中文摘要：

2015年对常熟市昆承湖的大型底栖动物进行了时空分布调查,开展了水质生物学评价与环境影响因子分析,并基于底栖动物分布特征对昆承湖2006—2012年环境修复工程效果进行初步评估。结果表明：4次调查共采集底栖动物12科22种,优势物种多为耐污型;底栖动物年均密度为38.3 ind/m~2,各季节密度分布存在差异,但均以摇蚊幼虫类密度占优,其次为寡毛类和软体动物,底栖动物年均生物量为24.54 g/m~2,主要为软体动物所贡献;底栖动物Shannon-Wiener多样性指数值（H＇）、Margalef多样性指数值（D）、Pielou均匀度指数值（J）和BI指数值表明,昆承湖总体处于中度污染状态;不同湖区因污染程度等环境因素不同,底栖动物物种、密度与生物量分布存在差异,典范对应分析表明水体DO、浊度、TN、TP等水质因子以及底泥TN、总有机物等是影响底栖动物分布的主要环境因子;昆承湖实施封闭湖泊口门、深度清淤等环境修复措施后,水质总体得到改善,但湖泊水深增大、基底形态单一以及水生植物分布少等因素也影响了湖泊底栖动物密度与种群分布。

英文摘要：

Spatial and temporal investigations on benthic macroinverbratesare carried out in Kuncheng Lake in 2015, the water quality of the lake, environmental factors, and effects of restorations in 2006 -2012, areexplored based on the structure of the macroinverte- brate community. Altogether 22 taxa areidentified from 6 sampling sites, and the dominant species aremostly high tolerance. The annu- al density of the benthic macroinvertebratesaverages 38.3 ind/m2, although with differences in different seasons, the chironomidsare- dominant, followed by oligchaetes and mollusks. The annual biomass average 24.54 g/m2, and molluscs have the most contribution. The values of Shannon - Wiener diversity index, Margalef species richness index, Pielou index, and Biotic index suggested that the Kuncheng Lake isof moderately polluted state, and species, density as well as biomass of benthic macroinvertebratesaredifferent in dif- ferent sites, due to differences of pollution levels and other interference factors. DO, turbidity, TN and TP in water, as well as TN, to- tal organic matter in sediment, are the key predictors of the community variance, by the method of Canonical Correspondence Analysis （ CCA）, which isapplied to explore the importance of environlnental variables in influencing maeroinvertebrate community structure. Af- ter the implementation of ecological restoration project in Kuncheng Lake, water quality of the lake is ilnproved, but water depth increa- ses, basal morphologysimplied, and submerged plant area decreased due to dredging, greatly affected the density and population distri- bution of benthic maeroinvertebrate.