Study On The Community Structure Of Macrobenthic Animals And The Influence Of Water Environmental Factors In The Middle And Lower Reaches Of Hulan Rive

The Hulan River is one of the main tributaries of the Songhua River.With the aggravation of urbanization around the Hulan River,the discharge of sewage from enterprises has increased,and pesticide residues and feces from livestock breeding have been discharged into the Hulan River,resulting in water ecology in the lower reaches of the Hulan River.There are many problems with the system.As an important component of river systems,macrobenthos play an important role in the detection of water ecological health and water environment in the watershed.This paper selects 11 sections in the lower reaches of Hulan River,and conducts outdoor sampling and laboratory tests on macrobenthos and water quality factors in the lower reaches of Hulan River in October 2018 and October 2021.Through the investigation of macrobenthos community structure characteristics,the temporal and spatial variation characteristics of macrobenthos community structure characteristics were studied.The Shanno-Wiener index(H’),Margalef richness index(d M),Pielou evenness index(J),BI index,and physical and chemical indicators of water quality were used to evaluate the water quality of the lower Hulan River.Biological evaluation.Pearson correlation analysis and redundancy analysis were used to analyze the main environmental factors affecting macrobenthos in the lower Hulan River.Studying the response relationship between macrobenthos community structure and water environmental factors provides an important basis for water ecology,water environment protection and restoration in the lower reaches of the Hulan River.(1)During the study period,a total of 42 species of macrobenthos were collected,belonging to 14 orders and 29 families.Among them,the dominant aquatic insects accounted for 25 species,accounting for 59.52% of the total.The dominant species are the small stink bug,the genus Chironomidae,the genus Lithoptera,and the genus Platyphae.(2)The biological evaluation of water quality in the lower Hulan River through biodiversity index and water quality physicochemical index found that the overall water quality evaluation results in the lower Hulan River were slightly polluted,and the water quality was between Class II and Class III.(3)According to pearson correlation analysis and redundancy analysis(RDA),the main environmental factors affecting the macrobenthos community structure in Hulan River were studied.The results showed that the main environmental factors affecting the community structure of macrobenthos in the lower reaches of Hulan River were biochemical oxygen demand(BOD),total nitrogen(TN),total phosphorus(TP),potassium permanganate(CODMn),water temperature(WT),conductivity(Cond),dissolved oxygen(DO).