Island Biogeography Theory

The theory of island biogeography is a model in ecology, developed by Robert MacArthur and Edward O. Wilson and published in their 1967 book of the same name, predicting the number of species that will come to inhabit an island or other isolated habitat as a balance between the rate at which new species arrive and the rate at which existing species go locally extinct. The theory holds that species richness at equilibrium depends chiefly on an island's size, which affects extinction rates, and its distance from a mainland source of colonizers, which affects immigration rates, so that larger, closer islands are predicted to support more species than smaller, more remote ones. The framework has since been extended well beyond literal islands to any fragmented or isolated habitat, including forest patches and nature reserves, and underlies much of modern conservation biology's approach to reserve design.