, 7) Phylogenetic diversity is a measure that takes servation of Nature (IUCN) in 1996 (2). These have been used in a variety of analyses, including account of phylogenetic relationships (and hence, IUCN Red List classifications of extinction risk recommending global conservation priorities evolutionary history) between taxa (16, 25)(fig. (fig. S1) for mammals have been used in nu- (7–9), and analyzing the coverage of protected S3). It is arguably a more relevant currency of merous studies, including the identification of areas (10). However, nearly 700 currently recog- diversity and less affected by variations in taxo- www.sciencemag.org SCIENCE VOL 322 10 OCTOBER 2008 225 RESEARCH ARTICLES nomic classification than species richness. Spe- million km2 (Red Fox, Vulpes vulpes;Eurasia Cameroonian, and Ethiopian Highlands) (Fig. cies richness (Fig. 1A) and phylogenetic diversity and North America). For marine species, ranges 1C). Marine restricted-range species are al- (Fig. 1B) are very closely related for land spe- vary from 16,500 km2 (Vaquita, Phocoena sinus; most entirely found around continental plat- cies (r2 = 0.98) (fig. S5), but less so in the ma- Gulf of California), to 350 million km2 (Killer forms, particularly in the highly productive rine environment (r2 = 0.73). Disproportionately Whale, Orcinus orca; all oceans). Despite these waters off the Southern Cone of South Amer- high phylogenetic diversity in the southern oceans extremes, most species have small ranges (fig. ica (Fig. 1C) (17). Both land and marine patterns suggests that either species here are less related S6): Most land taxa occupy areas smaller than of endemism are thus apparently associated than elsewhere, or that current species may in the UK, and the range of most marine mam- with highly productive areas subject to strong fact be poorly known complexes of multiple spe- mals is smaller than one-fifth of the Indian Ocean environmental gradients (altitudinal in land; cies, with new species awaiting discovery (con- (fig. S6). depth in marine). sistent with the poor species knowledge in this Among land mammals, restricted-range spe- A different perspective on patterns of spe- area, see below). cies (those 25% of species with the smallest cies’ endemism is obtained by mapping global The size of land species’ ranges varies from ranges) are concentrated on highly diverse is- variation in median range size (Fig. 1D). For land a few hundred square meters (Bramble Cay lands (e.g., Madagascar, Sri Lanka, and Sulawesi) species, there is a strong association between Melomys, Melomys rubicola; Australia), to 64.7 and tropical mountain systems (e.g., Andes, landmass width and median range size: The 1International Union for Conservation of Nature (IUCN) stitution, Washington, DC, 20013, USA.