title: Space race functional responses.
abstract: We derive functional responses under the assumption that predators and prey are engaged in a space race in which prey avoid patches with many predators and predators avoid patches with few or no prey. The resulting functional response models have a simple structure and include functions describing how the emigration of prey and predators depend on interspecific densities. As such, they provide a link between dispersal behaviours and community dynamics. The derived functional response is general but is here modelled in accordance with empirically documented emigration responses. We find that the prey emigration response to predators has stabilizing effects similar to that of the DeAngelis-Beddington functional response, and that the predator emigration response to prey has destabilizing effects similar to that of the Holling type II response. A stability criterion describing the net effect of the two emigration responses on a Lotka-Volterra predator-prey system is presented. The winner of the space race (i.e. whether predators or prey are favoured) is determined by the relationship between the slopes of the species' emigration responses. It is predicted that predators win the space race in poor habitats, where predator and prey densities are low, and that prey are more successful in richer habitats.
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, 90187 Umeå, Sweden Evolution and Ecology Program, International Institute for Applied Systems Analysis, 2361 Laxenburg, Austria sjodin.h@gmail.com.
authors.forename: Henrik
authors.initials: H
authors.lastname: Sjödin
authors.affiliation: Department of Mathematics and Mathematical Statistics, Umeå University, 90187 Umeå, Sweden Evolution and Ecology Program, International Institute for Applied Systems Analysis, 2361 Laxenburg, Austria.
authors.forename: Åke
authors.initials: Å
authors.lastname: Brännström
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, 90187 Umeå, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Englund
mesh_terms: D025041:Animal Migration; D000818:Animals; D017753:Ecosystem; D020387:Food Chain; D008954:Models, Biological; D011156:Population Density; D011235:Predatory Behavior
keywords: community dynamics; dispersal behaviours; functional response; space race