[Characteristics of Macrobenthos Community Structure and Their Relationships with Environmental Factors in Rivers of Beijing in Spring].

Macrobenthos from 20 sites of 17 rivers in Beijing were investigated in the spring of 2019, and the relationship between community structure characteristics and environmental factors was analyzed. A total of 64 classification units (species) of macrobenthos from 3 phyla, 6 classes, and 32 families were identified. We found that there were large spatial differences between the density composition and dominant species of macrobenthos. Mountainous river area had the highest density of aquatic insects (33.95 ind.·m-2), and the main dominant species were Simuliidae sp., Hydropsyche sp., and Paraciadius alpicola. In suburban areas, Chironomidae and Oligochaeta showed the largest average density, which was 82.58 ind.·m-2 and 36.21 ind.·m-2, respectively, and Polypedilum nubeculosum and Chironomus pallidivittatus were the dominant species in this area. Furthermore, macrobenthos in urban rivers were mainly Gastropods (88.75 ind.·m-2), and the dominant species were Bellamya aeruginosa and Bellamya purificata. Fourteen more species were found in the urban and suburban river areas than in mountain areas. According to the results of the canonical correspondence analysis, there were many factors affecting the community structure of macrobenthos, including water temperature, TN, Chl-a, pH, and human activity. Nutrient concentration was the main factor affecting the community structure of macrobenthos in the suburban river area, while human activities and water temperature were the major determinants of the macrobenthos community structure in mountainous and urban rivers.