Asymptotic stability of stochastic single-species model under regime switching

Author(s): Zhihao Geng1, Manqing Yang1
1School of Mathematics and Information Science, Henan Polytechnic University, Jiaozuo 454003, China.
Copyright © Zhihao Geng, Manqing Yang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper investigates the stationary probability distribution of the well-known stochastic logistic equation under regime switching. Sufficient conditions for the asymptotic stability of both the zero solution and the positive equilibrium are derived. The stationary distribution of the logistic equation under Markovian switching is obtained by computing the weighted mean of the stationary distributions of its subsystems. The weights correspond to the limiting distribution of the underlying Markov chain.

Keywords: logistic model, markov chains, regime switching, asymptotic stability.

1. Introduction: Background and Research Aims

Logistic equation is one of the most important models in mathematical ecology. The classical logistic equation can be expressed as follows \[\label{eq1} \mathrm{d}x(t)=r x(t)\Big(1-\frac{x(t)}{K}\Big)\mathrm{d}t. \tag{1}\] For model (1), a famous result is that if \(r<0\), then \(\lim\limits_{t\rightarrow \infty} x(t) = 0\); if \(r>0\), then \(\lim\limits_{t\rightarrow \infty} x(t) = K\) (see e.g., Murray [1]).

In recent years, random systems have received more and more attentions, and many people have studied this (see e.g., [2-8]). In [9], Mao pointed out that small environmental noise may have different effects on the growth rate of species, that is, white noise can be used to simulate environmental disturbance, which is the most common method, such as [10-18]. Suppose that the growth rate \(r\) is affected by environmental noise with \[r\rightarrow r+\sigma \dot{B}(t).\] From (1), we can obtain the Itô type stochastic model \[\label{eq112} \mathrm{d}{x}(t)=x(t)(1-\frac{x(t)}{K})\Big[r\mathrm{d}t+\sigma \mathrm{d}B(t)\Big]. \tag{2}\] Consider the natural growth of many populations vary with \(t\), Liu and Wang in [19] studied the stochastic non-autonomous logistic equation \[\label{eqliu2013} \mathrm{d}{x}(t)=x(t)(1-\frac{x(t)}{K})\Big[r(t)\mathrm{d}t+\sigma(t) \mathrm{d}B(t)\Big]. \tag{3}\] They investigated the effect of white noise on the stability of these two equilibria a: \(0\) and \(K\) for (3).

However, large and sudden environmental disturbance are unavoidable, such as earthquakes, tsunamis, hurricanes, floods, or droughts may have important consequences on the system. Therefore, in addition to the small disturbances described by the white noise, there are also some environmental noises that will obviously change the population growth at random times, making the population growth switch from one state to another. It cannot be represented by the stochastic differential equation driven by the standard Brownian motion, but needs to be modeled by the continuous time Markov chain. Many researches such as [20-26] and the references therein show that this regime switching can be described by a right-continuous Markov chain taking value in a finite state space. Suppose \(\xi(t)\) represents a right continuous Markov chain in state space \(S=\{1,2,…,N\},\) which is independent of \(B(t)\) . Thus it is reasonable and important to study the following logistic equation and stochastic logistic equation with Markovian switching \[\label{eq113} \mathrm{d}{x}(t)=r(\xi(t),t)x(t)\Big(1-\frac{x(t)}{K}\Big)\mathrm{d}t \tag{4}\] and \[\label{eq114} \mathrm{d}{x}(t)=x(t)\Big(1-\frac{x(t)}{K}\Big)\Big[r(\xi(t),t)\mathrm{d}t+\sigma(\xi(t),t)\mathrm{d}B(t)\Big]. \tag{5}\] Note that Eq. (4) has two equilibria: \(0\) and \(K\), so does Eq. (5). The aim of this paper is to investigate the effect of Markovian switching noise and white noise on the stability of these two equilibria. For (5), we shall show that

  • \(\displaystyle\lim\limits_{t\rightarrow \infty}x(t)=0,a.s.\) if \(b^*=:\limsup\limits_{t\rightarrow \infty}\displaystyle\frac{1}{t}\int_0^t[r(\xi(s),s)+\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s<0.\)

  • \(\displaystyle\lim\limits_{t\rightarrow \infty}x(t)=K,a.s.\) if \(b_*=:\liminf\limits_{t\rightarrow \infty}\displaystyle\frac{1}{t}\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s>0.\)

