流域治理后生态恢复期的沙颍河干流底栖动物群落结构分析

2013年4月,根据沙颍河干流闸坝分布设置21个采样站位对处于生态恢复期的沙颍河干流底栖动物进行了现场调查。共采集到底栖动物3门6纲10目25科38种,其中,水生昆虫20种、甲壳动物3种、寡毛类2种、软体动物11种、其他类群2种。沙颍河干流底栖动物平均密度242.40个/m2,平均生物量291.33 g/m2;软体动物占绝对优势,在现存量中占总个体数的64.74%,且在绝大部分站位占据优势地位;常见种为梨形环棱螺、环足摇蚊属一种、圆顶珠蚌和大沼螺。经生物多样性分析,Shannon-Wiener指数平均为1.20,Margalef指数平均为1.56,Pielou均匀度指数平均为0.52。将21个站位的底栖动物进行聚类分析,可分为8大组群,NMDS分析显示各组群分离较为明显,表明底栖动物群落结构的空间异质性较高;SIMPER分析表明空间变异度取决于梨形环棱螺、环足摇蚊、长臂虾科1种、水丝蚓属1种、大沼螺和摇蚊的种群动态变化。从底栖动物群落结构组成来看,周口闸以上河段水质要明显好于周口闸以下,周口闸以下河段水质状态也与污染严重时期相比有较大改善。

Zoobenthos Community of the Main Stream of Shaying River at Ecological Restoration Stage after Watershed Management

Macroinvertebrate samplers in the mainstem of Shaying River in restoration phase, were collected in April, 2013. In this study, 21 sampling sites were set up according to the distribution of floodgates. A total of 38 species (20 aquatic insects, 3 crustaceans, 2 oligochaetes, 11 species molluscs, 2 others animals), were recorded, belonging to 4 phylum, 7 class, 15 order and 31 family. The common species were Bellamya purificata, Cricotopus sp. Unio douglasiae and Parafossarulus exirnius The average density was 242.40ind./m2, the average biomass was 291.33g/m2, the average species number was 7.6 per site, the average Shannon-wiener index was 1.20, and the average Margalef index was 1.56, and the average Pielou evenness index was 0.52. Molluscs were the absolutely dominant group, which accounted for 64.74% of total individuals, and were also the dominant in most sampling stations. The 21 sampling sites were divided into eight groups by clustering analysis, and the eight groups were obviously separated from each other, indicating the spatial heterogeneity of macroinvertebrate community was high. By SIMPER analysis, we found the spatial variability of macroinvertebrate community depended on the population dynamics of these species, such as Bellamya purificata, Cricotopus sp., Palaemonidae sp., Limnodrilus sp., Parafossarulus exirnius and Chironomus sp. At present, according to the macroinvertebrate community structure, the water quality of the reaches above Zhoukou floodgate was obviously better than that below Zhoukou floodgate, and the water quality of the reaches below Zhoukou floodgate was improved compared to the past, which was consistent with the results of water quality based on pure physical and chemical monitoring in recent years.