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arXiv 2210.04097math.DS
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在一类表现出双稳态行为的捕食者-猎物模型中长暂态的分析与灭绝早期预警信号的检测

Analysis of long transients and detection of early warning signals of extinction in a class of predator-prey models exhibiting bistable behavior

Susmita Sadhu, Saikat Chakraborty Thakur

AI总结:

本文提出了一种分析具有双稳态行为的捕食者-猎物模型长暂态动力学的方法,通过规范型简化和移动平均技术确定了周期吸引子吸引域的充分必要条件,并设计出能显著提前预测捕食者灭绝危机的早期预警信号。

摘要:

本文提出了一种方法,用于分析一类捕食者-猎物模型中的长暂态动力学,该模型包含两种捕食者明确竞争其共同猎物,且猎物在比捕食者更快的时间尺度上演化。在共存平衡态的奇异零-Hopf分岔附近的参数区间内,我们假设所研究的系统在从奇异Hopf点分岔出的周期吸引子与另一吸引子(可以是周期吸引子或点吸引子)之间表现出双稳态,使得共存平衡点的不变流形在组织动力学中起核心作用。为了确定从共存平衡点附近出发的解是趋近于周期吸引子还是另一吸引子,我们将方程简化为合适的规范型,并检查奇异Hopf点附近的吸引域边界。我们研究的关键组成部分包括应用移动平均技术分析长暂态动力学,该动力学以振幅缓慢变化的快速振荡为特征。我们获得了一组关于解在共存平衡点附近初始值的充分必要条件,以确定其是否位于周期吸引子的吸引域内。作为分析结果,我们设计了一种方法,能够显著提前识别可能导致其中一种捕食者灭绝的未来危机的早期预警信号。该分析被应用于[Discrete and Continuous Dynamical Systems - B 2021, 26(10), pp. 5251-5279]中考虑的捕食者-猎物模型,我们发现理论与该模型的数值模拟结果高度一致。

英文摘要:

In this paper, we develop a method of analyzing long transient dynamics in a class of predator-prey models with two species of predators competing explicitly for their common prey, where the prey evolves on a faster timescale than the predators. In a parameter regime near a {\em{singular zero-Hopf bifurcation}} of the coexistence equilibrium state, we assume that the system under study exhibits bistability between a periodic attractor that bifurcates from the singular Hopf point and another attractor, which could be a periodic attractor or a point attractor, such that the invariant manifolds of the coexistence equilibrium point play central roles in organizing the dynamics. To find whether a solution that starts in a vicinity of the coexistence equilibrium approaches the periodic attractor or the other attractor, we reduce the equations to a suitable normal form, and examine the basin boundary near the singular Hopf point. A key component of our study includes an analysis of the long transient dynamics, characterized by their rapid oscillations with a slow variation in amplitude, by applying a moving average technique. We obtain a set of necessary and sufficient conditions on the initial values of a solution near the coexistence equilibrium to determine whether it lies in the basin of attraction of the periodic attractor. As a result of our analysis, we devise a method of identifying early warning signals, significantly in advance, of a future crisis that could lead to extinction of one of the predators. The analysis is applied to the predator-prey model considered in [\emph{Discrete and Continuous Dynamical Systems - B} 2021, 26(10), pp. 5251-5279] and we find that our theory is in good agreement with the numerical simulations carried out for this model.

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