For the Richards model ([27,28]) with Markovian switching \[\label{eq115} \mathrm{d}{x}(t)=x(t)(1-\frac{x^{\theta}(t)}{K})\Big[r(\xi(t))\mathrm{d}t+\sigma(\xi(t))\mathrm{d}B(t)\Big]. \tag{6}\] The similar results are obtained as

  • \(\lim\limits_{t\rightarrow \infty}x(t)=0,a.s.\) if \(D^*=:\limsup\limits_{t\rightarrow \infty}\displaystyle\frac{1}{t}\int_0^t[r(\xi(s),s)+\frac{\theta}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s<0.\)

  • \(\lim\limits_{t\rightarrow \infty}x(t)=\sqrt[\theta]{K},a.s.\) if \(D_*=:\liminf\limits_{t\rightarrow \infty}\displaystyle\frac{1}{t}\int_0^t[r(\xi(s),s)-\frac{\theta}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s>0.\)

2. Main Results

Lemma 1. For any initial value \(x_0>0\), Eq. (5) has a unique and positive solution \(x(t)\) on \(t\geq 0\) a.s..

Proof. The proof is similar to Mao et al. [29] by defining \(V(x)=4\sqrt{x}-4-2\ln x,x>0\), and hence is omitted. ◻

Lemma 2. For all \(t>0,\) the solution of Eq. (5) obeys that \(x(t)<K\) under \(0<x(0)<K.\)

Proof. Define \(U(x)\displaystyle=\ln\left|\frac{x}{K-x}\right|\), by using generalised Itô formula, we find that \[\begin{array}{ll} \mathrm{d}{U}(x(t))&\displaystyle=\frac{K}{x(t)(K-x(t))}\mathrm{d}x(t) \displaystyle-\frac{1}{2}\cdot\frac{K(K-2x(t))}{x^{2}(t)(K-x(t))^{2}}\cdot[x(t)\sigma(\xi(t),t)(1- \frac{x(t)}{K})]^{2}\mathrm{d}t\\ &\displaystyle=[r(\xi(t),t)-\frac{1}{2}\sigma^{2}(\xi(t),t)+\frac{x(t)}{K}\sigma^{2}(\xi(t),t)]\mathrm{d}t+\sigma(\xi(t),t)\mathrm{d}B(t). \end{array} \tag{7}\] Calculate the integral from \(0\) to \(t\) on both sides of the above equation, we get that \[\label{eq211} \ln\left|\frac{x(t)}{K-x(t)}\right|=\ln\left|\frac{x(0)}{K-x(0)}\right|+\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)+\frac{x(s)}{K}\sigma^{2}(\xi(s),s)]\mathrm{d}s+M_{1}(t). \tag{8}\] In other words \[\frac{x(t)}{K-x(t)}=\frac{x(0)}{K-x(0)}\exp\Big\{\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)+\frac{x(s)}{K}\sigma^{2}(\xi(s),s)]\mathrm{d}s+M_{1}(t)\Big\}.\] Where \(M_{1}(t)=\displaystyle\int_0^t\sigma(\xi(s))\mathrm{d}B(s),\) therefore \[\label{eq212} x(t)=\frac{K}{\displaystyle\frac{K-x(0)}{x(0)}\exp\Big\{-\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)+\frac{x(s)}{K}\sigma^{2}(\xi(s),s)]\mathrm{d}s-M_{1}(t)\Big\}+1}. \tag{9}\] So we can get that \(x(t)<K\) for all \(t>0\) when \(x(0)<K\). ◻

Theorem 1. Let \(0<x(0)=x_0<K\), and \[b^*=:\limsup_{t\rightarrow \infty}\frac{1}{t}\int_0^t[r(\xi(s),s)+\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s<0\] then (5) has globally asymptotically stable zero solution, i.e \[\lim\limits_{t\rightarrow \infty}x(t)=0,~~a.s..\]

