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Fitness-dependent dispersal in metapopulations and its consequences for persistence and synchrony |
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| Authors: | Graeme D Ruxton Pejman Rohani† |
| Institution: | Division of Environmental &Evolutionary Biology, Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK;and;Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, 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. |
| Keywords: | density-dependent dispersal extinction population cycles population dynamics synchronization |