城镇化对西苕溪大型底栖动物群落的影响

摘要

Urbanization is of great impact on stream ecosystem health .We sampled 20 reference sites , 5 moderately disturbed sites and 2 heavily disturbed sites in May from 2004 and 2010 in Xitiaoxi watershed .We identified a total of 226 species which belonged to 190 genera and 74 families.We found significant decrease in taxa richness of benthic macroinvertebrate , EPT taxa richness , Shannon-Wiener diversity index and B-IBI index in disturbed sites , and a significant increase of BI index .Canonical Correspon-dence Analysis ( CCA) well separated the benthic macroinvertebrate communities of the reference , moderately and heavily disturbed sites.The urbanization related factors , such as water temperature increase , nutrients enrichment , high load of fine sediments and bank stabilization greatly contributed to the decline of benthic macroinvertebrae diversity .%于2004—2010年5月对西苕溪流域20个参照点，5个中度干扰点以及2个重度干扰点的底栖动物进行了调查，共鉴定出74科190属226个种；受干扰后，底栖动物群落物种丰富度、EPT物种丰富度、Shannon-wiener多样性指数和B－IBI指数显著下降，BI指数显著升高。 CCA分析结果表明，参照、中度和重点干扰样点的底栖动物群落差异明显。城镇化引起的溪流水温上升、营养盐升高、泥沙输入量增多和堤岸固化是导致溪流底栖动物群落退化的主要原因。