中文摘要：

应用典范对应分析（CCA）对横石水河流域14个样点中的大型底栖动物与环境因子的关系进行了研究。结果表明,枯水期和丰水期的物种与环境因子的相关性均在90%以上,说明大型底栖动物在横石水河的分布很大程度上受到环境因子的影响。化学需氧量（COD）和pH值是影响枯水期大型底栖动物分布的两个主要因子,浊度和重金属Cu、Pb浓度对大型底栖动物分布也有一定程度的影响。在丰水期,重金属Cu、Pb浓度和pH值是影响大型底栖动物分布的关键因子。从种类水平看,耐污种类如蠓类、摇蚊和大蚊的丰富度与COD和重金属浓度的环境轴呈正相关,而敏感种类如腹足纲、毛翅目以及蜉蝣目昆虫与COD和重金属浓度的环境轴呈负相关。

英文摘要：

The relationship between macroinvertebrates and environmental factors at 14 sites on the Hengshishui River was studied by Canonical Correspondence Analysis（CCA）.The species-environment correlations in the dry season and wet season were both higher than 90%,which indicated the distribution of macroinvertebrates in Hengshishui River was strongly affected by environmental factors measured.Chemical oxygen demand（COD） and pH were the two major factors affecting macroinvertebrate distribution in the dry season.Turbidity and heavy metal concentrations（such as copper and lead） were also influential on macroinvertebrate distribution to some extent.In the wet season,copperand lead concentrations,and pH were the most important factors influencing macroinvertebrate distribution.At the species level,the abundance of pollution tolerant species such as Ceratopogonidae,Chironmidae and Tipulidae were positively correlated with the environmental axes of COD and heavy metal concentration,but the sensitive species such as Gastropoda,Trichoptera and Ephemereoptera were negatively correlated with COD and heavy metal concentrations.