Freshwater ecosystems contribute disproportionately to global biodiversity, but organisms in these ecosystems are declining at faster rates than those in terrestrial or marine environments. Among other stressors, both direct human activities and climate change are leading to increased irregularity of water flow in rivers and streams (flow intermittence), which has been shown to negatively impact biodiversity at local and regional scales.

Andros Gianuca, of the University of Rio Grande do Norte, Brazil, and INRAE, France, and colleagues analysed data from the French nationwide monitoring network to understand the impact of flow intermittence on stream macroinvertebrate biodiversity–stability relationships at different scales. They show that different processes stabilize metacommunities of perennial rivers compared with intermittent rivers, with local processes driving stability for the former and spatial asynchrony strongly driving stability for the latter. This highlights the need to consider not just local processes but also spatial dynamics when both monitoring and conserving freshwater species, particularly in the context of ongoing global change and increasing flow intermittence.

淡水生态系统对全球生物多样性的贡献不成比例，但这些生态系统中的生物体衰退速度比陆地或海洋环境中的生物体要快。在其他压力因素中，直接的人类活动和气候变化都导致河流和溪流的水流不规则性增加（水流间歇性），这已被证明会对当地和区域范围内的生物多样性产生负面影响。

巴西北里奥格兰德大学和法国 IRAE 的 Andros Gianuca 及其同事分析了法国全国监测网络的数据，以了解水流间歇性对不同规模的河流大型无脊椎动物生物多样性与稳定性关系的影响。他们表明，与间歇性河流相比，不同的过程可以稳定常年河流的元群落，局部过程推动前者的稳定性，而空间异步则强烈推动后者的稳定性。这凸显了在监测和保护淡水物种时不仅需要考虑局部过程，还需要考虑空间动态，特别是在持续的全球变化和不断增加的水流间歇性的背景下。