Spatial Models of Competition

Abstract

Traditional models of competition usually assume well-mixed populations, neglecting the localized nature of interactions between organisms and their environment. Because each individual organism affects mostly its local neighborhood, organisms create spatial heterogeneity in the environment; because organisms respond to their local neighborhoods, this biotically generated heterogeneity provides opportunities for novel ecological strategies and multispecies coexistence. Abiotically generated heterogeneity can also foster coexistence on a small scale and may explain the distribution of species across geographic gradients. In this chapter we discuss how spatial aspects of competition can be captured in theoretical models and how they affect coexistence. Because spatial models of competition cover many disparate systems, we focus here on models of terrestrial plants and other sessile organisms, but we suspect many of the phenomena we discuss are more widely applicable.