拉萨河中下游底栖动物群落结构特征分析

2013年10月,在拉萨河热震藏布-河口中下游河段及支流共设置16个采样断面(拉萨河干流10个、支流4个,雅鲁藏布江汇口2个),对底栖动物进行了调查。样品分析结果表明:拉萨河评价河段干、支流底栖动物共31种,其中环节动物5种,占16.13%;软体动物3种,占9.68%;节肢动物23种,占74.19%。优势种有正颤蚓(Lumbricus tubifex)、四节蜉(Baetidae sp)、多足摇蚊(Polypedilum sp)、隐摇蚊(Cryptochironomus sp)、网石蝇(Perlodidae sp)、钩虾(Gammaridae sp)等。直孔电站影响河段底栖动物现存量较高,密度、生物量平均分别为31 911个/m2、117.65 g/m2。剔除直孔电站影响河段,拉萨河干流底栖动物密度、生物量分别为32个/m2、0.92 g/m2,支流密度、生物量分别为63个/m2、0.78 g/m2。底栖动物Shannon-Wiener指数为0~2.02。直孔电站运行对拉萨河中、下游河段底栖动物整体影响较小;对库区河段底栖动物群落结构影响较大,群落结构由流水型向耐氧、静水型的环节动物、摇蚊转化。

Zoobenthos Community Structure in the Middle and Lower Reaches of Lhasa River

Abstract: Investigation on the macrozoobenthos was made for a period of one month from Pangduo to the estuary in the middle and lower reaches of Lhasa River and its tributaries in October 2013. Sample analysis results showed that there were 31 species of macrozoobenthos, including 5 species of annelids, accounting for 16.13%; 3 species of mollusks, accounting for 9.68%; and 23 species of arthropods representing 74.19%. The dominant species were Lumbricus Tubifex, Baetidae sp., Polypedilum sp., Cryptochironomus sp., Perlodidae sp. and Gammaridae sp.. The key factor effecting community structure of macrozoobenthos was organic pollution. Community structure of macrozoobenthos was comverted from eotic species to oxytolerant and lentic, and the amount of species, density, biomass of species were increased after the operation of Zhikong Hydropower Station. Keywords: Lhasa River; macrozoobenthos; community structure; Zhikong Hydropower Station