白洋淀河湖系统轮虫群落结构时空动态及与环境因子的关系

Temporal and Spatial Dynamics of the Rotifer Community and Relationship to Environmental Factors in Baiyangdian Lake and Primary Tributaries

为了探究白洋淀河湖系统中轮虫群落结构时空动态及其与水环境因子的关系,2019年春季(4月)、夏季(6月)和秋季(9月),分别对白洋淀淀区及府河、孝义河和白沟引河3条入淀河流的轮虫群落及水环境因子开展采样调查。结果显示,调查期间共检出轮虫30种,隶属于7科、15属,年均丰度为(1.43±1.15)×10^3个/L,年均生物量为(0.67±0.71) mg/L。Jaccard群落相似性系数和NMDS综合分析表明,白洋淀河湖系统轮虫群落组成在季节和区域尺度上相似性均较低,针簇多肢轮虫(Polyarthra trigla)、螺形龟甲轮虫无脊变种(Keratella cochlearis tecta)和异尾轮虫(Trichicerca sp.)是淀区和入淀河流的共同优势种,3条入淀河流的优势种丰度占比均显著高于淀区。除孝义河外,淀区、府河和白沟引河轮虫群落的Shannon-Wiener和Margalef指数均存在显著的季节性差异,且均在夏季最高。生物多样性指数和轮虫营养状态指数(TSIROT)表明,白洋淀河湖系统为中-富营养类型,处于中-重度污染状态;RDA分析表明,营养物质总氮(TN)和总磷(TP)、透明度(SD)、溶解氧(DO)是影响白洋淀河湖系统轮虫群落结构的重要环境因子。

Baiyangdian Lake is the largest shallow macrophytic lake on the North China Plain. Since the 1980 s, the ecosystem of the Baiyangdian Lake basin has been declining because of the influence of human activities and eutrophication is increasing. In this study, we analyzed the spatiotemporal characteristics, dominant species dynamics and biological indicators of the rotifer community in Baiyangdian Lake and its three main tributaries(Fuhe, Xiaoyi and Baigouyin Rivers), and explored the relationships among rotifers and environmental factors. The objective was to study ecosystem dynamics in the Baiyangdian River basin to support restoration of the aquatic environment of Xiong′an New District. Rotifers were sampled and environmental factors were monitored in the spring, summer and autumn in 2019. A total of 30 rotifer species were collected during the three seasons, belonging to 15 genera and 7 families. The abundance and biomass of rotifer community were(1.43±1.15) ×10^3 ind./L and(0.67±0.71) mg/L. The Jaccard similarity index of rotifers and non-metric multidimensional scaling(NMDS) analysis showed that the composition of the rotifer community displayed low spatial and seasonal similarity in the study area. Polyarthra trigla, Keratella cochlearis tecta and Trichicerca sp. were the dominant species both in the Baiyangdian Lake and the three tributaries. Further, the relative abundance of dominant species in the tributaries was higher than in Baiyangdian Lake. The Shannon-Wiener index and Margalef index showed seasonal variation in all tributaries and the lake, with the highest values all in summer, except for Xiaoyi River. The diversity indices and trophic state index(TSIROT) both indicated medium-heavy pollution and medium-eutrophic status at all sites. Redundancy analysis showed that nutrients(total nitrogen and total phosphorus), transparency and dissolved oxygen were the most four important environmental variables for explaining rotifer community dynamics in Baiyangdian Lake and primary tributaries.