The Effect of Habitat Destruction Pattern on Species Persistence: A Cellular Model

A simple, but spatially explicit, model of competition between two hypothetical species is presented. The two species exist as metapopulations, where habitat patches are characterised by local extinctions and colonizations. One species is a superior competitor and the other a superior disperser. The model determines the proportion of habitat patches that can be destroyed before the species become extinct, confirming the results of deterministic models. It further shows that the pattern of habitat destruction affects the minimum amount of habitat required to avoid extinction. If intensity of habitat loss occurs along a gradient, rather than at random, species persist until a much greater overall habitat loss has occurred. This is also the result if habitat is lost in blocks or in lines. The implication of this result for conservation policy is discussed.