Abstract：
One of the main reasons for the decline in global freshwater biodiversity can be attributed to alterations in hydrological conditions resulting from dam construction. However, the majority of current research has focused on single or limited numbers of dams. Here, we carried out a seasonal fish survey, using environmental DNA (eDNA) method, on the Wujiang River mainstream (Tributaries of the Yangtze River, China) to investigate the impact of large-scale cascade hydropower development on changes in fish diversity patterns. eDNA survey revealed that native fish species have decreased in contrast to alien fish. There was also a shift in fish community structure, with declines of the dominant rheophilic fish species, an increase of the small-size fish species, and homogenization of species composition across reservoirs. Additionally, environmental factors, such as temperature, dissolved oxygen and reservoir age, had a significant effect on fish community diversity. This study provides basic information for the evaluation of the impact of cascade developments on fish diversity patterns.
摘要：
全球淡水生物多样性下降的主要原因之一可以归因于大坝建设导致的水文条件变化。然而,当前的大多数研究都集中在单个或有限数量的水坝上。这里,我们进行了季节性鱼类调查，使用环境DNA(eDNA)方法，在吴江干流(长江支流，中国）以研究大规模梯级水电开发对鱼类多样性格局变化的影响。eDNA调查显示，与外来鱼类相比，本地鱼类物种有所减少。鱼类群落结构也发生了变化，随着优势嗜变鱼类的减少，小型鱼类的增加，以及储层物种组成的均质化。此外,环境因素,如温度，溶解氧和储层年龄，对鱼类群落多样性有显著影响。这项研究为评估级联发展对鱼类多样性模式的影响提供了基础信息。
