漓江大型底栖动物空间分布及水力驱动因子

大型底栖动物群落结构及其分布是评价河流生态健康的重要指标。基于典型水文年丰、枯两季调查,分析了漓江流域中、下游典型河段底栖动物群落结构空间分布格局、摄食类群及其与水力要素的响应关系。结果表明:①典型河段群落结构中腹足纲个体占优,优势物种为中华圆田螺和短沟蜷;丰水期底栖动物密度为829 ind/m²,枯水期为264 ind/m²;②摄食类群中刮食者占优势,且滤食者、收集者和捕食者枯水期的相对丰度高于丰水期,刮食者枯水期的相对丰度低于丰水期,摄食类群中游的相对丰度大于下游;③典型河段生物多样性呈现空间异质性,且中游明显低于下游;④流速、底部剪切力及底质粒径是影响漓江底栖生物枯水期分布的主要因素,水深和层流层厚度则是影响丰水期分布的主要因素,分选系数、层流层厚度是底栖生物多样性最主要的影响因素。研究成果可为变化水力条件下漓江水生态修复提供支持。

Spatial Distribution and Hydraulic Driving Factors of Macrobenthic Communities in Lijiang River

The structure and distribution of macrobenthos community are important indicators for evaluating the ecological health of rivers.Based on the surveys in wet and dry seasons of typical hydrological years,we analyzed the spatial distribution of benthic community structure,feeding groups and their responses to hydraulic factors in the middle and lower reaches of the Lijiang River Basin.The results demonstrate that:1) Gastropods are predominant in the community structure of a typical river section,and Cipangopaludina cathayensis and Semisulcospira sp.are dominant species;the density of benthic animals is 829 ind/m² in wet periods and 264 ind/m² in dry periods.2) Scrapers are dominant in the feeding groups,and their relative abundance in dry season is lower than that in wet season,while the relative abundances of collector-filterers,collector-gatherers,and predators in dry season are higher than those in wet season.The relative abundances of feeding groups in the middle reach are greater than those in the lower reach.3) The biodiversity of typical river sections is spatially heterogeneous,significantly lower in the middle reach than in the lower reach.4) Velocity,bottom shearing force and geological particle size are major factors affecting the distribution of benthic organisms in the Lijiang River during dry season;water depth and laminar layer thickness are major factors in wet season.The sorting coefficient and the thickness of laminar layer are the most important factors that affect the benthic biodiversity.