Document: MAR-3-8-3

A critique of biogeographic approaches to estimating extinction rates.

ANDERSEN, M.C.*

Department of Fishery and Wildlife Sciences, New Mexico State University ¹

Abstract:
Estimates of the rate at which the Earth's biodiversity is being lost have been a factor in raising awareness of the threats to biodiversity, both among scientists and among the public at large. Relatively little effort has gone into assessing the assumptions of these estimates, or into considering alternative estimates. In this presentation, I discuss estimates of extinction rates based on the classic species-area relationship, with particular emphasis on the theoretical and historical basis for these estimates. I also discuss alternative estimates based on other biogeographic relationships, in particular on distribution profiles and on distributions of species' geographic range sizes. These estimates differ substantially from those based on the species-area relationship. I discuss the nature of these differences, and possible reasons for them. Anthropogenic threats to global biodiversity are real and serious. Further refinements of our estimates of the extent of these threats can help focus conservation efforts in appropriate ways. I conclude by comparing the usefulness of conservation recommendations obtained from the various types of estimates of extinction rates. Estimates based on distribution profiles are very promising in terms of the specific conservation recommendations that can be derived from them.

Keywords: extinction, biodiversity, conservation

This abstract is being presented at: 3:00 PM in session:
Symposium # 18: The Role of Theoretical Ecology in Biodiversity Conservation and Management.