This material has been published in Ecology Letters (1999, vol 2, pp 44-51), the only definitive repository of the content that has been certified and accepted after peer review. Copyright and all rights therein are retained by Blackwell Science. This material may not be copied or reposted without explicit permission (Copyright 1999 by Blackwell Science Ltd / CNRS).
Density dependence in resource exploitation: empirical test of Levins' metapopulation model
C.P. Doncaster & L. Gustafsson
Levins' model of metapopulation dynamics is modified to incorporate variable degrees of density dependence in the per capita exploitation of resource patches. We demonstrate a simple means of testing for this density dependence in a sample of metapopulations, each at its equilibrium balance of local colonization to extinction. The fraction of habitable unoccupied patches equilibrates to a constant number under the null model of density independent colonization, and to a constant proportion under strong density dependence. We compare the null model to two density dependent alternatives, using data on exploitation of nest boxes by collared flycatchers Ficedula albicollis. The analysis shows how predicted trends in the equilibrium unoccupied fraction are similar for both spatial interference and net immigration. This needs to be recognized, since the null hypothesis of a constant unused resource applies also to the dynamics of consumable resources, where it is expressed in a constant stock of uneaten prey at the dynamic equilibrium of predators to prey.
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Doncaster, C.P. & Gustafsson, L. (1999) Density dependence in resource exploitation: empirical test of Levins' metapopulation model. Ecology Letters, 2: 44-51.
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