Efects of Habitat Destruction in a Prey Predator Metapopulation Model

Abstract

A mean _eld\ metapopulation model of a predator prey interaction is developed in order to understand the consequences of habitat destruction at di}erent trophic levels[ Such a model allows us to explore di}erent ecological scenarios "donor control vs[ top!down control# by changing a single parameter[ The response to habitat destruction is qualitatively the same for both predator and prey\ although there are interesting di}erences linked to the trophic position[ A similar decrease in the colonization rate a}ects the two species quite di}erently[ Predators diminish faster than prey\ and furthermore\ the fraction of occupied sites decreases more sharply as colonization rates are lowered\ i[e[ there is a nonlinear relationship between regional abundance and colonization rate[ There is a well!de_ned threshold in the colonization rate below which the predator becomes extinct[ Thus\ dispersal rate is critical for predicting the consequences of habitat destruction[ Finally\ these results are compared with the behavior of a spatially explicit simulation[ The only di}erence between the analytical model and the simulation is that colonization is no longer a global phenomenon in the latter\ but it is a local process\ constrained to the nearest patches[ The bulk of the results are similar to the mean _eld behavior\ and we comment on some di}erences related with non!homogeneity and real space[ Some general implications for conservation biology and biological control are outlined[