比率依赖型捕食者-食饵系统行波解的存在性

本文讨论一类比率依赖型捕食者 -食饵系统的反应扩散方程组 .首先 ,我们证明了时间周期定常解的存在性和稳定性 .其次 ,我们给出了扩散引起正常数平衡解失稳的条件 .最后 ,我们证明了比率依赖型捕食者 -食饵系统行波解的存在性和渐近性 .     

中立型时滞Lotka-Volterra系统正周期解的存在性

本文研究了具有m个捕食者n个食饵的中立型时滞Lotka-Volterra系统,并 利用重合度理论中的连续性引理,得到了该系统正周期解存在性的充分条件.     

一类三次Kolmogorov捕食者-食饵种群差分系统正周期解的存在性

研究了一类三次Kolmogorov捕食者-食饵种群差分系统正周期解的存在性,利用重合度理论中的连续性定理建立了存在正周期解的充分性依据,推广并改进了文献中的相关结果.     

脉冲Holling-Ⅱ型时滞捕食系统正周期解的存在性

本文研究了一类食饵有扩散的脉冲Holling-Ⅱ型时滞捕食者-食饵系统.利用重合度理论,获得了该系统至少存在一个正周期解的充分条件,从而使该种群达到了一个新的适宜各物种持续共存、发腱的稳定状态.     

一类捕食-被捕食模型的正平衡解存在性

针对自然界中捕食者染病的现象,建立了捕食者染病的捕食-被捕食模型,研究了捕食者为躲避疾病进行扩散,并且具有HollingⅡ功能性反应函数和齐次Neumann边界条件的问题,利用Harnack不等式和最大值原理给出反应扩散问题的正平衡解的先验估计,并利用拓扑度理论证明该问题的非常数正平衡解的存在性.讨论了对应平衡态问题的非常数正平衡解存在性。     

一类具有Holling Ⅲ型功能性反应的捕食者-食饵系统的周期解的存在性

利用重合度理论中的延拓定理研究带有开发利用项的具有Holling Ⅲ型功能性反应的捕食者-食饵系统,得到了两个正周期解存在的充分条件,得到了一些新的结果.     

一类具有时滞的比率依赖型捕食者-食饵系统周期正解的存在性

考虑一类具有时滞的比率依赖型捕食者-食饵系统,利用重合度理论中的延拓定理,得到系统存在正周期解的充分条件.     

带阶段结构的扩散的捕食者-食饵模型解的一致有界性和整体存在性

应用能量估计和Gagliardo-Nirenberg型不等式证明了捕食者带阶段结构的具有自扩散和交错扩散的捕食者-食饵模型解的一致有界性和整体存在性.     

一类具有交叉扩散捕食者-食饵系统的时间周期解的存在性与稳定性

本文讨论一类具有交叉扩散效应的捕食者-食饵系统的反应扩散方程组的时间周期解的存在性与稳定性．运用分歧理论、隐函数定理以及渐近展开的方法,获得了共存周期解的存在性与稳定性的结果．     

一个具有阶段结构的捕食者食饵系统的周期解

本文研究一类捕食者具有阶段结构的捕食者食饵系统,利用重合度理论建立了这类系统正周期解的存在性结果.     

Stationary pattern of a diffusive prey–predator model with trophic intersections of three levels

The paper is concerned with a diffusive prey–predator model subject to the homogeneous Neumann boundary condition, which models the trophic intersections of three levels. We will prove that under certain assumptions, even though the unique positive constant steady state is globally asymptotically stable for the dynamics with diffusion, the non-constant positive steady state can exist due to the emergence of cross-diffusion. We demonstrate that the cross-diffusion can create stationary pattern. Moreover, we treat the cross-diffusion parameter as a bifurcation parameter and discuss the existence of non-constant positive solutions to the system with cross-diffusion.     

Effects of the self- and cross-diffusion on positive steady states for a generalized predator–prey system

This paper deals with a generalized predator–prey system with cross-diffusion and homogeneous Neumann boundary condition, where the cross-diffusion is included in such a way that the prey runs away from the predator. We first give a priori estimate for positive steady states to the system. Then we obtain the non-existence result of non-constant positive steady states. Finally, we investigate the stability of constant equilibrium point and the existence of non-constant positive steady states. It is shown that the system admits a non-constant positive steady state provided that either of the self-diffusions is large or the cross-diffusion is small.     

