共查询到18条相似文献,搜索用时 93 毫秒
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捕食者有病的生态-流行病模型的分析 总被引:11,自引:1,他引:10
建立并分析了捕食者具有疾病且有功能反应的生态-流行病(SI)模型,讨论了解的有界性.应用特征根法得到了平衡点局部渐近稳定的充分条件,进一步分析了平衡点的全局稳定性,得到了边界平衡点和正平衡点全局稳定的充分条件。 相似文献
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本文研究一类具有空间扩散和食饵染病且垂直传染的的生态一流行病模型的在整体性态.首先讨论解的存在唯一性和一致有界性;其次由线性化方法得到了该模型非负平衡点的局部渐近稳定的充分条件,并构造恰当的Lyapunov泛函证明非负平衡点的全局渐近稳定性,得到了捕食者灭绝、疾病消失和疾病成为地方病的充分条件. 相似文献
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双密度制约的Holling Ⅱ型捕食动力系统的定性分析 总被引:1,自引:0,他引:1
研究食饵具有非线性密度制约捕食者具有线性密度制约的HollingⅡ型捕食动力系统.以食饵的环境容纳量为分支参数,由Hopf分支得到小振幅极限环的存在性,同时也得到了正平衡点的全局稳定性和非小振幅极限环的存在唯一性的充分条件. 相似文献
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本文讨论了一类具有强连续时滞的捕食-被捕食模型,分析了各非负平衡点的稳定性,利用区域连续收缩方法,得出非负平衡点全局稳定的充分条件,给出正平衡点全局稳定的充分条件,并给出系统出现Hopf的分支值. 相似文献
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Gary W. Harrison 《Bulletin of mathematical biology》1986,48(2):137-148
Necessary and sufficient conditions are given for three equilibria to occur in a predatorprey model and conditions are given
for two of these to be stable. The existence of two stable equilibria requires predator intraspecific competition for either
space or food, and the lower the prey growth rate the stronger this predator self-regulation must be. A prey growth rate that
is skewed to the right, the ability of a few predators to survive at low prey densities, and predators with high searching
effectiveness, long handling times, and large maximum per capita rate of increase all make two stable equilibria more likely. 相似文献
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A Leslie–Gower–Holling type II model is modified to introduce a contagious disease in the predator population, assuming that
disease cannot propagate to the prey. All the system’s equilibria are determined and the behaviour of the system near them
is investigated. The main mathematical issues are global stability and bifurcations for some of the equilibria, together with
sufficient conditions for persistence of the ecosystem. Counterintuitive results on the role played by intraspecific competition
are highlighted. 相似文献
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We propose and analyze a simple mathematical model for susceptible prey (S)–infected prey (I)–predator (P) interaction, where the susceptible prey population (S) is infected directly from external sources as well as through contact with infected class (I) and the predator completely avoids consuming the infected prey. The model is analyzed to obtain different thresholds of the key parameters under which the system exhibits stability around the biologically feasible equilibria. Through numerical simulations we display the effects of external infection and the infection through contact on the system dynamics in the absence as well as in the presence of the predator. We compare the system dynamics when infection occurs only through contact, with that when it occurs through contact and external sources. Our analysis demonstrates that under a disease-selective predation, stability and oscillations of the system is determined by two key parameters: the external infection rate and the force of infection through contact. Due to the introduction of external infection, the predator and the prey population show limit-cycle oscillations over a range parametric values. We suggest that while predicting the dynamics of such an eco-epidemiological system, the modes of infection and the infection rates might be carefully investigated. 相似文献
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《Journal of biological dynamics》2013,7(1):278-287
ABSTRACTA stage-structured predator–prey system with distributed maturation delay and harvesting is investigated. General birth and death functions are used. The local stability of each feasible equilibria is discussed. By using the persistence theory, it is proven that the system is permanent if the coexistence equilibrium exists. By using Lyapunov functional and LaSalle invariant principle, it is shown that the trivial equilibrium is globally stable when the other equilibria are not feasible, and that the boundary equilibrium is globally stable if the coexistence equilibrium does not exist. Finally, sufficient conditions are derived for the global stability of the coexistence equilibrium. 相似文献
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《Journal of biological dynamics》2013,7(2):959-973
The main objective of this work is to present a general framework for the notion of the strong Allee effect in population models, including competition, mutualistic, and predator–prey models. The study is restricted to the strong Allee effect caused by an inter-specific interaction. The main feature of the strong Allee effect is that the extinction equilibrium is an attractor. We show how a ‘phase space core’ of three or four equilibria is sufficient to describe the essential dynamics of the interaction between two species that are prone to the Allee effect. We will introduce the notion of semistability in planar systems. Finally, we show how the presence of semistable equilibria increases the number of possible Allee effect cores. 相似文献
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Intraguild predation (IGP) is a combination of competition and predation which is the most basic system in food webs that contains three species where two species that are involved in a predator/prey relationship are also competing for a shared resource or prey. We formulate two intraguild predation (IGP: resource, IG prey and IG predator) models: one has generalist predator while the other one has specialist predator. Both models have Holling-Type I functional response between resource-IG prey and resource-IG predator; Holling-Type III functional response between IG prey and IG predator. We provide sufficient conditions of the persistence and extinction of all possible scenarios for these two models, which give us a complete picture on their global dynamics. In addition, we show that both IGP models can have multiple interior equilibria under certain parameters range. These analytical results indicate that IGP model with generalist predator has “top down” regulation by comparing to IGP model with specialist predator. Our analysis and numerical simulations suggest that: (1) Both IGP models can have multiple attractors with complicated dynamical patterns; (2) Only IGP model with specialist predator can have both boundary attractor and interior attractor, i.e., whether the system has the extinction of one species or the coexistence of three species depending on initial conditions; (3) IGP model with generalist predator is prone to have coexistence of three species. 相似文献
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Schneider KA 《Theoretical population biology》2005,68(2):105-118
A haploid model of frequency-dependent selection and assortative mating is introduced and analyzed for the case of a single multiallelic autosomal locus. Frequency-dependent selection is due to intraspecific competition mediated by a quantitative character under stabilizing or directional selection. Assortment is induced by the same trait. We analyze the equilibrium structure and the local stability properties of all possible equilibria. In the limit of weak selection we obtain global stability properties by finding a Lyapunov function. We provide necessary and sufficient conditions for the maintenance of polymorphism in terms of the strength of stabilizing selection, intraspecific competition and assortment. Our results also include criteria for the ability of extreme types to invade the population. Furthermore, we study the occurrence of disruptive selection and provide necessary and sufficient conditions for intraspecific divergence to occur. 相似文献
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This article introduces a predator–prey model with the prey structured by body size, based on reports in the literature that predation rates are prey-size specific. The model is built on the foundation of the one-species physiologically structured models studied earlier. Three types of equilibria are found: extinction, multiple prey-only equilibria and possibly multiple predator–prey coexistence equilibria. The stabilities of the equilibria are investigated. Comparison is made with the underlying ODE Lotka–Volterra model. It turns out that the ODE model can exhibit sustain oscillations if there is an Allee effect in the net reproduction rate, that is the net reproduction rate grows for some range of the prey’s population size. In contrast, it is shown that the structured PDE model can exhibit sustain oscillations even if the net reproductive rate is strictly declining with prey population size. We find that predation, even size-non-specific linear predation can destabilize a stable prey-only equilibrium, if reproduction is size specific and limited to individuals of large enough size. Furthermore, we show that size-specific predation can also destabilize the predator–prey equilibrium in the PDE model. We surmise that size-specific predation allows for temporary prey escape which is responsible for destabilization in the predator–prey dynamics. 相似文献