To predict how quickly native species will migrate in response to climate change and biological invasions will expand in their new ranges requires understanding the ecological and evolutionary dynamics of spreading populations. Theory predicts that evolution can accelerate the spread velocity of a species, but empirical tests are rare, leaving the extent and predictability of evolution in spreading populations not well understood. Further, how much the patchiness of a landscape, which can be an important control over traits under selection, influences this process is unknown. We manipulated the response to selection in populations of a model plant species (Arabidopsis thaliana) spreading through replicated experimental landscapes that varied in patchiness.
After six generations of change, evolving populations spread 11% further than non-evolving populations in continuously favorable landscapes, and 200% further in the most fragmented landscapes. The greater effect of evolution on spread in patchier landscapes was consistent with the evolution of dispersal and competitive ability. We conclude that accounting for evolutionary change may be critical when predicting the velocity of range expansions.