长江流域鱼类物种多样性大尺度格局研究

Large-scale patterns in species diversity of fishes in the Yangtze River Basin

作者以长江流域鱼类编目数据库为基础数据,研究了长江流域鱼类物种多样性的大尺度格局。长江流域内共记录了鱼类378种(亚种),隶属于14目32科144属。其中淡水鱼338种(亚种),以鲤形目为主,达到269种(亚种),洄游鱼类11种,河口鱼类29种;流域内特有种和受威胁物种分别有162种(亚种)和69种(亚种)。根据鱼类分布特点,按水系将长江流域分为19个区域,除了江源区和金沙江中上游外,物种数和G-F多样性指数上游高于中下游,但各区域内差异不大,然而特有种比例从上游到下游随海拔降低而逐渐降低。利用Jaccard物种相似性系数对19个区域进行聚类分析,将整个流域分成三部分:(1)江源区和金沙江中上游,地理上属于青藏高原东南部波状平原部分和横断山区,(2)上游其他流域,地理上属于川西高原、云贵高原、四川盆地及秦巴山区,(3)中下游流域,地理上属于淮阳山地、江南丘陵和长江中下游平原,基本反映了流域内自然地理环境及我国大陆地势三级台阶变化的特点。

We synthesized the information on fish diversity in the Yangtze River Basin, documenting 378 species/subspecies that had been recorded and described from the basin, belonging to 14 orders, 32 families and 144 genera. Of these, 338 species/subspecies are freshwater fishes, of which 269 species/subspecies are from the Cypriniformes. Of the total, 11 species are migratory fishes, and 29 are species of brackish water of the estuary. A total of 162 species/subspecies are endemic to the river and 69 are threatened. We divided the Yangtze River Basin into 19 sub-basins. Except for the two sub-basins of the headwaters and the upper and middle reaches of Jinshajiang River, the other 17 sub-basins showed similar values in species richness and G-F diversity indices, although the values were higher in the upper reaches than in the middle and lower reaches. However, the proportion of endemic species decreased gradually from the headwater to the estuary of the basin in parallel with the gradient of elevation. Jaccard similarity analysis showed that the 19 sub-basins were clustered into three groups： （1） the headwaters and the upper and middle reaches of Jinshajiang River, located in the eastern Qinghai-Xizang Plateau and Hengduan Mountains; （2） the other sub-basins of the upper reaches, located in Western Sichuan Plateau, Yungui Plateau, Sichuan Basin, and Qinling-Daba Mountains; （3） the middle and lower reaches, belonging to the Huaiyang Mountains, Jiangnan Hills and the plain along the middle and lower reaches of the Yangtze River. This grouping reflects the environmental characteristics of the basins and the three large topographic platforms of the Chinese mainland.