INTERACTIONS BETWEEN SPATIAL AND TEMPORAL SCALES IN THE EVOLUTION OF DISPERSAL RATE

The evolution of dispersal rate is studied with a model of several loc al populations linked by dispersal. Three dispersal strategies are con sidered where all, half or none of the offspring disperse. The spatial scale (number of patches) and the temporal scale (probability of loca l extinction) of the environment are critical in determining the selec tive advantage of the different dispersal strategies. The results from the simulations suggest that an interaction between group selection a nd individual selection results in a different outcome in relation to the spatial and temporal scales of the environment. Such an interactio n is able to maintain a polymorphism in dispersal strategies. The main tenance of this polymorphism is also scale-dependent. This study sugge sts a mechanism for the short-term evolution of dispersal, and provide s a testable prediction of this hypothesis, namely that loss of disper sal abilities should be more frequent in spatially more continuous env ironments, or in temporally more stable environments.