嬉子湖国家级水产种质资源保护区冬季浮游动物群落特征及影响因子

The characteristics of zooplankton community and impact factors in national aquatic germplasm reserve of Xizi Lake in winter

摘要:

2014年冬季在嬉子湖国家级水产种质资源保护区进行现场调查,通过对物种组成、优势种结构、密度和生物量、群落多样性等指标进行统计分析,对保护区浮游动物群落特征进行了研究,并针对优势物种与主要水环境因子间的关系进行了RDA分析。在保护区所处的嬉子湖设置6个调查断面,共18个采样点。结果显示,在保护区共采集到浮游动物4门36属64种,原生动物、轮虫类、桡足类和枝角类物种数占浮游动物物种总数的比例分别为51.56%、29.69%、10.94%和7.81%。优势种类群为2门5属7种,其中原生动物4种,轮虫类3种。保护区浮游动物密度变幅为1 755.25～7 023.38 ind/L,平均为3 483.44 ind/L;生物量变幅为0.36～5.34 mg/L,平均为1.67 mg/L;群落丰富度指数(R)变幅为1.02～1.96,平均为1.37;香农指数(H')变幅为2.02～3.47,平均为2.72;均匀度指数(E)变幅为0.59～0.85,平均为0.72。在被摄食压力下降及饵料生物资源下降的共同影响下,冬季保护区外界环境对个体较小的原生动物和轮虫有利,群落生态优势度也集中于上述浮游动物类群。受到水文特征的影响,南部湖区的浮游动物物种数、密度和生物量以及多样性指数总体高于中部和北部湖区。

Abstract:

In order to explore the community structure of zooplankton in Xizi Lake and its relationship with environmental factors, the species structure,dominant groups and distribution of zooplankton in Xizi Lake were investigated in December 2014 while RDA analysis was conducted to grope for the nexus between dominant species and main water environmental factors. Totally 6 investigation sections which contained 18 sampling points were set in the national aquatic germplasm reserve of Xizi Lake. The results indicated that 33 species of protozoa(51.56%), 19 species of rotifer(29.69%), 7 species of copepoda(10.94%)and 5 species of cladocera(7.81%) were comprised. The dominant species of both core area and experimentation area were protozoa and rotifers. The range of zooplankton density was 1 755.25-7 023.38 ind/L and the average was 3 483.44 ind/L. The range of zooplankton biomass was 0.36-5.34 mg/L and the average was 1.67 mg/L. Community richness index(R) ranged from 1.02-1.96 while the average was 1.37; Shannon index(H') ranged from 2.02-3.47 and the average was 2.72; Evenness index(E) ranged from 0.59-0.85 and the average was 0.72. Under the common influence of both the degressive pressure of predators and the decrease of food resources, small individuals like protozoa and rotifers could benefit from the external winter circumstances of the reserve, and as a result, ecological dominance of zooplankton community were inclined to aforementioned groups. Besides, impacted by hydrological characteristics, the number and biomass of zooplankton species and diversity index of the southern part excelled those of the northern and central parts as a whole.