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BP: Fachverband Biologische Physik

BP 26: Posters II

BP 26.54: Poster

Thursday, February 28, 2008, 17:00–19:30, Poster A

influence of mass--dependent metabolic rates on food web stability — •Boris Kartascheff and Barbara Drossel — TU Darmstadt, Institute of Condensed Matter Physics, Hochschulstr. 6, D-64289 Darmstadt

Most basic approaches to modeling food web dynamics lead to a negative relation between the complexity and the stability of networks, if complexity is measured in terms of connectance or species number. This is in contrast to empirical data, which suggest that complex food webs are at least as likely to persist in time as simpler predator--prey systems.

In this study, we investigate the effect of allometric scaling, i.e. of metabolic rates that decrease as an inverse power of the body mass (which in turn depends on the trophic level), on food web stability. We randomly initiate networks and evaluate how many species survive until population dynamics reaches a stationary state. We investigate the effect of allometric scaling on the stability of networks with different structure (random, layered, niche models) and with different population dynamics (without and with adaptive foraging).

In this way, we are able to reveal the generic mechanisms that allow certain food web models to show remarkably increased stability when allometric scaling is included. Besides computer simulations, we also apply analytical methods to obtain answers to the question whether the existence of different sized species in ecosystems is crucial to their stability.