塔里木盆地鱼类入侵及区系演变趋势

鱼类入侵是塔里木盆地土著鱼类濒危的关键性影响因素之一,结合历史文献数据及近年调查数据,系统综述了塔里木盆地鱼类入侵现状,并就鱼类入侵引起的鱼类区系均一化问题进行了分析。结果显示,该地区记录鱼类63种,其中土著种19种,入侵种44种。尽管入侵鱼类提升了塔里木盆地鱼类群落属级及科级的多样性水平,但相应的G-F多样性指数却明显下降,表明该区鱼类群落从物种组成简单、分化明显的特点演变为物种成分复杂、分化贫乏的特点。入侵种中源于长江和额尔齐斯河分别有30种(68.2%)和7种(15.9%),源于美欧和亚洲其他区域的有7种(15.9%)。入侵鱼类的进入引起塔里木盆地与其相关区域鱼类区系相似性显著上升(P0.01),并导致该区鱼类区系从单一的中亚高原山区复合体演变为多区系混合体。进一步利用鱼类个体生态矩阵分析方法研究显示,外来种在塔里木盆地适应性广泛,能够占据水域各种栖息生境,显著压缩了土著种的栖息空间,进而通过捕食、食物竞争及其他作用途径严重危及土著鱼类种群的续存,提示须采取有力措施限制入侵种的进一步扩散及对濒危土著物种迅速开展人工保育工作。

Fish invasions and changes in the fish fauna of the Tarim Basin

Many native fish species in the Tarim Basin are endangered, owing to the invasion of alien fish species over the past decades. To better understand how to protect native fish and control the spread of alien fish, the number of alien fish species in the Tarim Basin and their potential ecological effects on native fish species should be assessed. In the present study, we used Jaccard''s Index of similarity to investigate the homogenization of fish fauna between the Tarim Basin and associated regions. Furthermore, we adopted the fish autecology matrix to test whether invasive fish would be able to spread widely in the Tarim Basin in the near future. These data were collected from the literature and from field investigations performed in recent years. Our results showed that a total of 63 fish species have been recorded in the Tarim Basin, including 19 native and 44 alien species. The introduction of alien fish species increased species, genus, and family diversity. However, the G-F diversity index (the ratio of genus diversity index and family diversity index) has decreased. The introduction of alien fish to the Tarim Basin is suggested to have changed the species composition from simple and highly differentiated to complicated and poorly differentiated. Moreover, among 44 alien species, 39 (68.2%) were originally from the middle and lower Yangtze River, 7 (15.9%) were originally from the Ertix River, and 7 (15.9%) were originally from America, Europe, and other regions of Asia. We also found that the index of similarity of fish fauna between the Tarim Basin and associated regions significantly increased before and after the introduction of alien species (P < 0.01), indicating that alien species caused homogenization of the fish fauna within the studied regions. Furthermore, the fish autecology matrix revealed that alien fish species can be well adapted to the habitats of the Tarim Basin, and can cause the decline of native fish species through predation and competition. Therefore, control measures against alien fish should be implemented and/or intensified in order to protect the native fish species of the Tarim Basin.