Department of Physics and Astronomy "Galileo Galilei," University of Padova, Padova 35131, Italy.
Department of Fundamental Microbiology, University of Lausanne, Lausanne 1015, Switzerland.
Proc Natl Acad Sci U S A. 2024 Oct 29;121(44):e2410932121. doi: 10.1073/pnas.2410932121. Epub 2024 Oct 22.
Metapopulation models have been instrumental in quantifying the ecological impact of landscape structure on the survival of a focal species. However, extensions to multiple species with arbitrary dispersal networks often rely on phenomenological assumptions that inevitably limit their scope. Here, we propose a multilayer network model of competitive dispersing metacommunities to investigate how spatially structured environments impact species coexistence and ecosystem stability. We introduce the concept of landscape-mediated fitness, quantifying how fit a species is in a given environment in terms of colonization and extinction. We show that, when all environments are equivalent, one species excludes all the others-except the marginal case where species fitnesses are in exact trade-off. However, we prove that stable coexistence becomes possible in sufficiently heterogeneous environments by introducing spatial disorder in the model and solving it exactly in the mean-field limit. Crucially, coexistence is supported by the spontaneous localization of species through the emergence of ecological niches. We show that our results remain qualitatively valid in arbitrary dispersal networks, where topological features can improve species coexistence by buffering competition. Finally, we employ our model to study how correlated heterogeneity promotes spatial ecological patterns in realistic terrestrial and riverine landscapes. Our work provides a framework to understand how landscape structure enables coexistence in metacommunities by acting as the substrate for ecological interactions.
复群模型在量化景观结构对焦点物种生存的生态影响方面发挥了重要作用。然而，对于具有任意扩散网络的多种物种的扩展通常依赖于不可避免地限制其范围的现象学假设。在这里，我们提出了一个竞争扩散元社区的多层网络模型，以研究空间结构环境如何影响物种共存和生态系统稳定性。我们引入了景观介导适合度的概念，根据物种在给定环境中的定居和灭绝能力来量化一个物种的适应度。我们表明，当所有环境都相同时，一个物种会排斥所有其他物种——除了物种适合度恰好相互抵消的边缘情况。然而，我们通过在模型中引入空间无序并在平均场极限下精确求解，证明了在足够异质的环境中稳定共存成为可能。至关重要的是，共存通过生态位的自发定位得到支持，从而出现物种的本地化。我们表明，我们的结果在任意扩散网络中仍然具有定性有效性，其中拓扑特征可以通过缓冲竞争来提高物种共存性。最后，我们利用我们的模型来研究相关异质性如何在现实的陆地和河流景观中促进空间生态模式。我们的工作提供了一个框架，通过作为生态相互作用的基质来理解景观结构如何使元社区中的共存成为可能。
