HABITAT DESTRUCTION AND COEXISTENCE OF COMPETITORS IN A SPATIALLY REALISTIC METAPOPULATION MODEL

Nee & May (1992) modelled the coexistence of two competing species in fragmented landscapes affected by varying levels of habitat destruction (permanent removal of habitat patches). One species was assumed to be a superior competitor, capable of immediately excluding its rival from any patch it would colonize. The inferior competitor could none the less persist regionally in a network of many patches, provided that it was a superior colonizer or had a lower intrinsic rate of extinction than the superior species. Nee & May (1992) showed that for such species habitat destruction can lead to an increase in the absolute abundance of the inferior competitor. This at first surprising result is due to an indirect effect: the direct negative effect of habitat destruction on the inferior competitor is more than compensated for by the reduced competition with the superior species, which suffers even more from habitat destruction because of