黄河山东段河岸带春季大型底栖动物群落结构与多样性

河岸带是河流生态系统与陆地生态系统相互作用的生态交错带,具有明显的边缘效应和丰富的生物多样性。近年来,由于受人类活动(如水利工程、堤坝和农业生产等)的干扰,黄河下游河岸带生态系统受到严重破坏。为了解黄河下游河岸带大型底栖动物的群落结构现状和影响因素,于2015年5月对黄河山东段河岸带8个断面的底栖动物群落进行了系统调查,采用相对重要性指数、物种多样性指数和均匀度指数等方法分析该区域大型底栖动物的群落特征。调查期间共采集到37种底栖动物,其中,环节动物3种,软体动物7种,水生昆虫27种。底栖动物物种组成主要以水生昆虫为主,尤其是摇蚊幼虫。该段河岸带大型底栖动物的平均密度为(2 129±436)ind/m2,平均生物量为(2.20±0.75)g/m2。就空间分布而言,各断面底栖动物的种类数、优势种、现存量和多样性均呈现出明显的空间分布差异,且呈现出不规则波动,这表明河岸带受到严重的人为活动干扰。综合分析表明,各断面的河岸带形态(如宽度和生境类型)和水生昆虫的繁殖行为是影响黄河山东段河岸带底栖动物空间分布的主要因素。

Distribution and Diversity of Riparian Macrozoobenthic Communities in Shandong Reach of the Yellow River in Spring

Riparian zone is an active transition zone and ecotone between river and land ecosystems, and have some edge-effects and harbor higher numbers of species. Riparian ecosystem in the Lower Reach of the Yellow River has greatly degraded due to disturbance of human activities (such as hydraulic engineering construction, embankment along the lower river and farming) in recent years. In order to reveal the present status of riparian macrozoobenthos and its affecting factors, systematic surveys at 8 sampling sections in aquatic banks of Shandong Reach of Yellow River were carried out in May 2005, under low flow conditions. The characteristics of macrozoobenthos were studied with the index of relative importance, Shannon-Weaver index, Margalef index and Pielou evenness index. Altogether 37 benthic taxa, including 3 annelids, 7 molluscs, and 27 arthropods were identified (Table 2). The main components of benthos are aquatic insects (especially Chironomid groups). The average density and biomass of benthos were 2 129 ± 436 ind/m2 and 2.20 ± 0.75 g/m2, respectively. The analysis of the spatial distributions of benthic community structure indicated that species richness, abundance, biomass, dominant species and diversity varied significantly among each sampling sections (Fig. 2, Fig.3, Fig. 5, Table 3), and exhibited irregular fluctuations, which indicates that riparian ecosystem in Shandong Reach of Yellow River has served severe disturbance of human activities. The comprehensive analyses indicated that channel cross-section morphology (such as width and habitat type of riparian zone) and oviposition behaviors of aquatic insects were the main factors influencing the structure and distribution of the macrozoobenthos assemblages in Shandong Reach of Yellow River.