黑河流域底栖动物群落结构及水质评价

为了解黑河流域上中游底栖动物群落结构特征及其与环境因子之间的关系，于2018年8月对研究区域17个采样点的底栖动物和水体理化指标进行调查研究.共鉴定出底栖动物43种，其中节肢动物34种（79.1%），软体动物7种（16.3%），环节动物2种（4.6%）；就整个研究区域而言，优势种为大蚊（Tipulidae）、豆娘幼虫（Damselfly）、水蜘蛛（Argyroneta）、耳萝卜螺（Radix auricularia）、琥珀螺（Suecinea sp.）、白旋螺（Gyraulusalbus），干、支流优势种分布趋势为干流（6种）优于支流（5种）；底栖动物平均密度和平均生物量分别为77ind/m²和3.7423g/m²现存量存在显著空间差异，整体上干流（1032ind/m²、60.0963g/m²）大于支流（276ind/m²、3.5233g/m²），物种数干流（36种）大于支流（15种）；单因素方差分析显示，Shannon-Wiener多样性指数、Margalef丰富度指数及Pielou均匀度指数分布特征为干流大于支流.黑河流域上游支流和中游干流不同河段底栖动物物种组成呈空间异质性，而多样性指数对物种组成依赖性强，但因黑河流域底栖动物物种组成受自然因素和人类活动双重影响程度差异较大，使得Shannon-Wiener多样性指数、Margalef丰富度指数及Pielou均匀度指数不适合黑河水质评价.依据BI指数和综合污染指数评价表明，黑河上游支流水质优于中游干流.根据底栖动物与环境因子之间的相关矩阵分析并结合RDA分析表明：BOD₅、水温（WT）、电导率（EC）、DO、溶解性总固体（TDS）、COD_Mn及盐度是影响底栖动物群落结构的主要环境因子.

Macrobenthos community structure and water quality evaluation of Heihe River Basin

To understand the community characteristics of macrozoobenthos and its relationship to environmental factors in the upper and middle reaches of the Heihe River basin, the species composition, inhabit density, biomass, dominant species and the aquatic physiochemical parameters were investigated in August 2018. A total of 43macrozoobenthos species including 34 species of arthropods (79.1%), 7 species of mollusks (16.3%) and 2 species of annelids (4.6%) were identified. The dominant species were Tipulidae, Damselfly, Argyroneta, Radixauricularia, Suecinea sp., Gyraulusalbus in the whole study area. All the 6 dominant species were distributed in main stream and 5 out of the 6 dominant species were found in the tributaries and the average density and biomass of macrozoobenthos were 77ind/m² and 3.7423g/m², respectively. An obvious spatial heterogeneity in existing stock was demonstrated in the mainstream and the tributaries, with the values the density and biomass to be 1032ind/m² and 60.0963g/m² in the main stream, and 276 ind/m² and 3.5233g/m² in the tributaries, respectively. The number of species in the main stream (36species) was larger than the tributaries (15species). The results of one-way ANOVA showed that the values including Shannon-Wiener diversity index, Margalef richness index and Pielou evenness index indicating the distribution characteristics in the mainstream were larger than those in the tributaries. The species composition of macrozoobenthos in upstream tributaries and middle mainstream reaches shows a feature of spatial heterogeneity, and the species composition was greatly dependent on the diversity index. However, since the species composition of macrozoobenthos was affected greatly by both natural factors and human activities in the Heihe River basin, the Shannon Wiener diversity index, Margalef richness index and Pielou evenness index were proven not suitable for the water quality evaluation of the Heihe River. The water quality was observed better in upstream and tributaries sampling sites than in the middle stream and stream sites based on the evaluation results of integrated biological index and comprehensive pollution index. According to the correlation matrix analysis between macrozoobenthos and environmental factors and RDA analysis, BOD₅, WT, EC, DO, TDS, COD_Mn, salinity were the main environmental factors affecting the community structure of macrozoobenthos.