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DY: Fachverband Dynamik und Statistische Physik

DY 32: Statistical Physics in Biological Systems III (joint with BP)

DY 32.4: Vortrag

Donnerstag, 14. März 2013, 15:45–16:00, H46

The influence of chaos on the stability of small food webs — •Fanny Groll and Alexander Altland — Institut für Theoretische Physik, Universität zu Köln, Germany

Ecological networks can show different types of dynamics. Experiments have demonstrated that they can actually be governed by deterministic chaos. In that case the population numbers evolve along a chaotic attractor; they show large fluctuations but do not go extinct.

We examine a mathematical model of a simple food web consisting of two prey and one predator population. In this model a control parameter triggers the onset of chaos via bifurcation. Such dynamics have already been observed in an aquatic system of few competing species.

In studying this system we aim to find a catalogue of techniques to approach such a system and to analyze its features. Starting from a general master equation approach we have explored routes to chaos in few-species ecological systems. Emphasis has been put on the mechanisms leading to chaotic attractors. Under ambient conditions ecological systems are subject to demographic and environmental fluctuations. We explore the stability and persistence of populations in chaotic regimes compared to more regular types of dynamics.