A scientific examination and critique of minimum viable population size

Abstract

A commonly voiced justification for preserving a particular obscure and apparently insignificant species is that species are interconnected in subtle ways, and we are likely to precipitate a cascade of extinction. The focus primarily on minimum viable populations (MVP) of single species carries the potential for suggesting conflicting research programs. If the focus is too heavily on «magic numbers» and rules, this conflict will become intense. Because many species are linked together, there are many cases in which conservation of one species will automatically entail conservation of many others. An understanding of the habitat and biology of the interacting species should allow conservation scientists to make a good estimate of what must be done to save the system, but simply focusing on the numbers that would constitute an MVP of any one interactant would be at best an inefficient approach, at worst extinction would ensure. To derive statistically reliable estimates for MVP is clearly a difficult if not impossible task. But it can be an even tougher task to extrapolate from the MVP into estimating the area of habitat necessary to support such a population, which requires a detailed understanding of a species habitat requirements. Patches of habitat must not only be larger than some critical size, they must also be in a suitable geometric configuration to ensure dispersal among habitat units.