ISEM, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France.
Sorbonne Université, CNRS, UPEC, IRD, INRA, Institut d'écologie et des sciences de l'environnement, iEES, Paris, France.
Ecology. 2024 Aug;105(8):e4369. doi: 10.1002/ecy.4369. Epub 2024 Jul 2.
Within communities, species are wrapped in a set of feedbacks with each other and with their environment. When such feedbacks are strong enough they can generate alternative stable states. So far, research on alternative stable states has mostly focused on systems with a small number of species and a limited diversity of interaction types. Here, we analyze a spatial model of plant community dynamics in stressed ecosystems such as drylands, where each species is characterized by a strategy, and the different species interact through facilitation and competition for space and resources, such as water. We identify three different types of multistability emerging from the interplay of competition and facilitation. Under low-stress levels, plant communities organize in small groups of coexisting species, maintained by space, competition and facilitation ("cliques"). Under higher stress levels, positive feedback from facilitation lead to the dominance of a single facilitating species ("mutual exclusion states"). At the highest stress levels, the single facilitating species left in the system coexists with the desert state. By linking community ecology and alternative stable states theory using a spatial plant community model for stressed ecosystems, our study contributes to highlight the importance of positive feedback loops for the stability of ecological communities.
在社区中，物种之间以及它们与环境之间存在着一系列的反馈。当这些反馈足够强大时，它们可以产生替代稳定状态。到目前为止，关于替代稳定状态的研究主要集中在物种数量较少和相互作用类型有限的系统上。在这里，我们分析了一个空间模型，该模型描述了干旱等压力生态系统中的植物群落动态，其中每个物种都有一个策略，不同的物种通过促进和竞争空间和资源（如水分）相互作用。我们从竞争和促进的相互作用中确定了三种不同类型的多稳定性。在低压力水平下，植物群落通过空间、竞争和促进（“小团体”）来维持共存的小物种群。在更高的压力水平下，促进的正反馈导致单一促进物种的优势（“相互排斥状态”）。在最高的压力水平下，系统中留下的单一促进物种与沙漠状态共存。通过使用压力生态系统的空间植物群落模型将群落生态学和替代稳定状态理论联系起来，我们的研究有助于强调正反馈循环对生态群落稳定性的重要性。
