U.S. Department of Commerce


Date of this Version



Published in THE IMPORTANCE OF SPECIES, ed. Peter Kareiva & Simon A. Levin (Princeton, NJ: Princeton University Press, 2003), pp. 305-329.


Simply mentioning the notion of species expendability may seem reprehensible, but it is a question raised often when conservation biology meets conservation practice, as in this volume. In particular, when arguing for the value of biodiversity, biologists are faced with the challenge of examining the roles that particular species might play in community function and whether there are redundancies in the functions of certain species. Does every species need to be conserved for our ecosystems to function? The question of expendability also is important in conservation planning that occurs at the species level: does every population need to be saved to maintain species viability? This question contains the same challenge aimed at community and ecosystem ecologists-do populations serve redundant roles in species viability, and if so, are some expendable?