Proof. By (8) and Lemma 2, we can get that \[\begin{array}{ll} \displaystyle\ln\left|\frac{x(t)}{K-x(t)}\right|&\displaystyle=\ln|\frac{x(0)}{K-x(0)}|+\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)+\frac{x(s)}{K}\sigma^{2}(\xi(s),s)]\mathrm{d}s +M_1(t)\\ &\displaystyle\leq\ln|\frac{x(0)}{K-x(0)}|+\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)+\sigma^{2}(\xi(s),s)]\mathrm{d}s +M_1(t)\\ &\displaystyle=\ln|\frac{x(0)}{K-x(0)}|+\int_0^t[r(\xi(s),s)+\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s+M_{1}(t), \end{array}\tag{10}\] where \(M_{1}(t)=\displaystyle\int_0^t\sigma(\xi(s),s)\mathrm{d}B(s)\). Through a series of calculations, we can obtain that \[\label{eq25} \begin{array}{ll} x(t)&\displaystyle\leq\frac{K}{\displaystyle\frac{K-x(0)}{x(0)}\exp\Big\{-\int_0^t[r(\xi(s),s)+\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s-M_{1}(t)\Big\}+1}\\ &\displaystyle\leq\frac{K}{\displaystyle\frac{K-x(0)}{x(0)}\exp\Big\{-\int_0^t[r(\xi(s),s)+\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s-M_{1}(t)\Big\}}. \end{array}\tag{11}\] Calculating the logarithmic function on both sides of the inequality (11) together, and we can get that \[\label{eq26} \begin{array}{ll} \ln x(t)&\displaystyle\leq \ln K-\ln\frac{K-x(0)}{x(0)}+\int_0^t[r(\xi(s),s)+\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s+M_{1}(t)\\ &\displaystyle=\ln\frac{Kx(0)}{K-x(0)}+\int_0^t[r(\xi(s),s)+\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s+M_{1}(t). \end{array}\tag{12}\] Note that \(M_1(t)\) is a martingale with quadratic variation \[\langle M_1(t),M_1(t)\rangle=\int_0^t\sigma^{2}(\xi(s),s)\mathrm{d}s\leq\max_{1\leq i\leq N}\widehat{\sigma_{i}^{2}}t,\] where \(\widehat{\sigma_{i}^{2}}=\sup_{t\geq 0}\sigma_i(t)\). By the strong law of large numbers for local martingales (see, e.g., [30,31]), \[\label{Martingale1} \lim\limits_{t\rightarrow \infty}\frac{M_1(t)}{t}=0~~a.s.. \tag{13}\] Therefore \[\limsup_{t\rightarrow \infty}\frac{\ln x(t)}{t}\leq \displaystyle \limsup_{t\rightarrow \infty}\frac{1}{t}\int_0^t[r(\xi(s),s)+\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s=b^*.\] The required assertion \[\lim\limits_{t\rightarrow \infty}x(t)=0~~a.s.\] follows from \(b^*<0\). ◻

Theorem 2. Let \(0<x(0)=x_0<K\), and \[b_*=:\liminf_{t\rightarrow \infty}\frac{1}{t}\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s>0\] then Eq. (5) has globally asymptotically stable positive equilibrium \(K\), i.e \[\lim\limits_{t\rightarrow \infty}x(t)=K,~a.s..\]

Proof. Define \[\displaystyle\eta(t)=\frac{K}{\displaystyle\frac{K-x(0)}{x(0)}\exp\Big\{-\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s-M_{1}(t)\Big\}+1}.\] In the light of (9), \(\eta(t)\leq x(t).\)  In addition, \(\eta(t)\) can also be expressed as \[\displaystyle\eta(t)=\frac{K}{\displaystyle\frac{K-x(0)}{x(0)}\exp\Big\{-t\Big(\frac{1}{t}\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)] \mathrm{d}s+\frac{1}{t}M_{1}(t)\Big)\Big\}+1}.\] Since \(b_*=:\liminf\limits_{t\rightarrow \infty}\displaystyle\frac{1}{t}\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s>0\) and (13), so \[\lim\limits_{t\rightarrow \infty}\exp\Big\{-t\Big(\frac{1}{t}\int_0^t[r(\xi(s),s)-\frac{1}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s+\frac{1}{t}M_{1}(t)\Big)\Big\}=0.\] Therefore \[\lim\limits_{t\rightarrow \infty}\eta(t)=K~~a.s.,\] This, along with \(x(t)<K\), imply that \[\lim\limits_{t\rightarrow \infty}x(t)=K~~a.s..\] ◻

Let Markov chain \(\xi(t)\) is irreducible, so it has a unique stationary (probability) distribution \(\pi_1\). By the ergodic property of the irreducible Markov chain, we can get the results for Eq. (5) with the special case.

