Estimating the normal background rate of species extinction

A key measure of humanity's global impact is by how much it has increased species extinction rates. Familiar statements are that these are 100–1000 times pre‐human or background extinction levels. Estimating recent rates is straightforward, but establishing a background rate for comparison is n...

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Vydáno v:	Conservation biology Ročník 29; číslo 2; s. 452 - 462
Hlavní autoři:	De Vos, Jurriaan M, Joppa, Lucas N, Gittleman, John L, Stephens, Patrick R, Pimm, Stuart L
Médium:	Journal Article
Jazyk:	angličtina
Vydáno:	United States Blackwell Scientific Publications 01.04.2015 Blackwell Publishing Ltd Wiley Periodicals Inc
Témata:	Animals Biological Evolution Chordata Computer Simulation Conservation biology Conservation of Natural Resources Contributed Papers diversification rates ecosystems Estimating techniques Extinction extinction rate Extinction, Biological filogenias moleculares fossil record Fossils Invertebrates linajes a través del tiempo lineages through time Models, Biological molecular phylogenies new species Phylogeny Plants plants (botany) registro fósil Speciation Species extinction tasa de diversificación tasa de extinción Taxa extinction rate lineages through time registro fósil tasa de extinción fossil record filogenias moleculares linajes a través del tiempo diversification rates tasa de diversificación molecular phylogenies
ISSN:	0888-8892, 1523-1739, 1523-1739
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Popis
Shrnutí:	A key measure of humanity's global impact is by how much it has increased species extinction rates. Familiar statements are that these are 100–1000 times pre‐human or background extinction levels. Estimating recent rates is straightforward, but establishing a background rate for comparison is not. Previous researchers chose an approximate benchmark of 1 extinction per million species per year (E/MSY). We explored disparate lines of evidence that suggest a substantially lower estimate. Fossil data yield direct estimates of extinction rates, but they are temporally coarse, mostly limited to marine hard‐bodied taxa, and generally involve genera not species. Based on these data, typical background loss is 0.01 genera per million genera per year. Molecular phylogenies are available for more taxa and ecosystems, but it is debated whether they can be used to estimate separately speciation and extinction rates. We selected data to address known concerns and used them to determine median extinction estimates from statistical distributions of probable values for terrestrial plants and animals. We then created simulations to explore effects of violating model assumptions. Finally, we compiled estimates of diversification—the difference between speciation and extinction rates for different taxa. Median estimates of extinction rates ranged from 0.023 to 0.135 E/MSY. Simulation results suggested over‐ and under‐estimation of extinction from individual phylogenies partially canceled each other out when large sets of phylogenies were analyzed. There was no evidence for recent and widespread pre‐human overall declines in diversity. This implies that average extinction rates are less than average diversification rates. Median diversification rates were 0.05–0.2 new species per million species per year. On the basis of these results, we concluded that typical rates of background extinction may be closer to 0.1 E/MSY. Thus, current extinction rates are 1,000 times higher than natural background rates of extinction and future rates are likely to be 10,000 times higher.
Bibliografie:	http://dx.doi.org/10.1111/cobi.12380 istex:E5867C98A3461F0122EA4D94D3D67C3B5CD6A457 ark:/67375/WNG-DW4QDQBS-N ArticleID:COBI12380 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 14 ObjectType-Article-1 ObjectType-Feature-2 content type line 23
ISSN:	0888-8892 1523-1739 1523-1739
DOI:	10.1111/cobi.12380