On the evolutionary ecology of species' ranges

A species’ range limits may shift in space either because of changes in ecological factors (e.g. climate, the abundances of interacting species) or because the traits which influence range limits (e.g. dispersal, niche characteristics) evolve by natural selection. In Geographical Ecology, Robert MacArthur (1972) provided a synthesis of the evolutionary factors that may drive range dynamics. In this paper, I revisit this theme in the light of recent theoretical studies of evolution in heterogeneous environments. These studies suggest that a rich range of evolutionary patterns in species’ ranges may occur, including expansions or contractions, leading to dynamism in ranges even in epochs without strong directional environmental change.