Reaction-diffusion models are often used to describe the spatial and temporal dynamics of populations under the infl uence of natural or cultural selection (where a species, gene, or cultural innovation expands its geographical range, typically because of some advantage over competitors in the means of capturing energy and converting it into a larger population size through self-reproduction, e.g., Murray 2002, 2003, Okubo and Levin 2001, Kandler and Steele 2009). In ecology they provide a way of translating assumptions or data about movement, mortality, and reproduction of individuals, at a local scale, into global conclusions about the persistence or extinction of populations and the coexistence of interacting populations (Cantrell and Cosner 2003).