白洋淀轮虫群落结构特征

Characteristics of rotifera community structure in the Baiyangdian Lake

选取白洋淀8个采样点于2005年9月—2006年12月对轮虫群落进行定性定量分析,共检出轮虫110种,采蒲台种类数最多,其次是枣林庄,南刘庄最少;从季节来看,春、秋轮虫种类数量最多,夏季其次,冬季最少;根据优势种比较,臂尾轮虫科、迈氏三肢轮虫、针簇多肢轮虫、龟甲轮虫属等甲型-中污性和乙型-中污性水体种类分布在污染较严重的南刘庄,而单趾轮属、腔轮属、鬼轮属等清洁种类则分布在采蒲台、枣林庄、烧车淀等淀区。除端村外,各采样点轮虫密度和生物量于2006年4月出现最大值。根据Q(B/T)指数评价白洋淀各采样点水质,南刘庄属富营养,圈头属寡营养,其它样点属中营养水质。白洋淀轮虫的Shannon-Wiener指数以及均匀度指数则在夏秋季较高,春季较低,而物种多样性指数并不能完全反映白洋淀各采样点的水质。

The Baiyangdian lake is the biggest shallow freshwater lake in north China,which provides important ecosystem services.In recent years,due to reduced precipitation and sewage discharge from upstreams,the Baiyangdian ecosystem is experiencing a rapid decline and degradation,resulting in the lower species diversity,and ecosystem services are being lost.It is urgent task to protect the biological resources currently.In order to understand status of biological resources of the Baiyangdian lake,the community structures of rotifera and environmental characteristics at 8 stations of the Baiyangdian lake were investigated from september,2005 to December,2006.The results showed that sampling stations were subject to different degrees of pollution according to water quality index（PI and Pb/n）.Three stations（Nanliuzhuang station,Wangjiazhuai station and Guangdian station） were in a very seriously polluted state,one station（Shaochedian station） was serious polluted,three stations（Quantou staion,Duancun station and Zaolinzhuang station） were moderately polluted,and only one station（Caiputai station） was lightly polluted.110 species of rotifera belonging to 38 genera,12 families and 2 orders were identified,in which there was the most species at Caiputai station acounting for 73.9% of total species,and then Zaolinzhuang station,Shaochedian station,Duancun station,Quantou station,and the least at Nanliuzhuang station acounting for 35.2% of total species.Comared to survey data in 1990,total species number was 13 less than that and 47 species were identified only in this survey.Rotifera displayed higher species number in Spring and Autumn than in Summer and Winter.The dominant species showed temporal and spatial changes.Filinia maior,Polyarthra trigla and the species of Brachionidae and Keratella that indicated α and β type of medium pollution distributed at Nanliuzhuang station,but the species of Monostyla,Lecana and Trichotria living in clean water distributed at Caiputai station,Zaolinzhuang station and Shaochedian station,which indicated the water quality in different stations.Except Duancun station,cell density and biomass of rotifera at other stations displayed the peak in April or May,another smaller peak appeared in September or October.According to Q（B/T） which are ratio of species number of Brachionus and Trichocerca,Nanliuzhuang station was eutrophic,Quantou station was Oligotrophic and the others were medium trophic.The Shannon-Weaver index and evenness index were higher in summer and autumn and lower in spring and winter.As the Baiyangdian lake was subject to frequent human activities in recent years,such as tourism,aquaculture,dredging and water diversion projects,the ecosystem was difficult to reach a steady state,the rotifer community structure was also constantly changing.Biodiversity index changed singnificantly in same station in different spampling time,which resuted in not indicating the water quality in the Baiyangdian lake completely.In conclusion,most of the water bodies of the Baiyangdian lake were in moderate pollution and severe pollution,rotifera community structure existed larger temporal and spatial heterogeneity.