滆湖入湖河流春季大型底栖动物群落结构及水质生物学评价

Community structure of benthic macro-invertebrates and biological assessment of water quality in the inflowing rivers of Lake Gehu in spring

分别于2018年4月和2019年4月对滆湖入湖河流底栖动物开展调查,并利用生物指数对水质进行生物学评价。结果表明:共鉴定滆湖入湖河流底栖动物28种,以重度耐污种霍甫水丝蚓(优势度为0.46)和中等耐污种铜锈环棱螺(优势度为0.11)占据绝对优势。生物多样性方面以鹤溪河最高,湟里河、扁担河次之,夏溪河及入湖河口最低,水生植物分布是影响各区域底栖动物多样性的重要因素。卡尔森营养状态指数(TSI)与水质污染等级生物评价结果基本一致,以新孟河延伸拓浚工程沿线为界,鹤溪河、夏溪河、湟里河中上游河段处于中度富营养化水平,水体为轻-中污染状态,而下游河段、扁担河及入湖河口处于重度富营养化水平,水体为中-重污染状态。

In this study,we investigated the community structure of benthic macro-invertebrates in the inflowing rivers of Lake Gehu in April of both 2018 and 2019,and evaluated water quality using biological indices.Twenty-eight species of benthic macro-invertebrates were identified in the inflowing rivers of Lake Gehu.Limnodrilus hoffmeisteri(dominance index:0.46)with high pollution resistance and Bellamya aeruginosa(dominance index:0.11)with moderate pollution resistance were the dominant species.In terms of biodiversity,Hexi River was the highest,followed by Huangli and Biandan rivers;Xiaxi River and the estuary into the lake were the lowest.The distribution of aquatic plants might be one of the most important factors determining the diversity of benthic macro-invertebrates in different regions.The Carlson nutrition status index was consistent with the biological indices in water quality assessment.With the extension of Xinmeng River and dredging project,the middle and upper reaches of Hexi,Xiaxi,and Huangli rivers were at a moderate eutrophication level,with water body being lightly to moderately polluted;whereas the lower reaches of Biandan River and estuaries into the lake were at a severe eutrophication level,with water body being moderately to heavily polluted.