太湖大型底栖动物群落结构与水环境生物评价∗

摘要

To characterize the community structure of macrozoobenthos and to examine their relationships with environmental fac-tors,macrozoobenthos were investigated at 116 sites of Lake Taihu in winter and summer of 2014. A total of 55 species were recor-ded, belonging to 3 phyla, 7 classes, 18 orders and 27 families. The mean density and biomass of macrozoobenthos were 405. 5 ind. /m2 and 146. 6 g/m2 , respectively. Corbicula fluminea, Bellamya aeruginosa, Limnodrilus hoffmeisteri, Grandidierella aihuensis, Nephtys oligobranchia and Paranthura sp. were the dominant species in Lake Taihu. The 116 sampling sites were classi-fied into three groups based on cluster analysis using environmental factors. One-way ANOVA showed that environmental factors differed significantly among the three groups. Analysis of similarities and non-metric multidimensional scaling showed that macrozo-obenthic assemblages exhibited remarkable difference among the three groups. Canonical correspondence analysis demonstrated that macrozoobenthic community structure was highly correlated with habitat-specific differences in water depth, total nitrogen, total phosphorus, ammonium nitrogen, macrophytes, dissolved organic carbon andΦ50. From the east and southwest to the north area of Lake Taihu, the diversity indexes of macrozoobenthos decreased but the density and biomass increased with the increase of troph-ic status index. Our results showed that the trophic level, bottom sediment type and macrophytes coverage were the key factors reg-ulating community structure and diversity of macrozoobenthos.%于2014年冬季和夏季调查太湖全湖116个样点的大型底栖动物,分析其群落结构及与环境因子的关系.共记录底栖动物55种,隶属3门7纲18目27科52属,底栖动物的平均密度和生物量分别为405.5 ind./m2和146.6 g/m2.优势度分析表明,河蚬(Corbicula fluminea)、铜锈环棱螺(Bellamya aeruginosa)、霍甫水丝蚓(Limnodrilus hoffmeisteri)、太湖大螯蜚( Grandidierella aihuensis)、寡鳃齿吻沙蚕( Nephtys oligobranchia)和拟背尾水虱属一种( Paranthura sp.)是太湖大型底栖动物的优势种.基于环境因子聚类分析,可将全湖分为3个区：敞水区、水生植被区和富营养区.方差分析表明各湖区间环境因子差异显著.统计分析表明,3个区底栖动物群落结构相似性低,差异显著.典范对应分析表明,水深、总氮、总磷、铵态氮、水生植物、溶解性有机碳和沉积物中值粒径与大型底栖动物群落结构显著相关.K-优势曲线、物种多样性指数显示,从水生植被区→敞水区→富营养区,营养水平增加,底栖动物多样性逐渐降低,生物量逐渐升高.研究结果表明营养水平、底质类型以及水生植被的分布是决定太湖大型底栖动物群落结构及多样性的关键因子.