Finite metapopulation models with density-dependent migration and stochastic local dynamics

The effects of small density-dependent migration on the dynamics of a metap opulation are studied in a model with stochastic local dynamics. We use a d iffusion approximation to study how changes in the migration rate and habit at occupancy affect the rates of local colonization and extinction. If the emigration rate increases or if the immigration rate decreases with local p opulation size, a positive expected rate of change in habitat occupancy is found for a greater range of habitat occupancies than when the migration is density-independent. In contrast, the reverse patterns of density dependen ce in respective emigration and immigration reduce the range of habitat occ upancies where the metapopulation will be viable. This occurs because densi ty-dependent migration strongly influences both the establishment and rescu e effects in the local dynamics of metapopulations.