Persistence and extinction of a nonautonomous switching single-species population model

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Abstract

A novel nonautonomous switching single-species population model is proposed and investigated. The sufficient conditions for persistence and extinction of the solutions of the model are obtained. Moreover, corresponding results are given for periodic switching system.

Introduction

A population model is a type of mathematical model that is applied to the study of population dynamics. Since the pioneer work of Malthusian growth model [1], there has been a fair amount of work on modeling single-species population growth using discrete models [2], continuous models [3], impulsive models [4] and even stochastic models [5]. Continuous model is comprised of autonomous model and non-autonomous model, whereas non-autonomous model can more exactly describe the population growth than autonomous one since it incorporates the effects of a time-varying environment on the growth of a population.

In [6], a general nonautonomous single-species population model ẋ=xf(t,x) was investigated, where growth function f(t,x):R+02R is continuous and differentiable with respect to x, here R+02={(t,x)R2:t0,x0}. Sufficient conditions for persistence and extinction of the population were obtained. However, in reality, the qualitative changes of the growth function form an essential aspect of the dynamics of the ecosystem. The change usually cannot be described by the continuous model owing to environmental switch, such as switching seasons (rainy season and dry season), switching sites (the north–south migration of migratory birds), and switching states. Therefore a nonautonomous counterpart of the fundamental growth equations with periodic switching time is introduced in this paper, namely ẋ=xfi(t,x),t(ti1,ti],in which fi represents the growth function of the population in different time interval, and {ti} are the switching times, and 0t0<t1<t2<. We assume that the switching rule satisfies titi1=wi with wi+q=wi, i=1,2,,q, where q is the number of switching subsystems, and then T=i=1qwi (means ti+q=ti+T) is the switching period. The subject of this paper is to investigate the persistence and extinction of the population to improve the work of [6], [7].

Section snippets

Persistence and extinction for system (2.1)

For convenience, we rewrite the system (1.1) as ẋ=xfi(t,x),t(nT+ti1,nT+ti],nZ+,i=1,2,,q,where Z+ is the set of nonnegative integers. Denote f(t,x)=f1(t,x),t(nT+t0,nT+t1],f2(t,x),t(nT+t1,nT+t2],fq(t,x),t(nT+tq1,(n+1)T+t0],andDni=(nT+ti1,nT+ti]×R+0,and give following assumptions for all nZ+ and i=1,2,,q.

A1. The function fi is continuous and differentiable with respect to x on Dni, and fix is continuous on Dni.

A2. The function fix0 on Dni.

A3. There exist constants β0 and k>0,

Persistence and extinction for periodic switching system

We now consider the special case in which fi is periodic in t with period T, that is,

A5. The function fi satisfies fi(t+T,x)=fi(t,x) for t(nT+ti1,nT+ti] and x0.

At the same time, the system (1.1) or (2.1) becomes the periodic switching system, and assumptions A3(ii), A4(ii) and A30(ii) can be simplified as the following forms:

A3(ii). There exists constant k>0, such that i=1qti1tifi(s,k)ds0.

A4(ii). There exists constant 0<δk such that i=1qti1tifi(s,δ)ds0.

A30(ii). i=1qti1tifi(s,0)

CRediT authorship contribution statement

Yan Xu: Writing - original draft. Shujing Gao: Conceptualization, Methodology. Di Chen: Formal analysis.

References (7)

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The research of S. Gao has been supported by the Natural Science Foundation of China (11961003, 11561004) and The Natural Science Foundation of Jiangxi Province, China (20192BCBL20004).

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