长江中下游干流大型底栖动物的分布模式

DISTRIBUTION PATTERNS OF MACROZOOBENTHOS IN THE MID-LOWER MAINSTEM OF THE YANGTZE RIVER

  • 摘要: 为研究长江中下游干流大型底栖动物的基本群落现状及其沿中下游的变化趋势, 于2019—2020年对长江中下游干流开展了3次野外调查。共记录大型底栖动物129属种, 总密度和总生物量(无灰干重)平均值分别为174 ind./m2和0.645 g/m2。自中游到下游干流, 大型底栖动物总种类数呈下降趋势; 水生昆虫密度下降, 其他类群密度上升; 直接收集者和刮食者密度呈下降趋势, 捕食者和撕食者密度上升。相关分析显示水深和平均流速是影响大型底栖动物分布的重要因素。总结了不同类群的分布模式: 寡毛类与摇蚊类均喜深水缓流, 两者适宜水深流速范围差异不大; 腹足类喜水浅缓流, 适宜水深与流速范围均较窄, 而双壳类则相反。其他水生昆虫类、多毛类和钩虾类适宜水深范围较宽, 流速范围相对较窄。研究结果可为今后开展长江中下游干流大型底栖动物环境水流需求研究和水库生态调度等保护与管理工作提供基础资料。

     

    Abstract: To understand the status quo and variation trend of macrozoobenthos along the mid-lower mainstem of the Yangtze River, three field surveys were carried out from 2019 to 2020. A total of 129 taxa of macrozoobenthos were recorded. The mean density and biomass of macrozoobenthos were 174 ind./m2 and 0.645 g/m2 (dry weight, similarly below), respectively. From the middle to the lower reaches, the total taxa number of macrozoobenthos decreased; the density of aquatic insects decreased, while the density of other taxa increased; the density of collector-gatherers and scrapers decreased, while predators and shredders increased. Correlation analysis showed that water depth and mean velocity were two parameters significantly affecting the distribution of macrozoobenthos. The distribution patterns of different groups were various. Oligochaetes and chironomids prefer slow flow and deep water, and there is little difference in the optimum range of water depth and mean velocity between them. Gastropods prefer shallow and slow flow, and both the optimum range of water depth and mean velocity are narrow, while bivalves are opposite. Other aquatic insects, polychaetes and gammarids are suitable for a wide range of water depth and a relatively narrow range of mean velocity. The results provide basic information for the research of environmental flow requirement of macrozoobenthos, reservoir ecological regulation and other protection and management work in the mid-lower mainstem of the Yangtze River.

     

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