杭州西溪湿地首期保护工程后浮游生物的生态响应

Ecological Responses of Plankon Community after the First Engineering Project in Hangzhou's Xixi Wetland

2007年3月至2008年5月,调查了西溪湿地（Ⅰ~Ⅳ站）浮游植物和轮虫群落的属（种）类组成、密度（生物量）和生物多样性指数,并将水质理化参数与生物群落指标进行相关性分析.4个采样站共发现8门56个属藻类,年平均密度为1.110×108cell/L,优势属为小球藻属（Chlorella）和隐藻属（Cryptomonas）.记录轮虫30种,平均生物量1.202 mg/L,优势属为针簇多肢轮虫（Polyarthra）和晶囊轮虫（As-planchna）.湿地藻类密度对数与水体中的CODMn指数和电导率之间均有极显著的正相关性（p〈0.01）.湿地疏通工程后间隔一年,春季水质的CODMn指数和电导率显著下降,水体中藻类密度和轮虫生物量显著减少.并且影响藻类多样性指数的水体电导率因子不复存在,影响轮虫多样性指数的主要环境因子也由水体电导率取代了高锰酸盐指数.藻类密度较低的Ⅱ站和Ⅲ站,能保持浮游生物内部群落的相对稳定.

Effects of environment and dredging on phytoplankon and rotifera community were investigated from March,2007 to May,2008 in Xixi Wetland（from Ⅰ station to Ⅳ station）,Hangzhou.Research includded genus（species） richness,density（biomass） and biodiversities,and regression analysis between community index of plankon and water quality parameters.56 genus of algae were found,and the annual mean density was 1.110×108cell/L,Chlorella and Cryptomonas dominanted the algae community.30 species of rotifera were recorded,and the annual average biomass was 1.202 mg/L,with Polyarthra and Asplanchna dominating the rotifera community.There were significant positive relationships at 0.01 level between Log no.of algae and CODMn content,conductivity of the water,respectively.After a year＇s interval,CODMn content and conductivity of the water were much lower in Xixi Wetland in Spring,2008 than that of in Spring,2007,and so on as algae density and rotifera biomass.Moreover,the important factor of water conductivity which affected biodiversity of algae and biomass of rotifera disappeared,and CODMn content which mainly affected biodiversity of rotifera was also replaced by conductivity.The low density of algae in station Ⅱ and station Ⅲ could keep stable plankon community.