生境过滤作用对长江下游菜子湖鱼类物种和功能组成的影响

于2018年6-8月在长江下游菜子湖流域沿岸带、敞水区、湖口和河道4种典型微生境分别设置样点进行鱼类调查,探讨生境过滤对鱼类物种和功能组成的影响.共采集鱼类5目31属43种,其中沿岸带湖泊定居性、山溪河流性及江湖洄游性鱼类物种数均较低,河道山溪河流性鱼类物种数较高.通过对各微生境间物种组成的差异分析,显示出4种微生境条件下的鱼类群落均有显著差异,且沿岸带、敞水区和河道的代表种分别为■、鳙、草鱼、鲢,华鳈、光唇蛇鮈、蛇鮈.通过单因素多元方差分析解析不同生境过滤条件下鱼类物种和功能多样性的差异,发现在物种多样性层面,沿岸带的Richness指数和Shannon-Wiener指数显著低于其他微生境;在功能多样性层面,不仅发现沿岸带显著较低的RaoQ指数,同时发现河道的FDiv指数显著高于其他微生境类型.

Impacts of habitat filtering on taxonomic and functional composition of fish communities in Lake Caizi, lower reaches of the Yangtze River

To assess the impacts of habitat filtering on taxonomical and functional compositions of fish communities, we conducted a fish survey in four typical microhabitats(i.e., littoral zone, open water, lake inlets and river channel) of the Lake Caizi, lower reaches of the Yangtze River Basin, in June-August, 2018. Forty-three fish species belonging to 5 orders and 31 genera were caught in total. More riverine species lived in the river channel microhabitat, while less of lacustrine biota, river-lake migratory and riverine species lived in the littoral zone microhabitat. Further analysis revealed that there exist significant differences in fish community compositions among the four microhabitats. Meanwhile, the dominant species of river channels were Sarcocheilichthys sinensis, Saurogobio gymnocheilus and Saurogobio dabryi, while Aristichthys nobilis, Ctenopharyngodon idellus, Hypophthalmichthys molitrix were dominant in the open water of the lake. In addition, Hemiculter leucisculus were found dominated in the littoral zone. By using one-way PERMANOVA analysis, we found both richness index and Shannon-Wiener index in littoral zone were significantly lower. In contrast, indices of functional diversity were stronger predictors for the impacts of habitat filtering on floodplain fishes, which showed that the RaoQ index in littoral zone was significantly lower while the FDiv index in river channel was significantly higher than those in the other three microhabitats.