The global stability and pattern formations of a predator–prey system with consuming resource

The paper deals with a model that describes a predator–prey system with a common consuming resource. We use Lyapunov functions to prove the global stability of the kinetic system and the diffusive system. The existence of non-constant positive steady state solutions is shown to identify the range of parameters of spatial pattern formation for the cross-diffusion system.     

Turing pattern formation in a three species model with generalist predator and cross-diffusion

In a natural ecosystem, specialist predators feed almost exclusively on one species of prey. But generalist predators feed on many types of species. Consequently, their dynamics is not coupled to the dynamics of a specific prey population. However, the defense of prey formed by congregating made the predator tend to move in the direction of lower concentration of prey species. This is described by cross-diffusion in a generalist predator–prey model. First, the positive equilibrium solution is globally asymptotically stable for the ODE system and for the reaction–diffusion system without cross-diffusion, respectively, hence it does not belong to the classical Turing instability scheme. But it becomes linearly unstable only when cross-diffusion also plays a role. This implies that cross–diffusion can lead to the occurrence and disappearance of the instability. Our results exhibit some interesting combining effects of cross-diffusion, predations and intra-species interactions. Furthermore, we consider the existence and non-existence results concerning non-constant positive steady states (patterns) of the system. We demonstrate that cross-diffusion can create non-constant positive steady-state solutions.     

Positive Solutions for a Lotka–Volterra Prey–Predator Model with Cross-Diffusion of Fractional Type

In this paper we consider a Lotka–Volterra prey–predator model with cross-diffusion of fractional type. The main purpose is to discuss the existence and nonexistence of positive steady state solutions of such a model. Here a positive solution corresponds to a coexistence state of the model. Firstly we study the stability of the trivial and semi-trivial solutions by analyzing the principal eigenvalue of the corresponding linearized system. Secondly we derive some necessary conditions to ensure the existence of positive solutions, which demonstrate that if the intrinsic growth rate of the prey is too small or the death rate (or the birth rate) of the predator is too large, the model does not possess positive solutions. Thirdly we study the sufficient conditions to ensure the existence of positive solutions by using degree theory. Finally we characterize the stable/unstable regions of semi-trivial solutions and coexistence regions in parameter plane.     

Spatial patterns of the Holling–Tanner predator–prey model with nonlinear diffusion effects

In this article, we study the Holling–Tanner predator–prey model with nonlinear diffusion terms under homogeneous Neumann boundary condition. The nonlinear diffusion terms here mean that the prey runs away from the predator, and the predator chases the prey. Nonexistence and existence of nonconstant positive steady states are obtained, which reveal that cross-diffusion can create spatial patterns even when the random diffusion fails to do so. Moreover, asymptotic behaviour of positive solutions as the cross-diffusion tends to ∞ is shown.     

Effect of cross-diffusion on the stationary problem of a prey-predator model with a protection zone

This paper is concerned with the stationary problem of a prey-predator cross-diffusion system with a protection zone for the prey. We discuss the existence and non-existence of coexistence states of the two species by using the bifurcation theory. As a result, it is shown that the cross-diffusion for the prey has beneficial effects on the survival of the prey when the intrinsic growth rate of the predator is positive. We also study the asymptotic behavior of positive stationary solutions as the cross-diffusion coefficient of the prey tends to infinity.     

Steady state in a cross-diffusion predator–prey model with the Beddington–DeAngelis functional response

The purpose of this paper is to study the existence of steady state in a linear cross-diffusion predator–prey model with Beddington–DeAngelis functional response. The proofs mainly rely on Fixed point index theory and analytical techniques.     

Turing pattern formation in a predator–prey system with cross diffusion

The paper explores the impacts of cross-diffusion on the formation of spatial patterns in a ratio-dependent predator–prey system with zero-flux boundary conditions. Our results show that under certain conditions, cross-diffusion can trigger the emergence of spatial patterns which is however impossible under the same conditions when cross-diffusion is absent. We give a rigorous proof that the model has at least one spatially heterogenous steady state by means of the Leray–Schauder degree theory. In addition, numerical simulations are performed to visualize the complex spatial patterns.