钱塘江桐庐渔业资源增殖放流区底栖动物群落结构特征分析

Analysis of community characteristics of macrozoobenthos in enhancement and releasing zone in Tonglu section of Qiantang River

2013年2月—2013年12月,对浙江钱塘江桐庐段渔业资源增殖放流区的底栖动物按季度进行了调查,共采集到底栖动物16种,主要由软体动物、环节动物及节肢动物3大类组成,软体动物种类数占优势。相对重要性指数(IRI)分析结果显示,河蚬(Corbicula fluminea)、湖沼股蛤(Limnoperna lacustris)和齿吻沙蚕(Nephthys sp.)为主要优势种。底栖动物可归纳为4个摄食功能群——滤食收集者、牧食收集者、刮食者和捕食者,其中,滤食收集者的密度和生物量占绝对优势。底栖动物的年均密度和生物量分别为(393.75±173.72)m^(-2)和(295.72±131.97)g·m^(-2)。方差分析显示,密度和生物量无显著性季节差异,但存在极显著的空间差异。底栖动物群落结构聚类分析表明,设置的6个断面4个季节均可分为A,B两个组群,A组群在春、夏、秋季均包含了断面Ⅰ、断面Ⅵ、断面Ⅴ和断面Ⅳ,B组群包含断面Ⅲ和断面Ⅱ,而冬季略有区别。

A seasonal investigation was conducted on the macrozoobenthos at 6 sections of enhancement and releasing zone in Tonglu section of Qiantang River from February to December in 2013. A total of 16 species were collected, which belonged to Mollusca,Annelida and Arthropoda,and Mollusca had the largest number of species. According to IRI value,Corbicula f lumin ea,Limnoperna lacustris and Nephthys sp. were the dominant species. All species were classified to 4 functional feeding groups： collector-filterer,collector-gatherer,scraper and predator,of which the collector-filterer was the predominant group. The mean annual density and biomass of the community were （ 393. 75 ± 173. 72） m^-2 and （295. 72 ± 131. 97） g.m^-2, respectively. There was no temporal significant difference in the mac-rozoobenthic density and biomass, but there was a significant variation in space. According to the community struc ture of macrozoobenthos, the sampling sections could be divided into 2 clusters, cluster A and B. In spring, summer and autumn, cluster A contained section Ⅰ , section , section V and section Ⅲ , while cluster B contained section n and section Ⅱ , which had a little difference in winter.