Small World Patterns in Food Webs

Jose M. Montoya and Ricard V. Solé

00-10-059

The analysis of some species-rich, well-defined food webs shows that they display the so-called small-world behavior shared by a number of disparate complex systems. The three systems analyzed (Ythan estuary web, Silwood web, and the Little Rock lake web) have different levels of taxonomic resolution, but all of them involve high clustering and short path lengths between species. Additionally, the distribution of connections $P(k)$ is skewed in all the webs analyzed and shows a power-law behavior $P(k) \propto k^{-\gamma}$ in two cases (with $\gamma \approx 1$). These features suggest that communities might be self-organized in such a way that high homeostasis to perturbations (with short transient times to recovery) would be at work. The consequences for ecological theory are outlined.