Biological conditions for oscillations and chaos generated by multispeciescompetition

We investigate biological mechanisms that generate oscillations and chaos i n multispecies competition models. For this purpose, we use a competition m odel concerned with competition for abiotic essential resources. Because ph ytoplankton and plants consume quite a number of abiotic essential resource s, the model is particularly relevant for phytoplankton communities and ter restrial vegetation. We show that the predicted dynamics depend crucially o n the relationship between the resource requirements and the resource consu mption characteristics of the species. More specifically, the model predict s that competition generates (1) stable coexistence if species consume most of the resources for which they have high requirements, (2) oscillations a nd chaos if species consume most of the resources for which they have inter mediate requirements, and (3) competitive exclusion with a winner that depe nds on the initial conditions if species consume most of the resources for which they have low requirements. The theoretical predictions are compared with available data on resource utilization patterns of phytoplankton speci es.