Corollary 1. For \(r(\xi(t),t)=r(\xi(t))\), \(\sigma(\xi(t),t)=\sigma(\xi(t))\). Let \(0<x(0)=x_{0}<K\). Then

(i) If \(\sum\limits_{i\in\mathbb{S}}\displaystyle \pi_i(r_i+\frac{1}{2}\sigma_i^2)<0\), then the zero solution of Eq. (5) is globally asymptotically stable a.s., that is, \[\lim _{t \rightarrow+\infty} x(t)=0, \quad a.s..\]

(ii) If \(\sum\limits_{i\in\mathbb{S}}\displaystyle\pi_i(r_i-\frac{1}{2}\sigma_i^2)>0\), then the positive equilibrium \(K\) of Eq. (5) is globally asymptotically stable a.s., that is, \[\lim _{t \rightarrow+\infty} x(t)=K, \quad a.s..\]

Corollary 2. For \(r(i,t+T)=r(i,t)\), \(\sigma(i,t+T)=\sigma(i,t)\). Let \(0<x(0)=x_{0}<K.\) Then

(i) If \(\sum\limits_{i\in\mathbb{S}}\displaystyle\frac{\pi_i}{T}\int_0^T(r_i(s)+\frac{1}{2}\sigma_i^2(s))\mathrm{d}s<0\), then \(\lim\limits_{t \rightarrow+\infty} x(t)=0, \quad a.s.;\)

(ii) If \(\sum\limits_{i\in\mathbb{S}}\displaystyle\frac{\pi_i}{T}\int_0^T(r_i(s)-\frac{1}{2}\sigma_i^2(s))\mathrm{d}s>0\), then \(\lim\limits_{t \rightarrow+\infty} x(t)=K, \quad a.s.\).

For Eq. (4), we have the following results.

Theorem 3. Let \(0<x(0)=x_{0}<K.\)

(i) If \(r^*=:\limsup\limits_{t\rightarrow \infty}\displaystyle\frac{1}{t}\int_0^t r(\xi(s),s)\mathrm{d}s<0\), then the zero solution of Eq. (4) is globally asymptotically stable a.s., that is, \[\lim _{t \rightarrow+\infty} x(t)=0, \quad a.s..\]

(ii) If \(r_*=:\liminf\limits_{t\rightarrow \infty}\displaystyle\frac{1}{t}\int_0^t r(\xi(s),s)\mathrm{d}s>0\), then the positive equilibrium \(K\) of Eq. (4) is globally asymptotically stable a.s., that is, \[\lim _{t \rightarrow+\infty} x(t)=K, \quad a.s..\]

Theorem 4. Let \(0<x(0)=x_{0}<K\). If \(r^{*}=r_{*}=r\) which is a constant, then Eq. (4) has the properties that

(i) If \(r<0\), then \(\lim\limits_{t \rightarrow+\infty} x(t)=0, \quad a.s.;\)

(ii) If \(r>0\), then \(\lim\limits_{t \rightarrow+\infty} x(t)=K, \quad a.s.\).

Following we introduce stochastic Richards model ([27,28]) with Markovian switching which can be expressed as \[\label{eq27} \mathrm{d}{x}(t)=x(t)(1-\frac{x^{\theta}(t)}{K})[r(\xi(t),t)\mathrm{d}t+\sigma(\xi(t),t)\mathrm{d}B(t)], \tag{14}\] where \(\theta\) is a positive constant. Note that model (14) is obtained from the generalized hybrid logistic model \[\mathrm{d}{x}(t)=x(t)r(\xi(t),t)(1-\frac{x^{\theta}(t)}{K})\mathrm{d}t.\] by changing \(r(\xi(t),t)\) to \(r(\xi(t),t)+\sigma(\xi(t),t) \dot{B}(t)\), it is worth mentioning that model (14) become to Eq. (5) if \(\theta=1\). Here we use a result of Theorem 2 from [32] to Eq. (14) which reads

if \(0<x_0<\sqrt[\theta]{K},\) then \(0<x(t)<\sqrt[\theta]{K}\)  for  \(t>0\), a.s..

Theorem 5. If \[D^*=:\limsup_{t\rightarrow \infty}\frac{1}{t}\int_0^t[r(\xi(s),s)+\frac{\theta}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s<0\] and \(0<x(0)<\sqrt[\theta]{K}\), then the zero solution of Eq. (14) is asymptotically stable a.s., that is, \(\lim\limits_{t\rightarrow \infty}x(t)=0\) a.s..

