Community Structure of Macrozoobenthos in Lake Nanhu, Wuhan, China

Abstract

2003年7月至2004年4月,每季度对武汉市南湖大型底栖动物进行定量和定性的采样分析,共发现大型底栖动物30种;优势种为霍甫水丝蚓和刺铗长足摇蚊,均呈聚集分布;大型底栖动物的年均密度和生物量分别为4437 ind/m²和 17.79 g/m²,其密度和生物量春季最高,Shannon-Wiener多样性指数和 Margalef多样性指数的年均值分别为1.515和 1.123.比较分析了南湖大型底栖动物组成的历史变化,对水环境进行了生物学评价,并提出了南湖大型底栖动物合理利用的建议.;Lake Nanhu (30°30'N, 114°21'E) situated in Wuhan City, Hubei Province of China, is an eutrophic shallow lake a-long the middle reaches of Yangtze River, with a main surface area 400 hm² of aquaculture. In order to provide academic data for reasonable utilization of aquatic resource and ecological strategy to protect aquatic environment, macrozoobenthos were collected at 10 sampling stations seasonally and some random sampling stations frequently in Lake Nanhu, during the period of investigation from July 2003 to April 2004. A total of 30 species were identified, including 10 species of oligochaeta, 4 mollusca, 14 aquatic in-secta, 1 hirudinea and 1 decapoda. Only oligochaeta and aquatic insecta were found at 10 sampling stations. The dominant species were Limnodrilus hoffmeisteri and Tanypus punctipennis, and I_δ-index indicated their distribution were aggregated. llie density and biomass of macrozoobenthos in the lake were 4437 ind/m² and 17.79 g/m², respectively. The seasonal change of density was in spring > summer > autumn > winter; and biomass ranked as in spring > winter > summer > autumn. The animal average value of Shannon-Wiener diversity index and the Margalef diversity index were 1.515 and 1.123, respectively. Macrozoobenthos was mainly composed of several polluted species, and many macrozoobenthos have disappeared within recent years based on comparing to the former study in take Nanhu. The fishery potential production of macrzoobenthos was 1.504×10⁴kg. However, the omnivorous fishes annual stocking was 1.60×10⁴kg since 2000, which was unreasonable and should be decreased to 5.0×10³ kg. Lake Nanhu was eulrophicated according to macrozoobenthos communities structure and the content of N, P in water. The water quality was evaluated by the diversities of macrozoobenthos communities structure.