Adding realism to foraging arena predictions of trophic flow rates in Ecosim ecosystem models: Shared foraging arenas and bout feeding

We update the Ecopath with Ecosim software for aquatic ecosystem modeling to allow users to represent intensification of inter-specific competition through shared use of space–time restricted foraging arenas, as well as predation occurring in periodic short feeding bouts rather than continuously over time. Our study indicates that assuming shared use of foraging arenas can have pathological impact on the ability of ecosystem models to predict maintenance of biological diversity in complex food webs, in cases where multiple predators have similar diet compositions but in fact avoid direct competition through fine-scale separation of feeding locations or times. We further find that the assumption of bout feeding leads to essentially the same predictions about how predation rates ought to vary with predator abundances as does the more unrealistic assumption of continuous feeding. © 2007 Elsevier B.V. All rights reserved.