Proof. Define \(V\displaystyle=\ln\left|\frac{x^{\theta}(t)}{K-x^{\theta}(t)}\right|,\) by using generalised Itô formula, we find that \[\label{eq29} \mathrm{d}{V}(t)\displaystyle=[\theta r(\xi(t),t)-\frac{\theta}{2}\sigma^{2}(\xi(t),t)+\frac{\theta(\theta+1)}{2K}x^{\theta}(t) \sigma^{2}(\xi(t),t)]\mathrm{d}t+\theta\sigma(\xi(t),t)\mathrm{d}B(t). \tag{15}\] Therefore we have that \[\mathrm{d}{V}(t)\displaystyle\leq[\theta r(\xi(t),t)-\frac{\theta}{2}\sigma^{2}(\xi(t),t)+\frac{\theta(\theta+1)}{2}\sigma^{2}(\xi(t),t)]\mathrm{d}t+\theta\sigma(\xi(t),t)\mathrm{d}B(t).\] Integrating both sides from \(0\) to \(t\) implies that \[\ln\left|\frac{x^{\theta}(t)}{K-x^{\theta}(t)}\right|\leq\ln\left|\frac{x^{\theta}(0)}{K-x^{\theta}(0)}\right|+\int_0^t[\theta r(\xi(s),s)+\frac{\theta^{2}}{2}\sigma^{2}(\xi(s),s)\mathrm{d}s+M_{2}(t).\] Therefore \[\begin{array}{ll} x^{\theta}(t)&\displaystyle\leq\frac{K}{\displaystyle\frac{K-x^{\theta}(0)}{x^{\theta}(0)}\exp\Big\{-\int_0^t[\theta r(\xi(s),s)+\frac{\theta^{2}}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s-M_{2}(t)\Big\}+1}\\ &\displaystyle\leq\frac{K}{\displaystyle\frac{K-x^{\theta}(0)}{x^{\theta}(0)}\exp\Big\{-\int_0^t[\theta r(\xi(s),s)+\frac{\theta^{2}}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s-M_{2}(t)\Big\}}. \end{array}\tag{16}\] The logarithm of both sides for the above equation \[\label{eq51} \ln x^{\theta}(t)\leq \ln\frac{Kx^{\theta}(0)}{K-x^{\theta}(0)}+\int_0^t[\theta r(\xi(s),s)+\frac{\theta^{2}}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s+M_{2}(t), \tag{17}\] where \[M_{2}(t)=\int_0^t\theta\sigma(\xi(s),s)\mathrm{d}B(s).\] Note that \(M_{2}(t)\) is a martingale with quadratic variation \[\langle M_{2}(t),M_{2}(t)\rangle=\int_0^t\theta^{2}\sigma^{2}(\xi(s),s)\mathrm{d}s.\] For \(\sigma(\xi(t))\) is a bounded function on  \([0,+\infty)\) , we have that \[\limsup\limits_{t\rightarrow \infty}\frac{\langle M_{2}(t),M_{2}(t)\rangle}{t}<+\infty.\] By virtue of the strong law of large numbers for martingales, we can see that \[\label{eqMarkov2} \lim\limits_{t\rightarrow \infty}\frac{M_{2}(t)}{t}=0. \tag{18}\] For arbitrary \(\varepsilon>0\), there exists \(T>0\) such that for \(t\geq T,\) \[\frac{M_{2}(t)+\ln\displaystyle\frac{Kx^{\theta}(0)}{K-x^{\theta}(0)}}{t}<\frac{\theta\varepsilon}{2},~~~\displaystyle\frac{1}{t}\int_0^t[\theta r(\xi(s),s)+\frac{\theta^{2}}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s\leq \theta(D^*+\frac{\varepsilon}{2}).\] Using these inequalities in (17), one can obtain that \[\frac{\ln x^{\theta}(t)}{t}\leq \frac{\theta\varepsilon}{2}+\theta(D^*+\frac{\varepsilon}{2}).\] Then, \[\frac{\ln x(t)}{t}\leq (D^*+\varepsilon)<0.\] Therefore we have \(\lim\limits_{t\rightarrow \infty}x(t)=0\),  a.s.. ◻

Theorem 6. If \[D_*=:\liminf_{t\rightarrow \infty}\frac{1}{t}\int_0^t[r(\xi(s),s)-\frac{\theta}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s>0\] and \(0<x(0)<\sqrt[\theta]{K}\), then the positive equilibrium \(\sqrt[\theta]{K}\) of (14) is asymptotically stable a.s., that is, \(\lim\limits_{t\rightarrow \infty}x(t)=\sqrt[\theta]{K}\).

