Distance-limited dispersal promotes coexistence at habitat boundaries: reconsidering the competitive exclusion principle.
Understanding the conditions for the stable coexistence of different alleles or species is a central topic in theoretical evolution and ecology. Different causes for stable polymorphism or species coexistence have already been identified but they can be grouped into a limited number of general processes. This article is devoted to the presentation and illustration of a new process, which we call 'habitat boundary polymorphism', and which relies on two key ingredients: habitat heterogeneity and distance-limited dispersal. Under direct competition and with fixed population densities, we show that this process allows for the equilibrium coexistence of more than n types in a n-habitat environment. Distance-limited dispersal indeed creates local maladaptation at habitat edges, which leaves room for the invasion of more generalist alleles or species. This mechanism provides a generic yet neglected process for the maintenance of polymorphism or species coexistence.
Centre d'Écologie Fonctionnelle et Évolutive, CNRS - UMR 5175, 1919 Route de Mende, F-34293 Montpellier Cedex 5, France.
Florence
F
Débarre
Thomas
T
Lenormand
D000818:Animals; D058448:Biota; D003163:Competitive Behavior; D003710:Demography; D017753:Ecosystem; D008954:Models, Biological; D010944:Plants / Q000235:genetics; D011110:Polymorphism, Genetic