The Effect of Complex and Discrete Life History on Predator-Prey Dynamics

Discrete life style and complex life history are common features of many fish populations. We examined the effect of discrete life style on predator-prey model using difference equations, and then explored various aspects of the model. In our unstructured model, as the predator’s ability to exploit their prey source increases above a threshold determined by prey population, the shape of prey isocline changes from ‘limited predation’ case with an vertical asymptote to classic humped shaped ‘unlimited predation’ case. These two cases are the same as its continuous time counterpart studied by Wayne (1984), but this discrete model gives more stability to the system. Finally, we used juvenile-adult stage-structured matrices to add the complex life history component to our existing model. The dynamics of this stage structured predator-prey matrix model are similar to the unstructured model, but now system behavior is explicitly determined by the life history parameters of both prey and predator population. This study proposed a novel and convenient way of explicitly incorporating life history parameters into a predator-prey model for animals with discrete life styles, and also combining short time manipulative studies to analyze the long term dynamics of the ecological system.