EVOLUTIONARY RESPONSES OF DISPERSAL DISTANCE TO LANDSCAPE STRUCTURE AND HABITAT LOSS

It is generally well understood that some ecological factors select for increased and others for decreased dispersal. However, it has remained difficult to assess how the evolutionary dynamics are influenced by the spatio-temporal structure of the environment. We address this question with an individual-based model that enables habitat structure to be controlled through variables such as patch size, patch turnover rate, and patch quality. Increasing patch size at the expense of patch density can select for more or less dispersal, depending on the initial configuration. In landscapes consisting of high-quality and long-lived habitat patches, patch degradation selects for increased dispersal, yet patch loss may select for reduced dispersal. These trends do not depend on the component of life-history that is affected by habitat quality or the component of life-history through which density-dependence operates. Our results are based on a mathematical method that enables derivation of both the evolutionary stable strategy and the stationary genotype distribution that evolves in a polymorphic population. The two approaches generally lead to similar predictions. However, the evolutionary stable strategy assumes that the ecological and evolutionary time scales can be separated, and we find that violation of this assumption can critically alter the evolutionary outcome.