Résumé
Dispersal is a central process to almost all species on earth, as it
connects spatially structured populations and thereby increases population
persistence. Dispersal is subject to (rapid) evolution and local patch
extinctions are an important selective force in this context. In contrast
to the randomly distributed local extinctions considered in most
theoretical studies, habitat fragmentation or other anthropogenic
interventions will lead to spatially correlated extinction patterns. Under
such conditions natural selection is thought to lead to more long-distance
dispersal, but this theoretical prediction has not yet been verified
empirically. We test this hypothesis in experimental spatially structured
populations of the spider mite Tetranychus urticae and supplement these
empirical results with insights from an individual-based evolutionary
model. We demonstrate that the spatial correlation of local extinctions
changes the entire distribution of dispersal distances (dispersal kernel)
and selects for overall less emigration but more long-distance dispersal.