Variation of the rotifer community structure and its responses to environmental factors in Lake Liuye and its adjacent waters in Changde City, Lake Dongting Basin

Abstract

城市河-湖连通使不同水文特征的水体连通构成多样化水环境，环境异质性为提高浮游动物多样性提供了多样性生境条件.为了解湖南常德柳叶湖及其邻近水体轮虫群落结构变化对不同水体连通性和异质性的响应，于2018年对柳叶湖、穿紫河和沅江常德市区河段共15个站点进行了每季度1次的轮虫群落结构和环境特征调查分析.调查期间，不同水体的营养水平呈现：穿紫河 > 柳叶湖 > 沅江，穿紫河和柳叶湖呈富营养化状态，沅江呈中营养状态.本研究共检出轮虫88种（包括亚种8种和变种1种），其中，长肢多肢轮虫（Polyarthra dolichoptera）为水系第一优势种.轮虫最高丰度为2535 ind./L，全年平均丰度空间分布呈现：柳叶湖 > 穿紫河 > 沅江；季节分布呈现：6月 > 9月 > 3月 > 12月.轮虫群落对水体连通性的响应表现为：柳叶湖、穿紫河和沅江3个水体轮虫种类组成具有一定的相似性且第一优势种相同.对异质性的响应表现为：不同水体轮虫群落年平均丰度和多样性指数存在空间差异.典范对应分析表明水温是影响轮虫群落结构变化的主要环境因子.;Urban river-lake connections in different hydrological characteristics waters result in a diverse aquatic environment, which provides heterogeneous habitat conditions and contributes to increase zooplankton diversity. To understand the effects of connectivity and heterogeneity on the rotifer community structure of Lake Liuye and its adjacent waters in Changde city of Hunan, we conducted the survey quarterly on the rotifer community structure and environmental characteristics at 15 sampling sites in Lake Liuye, Chuanzi River and the Changde section of the Yuan River in 2018. During our investigation, the trophic status in different waters decreased in the order: Chuanzi River > Lake Liuye > Yuan River. The Chuanzi River and Lake Liuye were eutrophic, and the Yuan River was mesotrophic. A total of 88 rotifer species (including 8 subspecies and 1 varietas) were recorded. Polyarthra dolichoptera was the dominant species in this system. The highest abundance of rotifers reached 2535 ind./L, and the spatial distribution of annual average abundance decreased in the order: Lake Liuye > Chuanzi River > Yuan River. The temporal distribution of abundance decreased in the order: June > September > March > December. The composition of rotifer species was similar among the three waters with the same first dominant species, while the annual average abundance and diversity indices varied according to spatial heterogeneity. Canonical correspondence analysis indicated that water temperature was the key factor to the variation of rotifer community structure.