On August 2017, a massive rock slope failure triggered an extreme sedimentation event in a regulated Alpine river. Consequently, high sediment load affected the river for about 1 month, with sediment concentration peaking up to several hundred g/L, and overall sediment yield of 0.4–0.8 Mm³. The availability of sound pre‐event data concerning benthic macroinvertebrate assemblages gave us the opportunity to assess the impact of this unusually severe sediment disturbance through before/after comparison. Within 1 month from the event, all the monitored communities displayed low density, richness and diversity, with minimum values never recorded before, particularly at the most upstream investigated reach, and where riverbed aggradation was comparatively larger. Persisting riverbed alteration was also identified as a major determinant justifying the slow recovery observed during the year after the event. Overall, the high resilience of some taxa, suited to a baseline unnatural condition, allowed the fast recolonization of the investigated river reaches. However, the recovery of other taxa, more sensitive to sediment pressure, was slow or did not occur during the monitored year.

中文翻译：

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受管制的高山河流域发生异常沉积事件后的第二年：对底栖大型无脊椎动物群落的影响

2017年8月，一场大规模的岩石边坡破坏引发了一条受监管的高山河流中的极端沉积事件。因此，高的泥沙负荷影响了河流约1个月，泥沙浓度最高达到数百克/升，泥沙总产量为0.4-0.8 Mm ³。有关底栖大型无脊椎动物组合的准确的事前数据，使我们有机会通过比较前后评估这种异常严重的沉积物扰动的影响。在事件发生后的1个月内，所有受监测的社区都表现出低密度，丰富性和多样性，从未有过记录的最小值，特别是在调查的最上游，河床积聚相对较大。持续的河床蚀变也被认为是证明事件发生后一年中缓慢恢复的主要决定因素。总体而言，某些分类单元的高回弹力（适合于基线非自然条件）可以使被调查河段快速重新定殖。但是，其他的恢复在受监测的年份中，对沉积物压力更敏感的分类单元缓慢或未发生。