Disturbance events govern how the biodiversity of ecological communities varies in both space and time. In freshwater ecosystems, there is evidence that local and regional‐scale drivers interact to influence ecological responses to drying disturbances. However, most research provides temporal snapshots at the local scale, whereas few studies encompass a gradient of drying severity spanning multiple years. Using a dataset of rare spatiotemporal extent and detail, we demonstrate how independent and interacting local and regional‐scale factors drive shifts in the α and β diversities of communities in dynamic river ecosystems. We examined aquatic invertebrate assemblage responses to hydrological variability (as characterized by monthly observations of instream conditions) at 30 sites over a 12‐year period encompassing typical years and two severe drought disturbances. Sites varied in their disturbance regimes and hydrological connectivity at both local (i.e. site‐specific) and regional (i.e. river catchment) scales. Whereas α diversity was mainly influenced by local factors including flow permanence and the temporal extent of ponded and dry conditions, both temporal and spatial β diversities also responded to regional‐scale metrics such as the spatial extent of flow and hydrological connectivity. We observed stronger local negative responses for taxa with lower capacities to tolerate drying (i.e. resistance) and/or to recover after flow resumes (i.e. resilience), whereas taxa with functional traits promoting resilience made an increasing contribution to spatial β diversity as hydrological connectivity declined. As droughts increase in extent and severity across global regions, our findings highlight the functional basis of taxonomic responses to disturbance and connectivity, and thus advance understanding of how drying disturbances shape biodiversity in river networks. Our identification of the role of regional hydrological factors could inform catchment‐scale management strategies that support ecosystem resilience in a context of global change.

中文翻译：

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地方和区域驱动因素影响水生生物多样性，抵抗力和适应力如何因干旱而变化

干扰事件决定着生态社区的生物多样性在空间和时间上如何变化。在淡水生态系统中，有证据表明，地方和区域尺度的驱动因素相互作用，从而影响对干旱干扰的生态响应。但是，大多数研究提供了局部尺度的时间快照，而很少有研究涵盖多年跨度的干燥严重程度梯度。通过使用罕见的时空范围和细节数据集，我们证明了独立且相互作用的局部和区域尺度因素如何驱动动态河流生态系统中社区的α和β多样性的变化。我们在过去12年（包括典型年份和两次严重干旱）中，检查了30个地点的水生无脊椎动物组合对水文变异的响应（以每月观察到的入流条件为特征）。站点在地方（即特定于站点）和区域（即流域）规模上的干扰机制和水文连通性各不相同。尽管α多样性主要受局部因素的影响，包括水流的持久性以及池塘和干旱条件的时间范围，但时间和空间的β多样性也对区域尺度的指标（如水流的空间范围和水文连通性）做出了响应。我们观察到对分类单元的较强的局部负面反应，具有较低的耐受干燥（即抵抗力）和/或在流量恢复后恢复的能力（即复原力），随着水文连通性的下降，具有促进回弹力的功能性状的分类单元对空间β多样性的贡献越来越大。随着全球范围内干旱程度和严重性的增加，我们的发现强调了对扰动和连通性进行分类反应的功能基础，从而加深了对干旱扰动如何影响河流网络中生物多样性的理解。我们对区域水文因素的作用的识别可以为流域规模的管理策略提供参考，从而在全球变化的背景下支持生态系统的复原力。我们的发现强调了生物分类学对干扰和连通性反应的功能基础，从而进一步了解了干燥干扰如何影响河流网络中的生物多样性。我们对区域水文因素的作用的识别可以为流域规模的管理策略提供参考，从而在全球变化的背景下支持生态系统的复原力。我们的发现强调了生物分类学对干扰和连通性反应的功能基础，从而进一步了解了干燥干扰如何影响河流网络中的生物多样性。我们对区域水文因素的作用的识别可以为流域规模的管理策略提供参考，这些策略可以在全球变化的背景下支持生态系统的复原力。