北京河流大型底栖动物空间格局及其环境响应研究

大型底栖动物群落结构及多样性对于区域河流环境状况具有重要的指示意义。基于2014年5月—2015年8月间北京市河流大型底栖动物群落结构调查数据,分析底栖动物的生物多样性特征和空间格局。调查共发现大型底栖动物151种(或分类单元),隶属于5门9纲67科127属,水生昆虫占绝对优势。聚类分析表明76个采样点可被分为4组,组1主要包含北部山区的潮白河水系,具有较为典型的山溪型河流底栖动物特征,组2主要包含永定河山峡段和北运河水系的清河,组3主要包含大清河水系和北运河水系的温榆河、北沙河、南沙河等,二者具有城市河流兼有山溪型河流底栖动物的特征,组4主要包含北运河水系,具有典型的城市河流底栖动物特征。优势种分析表明:组1的优势种为热水四节蜉(Baetis thermicus)、秀丽白虾(Exopalaemon modestus)和网栖石蛾(Cheumatopsyche sp.),组2为直突摇蚊(Orthocladius sp.)、钩虾(Gammarus sp.)和长足摇蚊(Tanypus sp.),组3为摇蚊科幼虫(larvae of Chironomidae)和寡毛类(Oligochaeta),组4是以中华摇蚊(Chironomus sinicus)为代表的摇蚊幼虫。功能摄食类群研究表明:组1以收集者和滤食者占绝对优势,相对丰度分别为60%和29.6%;组2、组3、组4均以收集者占绝对优势,相对丰度分别为97.7%、90%、97.5%。物种数、Shannon-Wiener多样性指数、Pielou均匀度指数和Margalef丰富度指数的组间差异性显著(P0.05)。研究表明,北京河流大型底栖动物受河流自然环境变化的影响显著,形成了典型的山区-城市底栖动物空间格局,山区河流中保持了较高的生物多样性,城市河流及其过渡区的大型底栖动物退化明显,大型底栖动物能够明显指示环境状况的变化并可指导河流环境的保护与恢复。

Study on the Spatial Pattern of Macroinvertebrate and Their Responses to Environmental Changes in Beijing Rivers

Macroinvertebrate community and diversity are significant indicators for understanding the river health status and riverine environment. The biodiversity characteristics and spatial patterns of macroinvertebrates are analyzed, using survey data from May 2014 to August 2015 in Beijing. A total number of 151 macroinvertebrate species were identified and dominated by aquatic insects of Arthropods. Using the cluster analysis, 76 sampling sites were divided into Group 1, Group 2, Group 3 and Group 4. The sites of Group 1 are mainly located in Chaobai Rivers, distributing in the mountainous areas of northern Beijing. The sites of Group 2 and Group 3 are distributed in both urban and mountainous rivers, including Yongding River, Qinghe River, Wenyu River, Beisha River, Nansha River, and Daqing River. The sites of Group 4 are mainly distributed in Beiyun River and represented a typical urban stream system. The dominant species showed significant differences among the four groups. The Baetis thermicus, Exopalaemon modestus, and Cheumatopsyche sp. are the dominate taxa for Group 1. Orthocladius sp, Gammarus sp, and Tanypus sp are the dominant taxa for Group 2. The dominant taxa of Group 3 are mainly the larvae of Chironomidae and Oligochaeta. The dominant taxa of Group 4 are the Chironomus sinicus of Chironominae. Functional feeding group studies showed that group 1 mainly consists of gather- collectors (GC) and filter-collectors (FC), with relative abundances of 60% and 29.6%, respectively. All the sites of Group 2, Group 3 and Group 4 were dominated by GC, with the relative abundance of 97.7%, 90%, and 97.5%, respectively. The differences of Shannon-Wiener diversity, Pielou evenness and Margalef are significant (P <0.05) among the four groups. The results of this study indicate that the effects of nature environment on communities of macroinvertebrate in streams of Beijing was significant. The typical spatial distribution pattern of macroinvertebrate was identified from mountainous to urban regions, in which mountainous streams maintained higher biodiversity, and meanwhile a phenomenon of obvious degradation was found in region of urban streams. It can be concluded that the distribution of macroinvertebrates is the indicator for the changes of environment and can guide the protection and restoration of rivers.