Habitat diversity and the species-area relationship: alternative models and tests

Abstract

Reviews a variety of models which have sought to account for species-area relationships: passive sampling models; fragmentation models (immigration, extinction, keystone species, allopatric species and complete disturbance models); habitat diversity models (partial disturbance, edge/centre habitat, specific habitat and probabilistic habitat models); and species-area curves resulting from heterogeneity-area relationships. Protocols for separating causal mechanisms are discussed. An example demonstrates that straightforward relationships between habitat diversity and species richness may be complicated by non-random dispersion patterns of individual species, and by differences among habitats in the density, species richness and habitat specificity of organisms. Explicit specification and testing of alternative explanations for species-area effects will result in greater understanding of this phenomenon. -P.J.Jarvis