新薛河溪流生境底栖动物群落结构季节动态

明确底栖动物在时空尺度上的自然变化规律对有效评估和保护水生态系统十分重要。基于2012年季节调查数据,对新薛河典型生境底栖动物群落季节动态进行了研究。共鉴定底栖动物108种,隶属5门10纲74属。短脉纹石蛾、长钝直突摇蚊、拟长跗摇蚊、Neozarelia sp.为研究区域优势分类单元,相对丰度分别为25.1%、9.8%、9.0%、8.6%;各季节间优势分类单元组成差异较大,3个季度共同优势物种仅短脉纹石蛾1种。密度、物种丰度、香农指数表现为4月和12月显著高于10月;均匀度指数10月份最高。非度量多维标度排序表明,不同季节底栖动物群落结构差异显著;对照河段(D河段)群落结构季节间差异相对较小。指示物种法分离出了新薛河及各河段代表性物种41种,但B河段未分离出指示物种;双向聚类分析进一步明确了指示物种的指示属性(特有或者相对丰度最高)。

Seasonal dynamics of macroinvertebrate community structure in stream habitats of the Newxue River

Identifying naturally-regulated spatial and temporal variations of benthic macroinvertebrates is critical for effective assessment and conservation of aquatic ecosystems. A clear identification of spatial and temporal trends of these communities could enhance our understanding of the ecology of macroinvertebrates, definitions of effects of anthropogenic or natural disturbances on lotic communities, and assessment and conservation of lotic biodiversity. In the present study, macroinvertebrate community structure was compared among different seasons in the upper Newxue River in the year 2012 (April, October, and December), where a total of 108 macroinvertebrate taxa belonging to 74 genera and 10 classes were recorded; Cheumatopsyche sp., Orthocladius vaillanti, Paratanytarsus sp., and Neozarelia sp. were the dominant taxa, with relative abundances of 25.1%, 9.8%, 9.0%, and 8.6%, respectively. Dominant species composition was very different across seasons; Cheumatopsyche sp. was the only common taxon in all three seasons. Density, species richness, and Shannon index were significantly higher in April and December than in October; evenness was highest in October. Non-metric Multidimentional Scaling (NMS) analysis was used to compare the community structure among different seasons in the Newxue River and typical reaches, and the results all showed significant differences; seasonal differences in the control reach (reach D) were relatively small. A total of 41 representative species of the Newxue River and typical habitats were separated by indicator species analysis, but no species was isolated from reach B. Two-way cluster analysis further clarified the indicator attributes (unique or highest relative abundance) of the indicator species.