永定河流域春季大型底栖动物群落结构和空间格局

为了解永定河流域大型底栖动物群落结构与空间分布状况,2017年春季调查了永定河流域大型底栖动物群落,采集并鉴定出大型底栖动物77个分类单元,其中水生昆虫为绝对优势类群。聚类分析表明,永定河流域底栖动物群落结构在空间上与流域地理格局基本一致,上游区洋河、妫水河、桑干河以直突摇蚊、流水长跗摇蚊、间摇蚊为优势类群,中游区永定河山峡段以钩虾、台湾蜉、近岸细蜉为主,下游区五湖一线段以德永摇蚊、恩菲摇蚊、沼虾为优势类群。直接收集者成为流域内绝对优势功能摄食类群,在不同区域的相对丰度均达到90%以上。单因素方差分析显示,Shannon-Wiener多样性指数和Pielou均匀度指数无组间差异,Margalef丰富度指数和物种数在中游区和下游区差异显著(P0.05)。研究表明流域大型底栖动物群落出现了整体退化,生物多样性下降,重度-中度耐污类群成为优势,多数河段功能摄食类群不完整,永定河流域生态系统保护和修复工作亟待开展。

Study on the Community Structure and Spatial Pattern of Macroinvertebrate in the Yongding River Basin in Spring

To explore the status of community structure and spatial distribution of macroinvertebrate in the Yongding River basin, an investigation was carried out in 38 sections of the Yongding River in spring of 2017. A total of 77 species were identified, among which aquatic insects were absolute dominant groups. Cluster analysis showed that the community structure of macroinvertebrate in the Yongding River basin was basically consistent with the geographical pattern of the basin. The Orthocladius sp., Rheotanytarsus sp. and Paratendipes sp. were the dominate taxa for the upper reaches. Gammarus sp., Ephemera formosana and Caenis rivulorum were the dominate taxa for the middle reaches. The dominant taxa of lower reaches were mainly the Tokunagayusurika sp., Einfeldia sp. and Macrobrachium sp.. The collector-gatherers became the absolute dominant functional feeding group in the basin, and the relative abundance in different regions reached more than 90%. One-way ANOVA analysis showed that there was no difference between the Shannon diversity index and the evenness index, and the Margalef index and the number of species were significantly different in the middle and lower reaches (P<0.05). Studies showed that the macroinvertebrate community in the basin had undergone overall degradation, biodiversity was declined, severe-moderate pollution-tolerant groups became dominant and most of the functional feeding groups were incompleted in the river. It would be urgent to protect and restore the structure and fnuction of the river ecosystem in the Yongding River.