论文标题

在旱地植被系统降低的模型中存在局部植被模式

The existence of localized vegetation patterns in a systematically reduced model for dryland vegetation

论文作者

Jaibi, Olfa, Doelman, Arjen, Chirilus-Bruckner, Martina, Meron, Ehud

论文摘要

在本文中,我们考虑了最近通过系统降低3组分Gilad等人获得的2组分反应扩散模型。旱地生态系统动力学的模型。该模型的非线性结构比其他更多概念模型(例如扩展的Klausmeier模型)更具参与度,而先验分析更为复杂。但是,当前模型比这些更概念上的模型具有强大的优势,因为它可以与生态机制和观测更直接地联系在一起。此外,我们发现该模型表现出丰富的可分析模式,超过了Klausmeier型模型的模型。我们的研究重点是通过考虑1个空间维度的行进波来考虑与反应扩散模型相关的4维动力系统。我们使用几何奇异扰动理论的方法来建立存在多种杂斜/同质/周期性轨道的存在,它们在(通常是双曲线)慢歧管之间“跳跃”,代表各种局部植被模式。构成我们分析的起点的基本的1-前入侵模式和2五个点/间隙模式具有直接的生态解释,并且自然而然地出现在模型的模拟中。通过利用该模型的丰富非线性结构,我们从生态和数学的角度构建了许多新颖的多面模式。实际上,我们认为这些轨道/模式不是此处考虑的模型的特定特定的,但也将发生在更通用的(奇异的扰动反应扩散)设置中。最后,我们讨论了我们发现的生态和数学含义。

In this paper we consider the 2-component reaction-diffusion model that was recently obtained by a systematic reduction of the 3-component Gilad et al. model for dryland ecosystem dynamics. The nonlinear structure of this model is more involved than other more conceptual models, such as the extended Klausmeier model, and the analysis a priori is more complicated. However, the present model has a strong advantage over these more conceptual models in that it can be more directly linked to ecological mechanisms and observations. Moreover, we find that the model exhibits a richness of analytically tractable patterns that exceeds that of Klausmeier-type models. Our study focuses on the 4-dimensional dynamical system associated with the reaction-diffusion model by considering traveling waves in 1 spatial dimension. We use the methods of geometric singular perturbation theory to establish the existence of a multitude of heteroclinic/homoclinic/periodic orbits that `jump' between (normally hyperbolic) slow manifolds, representing various kinds of localized vegetation patterns. The basic 1-front invasion patterns and 2-front spot/gap patterns that form the starting point of our analysis have a direct ecological interpretation and appear naturally in simulations of the model. By exploiting the rich nonlinear structure of the model, we construct many multi-front patterns that are novel, both from the ecological and the mathematical point of view. In fact, we argue that these orbits/patterns are not specific for the model considered here, but will also occur in a much more general (singularly perturbed reaction-diffusion) setting. We conclude with a discussion of the ecological and mathematical implications of our findings.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源