Extinction rates under nonrandom patterns of habitat loss
- *National Center for Ecological Analysis and Synthesis, 735 State Street, Suite 300, Santa Barbara, CA 93101; ‡Department of Ecology and Evolutionary Biology, Eno Hall, Princeton University, Princeton, NJ 08544-1003; and §Institute for Computational Earth System Science, University of California, Santa Barbara, CA 93106-3060
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Edited by Harold A. Mooney, Stanford University, Stanford, CA, and approved May 24, 2002 (received for review February 4, 2002)
Abstract
Most models that examine the effects of habitat conversion on species extinctions assume that habitat conversion occurs at random. This assumption allows predictions about extinction rates based on the species–area relationship. We show that the spatially aggregated nature of habitat conversion introduces a significant bias that may lead species-loss rates to exceed those predicted by species–area curves. Correlations between human activity and major compositional gradients, or species richness, also alter predicted species extinction rates. We illustrate the consequences of nonrandom patterns of habitat conversion by using a data set that combines the distribution of native vascular plants with human activity patterns in California.
Footnotes
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↵ † To whom reprint requests should be addressed. E-mail: seabloom{at}nceas.ucsb.edu.
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This paper was submitted directly (Track II) to the PNAS office.
- Copyright © 2002, The National Academy of Sciences
