The aquatic Coleoptera in a Mediterranean climate region were studied in order to assess the main factors affecting the assemblage structure. We tested the effects of different land use types (native forest, agriculture and urban) on environmental features and water beetles in Chilean streams. Eighteen stream sites were sampled in the austral summer of 2016. Physical variables including water temperature, dry width of channel, altitude, proportion of fine sediment, gravel/pebbles and boulders were significantly different among land uses. Eight Coleoptera taxa were collected across all sites; five were recorded in native forest and agriculture streams and three in urban streams. The riffle beetles Stethelmis chilensis, Austrelmis sp., Austrolimnius sp. and Tychepsephenus felix were found in native forest and in low density in agriculture streams. Hydraenidae appear to be the most tolerant taxon, dominant in agriculture and urban streams. Canonical analysis of principal coordinates based on environmental features and Coleoptera density data showed a clear separation of native forest streams from agriculture and urban area streams. Using distance-based linear models, cobble proportion was the most important variable structuring the water beetle assemblage. Our findings suggest that aquatic beetles are good ecological indicators of anthropogenic land use types in aquatic ecosystems in Mediterranean streams. This is the first study using aquatic coleopteran species for Chilean Mediterranean streams. Our study highlights the importance of the native forest for the conservation of stream insects.

为了评估影响组合结构的主要因素，对地中海气候区域的水生鞘翅目进行了研究。我们测试了不同土地利用类型（天然林，农业和城市）对智利河流环境特征和甲虫的影响。2016年南半球采样了18个溪流场。土地使用之间的物理变量（包括水温，河道干宽度，海拔，细沙的比例，砾石/卵石和巨石）存在显着差异。在所有地点收集了八种鞘翅目类群；在本地森林和农业流中记录了五种，在城市流中记录了三种。浅滩甲虫Stethelmis chilensis，Austrelmis sp。，Austrolimnius sp。和菲氏耳蜗在原生森林中发现，在农业溪流中密度低。鬣蜥科似乎是最能容忍的分类单元，在农业和城市河流中占主导地位。根据环境特征和鞘翅目密度数据对主坐标进行规范分析，结果表明原始森林流与农业和城市流之间存在明显的分离。使用基于距离的线性模型，卵石比例是构成水甲虫组合的最重要变量。我们的发现表明，水生甲虫是地中海河流水生生态系统中人为土地利用类型的良好生态指标。这是对智利地中海河流域使用水生鞘翅目物种的第一项研究。我们的研究强调了原生森林对于溪流昆虫保护的重要性。