浙江分水江水库大型底栖动物群落结构及水质评价

2008年11月-2009年10月,在浙江桐庐分水江水库设置7个站点对大型底栖动物进行逐月调查.结果表明:调查共采集到37种底栖动物,主要由寡毛纲和摇蚊科物种组成.春、夏、秋季优势种均为霍甫水丝蚓,冬季优势种为羽摇蚊.直接收集者在物种数量、密度和生物量上均占绝对优势.群落年均密度和年均生物量分别为(488.0±48.8) ind·m-2和(1.86±0.49) g·m-2.底栖动物密度在站点间无明显差异但存在显著的季节变化,呈现春季＞夏季＞冬季＞秋季的趋势,生物量在站点、季节间均无显著差异.水温和水深是影响底栖动物时空分布的主要因子.Shannon多样性指数和Goodnight-Whitley指数不适合用于该水库的水质评价,其他指数综合显示分水江水库属于轻度污染.

Macrozoobenthos community structure and its indicative significance in water quality bioassessment of Fenshuijiang Reservoir, Zhejiang Province of East China

A monthly investigation was conducted on the macrozoobenthos at 7 stations of Fenshuijiang Reservoir in Zhejiang Province of East China from November 2008 to October 2009. A total of 37 taxa were collected, most of which belonged to Oligocheata and Chironomidae. Limnodrilus hoffmeisteri was dominant in spring, summer and autumn, and Chironomus gr. plumosus was prevailing in winter. The collector-gatherer was the predominant group in species number, density and biomass. The mean annual density and biomass of the community were (488.0 +/- 48.8) ind X m(-2) and (1.86 +/- 0.49) g X m(-2), respectively. There were no significant differences in the macrozoobenthic density among the stations and in the macrozoobenthic biomass among the stations and among the seasons, but the macrozoobenthic density had a significant seasonal variation, with the sequence of spring > summer > winter > autumn. Water temperature and water depth were the main factors affecting the spatial distribution of the macrozoobenthos. Shannon index and Goodnight-Whitley index were not suitable for the assessment, whereas the Wright index, Carlander index, Pielou index and trophic level index showed that this reservoir was slightly polluted.