Global dispersal reduces local diversity.
Metapopulation models and stepping-stone models in genetics are based on very different underlying dispersal structures, yet it can be difficult to distinguish the behaviour of the two kinds of models. We demonstrate a striking qualitative difference in the equilibrium behaviour possible with these two kinds of dispersal. If, in a local patch, there are multiple stable equilibria (and consequently an unstable equilibrium), we demonstrate that, for the spatial system with a metapopulation structure, at equilibrium every patch has to be near one of the stable equilibria. This contrasts with the clinal structure possible with a stepping-stone or continuous space model; thus the result can be used to deduce qualitative information about the form of dispersal from observations of allele frequencies.
Hastings
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Department of Environmental Science and Policy, and Institute of Theoretical Dynamics, University of California, Davis 95616, USA. amhastings@ucdavis.edu
Gavrilets
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D000818:Animals; D005787:Gene Frequency; D014644:Genetic Variation; D006801:Humans; D008957:Models, Genetic