渭河陕西段浮游动物群落结构时空特征及其驱动因子

Spatio-temporal characteristics and driving factors of zooplankton community structure in the Shaanxi section of Weihe River,China

渭河作为黄河的支流之一,在黄河流域生态保护与高质量发展中占有重要位置。随着气候变化和流域环境综合治理的加强,近年来渭河水生生物群落结构和水环境质量发生了明显变化。为了摸清浮游动物的时空分布特征及其关键驱动因子,更好地为渭河水资源管理及水生态保护提供理论基础,本研究于2017年枯水期(3、4、5月)和丰水期(8、9、10月)分别对渭河陕西段9个断面(27个采样点)的浮游动物及环境因子进行了调查。结果表明:共检出浮游动物41种,轮虫占主导(18种),丰水期浮游动物种类数(32种)多于枯水期(26种);浮游动物密度和生物量变化范围分别为1.7~499.5 ind·L^(-1)和0.0017~0.616 mg·L^(-1),枯水期大于丰水期,空间上整体呈现河段中下游大于河段上游;浮游动物优势种主要为节盖虫(Opercularia articulate)、球形砂壳虫(Difflugia globulosa)、壶状臂尾轮虫(Brachionus urceus)、角突臂尾轮虫(Brachionus angularis)和萼花臂尾轮虫(Brachionus calyciflorus);浮游动物Shannon指数为1.74~3.62,Pielou均匀度指数为0.47~0.98,Margalef指数为0.48~3.00,渭河陕西段水质呈现中污染状态;相关性分析表明,驱动渭河陕西段枯水期浮游动物群落的环境因子主要有海拔和总溶解性固体,而驱动丰水期浮游动物群落结构的环境因子主要是流速和溶解氧。

As one of the tributaries of the Yellow River,Weihe River occupies an important position in the ecological protection and high quality development of the Yellow River basin.With the intensification of climate change and comprehensive catchment environmental management,aquatic community and water environmental quality in Weihe River had substantially changed in recent years.To identify the spatio-temporal variations of zooplankton communities and the key driving factors,and to provide theoretical basis for water resources management and aqua-tic ecological protection,we conducted six times survey in dry season(March,April,and May) and wet season(August,September,and October) of 2017 in nine transects(27 sampling sites) of the Shaanxi section of Weihe River.A total of 41 zooplankton species were recorded,with rotifers as the dominant group(18 species).The zooplankton species richness was higher in wet season(32 species) than that in dry season(26 species).The zooplankton density and biomass was 1.7-499.5 ind·L^(-1) and 0.0017-0.616 mg·L^(-1),respectively.Zooplankton density and biomass were higher in dry season than in wet season,and both were generally increased from upstream to downstream.The dominant species were Opercularia articulate,Difflugia globulosa,Brachionus calyciflorus,Brachionus angularis,and Brachionus urceus.The Shannon diversity index,Pielou evenness index and Margalef richness index were 1.74-3.62,0.47-0.98,and 0.48-3.00,respectively.According to the diversity index of zooplankton,water quality in the Shaanxi section of Weihe River was at the medium pollution level.Results of canonical correspondence analysis showed that altitude and total dissolved solids were the main factors driving the zooplankton community structure in dry season,while the current velocity and dissolved oxygen were important in wet season in the Shaanxi section of Weihe River.