黄河源区典型弯曲河流底栖动物的生态格局

通过探究黄河源区典型弯曲河流河岸带不同水体(干流、支流和牛轭湖)的底栖动物生态格局,可为黄河生态保护提供基础数据。于2012年7月和2013年6月对兰木错曲12个样点的底栖动物进行采样,同时对样点环境参数进行调查监测,对河流水质、底栖动物组成、多样性及其格局进行分析。结果表明,研究河段基本处于自然状态,水质为I-III类。调查期间共采集底栖动物23科、36属、39种;以水生昆虫为主,占物种总数的76.9%;其次为寡毛纲、腹足纲、甲壳纲,分别占5.1%;线虫纲、双壳纲和蛛形纲最少,仅各占2.6%。除趋势对应分析(DCA)表明,干流、支流和牛轭湖的底栖动物群落存在差异,水文连通性是引起这种差异的主要原因,对群落变化的解释率为37.0%。干流、支流和牛轭湖的底栖动物多样性也存在差异,干流的底栖动物多样性最高,其次是支流和牛轭湖。昆虫纲是干流和牛轭湖中的主要类群,密度组成分别大于53%和85%,甲壳纲是支流中的主要类群,密度组成大于70%;干流的底栖动物功能摄食类群组成最均匀,其中撕食者、直接收集者和刮食者占优势,其密度之和超过90%,支流和牛轭湖的均匀性相对较差,支流中直接收集者的密度比例最大,超过78%,牛轭湖中撕食者的密度比例最大,超过82%。

Macroinvertebrate Ecology in a Meandering River of the Yellow River Headwaters

Meandering rivers are the most common river type in the headwater area of the Yellow River. In this study, we systematically studied the ecology of the macroinvertebrate community in different sections (main stem, tributaries, and oxbow lakes) of Lanmucuoqu River, a typical meandering river of the Yellow River headwaters. Additionally, the primary environmental parameters affecting macroinvertebrate ecology were measured. The study aimed to explore the ecological characteristics of meandering rivers in the Yellow River headwater area and provide scientific data for ecological conservation and management of the area. The investigation was carried out at 12 sampling sites in the three river sections in July 2012 and June 2013, focusing on water quality and macroinvertebrate community composition, diversity and ecology. The surveyed river section was basically in a natural condition, with a gravel and sand bed, and water quality was grade I-III. A total of 39 macroinvertebrate species from 36 genera and 23 families were identified. Aquatic insects dominated, accounting for 76.9% of the total species, followed by Oligochaeta, Gastropoda and Crustacea (5.1% per taxon) and Nematoda, Bivalvia, and Arachnida (2.6% per taxon). Detrended Correspondence Analysis (DCA) showed that the macroinvertebrate community structure was very different in the three sections (main stem, tributaries, and oxbow lakes). Hydrological connectivity explained 37.0% of the variance and was the main factor for the differences in community structure. The macroinvertebrate biodiversity of the three sections also varied greatly, with the highest diversity occurring in the main stem. Insecta was the primary group in the main stem (> 53%) and oxbow lakes (> 85%), while Crustacea was the main group in the tributaries (> 70%). The composition, by functional feeding group, in the main stem was nearly even with shredders, collectors, and scrapers dominating (> 90%). Collectors dominated in the tributaries (> 78%) and shredders dominated the oxbow lakes (> 82%).