JUVENILE DISPERSAL, LIMITED BREEDING SITES, AND THE DYNAMICS OF METAPOPULATIONS

Demographic models of metapopulations show a wide range of outcomes depending upon life history and dispersal parameters. In this paper we analyze metapopulations consisting of demographically viable (source) and demographically non-viable (sink) subpopulations. Our analysis identifies conditions under which intrinsic dispersal may have positive, negative, or no effect on metapopulation size. While genetically based dispersal behavior might have selective advantages at the level of the individual, it may become a liability when habitat quality deteriorates. We describe the effects of limited breeding opportunities in source and sink populations. Under a wide range of conditions, sink populations may have a positive influence on metapopulation size, but a point is reached where the metapopulation is limited solely by production in the source habitats. The complexity of these dynamics suggests that habitat-specific or patch-specific demographic variables are needed in order to understand population dynamics in heterogeneous landscapes. © 1992.