雅鲁藏布江流域原生动物群落结构及其与环境因子的关系

Community Structure of Protozoan and Its Relation to Environmental Factors in the Yarlung Zangbo River Basin

数量庞大、体积微小且高度多样化的原生动物是水生态系统中的初级生产者和初级消费者,对淡水生态系统功能具有重要影响。为探究雅鲁藏布江及其主要支流原生动物群落特征及其与环境因子之间的关系,分别于2013年6月20日—8月8日(丰水期),2013年10月27日—11月14日(平水期),2014年4月20日—4月30日(枯水期)在雅鲁藏布江干流及其一级支流选取了26个采样点对原生动物群落结构及其环境因子进行调查。结果表明:鉴定出原生动物2门4纲12目24科30属,其中肉足虫12属、纤毛虫18属;食菌和碎屑者(B类)16属,食藻者(A类)15属,无选择的杂食者(N类)2属,捕食者(R类)5属。原生动物密度均值为984.67 ind./L,变化范围为93.33~4153.33 ind./L。Shannon-Wiener多样性指数(H’)、Pielou均匀度指数(J’)平均值分别为4.49和0.86,多样性和均匀度状况较好,群落结构稳定性较强。主成分分析(PCA)和冗余分析(RDA)表明雅鲁藏布江流域的原生动物的种类数和丰富度存在明显的空间差异,影响其群落结构的主要环境因子有硅酸根离子、硝酸根离子、钠离子、海拔和总磷。

The massive,small and highly diversified protozoa are primary producers and primary consumers in the aquatic ecosystem,and have an important impact on the functions of the freshwater ecosystem.To explore the community characteristics of protozoa in the Yarlung Zangbo River Basin and their relationships with environmental factors,26 sample sites were set up in the Yarlung Zangbo River Basin.Protozoan community and environmental survey were conducted from June 20 to August 8(high water period)in 2013,October 27 to November 14(normal water period)in 2013,April 20 to April 30(dry water period)in 2014,respectively.The results showed that the protozoa were identified as 2 phyla,4 classes,12 orders,24 families and 30 genera,including 12 genera of sarcopds,18 genera of ciliates;16 species of fungi and detritus(class B),15 species of algae eaters(class A),2 species of indiscriminate omnivores(class N),and 5 species of predators(class R).The average density of protozoa was 984.67 ind./L,and the range was 93.33-4153.33 ind./L.The average values of Shannon-Wiener diversity index(H’)and Pielou evenness index(J’)were 4.49 and 0.86,respectively.The status of diversity and uniformity was good,and the stability of community structure was strong.Principal component analysis(PCA)and redundancy analysis(RDA)show that there were obvious spatial differences in the number and abundance of protozoa in the Yarlung Zangbo River Basin.The main environmental factors affecting the community structure are silicate ion,nitrate ion,sodium ion,altitude and total phosphorus.