太湖流域江苏片区底栖大型无脊椎动物群落结构及物种多样性

摘要

为探明现阶段太湖流域江苏片区底栖大型无脊椎动物群落结构及物种多样性,于2013年1-3、7-8和10-11月对120个样点开展了调查.共记录6门124科280种,各点位物种数(4～51种)、个体密度(5.5 ～ 23363.4 ind./m2)和生物量(0.1 ～ 6269.2 g/m2)差异较大.不同水体类型的群落结构存在显著差异,其中溪流以蜉蝣目和毛翅目等水生昆虫为优势,水库以摇蚊为优势,河流以寡毛纲为绝对优势,湖荡以寡毛纲、摇蚊幼虫和软体动物为优势.聚类结果显示,同水体类型点位的群落结构也呈现不同程度的空间差异.结合丰度/生物量曲线、特征种及多样性分析,各聚类组受胁迫程度从轻到重依次为溪流(组Ⅸ),太湖敞水区(组Ⅱ)和东部水草区(组Ⅲ),太湖下游湖荡(组Ⅳ)、河流(组Ⅵ)和水库(组Ⅶ),太湖上游湖荡(组Ⅰ)、其他河流(组Ⅴ)和水库(组Ⅷ)点位.底栖大型无脊椎动物的分布与物理生境和水质条件呈较好的空间一致性,生境的多样性和良好的水质条件是保护和恢复物种多样性的关键因素.%To explore the characteristic of community structure and species diversity of benthic macroinvertebrates,samples were collected three times at 120 sampling sites in Taihu Basin of Jiangsu Province.Twenty-nine sampling sites were located in Lake Taihu,and the number of sites in other lakes,rivers,reservoirs and streams were 20,40,15 and 16,respectively.The three investigations were conducted in the periods from January to March,from July to August and from October to November in 2013.In total,280 taxa of benthic macroinvertebrates from 124 families and 6 phyla were recorded.The taxa number (4-51),density (5.5-23363.4 ind./m2) and biomass (0.1-6269.2 g/m2) varied greatly among sites,and community structure differed significantly among water bodies.In the western hilly region,the community of streams were dominated by aquatic insects from Ephemeroptera,Trichoptera and Odonata,while reservoirs were mainly dominated by Chironomidae larvae.In the eastern plain area,pollution-tolerant oligochaetes dominated the community of rivers,while lakes were dominated by Chironomidae larvae,Oligochaeta and Mollusca.Cluster analysis and One-way analysis of similarity classified the 120 sites into nine groups characterized by different characteristics species,showing the hierarchical gradient of sampling sites in lakes,rivers,reservoirs and streams.Streams(group ⅨX) were the least stressed by integrating the results of abundance-biomass curves,characteristics species and diversity of each affinity group.Species richness and evenness were relatively lower in central region (group Ⅱ) and macrophytes dominated areas (group Ⅲ) of Lake Taihu,whose biomass curves were above the abundance curves and dominated by Mollusca,Malacostraca and Oligochaeta,indicating that the communities suffered relatively weak disturbance.The biomass curves of groups including reservoirs (group Ⅶ),lakes (group Ⅳ) and rivers (group Ⅵ),which were in the out-flow direction of Lake Taihu,were very close to or intersected with the abundance curves and dominated by Chironomidae larvae,Oligochaeta and Gastropoda,indicating that the communities were moderately disturbed.However,the other groups (group Ⅰ,Ⅴ and Ⅷ) were only dominated by Chironomidae larvae and Oligochaeta,indicating intense disturbance.Community structure and spatial distribution of benthic macroinvertebrates in Taihu Basin of Jiangsu Province were strongly correlated to two ecological factors-habitat complexity and water quality,which could be used by managers and policy makers to evaluate and improve restoration practices.