Predator Mediated Competition: Predator Feeding on Two Different Trophic Levels

Abstract

<p> We consider a model of the chemostat in which three competitor populations compete for a single, essential, growth-limiting nutrient. As well, the least efficient competitor population also acts as a predator on the most efficient competitor population. Bifurcation methods are used to obtain information about the qualitative behaviour of the model. A complete description of the global stability is given for the case when Lotka-Volterra response functions describe both competitor-nutrient and predator-prey interactions. For certain parameter values, the model predicts coexistence of the three species. The model also shows that the elimination of the predator population or the elimination of a competitor population can cause the system to collapse from three species to one.</p>