Island biogeographic theory and conservation practice: Species-area or specious-area relationships?

Abstract

We present statistical techniques to evaluate species-area regressions and models of faunal and floral collapse and apply these techniques to several recent examples from the literature. The application of these models to the design of nature reserves is unwarranted. These models have low explanatory power; they typically explain only half the variation in species number. Their parameter estimates are sensitive to particular cases. Consequently, estimates from these models range over several orders of magnitude following the deletion of a single observation. Species-area and faunal collapse models give unreliable estimates; 95% prediction intervals and inverse prediction intervals routinely span two or more orders of magnitude. These models should be subordinate to autecological considerations in policy formulation.