Population Dynamics on Complex Food Webs

In this work we analyze the topological and dynamical properties of a simple model of complex food webs, namely the niche model. We describe the system as an oriented weighted graph and we assign a Lotka-Volterra population dynamics on the structure created by the niche model. After this we introduce “predators” and “prey” weighted graphs from which we underline patterns of competition among species. We measure topological properties of such graphs comparing simulated food webs with real data. We find that, using a combination of projections weights as competition kernel in the LotkaVolterra equations, the stability of food webs decreases with its complexity (measured as the average degree of the web).