玛瑙河干流大型底栖动物群落结构特征分析及水生态评价

为探究玛瑙河干流大型底栖动物群落结构及其影响因素，于2021年1月(枯水期)和2021年7月(丰水期)分别对其进行水质监测和大型底栖动物样品采集，调查并记录生境状况和环境特征，采用FBI (family biotic index, 科级生物指数)评价法和冗余分析法(RDA)探究不同水情期水环境状况及大型底栖动物群落结构的主要影响因子. 结果表明:①玛瑙河干流大型底栖动物群落结构时空差异显著，丰、枯水期共采集到大型底栖动物691个，隶属于2门4纲10目26科28种，优势物种共18种，个体数量、丰富度及优势物种数均呈现丰水期>枯水期，其中枯水期以双壳纲种类最多，丰水期以昆虫纲种类最多；②玛瑙河干流枯水期FBI评价结果以一般和轻度污染为主，丰水期以很清洁和极清洁为主，上游和中游河段水体污染较为严重，水质状况总体较2020年有所提升；③影响枯水期大型底栖动物群落结构的主要环境因子为水温、流速和PO₄3?浓度，丰水期为COD_Mn. 研究显示，玛瑙河干流大型底栖动物群落结构及其主要环境影响因子在不同水情期存在显著差异，丰水期水质状况良好，枯水期部分河段水体存在污染，需引起重视. 

Community Structure and Aquatic Ecological Evaluation of Macrobenthos in Manao River

In order to explore the macrobenthic community structure and its influencing factors in the main stream of the Manao River, water quality monitoring and macrobenthic sample collection were carried out in January 2021 (low-water period) and August 2021 (high-water period), and habitat conditions and environmental characteristics were investigated and recorded. The FBI and RDA were used to explore the main influencing factors of water environment and macrobenthic community structure in each period. The results show that: (1) There were significant spatial and temporal differences of the macrobenthic community structure in the main stream of the Manao River. A total of 691 macrobenthos were collected in high and low water periods, belonging to 2 phyla, 4 classes, 10 orders, 26 families, 28 species, and a total of 18 dominant species. The number of individuals, abundance, and the number of dominant species all showed a high-water period > low-water period, among which the species of Bivalvia were the most abundant in low-water period, and the species of Insecta were the most abundant in high-water period. (2) The water quality of the main stream of the Manao River in low-water period is mainly moderate and mild pollution, while the high-water period the water was mainly very clean and extremely clean. Water pollution was mainly concentrated in the upper and middle reaches of the river, and the water quality was improved compared with the previous year. (3) Water temperature (WT), flow rate (Vel) and phosphate (PO₄3?) were the main environmental factors affecting the community structure of macrobenthos in low-water periods, and COD_Mn in high-water periods. The results showed that there were significant differences in the community structure of macrobenthos and its main environmental factors in the main stream of The Manao River in different water cycles. The water quality was good in wet season, but there were pollution in some reaches of the river in dry season, which should be paid more attention to.