Evol Ecol Res 1: 635-640 (1999)     Full PDF if your library subscribes.

Multiple ideal free distributions of unequal competitors

Graeme D. Ruxton* and Stuart Humphries

Division of Environmental & Evolutionary Biology, University of Glasgow, Graham Kerr Building, Glasgow G12 8QQ, UK

Author to whom all correspondence should be addressed.
e-mail: g.ruxton@bio.gla.ac.uk


We studied an individual-based model of a number of competitors each able to move freely between two resources. If individuals move only so as to improve their resource-gathering rate, then the system settles to one of a finite number of equilibria (often called ‘ideal free distributions’). The addition of occasional switching of a randomly selected individual between resources does not (contrary to the predictions of Hugie and Grand, 1998) lead to this distribution of equilibria collapsing to a single point. In fact, it can induce the population to shift periodically between equilibria, thereby increasing spatio-temporal variation in competitor numbers. Furthermore, we show that the probability of the system reaching a given equilibrium is critically dependent on the fine detail of the rules describing individual movements.

Keywords: habitat selection, ideal free distribution, patch switching, unequal competitors.

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        © 1999 Graeme D. Ruxton. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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