Patchy environments, metapopulations, and fugitive species

Abstract

Populations and species are distributed heterogeneously across the landscape and this has important consequences for their abundance, persistence, and interactions with other species. This chapter introduces the concept of a metapopulation, a “population of populations”, where populations occur in patches of suitable habitat surrounded by areas of unsuitable habitat (“matrix”), and where dispersal serves to connect patch dynamics. Metapopulation theory provides an important conceptual underpinning to the field of conservation biology, fostering the study of corridors and assisted migration as important conservation tools. There also are important parallels between metapopulation theory and epidemiology. The study of patchily distributed populations leads naturally to considerations of species interactions, where it is shown that an inferior competitor may coexist with a superior competitor if the inferior competitor is better a colonizing open patches—a “fugitive species”. This competition-colonization trade-off can be a strong stabilizing mechanism for maintaining biodiversity in a patchy environment.