Sequential Predation: A Multi-model Study

In many ecosystems food resources are available sequentially. The paper analyses a situation with two competing prey species both of which are consumed by a common predator species. Within a season the two prey species are available sequentially, although there may be an overlap. Three modelling methodologies are applied to this system] discrete dynamical systems (difference equations), individual-oriented event-driven simulations and cellular automata. The presence of the predator is shown to have a strong impact on the outcome of the prey species competition. The system of coexisting prey species changes to a system of founder-controlled competition. It appears that sequential predation can even have counterintuitive evolutionary consequences for the prey species. The species which appears later in the season will be more successful in its competition with the early species if it favours the predator; for example, by a high leaf palatability. Spatial structuring and topological issues are found to play a crucial role in both the ecological and evolutionary dynamics. The advantages of a multi!model approach are discussed