The response of species to perturbations strongly depends on spatial aspects in populations connected by dispersal. Asynchronous fluctuations in biomass among populations lower the risk of simultaneous local extinctions and thus reduce the regional extinction risk. However, dispersal is often seen as passive diffusion that balances species abundance between distant patches, whereas ecological constraints, such as predator avoidance or foraging for food, trigger the movement of individuals. Here, we propose a model in which dispersal rates depend on the abundance of the species interacting with the dispersing species (e.g., prey or predators) to determine how density-dependent dispersal shapes spatial synchrony in trophic metacommunities in response to stochastic perturbations. Thus, unlike those with passive dispersal, this model with density-dependent dispersal bypasses the classic vertical transmission of perturbations due to trophic interactions and deeply alters synchrony patterns. We show that the species with the highest coefficient of variation of biomass governs the dispersal rate of the dispersing species and determines the synchrony of its populations. In addition, we show that this mechanism can be modulated by the relative impact of each species on the growth rate of the dispersing species. Species affected by several constraints disperse to mitigate the strongest constraints (e.g., predation), which does not necessarily experience the highest variations due to perturbations. Our approach can disentangle the joint effects of several factors implied in dispersal and provides a more accurate description of dispersal and its consequences on metacommunity dynamics.

物种对扰动的反应在很大程度上取决于通过扩散连接的种群的空间方面。种群间生物量的异步波动降低了同时局部灭绝的风险，从而降低了区域灭绝风险。然而，散布通常被视为平衡远距离斑块之间物种丰富度的被动扩散，而生态约束，例如避免捕食者或觅食，会触发个体的移动。在这里，我们提出了一个模型，其中扩散率取决于与扩散物种相互作用的物种的丰度（例如，猎物或捕食者）以确定密度依赖的扩散如何在响应随机扰动的营养元群落中塑造空间同步。因此，与被动扩散的模型不同，这种具有密度依赖扩散的模型绕过了由于营养相互作用而引起的扰动的经典垂直传输，并深刻地改变了同步模式。我们表明，具有最高生物量变异系数的物种控制着分散物种的扩散速率，并决定了其种群的同步性。此外，我们表明这种机制可以通过每个物种对分散物种生长速率的相对影响来调节。受几个约束影响的物种分散以减轻最强的约束（例如，捕食），由于扰动，它不一定会经历最大的变化。我们的方法可以解开扩散中隐含的几个因素的联合效应，并提供对扩散及其对元社区动态的影响的更准确描述。