神农架大九湖后生浮游动物群落结构和水质评价

Metazooplankton Community Structure and Saprobity Evaluation in Dajiuhu Wetland of Shennongjia Alpine

大九湖是南水北调中线工程的重要水源涵养地之一。为了解实施生态修复工程后浮游动物群落结构特征及水质污染情况,于2014年11月(枯水期)、2015年5月(平水期)和9月(丰水期)进行了3次采样调查。研究表明:共检出后生浮游动物36种,其中桡足类2种、枝角类5种和轮虫29种,轮虫丰度在3次采样中均占总丰度的80%以上,仅有的几种枝角类和桡足类也是小型种类或以幼体为主。11月优势种是寡污-β中污型—螺形龟甲轮虫(Keratella cochlearis)和晶囊轮虫(Asplachna sp.);5月优势种为寡污-β中污和β中污型—螺形龟甲轮虫、迈氏三肢轮虫(Filinia maior)、无棘螺形龟甲轮虫(Keratella cochlearis tecta)、广生多肢轮虫(Polyarthra vulgaris)和萼花臂尾轮虫(Brachionus calyciflorus);9月优势种是β-中污型—裂足臂尾轮虫(Brachionus diversicornis)、迈氏三肢轮虫和剪形臂尾轮虫(Brachionus forficula)。冗余分析(RDA)表明高锰酸盐指数(CODMn)是影响后生浮游动物污染类型分布的最关键环境因子。

Dajiuhu wetland is a rare subtropical alpine in the central China. The Dajiuhu wetland is the source of the Du river,a first-grade tributary of the Han River,and the wetland also serves as one of the important water conservation area of the middle routes of South-to-North Water Diversion Project. The human activities such as ditches digging,holes dredging and bog draining have led to severe degradation of ecological function and the shrinking of lake surface area in Dajiuhu wetland since 1986. After the implementation of ‘the Dajiuhu wetland protection and ecological restoration project ＇ from 2005 until present,we conducted a field survey on the metazooplankton community and lake saprobity status from November 2014 to September 2015 to reveal the status quo post the restoration project. A total of 36 metazooplankton species were observed,including 29 rotifer species,2 copepod species and 5 cladoceran species. Keratella cochlearis and Asplachna sp. were the common dominant species in November 2014, and Keratella cochlearis, Filinia maior, Keratella cochlearis tecta,Polyarthra vulgaris,and Brachionus calyciflorus in May 2015; Brachionus diversicornis, Filinia maior,and Brachionus forficula in September 2015. The dominant species were o-βmesosaprobity in November 2014,o-βand β-mesosaprobity in May 2015,and β-mesosaprobity in September 2015. Redundancy analyses indicated that CODMnwere the key drivers behind this difference of metazooplankton saprobity distribution.