How many populations does the metapopulation consist of? How is the landscape structure represented in the model? Models may consider only two local populations connected by migration, which represents a minimal
Table 1 Four types of stochasticity affecting metapopulation dynamics
Type of stochasticity Entity affected Correlation among entities
Demographic Individuals in local populations No
Environmental Individuals in local populations Yes
Extinction-colonization Populations in metapopulations No
Regional Populations in metapopulations Yes metapopulation but is nonetheless sufficient to address some general questions about the role of migration in local dynamics. In the other extreme, other models assume an infinite number of habitat patches to simplify model analysis; these models are typically focused on the processes of population extinction and colonization. The treatment of space can be implicit, explicit, or realistic. In the first case, the model includes no information on the spatial locations of habitat patches and local populations, which implies that all local populations are equally coupled to each other. The archetypal spatially explicit model assumes a regular lattice, where lattice cells represent habitat patches. Finally, spatially realistic models involve a description of habitat patches in terms of their spatial coordinates, areas, qualities, and so forth, in a manner that allows the application of the models to networks of real habitat patches.
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