Stochastic persistence and extinction for degenerate stochastic Rosenzweig-MacArthur model

TL;DR

This paper analyzes the stochastic Rosenzweig-MacArthur prey-predator model with degenerate noise, establishing conditions for species persistence, extinction, and convergence rates of the invariant measure.

Contribution

It extends previous work by providing convergence rates, detailed proofs, and conditions for persistence and extinction in a degenerate stochastic prey-predator model.

Findings

Conditions for species persistence and extinction identified.

Polynomial convergence rate of the invariant measure established.

Complete proofs of intermediary results provided.

Abstract

We consider the classical two-dimensional Rosenzweig-MacArthur prey-predator model with a degenerate noise, whereby only the prey variable is subject to small environmental fluctuations. This model has already been introduced in arXiv:1806.08450 and partially investigated by exhibiting conditions ensuring persistence. In this paper, we extend the results to study the conditions for persistence, the uniqueness of an invariant probability measure supported on the interior of $\mathbb R^2_+$ with a smooth density, and convergence in Total variation at a polynomial rate. Our contribution lies in providing a convergence rate in the case of persistence, as well as detailing the situations involving the extinction of one or both species. We also specify all the proofs of the intermediary results supporting our conclusions that are lacking in arXiv:1806.08450.