THE EFFECT OF HABITAT DESTRUCTION PATTERN ON SPECIES PERSISTENCE - A CELLULAR-MODEL

A simple, but spatially explicit, model of competition between two hyp othetical species is presented. The two species exist as metapopulatio ns, where habitat patches are characterised by local extinctions and c olonizations. One species is a superior competitor and the other a sup erior disperser. The model determines the proportion of habitat patche s 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 grad ient, rather than at random, species persist until a much greater over all habitat loss has occurred. This is also the result if habitat is l ost in blocks or in lines. The implication of this result for conserva tion policy is discussed.