Beavers can profoundly alter riparian environments, most conspicuously by creating dams and wetlands. Eurasian beaver (Castor fiber) populations are increasing and it has been suggested they could play a role in the provision of multiple ecosystem services, including natural flood management. Research at different scales, in contrasting ecosystems is required to establish to what extent beavers can impact on flood regimes. Therefore, this study determines whether flow regimes and flow responses to storm events were altered following the building of beaver dams and whether a flow attenuation effect could be significantly attributed to beaver activity. Four sites were monitored where beavers have been reintroduced in England. Continuous monitoring of hydrology, before and after beaver impacts, was undertaken on streams where beavers built sequences of dams. Stream orders ranged from 2nd to 4th, in both agricultural and forest‐dominated catchments. Analysis of >1000 storm events, across four sites showed an overall trend of reduced total stormflow, increased peak rainfall to peak flow lag times and reduced peak flows, all suggesting flow attenuation, following beaver impacts. Additionally, reduced high flow to low flow ratios indicated that flow regimes were overall becoming less “flashy” following beaver reintroduction. Statistical analysis, showed the effect of beaver to be statistically significant in reducing peak flows with estimated overall reductions in peak flows from −0.359 to −0.065 m³ s⁻¹ across sites. Analysis showed spatial and temporal variability in the hydrological response to beaver between sites, depending on the level of impact and seasonality. Critically, the effect of beavers in reducing peak flows persists for the largest storms monitored, showing that even in wet conditions, beaver dams can attenuate average flood flows by up to ca. 60%. This research indicates that beavers could play a role in delivering natural flood management.

中文翻译：

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海狸水坝减弱流量：一项多点研究

海狸可以通过创建水坝和湿地来深刻改变河岸环境。欧亚海狸（蓖麻纤维）人口在增加，有人建议他们可以在提供多种生态系统服务（包括自然洪水管理）中发挥作用。与生态系统形成对比的是，需要进行不同规模的研究，以确定海狸在多大程度上可以影响洪水状况。因此，这项研究确定了在建造海狸大坝之后，水流状态和对风暴事件的水流响应是否发生了变化，以及水流衰减效应是否可以明显归因于海狸的活动。监测了四个在英国重新引入海狸的地点。在海狸撞击大坝之前和之后，对河水进行了连续的水文监测。在农业和以森林为主的流域，河流定单的范围从第二到第四。分析> 在四个站点上发生的1000次暴风雨事件显示出总体趋势：总暴雨流量减少，峰值降雨增加到峰值流量滞后时间以及峰值流量减少，所有这些都表明在海狸撞击之后流量衰减。此外，从高流量到低流量的比率降低表明，在重新引入海狸之后，流态总体上变得“浮华”。统计分析表明，海狸的作用在减少峰值流量方面具有统计学上的显着性，估计峰值流量总体上从-0.359减少到-0.065 m 从高流量到低流量的比率降低表明，在重新引入海狸之后，流态总体上变得“浮华”。统计分析表明，海狸的作用在减少峰值流量方面具有统计学上的显着性，估计峰值流量总体上从-0.359减少到-0.065 m 从高流量到低流量的比率降低表明，在重新引入海狸之后，流态总体上变得“浮华”。统计分析表明，海狸的作用在减少峰值流量方面具有统计学上的显着性，估计峰值流量总体上从-0.359减少到-0.065 m跨站点³ s ^-1。分析表明，站点之间对海狸的水文响应的时空变化取决于影响程度和季节性。至关重要的是，对于所监测的最大暴风雨，海狸降低峰值流量的作用仍然存在，这表明即使在潮湿条件下，海狸大坝也可以使平均洪水流量最多衰减约20％。60％。这项研究表明，海狸可以在自然洪水管理中发挥作用。