Centre for Hydrological and Ecosystem Science, Department of Geography and Environment, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom.
Centre for Ecology & Hydrology, Crowmarsh Gifford, Wallingford OX10 8BB, United Kingdom.
Sci Total Environ. 2019 Feb 10;650(Pt 2):2648-2656. doi: 10.1016/j.scitotenv.2018.09.264. Epub 2018 Sep 27.
River impoundment by the construction of dams potentially modifies a wide range of abiotic and biotic factors in lotic ecosystems and is considered one of the most significant anthropogenic impacts on rivers globally. The past two decades have witnessed a growing body of research centred on quantifying the effects of river impoundment, with a focus on mitigating and managing the effects of individual large dams. This study presents a novel multi-scale comparison of paired downstream and control sites associated with multiple water supply reservoirs (n = 80) using a spatially extensive multi-year dataset. Macroinvertebrate community structure and indices were analysed in direct association with spatial (e.g. region) and temporal variables (e.g. season) to identify consistent patterns in ecological responses to impoundment. Macroinvertebrate communities at monitoring sites downstream of water supply reservoirs differed significantly from those at control sites at larger spatial scales, both in terms of community structure and taxa richness. The effect was most significant at the regional scale, while biogeographical factors appeared to be important drivers of community differences at the national scale. Water supply reservoirs dampened natural seasonal patterns in community structure at sites downstream of impoundments. Generally, taxonomic richness was higher and %EPT richness lower at downstream sites. Biomonitoring indices used for river management purposes were able to detect community differences, demonstrating their sensitivity to river regulation activities. The results presented improve our understanding of the spatially extensive and long-term effects of water supply reservoirs on instream communities and provide a basis for the future implementation of mitigation measures on impounded rivers and heavily modified waterbodies.
筑坝蓄水可能会改变河流生态系统中的多种非生物和生物因素，被认为是全球范围内对河流影响最大的人为因素之一。在过去的二十年中，越来越多的研究集中在量化河流蓄水的影响，重点是减轻和管理单个大型水坝的影响。本研究使用空间广泛的多年数据集，对与多个供水水库相关的下游和对照点进行了新颖的多尺度比较（n=80）。直接将大型底栖无脊椎动物群落结构和指数与空间（例如地区）和时间变量（例如季节）相关联，以确定对蓄水的生态响应的一致模式。供水水库下游监测点的大型底栖无脊椎动物群落与对照点的群落结构和分类丰富度在较大的空间尺度上存在显著差异。这种影响在区域尺度上最为显著，而生物地理因素似乎是国家尺度上群落差异的重要驱动因素。供水水库减弱了蓄水下游站点自然的季节性群落结构模式。通常，下游站点的分类丰富度较高，而 EPT 丰富度较低。用于河流管理目的的生物监测指数能够检测到群落差异，证明它们对河流调节活动的敏感性。所提出的结果提高了我们对供水水库对河流内群落的空间广泛和长期影响的理解，并为未来对蓄水河流和受严重改造的水体实施缓解措施提供了基础。
