赣江干流底栖动物群落结构与环境因素的关系

Characteristics of benthos community structure and its relationship with environmental factors within the mainstream of Ganjiang River

底栖动物是河流水生态系统的重要组成部分,对水环境的变化极其敏感。为分析赣江干流底栖动物群落结构特征及其与环境因素的关系,本研究于2018年8月、2019年1月及4月在赣江干流布设12个采样点进行底栖动物调查。赣江干流共检出底栖动物3门6纲24种属,上游的优势种分别为苏氏尾鳃蚓和铜锈环棱螺,中游的优势种为铜锈环棱螺和河蚬,下游的优势种为大沼螺和圆顶珠蚌。经统计得出底栖动物丰度为49ind./m^(2),而生物量达46.82 g/m^(2)。不同水情期物种数变化趋势为:1月枯水期(18种)大于4月丰水期(12种),枯水期的生物多样性指数要高于丰水期。典型对应分析法分析表明,枯水期影响赣江干流底栖动物群落分布的主要环境因素为总氮、电导率和溶解氧;而丰水期却为透明度、溶解氧、电导率等。研究结果可为赣江流域生态系统的保护和修复提供数据参考和技术支撑。

Benthos are an important part of the river water ecosystem and are extremely sensitive to chang⁃es in the water environment.In order to analyze the characteristics of the benthic community structure in the main stream of the Ganjiang River and its relationship with environmental factors,this study was con⁃ducted in August 2018,January and April 2019,and 12 sampling points were set up in the main stream of the Ganjiang River for benthic animal surveys.A total of 24 species of benthic animals in 3 phyla and 6 classes were detected in the main stream of the Ganjiang River.The dominant species of benthos in the upper reaches were urobranchis Soxhlet and Cyclobalanopsis aeruginosa,while in the middle reaches were Cyclobalanopsis aeruginosa and Corbicula fluminea,and in the lower reaches were macrobalanopsis macro⁃cephala and pearl oyster.The benthic abundance is 49ind./m^(2),and the biomass up to 46.82g/m^(2).The change trend of the number of species in different water regimes is:the dry season in January(18 spe⁃cies)is greater than the wet season in April(12 species),and the biodiversity index in the dry season is higher than in the wet season.CCA analysis shows that the main environmental factors affecting the distribu⁃tion of benthic communities in the mainstream of the Ganjiang River during the dry season are total nitro⁃gen,electrical conductivity,and dissolved oxygen,while in the wet season;they are transparency,dis⁃solved oxygen,and electrical conductivity.The results can provide data reference and technical support for the protection and restoration of ecosystem in the Ganjiang River basin.