广西贝江大型底栖动物群落结构时空分布特征

为了解贝江大型底栖动物群落结构特征并对其水质进行生物学评价,于2015年1、8月对贝江流域17个采样点进行了调查,共采集大型底栖动物146个分类单元,隶属于8纲20目52科,其中昆虫纲所占比例最高(86.99%),软体动物次之(6.16%)。贝江底栖动物群落结构存在季节性差异,群落数量特征和结构复杂性均表现为冬季>夏季。无度量多维标定排序和ANOSIM分析发现,贝江流域冬季和夏季底栖动物群落组成存在显著差异(r=0.26,P<0.001)。群落相似性分析表明,贝江底栖动物存在显著的空间差异,整个流域可以分为2组,组1基本分布在自然河段,组2主要包括电站采样点和贝江下游采样点,各组间差异显著(P<0.01)。底栖动物功能摄食类群以集食者(55%)和撕食者为主(16%),其次为滤食者(14%)和捕食者(11%),刮食者(4%)所占比例较小。水质评价结果显示,Shannon-Wiener生物多样性指数(H′)评价贝江水质为轻污-清洁。Hilsenhoff生物指数(BI)评价贝江流域水质属于清洁,与实际水质情况最接近。总体上,贝江流域自然河段底栖动物群落结构复杂多样,整体水质清洁。

Spatial and Temporal Distributions of Macroinvertebrate Communities in the Beijiang River,Guangxi

To explore the macroinvertebrate community structure characteristics and water quality conditions based biologic assessment, a total of 17 sections of the Beijiang River were surveyed in January and August 2015, respectively.Results showed that 146 taxa, belonging to 52 families,20 orders and 8 classes were identified.Insecta(86.99%) was a dominant class, followed by Mollusca(6.16%).The macroinvertebrate community structure exhibited the significant temporal and spatial differences through non-metric multi-dimensional scaling analysis, ANOSIM analysis and cluster analysis. The quantitative features and complexity of macroinvertebrate community structure in winter exceed that in summer. The 17 sections could be divided into two groups by the cluster analysis.The sections of one group distributed in the natural reach, whereas the sections of another group located in the power station and the lower reach of the Beijiang River. The results of functional feeding groups showed that gather-collectors(55%) and shredders(16%) were the main components in the Beijiang River, followed by filter-collectors(14%) and predators(11%), while scrapers(4%) only accounted for small percentages. The water quality of the Beijiang River was in the level of clean-mild pollution evaluated by Shannon-Wiener biodiversity index(H′). Hilsenhoff biotic index(BI) showed the water quality was clean, which was in accordance with the actual observations. As a whole, the macroinvertebrate community structures were more complexity in upper natural reaches than in artificial and lower reaches, and the water quality of the Beijiang River was in a good conditions.