The Effects of Harvesting on Ecological Communities

In this paper, we derive and study a model for three species interacting via intraguild predation. We assume logistic growth for both the resource and consumer species, and functional responses with saturation, interspecific interference, and intraspecific interference for the predator-prey interactions. This leads to Beddington-DeAngelis-type functional responses. We consider local and global properties of the resource-consumer subsystem, and give conditions for permanence. We then consider permanence in the full system, along with the effects varying some of the parameters has on the invasibility and exclusion of each species. We also look at the effects that harvesting each species in the system has on the ecological community. We then consider a linear food chain, apparent competition, resource competition, and interspecific killing as special cases of our intraguild predation model. Finally, we discuss the biological mechanisms underlying our results