Dresden 2011 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 36: Statistical Physics in Biological Systems IV (organised by BP)

DY 36.2: Talk

Thursday, March 17, 2011, 14:15–14:30, ZEU 260

Complexity-stability relations in generalized food-web models with realistic parameters — •Sebastian Plitzko, Christian Guill, and Barbara Drossel — Institut für Festkörperphysik, TU Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany

We investigate conditions for positive complexity-stability relations in the niche model for food webs by evaluating the local stability of the fixed points of the system. We use a generalized method, where the fixed points are normalized to 1, which allows for an efficient numerical evaluation. We find that positive relations between local stability and complexity can be obtained if prey is not scarce, biomass loss due to predation is low and density-dependent mortality effects dominate over other contributions to mortality. Since these conditions are expressed in terms of the generalized parameters, we then determine the range of values of these parameters within locally stable niche model food webs with explicit dynamical equations. These equations include allometric scaling and parameter values that are realistic. We find that the values of the generalized parameters obtained from this explicit dynamical model depend on the trophic level. The range of these parameters is such that positive complexity-stability relations can be obtained.