Impact of alternative food on predator diet in a Leslie-Gower model with prey refuge and Holling Ⅱ functional response.

Since certain prey hide from predators to protect themselves within their habitats, predators are forced to change their diet due to a lack of prey for consumption, or on the contrary, subsist only with alternative food provided by the environment. Therefore, in this paper, we propose and mathematically contrast a predator-prey, where alternative food for predators is either considered or not when the prey population size is above the refuge threshold size. Since the model with no alternative food for predators has a Hopf bifurcation and a transcritical bifurcation, in addition to a stable limit cycle surrounding the unique interior equilibrium, such bifurcation cases are transferred to the model when considering alternative food for predators when the prey size is above the refuge.

Bifurcations in a discontinuous Leslie-Gower model with harvesting and alternative food for predators and constant prey refuge at low density.

Since environmental studies have shown that a constant quantity of prey become refuges from the predator at low densities and become accessible again for consumption when they reach a higher density, in this work we propose a discontinuous mathematical model, Lesli-Gower type, which describes the dynamics between prey and predators, interacting under the same environment, and whose predator functional response, of linear type, is altered by a refuge constant in the prey when below a critical value. Assuming that predators can be captured and have alternative food, the qualitative analysis of the proposed discontinuous model is performed by analyzing each of the vector fields that compose it, which serves as the basis for the calculation of the bifurcation curves of the discontinuous model, with respect to the threshold value of the prey and the harvest rate of predators. It is concluded that the perturbations of the parameters of the model leads either to the extinction of the predators or to a stabilization in the growth of both species, regardless of their initial conditions.

Bifurcations in discontinuous mathematical models with control strategy for a species.

In this paper a preliminary mathematical model is proposed, by means of a system of ordinary differential equations, for the growth of a species. In this case, the species does not interact with another species and is divided into two stages, those that have or have not reached reproductive maturity, with natural and control mortality for both stages. When performing a qualitative analysis to determine conditions in the parameters that allow the extinction or preservation of the species, a modification is made to the model when only control is assumed for each of the stages if the number of species in that stage is above a critical value.