We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
The influence of patch demographics on metapopulations, with particular reference to successional landscapes.
- Authors
Johnson, Mark P.
- Abstract
The classical view of metapopulations relates the regional abundance of a species to the balance between the extinction and colonization dynamics of identical local populations. Species in successional landscapes may represent the most appropriate examples of classical metapopulations. However, Levins-type metapopulation models do not explicitly separate population loss due to successional habitat change from other causes of extinction. A further complication is that the chance of population loss due to successional habitat change may be related to the age of a patch. I developed simple patch occupancy models to include succession and included consideration of patch age structure to address two related questions: what are the implications of changes in patch demographic rates and when is a move to a structured patch occupancy model justified? Age-related variation in patch demography could increase or decrease the equilibrium fraction of the available habitat occupied by a species when compared to the predictions of an unstructured model. Metapopulation persistence was enhanced when the age class of patches with the highest species occupancy suffered relatively low losses to habitat succession. Conversely, when the age class of patches with the highest species occupancy also had relatively high successional loss rates, extinction thresholds were higher that would be predicted by a simple unstructured model. Hence age-related variation in patch successional rate introduces biases into the predictions of simple unstructured models. Such biases can be detected from field surveys of the fraction of occupied and unoccupied patches in each age class. Where a bias is demonstrated, unstructured models will not be adequate for making predictions about the effects of changing parameters on metapopulation size. Thinking in successional terms emphasizes how landscapes might be managed to enhance or reduce the patch occupancy by any particular metapopulation.
- Subjects
POPULATION biology; BIOLOGICAL extinction; ANIMAL populations; PLANT populations; HABITATS; ENVIRONMENTAL protection
- Publication
Oikos, 2000, Vol 88, Issue 1, p67
- ISSN
0030-1299
- Publication type
Article
- DOI
10.1034/j.1600-0706.2000.880108.x