Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 30: Poster Session I

AKB 30.1: Poster

Monday, March 27, 2006, 15:30–18:00, P1

Effects of Foraging Dynamics on Food-web Topology and Stability — •Satoshi Uchida and Barbara Drossel — Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, D-64289 Darmstadt, Germany

We investigate dynamic food web models including both population dynamics and foraging dynamics. The population dynamics determines the population density of each species, and the foraging dynamics describes the adaptation of individuals to the abundacies of their prey, given a limited total search time. We explain that the topology and stability of the resulting food webs are strongly influenced by the foraging dynamics, and are much less sensitive to the types of functional responses in the population dynamics (Lotka-Volterra, Holling or Beddington type). In particular, we see that the nature of the constraints on foraging behavior is crucial to the web structure and stability. It is known that with conventional linear constraints, the resulting food webs are more stable than simple model food webs including only population dynamics, in the sense that species are less likely to become extinct. However, at the same time adaptive dynamics introduces a strong constraint on the topology of webs, namely that the number of visible links must be smaller than twice the number of species. If we take into account in the model that a predator can feed on accidentally encountered species that are similar to the one it is searching for, which leads to nonlinear constraints, the resulting food webs are stable and have more links.