春季北京市河流大型底栖动物群落结构特征及影响因子分析

2019年春季(3～5月)在北京市开展了17个水体20个断面的大型底栖动物调查,分析其群落结构特征与环境因子的关系.共采集并鉴定出大型底栖动物64个分类单元(种),分属3门6纲32科.结果发现,北京不同区域河流大型底栖动物的密度组成、优势种和物种数存在较大的空间差异,山区是水生昆虫密度最大的区域,平均密度为33.95ind.·m~(-2),主要优势种为蚋科(Simuliidae sp.)、纹石蛾(Hydropsyche sp.)和高山似突摇蚊(Paraciadius alpicola);郊区摇蚊幼虫和寡毛纲的平均密度最大,分别为82.58ind.·m~(-2)和36.21ind.·m~(-2),主要优势种为小云多足摇蚊(Polypedilum nubeculosum)和苍白摇蚊(Chironomus pallidivittatus);市区以腹足纲的密度最大,为88.75ind.·m~(-2),主要优势种为铜锈环棱螺(Bellamya aeruginosa)和梨形环棱螺(Bellamya purificata).市区和郊区发现的物种数均比山区多14种.CCA典范对应分析结果表明,营养盐浓度是影响郊区大型底栖动物群落结构的主要因素,人类活动强度和水温是影响市区和山区大型底栖动物群落结构的主要因素.

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.