三峡库区生态牧场底栖动物群落特征及影响因素分析

Analysis of characteristics and influencing factors of macroinvertebrates from ecological ranch in Three Gorges Reservoir

为掌握三峡库区忠县甘井河生态牧场养殖对水生态系统的影响效应,于2018年6月至2019年3月按照季度对底栖动物和环境因子进行了调查。结果表明,生态牧场底栖动物出现37种,主要由寡毛类和水生昆虫组成,常见种和优势种为霍甫水丝蚓、水丝蚓、前突摇蚊和多足摇蚊。寡毛类占据绝对优势地位,数量百分比高达66.67%,其次是水生昆虫,占31.63%。底栖动物平均密度72.58 ind./m^(2),平均生物量0.0926 g/m^(2),与非牧场的香溪河库湾相比,现存量处于较低水平。现存量和多样性夏秋季高于冬春季,空间分布格局为拦网内低于拦网外。偏最小二乘法分析结果表明,水温、盐度、电导率和总溶解固体对寡毛类的密度有重要影响,氧化还原电位、pH和水温对寡毛类生物量有重要影响,pH和氧化还原电位对水生昆虫的密度和生物量均有重要影响。

To understand the impact of ecological pasture aquaculture on the aquatic ecosystem in Ganjing River of Three Gorges Reservoir located in Zhongxian County,a quarterly investigation of macroinvertebrates and environmental factors was conducted from June 2018 to March 2019.The results showed that there were 37 species of macroinvertebrates in the ecological ranch,mainly composed by oligochaetes and aquatic insects.The common and dominant species were Limnodrilus sp.,Procladius sp.,Polypedilum sp.and Limnodrilus hoffmeisteri.Oligochaetes occupied the dominant position,with a percentage of 66.67%,followed by aquatic insects,accounting for 31.63%.The average density of macroinvertebrates was 72.58 ind·m^(-2),and the average biomass was 0.0926 g·m^(-2).Compared with the non-pasture Xiangxi River Reservoir Bay,the standing stock was at a lower level.The standing stock and diversity in summer and autumn were higher than that in winter and spring,and the spatial distribution pattern was that inside the net were lower than outside the net.The results of partial least square(PLS)analysis showed that water temperature,salinity,electrical conductivity and total dissolved solids had important effects on the density of oligochaetes.Redox potential,pH and water temperature had important effects on the biomass of oligochaetes.pH and redox potential had important effects on the density and biomass of aquatic insects.