滁河襄河口至马汊河段冬春季鱼类群落结构及其多样性

为了解滁河水域鱼类群落结构特征，于2015年12月和2016年5月对滁河襄河口至马汊河段鱼类进行了2次调查，共采集鱼类45种，隶属于6目13科36属，其中55.56%为鲤科（Cyprinidae）鱼类。单因素方差分析表明，该群落多样性空间差异显著，季节差异不明显。滁河水域鱼类群落优势种为鲫（Carassius auratus）、鲤（Cyprinus carpio）、棒花鱼（Abbottina rivularis）、黄颡鱼（Pseudobagrus fulvidraco）和似鳊（Pseudobrama simoni）。4种摄食功能群中，杂食性和碎屑食性鱼类物种数比例较高，占总物种数的63.04%；3种生态类群中，淡水定居性鱼类占绝对优势（89.13%）；3种栖息水层类型中，底层鱼类物种数比例较高，为45.65%。大型经济鱼类占总渔获物比例小，相对重要性指数（IRI）低。以物种数和多样性指数分析群落多样性特征，结果表明：4个不同河段间鱼类多样性有所差异，下游河段鱼类多样性较低，清流河与来安河水域居中，上游河段较高；不同季节间鱼类群落存在明显重叠，几乎不分离，不同河段间鱼类群落分离程度相对较高。鱼类群落结构存在的显著差异主要与鲫、鲤、棒花鱼和黄颡鱼等优势种空间分布差异有关。

Spatial and temporal patterns of fish assemblages in Chuhe River between Xianghe estuary and Macha River

Mastering the distribution of species composition and their abundance of fishes is basic for the conservation and management of fish diversity. Based on the data collected from Chuhe River in December 2015 and May 2016, we examined how the fish assemblages vary spatially and seasonally in this study area. A total of 4 798 individuals representing 45 species were collected, a total of 45 fish species belonging to 37 genera, 13 families, and 6 orders were collected during the investigation, with cyprinids accounting for 55.56% of the collected species. One-way ANOVA indicated that there were no significant seasonal differences in fish diversity,however, notable differences in fish diversity were observed among sampling sites. Carassius auratus, Cyprinus carpio, Abbottina rivularis, Pseudobagrus fulvidraco, and Pseudobrama simoni, were the dominant species. Omnivorous and detritivore fish species were the most frequent of the four feeding functional groups, which account for 63.04% of the total, and sedentary fish species (89.13%) were the most frequent of the three ecological groups, whereas demersal fishes (45.65%) were the most frequent of the three habitat types. Large commercial fishes account for a very small percentage of the whole fishes and the relative importance index (IRI) value is low. Analysis of species richness and diversity indicated that the fish diversity of the downstream of Chuhe River was low, with great spatial variation. The species richness and diversity of the upstream of Chuhe River was high, while the fish species in Qinliu River and Lai''an River take the second place. Fish species were similar between two seasons, and fish assemblage structures showed no significant difference between seasons. Variations among different reaches were observed for both fish species diversity and assemblage structures. Generally, the downstream of the river had relatively lower species diversity, while those in the upstream were relatively higher. Obviously fish community overlaps, hardly any separation were observed between seasons, when the spatial variations in fish assemblages among sections were considered, fish assemblage structures, not species diversity, showed significantly variation. Fish assemblage structures variation were mainly due to the spatial distribution of some dominant fishes, such as Carassius auratus, Cyprinus carpio, Abbottina rivularis and Pseudobagrus fulvidraco.