A survey on macrozoobenthos was conducted seasonally and 14 aquatic physicochemical parameters were monitored monthly to reveal the community characteristics of macrozoobenthos and their relationship with aquatic environmental factors at 20 sampling sites in the Lake Gehu from July 2013 to December 2014. A total of 25 macrozoobenthos species including 3 species (12% of total) of Mollusca, 12 species (48%) of Chironomidae, 4 species (16%) of Oligochaeta, 4 species (16%) of Crustacean were identified. The dominant species were Limnodrilus hoffmeisteri, Branchiuras owerbyi, Tanypus chinensis, and Propsilocerus taihuensis. Density and biomass of Chironomid larvae and Oligochata had significant spatial and seasonal changes. The state of aquatic environment was mainly affected by the nitrogen, phosphorus and water temperature in the Lake Gehu, and TN, NO3--N and DO changed significantly with space and season. The Spearman correlation analysis indicated that TN and NO3--N played a key role in the community structure characteristics of the macrozoobenthos in the Lake Gehu. The environmental variables could well explain the changes of main macrobenthic species.
为了解滆湖大型底栖动物群落结构特征及其与环境因子的关系,于2013—2014年对滆湖20个采样点的大型底栖动物按季节进行了8次调查,同时对14项水环境指标进行了逐月监测.结果表明: 共采集到大型底栖动物25种,其中软体动物3种,占12%,摇蚊幼虫12种,占48%,寡毛类4种,占16%,甲壳类4种,占16%.优势种为霍甫水丝蚓、苏氏尾鳃蚓、中国长足摇蚊和太湖裸须摇蚊.摇蚊幼虫和寡毛类存在显著的空间和季节变化.氮、磷营养元素和水温对滆湖水域环境状况有较大影响,且总氮(TN)、硝态氮(NO3--N)和溶解氧(DO)均表现出显著的空间和季节变化.相关性分析表明,TN和NO3--N是影响滆湖大型底栖动物群落结构的主要水环境因子,环境变量可以较好地解释主要类群的变化.
Keywords: Lake Gehu; PCA; biodiversity; macrozoobenthos; spatial distribution pattern.