Fitness-dependent dispersal in metapopulations and its consequences for persistence and synchrony

Authors


Dr G. D. Ruxton, Division of Environmental & Evolutionary Biology, Graham Kerr Building, University of Glasgow G12 8QQ, UK. Tel: 0141 330 6617. Fax: 0141 330 5971. E-mail: g.ruxton@bio.gla.ac.uk

Abstract

1. We present a novel metapopulation model where dispersal is fitness dependent: the strength of migration from a site is dependent on the expected reproductive fitness of individuals there. Furthermore, individuals continue to migrate until they reach a suitable habitat where their expected fitness is above a threshold value.

2. Fitness-dependent dispersal has a very strong stabilizing effect on population dynamics, even when the intrinsic dynamics of populations in the absence of dispersal exhibit complex high-amplitude oscillations. This stabilizing effect is much stronger than that of the density-independent dispersal normally considered in metapopulation models.

3. Even when fitness-dependent dispersal does not stabilize the dynamics in a formal sense, it generally leads to simplification, with complex or even chaotic fluctuations being reduced to simple cycles.

4. This form of dispersal also has a strong tendency to synchronize local population dynamics across the spatial extent of the metapopulation.

5. These conclusions are robust to the addition of strong stochasticity in the migration threshold.

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