北京密云水库底栖动物群落结构及其时空变化

为了研究南水北调中线调水工程运行对密云水库底栖动物群落结构及其生物多样性的影响,2014-2016年在密云水库设置了7个采样点每月采样1次(冰封期除外),进行底栖动物调查,分析了底栖动物群落结构、密度、生物量、优势种及其生物指数变化。结果显示,调查期间共检出底栖动物17种,其中摇蚊幼虫12种,环节动物5种。底栖动物平均密度为455.0个/m~2,平均生物量为2.70g/m~2,其中优势种为红裸须摇蚊(Propsilocerus akamusi)和克拉泊水丝蚓(Limnodrilus claparedianus)。底栖动物群落呈现出明显的时空变化,11月密度和生物量达最大值,分别为808.9个/m~2、6.94g/m~2;8月出现最小值,分别为180.4个/m~2、0.72g/m~2。水平分布上,水库中心底栖动物密度和生物量达最大值,分别为916.7个/m~2、6.08g/m~2;白河坝为最小值,分别为307.1个/m~2、0.70g/m~2。底栖动物Shannon-Wiener多样性指数、Pielou均匀度指数、Margalef丰富度指数均在4月达最大值,分别为1.43、1.13、1.14;9月出现最小值,分别为0.38、0.27、0.31;3项指数在潮河口达最大值,分别为1.08、0.64、1.01,在潮河坝、白河坝指数相对较低。同时分析了随着密云水库水深增加,底栖动物群落的结构变化。研究表明,受调水的影响,目前密云水库底栖动物群落结构不稳定,处于重构期。

Community Structure and Spatial-temporal Variation of Zoobenthos in Miyun Reservoir, Beijing

Miyun Reservoir is the only surface drinking water resource for Beijing City and its water quality has received much attention. The community structure and spatiotemporal variation of zoobenthos is important for a full understanding of the water quality status and trends in Miyun Reservoir. To study the influence of the South-to-North Water Transfer Project on the community structure of zoobenthos in Miyun Reservoir, a monthly investigation of zoobenthos was carried out at seven sampling sites from 2014 to 2016, except for ice cover period, focusing on species composition, density, biomass, dominant species and biodiversity. A total of 17 zoobenthos species were observed in Miyun Reservoir, including the larvae of 12 Chironomid species and 5 species of Annelida. Dominant species included Propsilocerus akamusi and Limnodrilus claparedianus, both indicators of eutrophic water. The average zoobenthos density and biomass were 455.0 ind/m2 and 2.70 g/m2 and there was distinct spatiotemporal variation. Temporally, zoobenthos density and biomass peaked in November (808.9 ind/m2 and 6.94g/m2), while minimum values (180.4ind./m2 and 0.72g/m2) occurred in August. Spatially, zoobenthos density and biomass were highest (916.7ind./m2, 6.08g/m2) at the reservoir center and lowest (307.1 ind/m2, 0.70g/m2) at the Baihe River Dam. Biodiversity was highest in April, with respective Shannon-Wiener diversity, Pielou evenness, Margalef richness index values of 1.43, 1.13, 1.14, and lowest in September, with respective values of 0.38, 0.27, 0.31. The highest biodiversity indices (1.08, 0.64, 1.01) were observed in Chaohe River cove and values were relatively low at Chaohe River Dam and Baihe River Dam. The results indicate that the zoobenthos community structure in Miyun Reservoir is depth dependent and that the community structure is unstable as zoobenthos continue responding to the South-to-North Water Transfer Project.