Abstract Mediterranean rivers are affected by natural disturbances and human pressures, which may alter their hydrology, water quality and habitat structure. In this study an analysis of macroinvertebrates community structure has been used to determine how distinct human pressures, such as point and non-point sources of pollution, together with groundwater withdrawal, may affect these ecosystems. A total of 4 sampling campaigns were conducted in the middle reach of the Onyar River (NE Spain), which was affected by agricultural and urban uses. Stream discharge and physicochemical parameters were measured in situ, and water samples and macroinvertebrates assemblages were taken and properly preserved for subsequent analysis and identification. Variation partitioning showed that macroinvertebrate community structure was particularly dependent on hydrochemical characteristics, but also on hydrological variations. In addition, results indicated that groundwater withdrawal altered stream hydrology, and the main reach of the Onyar River became intermittent and even completely dry in downstream positions. This reduction on stream discharge caused changes in habitat characteristics, as well as in the proportion of wastewater. Some wastewater dilution occurred, linked to groundwater with high nitrate concentrations inputs to the stream, and even though the macroinvertebrate community recovered its quality in some sampling campaigns, it presented a different structure than in sampling points not affected by any of these pressures. Therefore, the approach here used to analyze the hydrological effects on macroinvertebrate communities allowed us to determine their influence on hydrochemical and habitat characteristics.

中文翻译：

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大型无脊椎动物群落对地中海河流水文和水化学变化的响应

摘要 地中海河流受自然干扰和人类压力的影响，可能会改变其水文、水质和栖息地结构。在这项研究中，对大型无脊椎动物群落结构的分析已被用于确定不同的人类压力，例如点和非点污染源，以及地下水抽取，如何影响这些生态系统。在受到农业和城市用途影响的 Onyar 河中游（西班牙东北部）共进行了 4 次采样活动。原位测量河流流量和理化参数，采集水样和大型无脊椎动物组合并妥善保存以备后续分析和鉴定。变异划分表明大型无脊椎动物群落结构特别依赖于水化学特征，但也依赖于水文变化。此外，结果表明地下水抽取改变了河流水文，Onyar 河的主要河段在下游位置变得断断续续甚至完全干涸。河流排放的减少导致栖息地特征以及废水比例的变化。发生了一些废水稀释，与输入到河流中的高硝酸盐浓度的地下水有关，即使大型无脊椎动物群落在一些采样活动中恢复了其质量，但它呈现出与不受任何这些压力影响的采样点不同的结构。所以，