Proof. Define \[\displaystyle\eta^{\theta}(t)=\frac{K}{\displaystyle\frac{K-x^{\theta}(0)}{x{\theta}(0)}\exp\Big\{-\int_0^t[\theta r(\xi(s),s)-\frac{\theta^2}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s-M_{2}(t)\Big\}+1}.\] In the light of the expression of \(x^{\theta}(t)\)\(\eta^{\theta}(t)\leq x^{\theta}(t).\)  In addition, \(\eta^{\theta}(t)\) can also be expressed as \[\displaystyle\eta^{\theta}(t)=\frac{K}{\displaystyle\frac{K-x^{\theta}(0)}{x^{\theta}(0)}\exp\Big\{-t\Big(\frac{1}{t}\int_0^t[\theta r(\xi(s),s)-\frac{\theta^2}{2}\sigma^{2}(\xi(s),s)] \mathrm{d}s+\frac{1}{t}M_{2}(t)\Big)\Big\}+1}.\] Since \(D_*=:\liminf\limits_{t\rightarrow \infty}\displaystyle\frac{1}{t}\int_0^t[ r(\xi(s),s)-\frac{\theta}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s>0\) and (18), so \[\lim\limits_{t\rightarrow \infty}\exp\Big\{-t\Big(\frac{1}{t}\int_0^t[\theta r(\xi(s),s)-\frac{\theta^2}{2}\sigma^{2}(\xi(s),s)]\mathrm{d}s+\frac{1}{t}M_{2}(t)\Big)\Big\}=0.\] Therefore \[\lim\limits_{t\rightarrow \infty}\eta(t)=\sqrt[\theta]{K}~~a.s.,\] This, along with \(x(t)<\sqrt[\theta]{K}\), imply that \[\lim\limits_{t\rightarrow \infty}x(t)=\sqrt[\theta]{K}~~a.s..\] This completes the proof. ◻

Remark 1.

The same results as Corollary 1 and Corollary 2 can be obtained for model (14) under the condition that Markov chain \(\xi(\cdot)\) is irreducible.

3. Conclusion

This paper investigates the stochastic logistic equation under regime switching. We establish sufficient conditions for the global asymptotic stability of both the zero solution and the positive equilibrium. Furthermore, we derive an explicit expression for the limiting behavior of hybrid models. Our findings reveal several significant and biologically relevant insights: both white noise and switching noise can profoundly influence population dynamics.

While our study addresses key aspects of the stochastic logistic equation, several intriguing questions remain open for future research. For instance, exploring the dynamics of state-dependent or infinite-state Markov chains presents a promising direction for further investigation.

References:

  1. Murray, J. D. (2002). Mathematical Biology. I. An Introduction (3rd ed.). Springer-Verlag, New York.

  2. Carlos, C., & Braumann, C. A. (2017). General population growth models with Allee effects in a random environment. Ecological Complexity, 30, 26–33.

  3. Dieu, N. T., Fugo, T., & Du, N. H. (2020). Asymptotic behaviors of stochastic epidemic models with jump-diffusion. Applied Mathematical Modelling, 86, 259–270.

  4. Mohammed, A. H., & Almurad, A. B. (2022). Global asymptotic stability of constant equilibrium point in attraction-repulsion chemotaxis model with logistic source term. Open Journal of Mathematical Analysis, 6(2), 102–119.

  5. Ji, W. (2019). Permanence and extinction of a stochastic hybrid population model with Allee effect. Physica A, 533, 122075.

  6. Liu, M., Bai, C., & Wang, K. (2014). Asymptotic stability of a two-group stochastic SEIR model with infinite delays. Communications in Nonlinear Science and Numerical Simulation, 19, 3444–3453.

  7. Sartabanov, Z. A., Aitenova, G. M., & Abdikalikova, G. A. (2022). Multiperiodic solutions of quasilinear systems of integro-differential equations with \(D_c\)-operator and \(\epsilon\)-period of heredity. Eurasian Mathematical Journal, 13(1), 86–100.

  8. Lv, J., & Wang, K. (2005). Almost sure permanence of stochastic single species models. Journal of Mathematical Analysis and Applications, 422, 675–683.

