南四湖大型底栖动物群落结构及水质生物学评价

Community structure of macrozoobenthos and bioassessment of water quality in Lake Nansi

2010年4—12月对南四湖大型底栖动物群落进行了季度调查,分析了底栖动物群落的时空动态,并进行了水质评价。调查期间共采集到底栖动物36种,其中寡毛类5种,软体动物10种,水生昆虫15种,其他动物6种。底栖动物的优势种为霍甫水丝蚓(Limnodrilus hoffmeisteri)、梨形环棱螺(Bellamya purificata)、长角涵螺(Alocinma longicornis)和红裸须摇蚊(Propsilocerusi akamusi),四者密度之和占总密度的88.1%。大型底栖动物的密度和生物量分别为1119 ind·m-2和83.23 g·m-2。底栖动物的种类数、优势种和现存量均呈现出明显的季节变化,空间分布差异亦较大。采用Shannon多样性指数、Margalef多样性指数和Hilsenhoff生物指数对南四湖的水质进行了综合评价,结果表明,南四湖总体上处于中污染状态,从季节上来看,春季和冬季的水质略好于夏季和秋季;从各湖区来看,南阳湖和昭阳湖处于重污染状态,独山湖处于中-重污染状态,微山湖处于中污染状态。

A seasonal investigation of macrozoobenthos in Lake Nansi was carried out during April to December, 2010. Altogether 36 benthic taxa, including 5 annelids, 10 molluscs, 15 arthropods, and 6 other animals, were identified. Among them, Limnodrilus hoffmeisteri, Bellamya purificata, Alocinma longicornis and Propsilocerusi akamusi were dominant, accounting for 88.1% of the total number. Density and biomass of macrozoobenthos were 1119 ind·m-2 and 83.23 g·m-2, respectively. Species richness, dominant species and standing crops varied significantly in different seasons, and also in different areas. Water quality was assessed using Shannon index, Margalef index and Hilsenhoff biotic index. It was shown that Lake Nansi was moderately polluted in general during the sampling period; water quality in spring and winter was slightly better than that in summer and autumn. In terms of the four lake regions, Lake Nanyang and Lake Zhaoyang were heavily polluted, Lake Dushan was moderately to heavily polluted, and Lake Weishan was moderately polluted.