太浦河大型底栖动物群落组成及时空分布特征

太浦河连接东太湖和黄浦江，是东太湖向下游行洪的主河道，也是黄浦江上游重要的引水水源。分别于2017年10月、12月和2018年3月、6月在太浦河沿程设置的5个站点开展了大型底栖动物季节频次的取样调研，分析了太浦河大型底栖动物群落的结构特征及其主要影响因子。调查期间共采集到大型底栖动物25种，隶属于3门6纲14科，其中以河蚬（Corbicula fluminea）为代表的双壳类和以铜锈环棱螺（Bellamya aeruginosa）为代表的腹足类处优势地位。太浦河大型底栖动物群落的密度、生物量及多样性特征在不同站点间均存在显著差异（P<0.05）；而在不同季节间均不存在显著差异（P>0.05）。聚类排序分析表明，太浦河大型底栖动物群落在空间上的差异较季节间的变化更为明显。太浦河大型底栖动物群落的物种组成特征与太浦河、东太湖的水文连通格局密切相关；而沿程不同程度人为干扰下的水体营养水平以及底质类型与生境异质性等生境条件对太浦河大型底栖动物群落的分布特征具有重要影响，其综合作用机理有待进一步研究。

Community composition and spatio-temporal distribution characteristics of benthic macroinvertebrates in Taipu River

Taipu River connects East Taihu Lake and Huangpu River. It is the main channel for flood discharge from East Taihu Lake to the downstream, and also the important water supply source for the upper reaches of Huangpu River. We set five fixed sampling sites along the Taipu River and carried out seasonal surveys from October 2017 to June 2018. Community structure of benthic macroinvertebrates and corresponding influential factors were analyzed based on these surveys. A total of 25 species of benthic macroinvertebrates were collected, belonging to 3 phyla, 6 classes, and 14 families. Among these assemblages, bivalves represented by Corbicula fluminea and gastropods represented by Bellamya aeruginosa were the dominant groups. The significant differences (P<0.05) were found in the abundance, biomass and diversity of benthic macroinvertebrates between the different sites, but not between the different seasons (P>0.05). Cluster and NMDS analysis showed that the difference between the sampling sites was more obvious than that between the sampling seasons to benthic macroinvertebrates. The species composition characteristics of the benthic macroinvertebrates in the Taipu River were closely related to the hydrological connectivity to the East Taihu Lake. The distribution characteristics of the benthic macroinvertebrates along the Taipu River were greatly affected by human disturbance and habitat conditions such as water nutrient level, substrate type and habitat heterogeneity, etc. The interaction mechanisms among them need further studies.