Neutral theory as a predictor of avifaunal extinctions after habitat loss.
The worldwide loss of natural habitats leads not only to the loss of habitat-endemic species but also to further and protracted extinctions in the reduced areas that remain. How rapid is this process? We use the neutral theory of biodiversity to answer this question, and we compare the results taken with observed rates of avifaunal extinctions. In the neutral model, we derive an exact solution for the rate of species loss in a closed community. The simple, closed-form solution exhibits hyperbolic decay of species richness with time, which implies a potentially rapid initial decline followed by much slower rates long term. Our empirical estimates of extinction times are based on published studies for avifaunal extinctions either on oceanic islands or in forest fragments, which span a total of six orders of magnitude in area. These estimates show that the time to extinction strongly depends on the area. The neutral-theory predictions agree well with observed rates over three orders of magnitude of area (between 100 and 100,000 ha) both for islands and forest fragments. Regarding the species abundance distribution, extinction times based on a broken-stick model led to better agreement with observation than if a log-series model was used. The predictions break down for very small or very large areas. Thus, neutrality may be an affordable assumption for some applications in ecology and conservation, particularly for areas of intermediate size.
Department of Biological Applications and Technology, University of Ioannina, 451 10 Ioannina, Greece. jhalley@cc.uoi.gr
John M
JM
Halley
Yoh
Y
Iwasa
D000818:Animals; D005075:Biological Evolution; D017753:Ecosystem; D053476:Extinction, Biological; D008954:Models, Biological
Nature. 2003 Jun 5;423(6940):635-8
12789337
J Evol Biol. 2007 Nov;20(6):2075-91
17956380
Am Nat. 2006 Sep;168(3):304-17
16947106
Ecol Lett. 2010 Jan;13(1):87-95
19909313
Trends Ecol Evol. 2009 Jan;24(1):8-15
19026462
Proc Natl Acad Sci U S A. 1972 Nov;69(11):3199-203
16592024
Proc Natl Acad Sci U S A. 2003 Nov 25;100(24):14069-73
14614134
Theor Popul Biol. 2002 Sep;62(2):153-68
12167354
Proc Natl Acad Sci U S A. 2003 Apr 29;100(9):5246-51
12702773
Proc Natl Acad Sci U S A. 2008 Aug 12;105 Suppl 1:11498-504
18695228
Proc Natl Acad Sci U S A. 1957 Mar 15;43(3):293-5
16590018
Science. 1995 Jul 21;269(5222):347-50
17841251
Ecology. 2006 Jun;87(6):1424-31
16869416
Trends Ecol Evol. 2009 Oct;24(10):564-71
19665254
Nature. 2006 Dec 14;444(7121):926-8
17167485
Curr Biol. 2008 Feb 12;18(3):R117-9
18269905
PLoS Biol. 2006 Aug;4(8):e278
16895443
Ecol Lett. 2007 Mar;10(3):219-29
17305805
Trends Ecol Evol. 2006 Aug;21(8):451-7
16766082
Nature. 2007 Nov 1;450(7166):45-9
17972874