南淝河和十八联圩湿地底栖动物群落结构特征及其与环境因子的关系

2018年7月对合肥十八联圩湿地及南淝河下游51个点位底栖动物进行了调查，并运用生物学污染指数（BPI）对该区域进行了生态评价，结果显示十八联圩湿地圩区内重污染点位共有32个，α中污染点位9个，β中污染点位2个，而轻污染点位仅3个，南淝河的5个点位均为重污染状态。此次调查共采集到大型底栖动物定性与定量样品共47种，隶属于3门20科35属。十八联圩湿地内大型底栖动物优势种有霍甫水丝蚓（Limnodrilus hoffmeisteri）、梨形环棱螺（Bellamya purificata）、多巴小摇蚊（Micropsectra chuzeprima）、黄色羽摇蚊（Chironomus flaviplumus）、中国长足摇蚊（Tanypus chinensis）；南淝河底栖动物优势种主要为霍甫水丝蚓（Limnodrilus hoffmeisteri）。RDA分析结果显示，NH4+-N、CODMn、pH、重金属Cr是影响大型底栖动物群落结构的主要环境因子，其中NH4+-N是造成十八联圩湿地与南淝河底栖动物群落结构差异的关键环境因子。

Macroinvertebrate Community Structure and Its Relationship with Environmental Factors in Shibalianwei Wetland and Nanfei River

Shibalianwei wetland receives and purifies the water of Nanfei River before it flows into Chaohu Lake, and is a green wetland and ecological corridor for Hefei City. In July, 2018, we investigated the macroinvertebrates and environmental factors (water quality indices and sediment heavy metal pollution) at 46 sampling sites in Shibalianwei wetland and 5 sampling sites in Nanfei River. The macroinvertebrate community structure and its relationship with environmental factors were then analyzed based on the results. The aim was to provide scientific support for the ecological management of Shibalianwei wetland and Nanfei River. A total of 45 macroinvertebrate species from 35 genera, 20 families and 3 phyla were identified, and consisting of 39 species in Shibalianwei wetland and 6 species in Nanfei River. Limnodrilus hoffmeisteri, Bellamya purificata, Micropsectra chuzeprima, Chironomus flaviplumus and Tanypus chinensis were the dominant species in Shibalianwei wetland, while the dominant species was Limnodrilus hoffmeisteri in Nanfei River, accounting for 98.52% of the total density. Macroinvertebrate diversity was low in both areas, and the ranges of the Shannon-Wiener Diversity Index (H'') for Shibalianwei Wetland and Nanfei River were 0-1.73 and 0.04-0.53, with average values of 0.72 and 0.20. The Biological Pollution Index (BPI) was used to evaluate the ecological status of the study area: 32 sites in Shibalianwei Wetland were heavily polluted, 11 sites moderately polluted and 3 sites lightly polluted, and all 5 sites of Nanfei River were heavily polluted. Redundancy analysis showed that NH4+-N, CODMn, and the heavy metals Pb and Cd were the primary factors affecting macroinvertebrate community structure. Regression clustering analysis showed that NH4+-N was the key factor leading to differences in the community structures of Shibalianwei wetland and Nanfei River. Overall, organic and heavy metal pollution, eutrophication and low biodiversity are serious in Shibalianwei wetland and Nanfei River.