Community characteristics of macrozoobenthos and its relationship to environmental factors in Lake Nansi

Abstract

为了解南四湖大型底栖动物群落结构特征及其与环境因子的关系,于2010年对南四湖15个采样点的底栖动物和生态环境进行4次调查研究.结果表明:共检出底栖动物23种,栖息密度和生物量为311.57 ind./m²和44.39 g/m²;群落物种优势度指数较高,优势种集中于羽摇蚊幼虫(Chironomus plumosus)和霍甫水丝蚓(Limnodrilus hoffmeisteri),分别占个体总数的77.45%和11.39%;水生植物生物量为1613 g/m²,盖度为33%,存在显著季节变化与空间差异,但底栖动物群落特征与之无显著相关性;南四湖水域主要污染物为氮,其次为磷,最后为高锰酸钾指数;2010年度除底栖动物物种数与水体COD_Mn含量呈显著负相关以及栖息密度与水体相关加权综合营养状态指数呈显著正相关外,其余底栖动物群落特征与水生植物、水质理化指标及营养状态间均未表现出显著相关性;依据底栖动物Goodnight-Whitley生物指数和水质相关加权综合营养状态指数评价结果,南四湖除局部区域受到严重的外源污染外,总体为清洁-中度营养类型.;To understand the community characteristics of macrozoobenthos and its relationship to environmental factors in Lake Nansi,the species composition,inhabit density,biomass,dominant species,the conditions of aquatic plants and water quality were investigated in June 2010.There were 23 species of macrozoobenthos with the inhabit density of 311.57 ind./m² and biomass of 44.39 g/m².The dominance index was relative high,and the dominant species consist of Chironomus plumosus and Limnodrilus hoffmeisteri which were accounted for 77.45% and 11.39% of the total individuals,respectively.The biomass and coverage of aquatic plants were 1613 g/m² and 33%,and there was no significant correlation between the biomass of aquatic plants and the community characteristics of macrozoobenthos.Lake Nansi was polluted majorly by nitrogen,next by phosphorus and finally by COD_Mn.The community characteristic of macrozoobenthos was not significantly correlated with the community characteristics of aquatic plant and with the water quality.The number of macrofaunal species was significantly negative correlated with the concentration of COD_Mn of water,and the inhabit density of macrozoobenthos was significantly positive correlated with the TLI(Σ) of water in 2010.According to evaluation of Goodnight-Whitley index and TLI(Σ),Lake Nansi has been in the state of clean and mesotropher, but serious pollution in some water areas.