  9. Mao, X. (2005). Delay population dynamics and environmental noise. Stochastic Dynamics, 5(2), 149–162.

  10. Ji, W., Zhang, Y., & Liu, M. (2021). Dynamical bifurcation and explicit stationary density of a stochastic population model with Allee effects. Applied Mathematics Letters, 111, 106662.

  11. Wang, K. (2010). Stochastic Mathematical Biology Models. Science Press, Beijing.

  12. Li, X., Jiang, D., & Mao, X. (2009). Population dynamical behavior of Lotka-Volterra system under regime switching. Journal of Computational and Applied Mathematics, 232, 427–448.

  13. Deng, M. (2019). Dynamics of a stochastic population model with Allee effect and Lévy jumps. Physica A, 531, 121745.

  14. Liu, M., Du, C., & Deng, M. (2018). Persistence and extinction of a modified Leslie-Gower Holling-type II stochastic predator-prey model with impulsive toxicant input in polluted environments. Nonlinear Analysis: Hybrid Systems, 27, 177–190.

  15. Liu, M., Yu, J., & Mandal, P. S. (2018). Dynamics of a stochastic delay competitive model with harvesting and Markovian switching. Applied Mathematics and Computation, 337, 335–349.

  16. Liu, M., & Zhu, Y. (2018). Stationary distribution and ergodicity of a stochastic hybrid competition model with Lévy jumps. Nonlinear Analysis: Hybrid Systems, 30, 225–239.

  17. Liu, M., & Deng, M. (2019). Permanence and extinction of a stochastic hybrid model for tumor growth. Applied Mathematics Letters, 94, 66–72.

  18. Liu, M. (2019). Dynamics of a stochastic regime-switching predator-prey model with modified Leslie-Gower Holling-type II schemes and prey harvesting. Nonlinear Dynamics, 96, 417–442.

  19. Liu, M., & Wang, K. (2013). A note on stability of stochastic logistic equation. Applied Mathematics Letters, 26, 601–606.

  20. Yu, X., Yuan, S., & Zhang, T. (2018). Persistence and ergodicity of a stochastic single species model with Allee effect under regime switching. Communications in Nonlinear Science and Numerical Simulation, 59, 359–374.

  21. Yu, X., Yuan, S., & Zhang, T. (2019). Survival and ergodicity of a stochastic phytoplankton-zooplankton model with toxin-producing phytoplankton in an impulsive polluted environment. Applied Mathematics and Computation, 347, 249–264.

  22. Li, X., Gray, A., Jiang, D., & Mao, X. (2011). Sufficient and necessary conditions of stochastic permanence and extinction for stochastic logistic populations under regime switching. Journal of Mathematical Analysis and Applications, 376, 11–28.

  23. Liu, M., & Wang, K. (2011). Persistence and extinction in stochastic non-autonomous logistic systems. Journal of Mathematical Analysis and Applications, 375, 443–457.

  24. Liu, M., & Wang, K. (2012). Asymptotic properties and simulations of a stochastic logistic model under regime switching II. Mathematical and Computer Modelling, 55, 405–418.

  25. Luo, Q., & Mao, X. (2007). Stochastic population dynamics under regime switching. Journal of Mathematical Analysis and Applications, 334, 69–84.

  26. Wu, R., Zou, X., & Wang, K. (2014). Asymptotic properties of stochastic hybrid Gilpin-Ayala system with jumps. Applied Mathematics and Computation, 249, 53–66.

  27. Richards, F. J. (1959). A flexible growth function for empirical use. Journal of Experimental Botany, 10(29), 290–300.

  28. Birch, C. P. (1999). A new generalized logistic sigmoid growth equation compared with the Richards growth equation. Annals of Botany, 83, 713–723.

  29. Mao, X., Marion, G., & Renshaw, E. (2002). Environmental Brownian noise suppresses explosions in populations dynamics. Stochastic Processes and Their Applications, 97, 95–110.

  30. Mao, X., & Yuan, C. (2006). Stochastic Differential Equations with Markovian Switching. Imperial College Press.

  31. Liptser, R. (1980). A strong law of large numbers for local martingales. Stochastics, 3, 217–228.

  32. Lv, J., Wang, K., & Jiao, J. (2015). Stability of stochastic Richards growth model. Applied Mathematical Modelling, 39, 4821–4827.