Ecological competition and the role of an apex predator

In this work we propose an agent-based model to study the process of ecological competition between two species coexisting with a common predator, including inter and intra-specific competition. Without the predator, the ecosystem always reaches a configuration in which one of the prey species faces extinction and the other survives, as is well known. However, we find that there is an optimum value for the amount of food consumed by the prey species for which the mean extinction time (MET) is maximum. In the presence of predators, the average extinction time may increase or decrease with respect to the non-predator case, depending on the food availability. It is also observed that the average extinction time has an optimum value depending on the efficiency of prey of the predator.