How landscapes affect the evolution of dispersal behaviour in reef fishes: results from an individual-based model

The vast majority of tropical reef fishes have a sedentary adult phase and pelagic larval phase that is potentially highly dispersive. Dispersal may be favoured by a wide range of factors including the arrangement of suitable habitat in space. In this paper the dispersal strategy of individuals is followed and allowed to evolve in a simplified model of three different landscapes: an enclosed sea, art open archipelago and a barrier reef. The three landscapes have very different characteristics, but all have similar spatial clumping of reef habitat. In all landscapes, as minimum time to settlement increases, evolved movement strategy also increases and longer settlement windows favour dispersal. In the archipelago movement is not maximized until the minimum pelagic duration is longer than in the other landscapes. The model predicts that, given the same pelagic duration, species from enclosed seas should have more dispersive behaviours than those from open archipelagos, because of the density of habitat and the aggregation of habitat in space affect the likelihood of larvae Finding suitable habitat for settlement. (C) 2003 The Fisheries society of the British Isles.