PDF(Pubmed)
Abstract：
Freshwater ecosystems are under great threat from humans, among which habitat heterogeneity is the most obvious, being one of the important reasons for the decline of fish diversity. This phenomenon is particularly prominent in the Wujiang River, where the continuous rapids of the mainstream have been divided into 12 mutually isolated sections by 11 cascade hydropower reservoirs. Based on the fact that conventional survey methods are more harmful to the ecological environment, the efficient and noninvasive environmental DNA metabarcoding (eDNA) approach was used in this study to conduct an aquatic ecological survey of the 12 river sections of the mainstream of the Wujiang River. A total of 2299 operational taxonomic units (OTUs) were obtained, corresponding to 97 species, including four nationally protected fish species and 12 alien species. The results indicate that the fish community structure of the Wujiang River mainstream, which was originally dominated by rheophilic fish species, has been changed. And there are differences in fish species diversity and species composition among the reservoir areas of the mainstream of the Wujiang River. The fish species in the area have gradually declined under the influence of anthropogenic factors such as terraced hydropower and overfishing. The fish populations consequently have demonstrated a tendency to be species miniaturized, and the indigenous fish are severely threatened. In addition, the fish composition monitored by the eDNA approach was found to be close to the fish composition of historical information on the Wujiang River, indicating that eDNA approach may be used as a complementary tool to conventional methods in this basin.
摘要：
淡水生态系统受到人类的巨大威胁，其中生境异质性最为明显，是鱼类多样性下降的重要原因之一。这种现象在乌江特别突出,其中，干流的连续急流被11个梯级水电水库划分为12个相互隔离的部分。基于常规调查方法对生态环境的危害更大的事实，本研究采用高效、无创的环境DNA元编码(eDNA)方法对乌江干流12个河段进行了水生态调查。共获得2299个操作分类单位(OTU)，对应97种，包括4种国家保护鱼类和12种外来物种。结果表明,乌江干流鱼类群落结构,最初是由嗜流变鱼物种主导的，已经改变了。乌江干流库区之间的鱼类物种多样性和物种组成存在差异。在梯田水电和过度捕捞等人为因素的影响下，该地区的鱼类种类逐渐减少。因此，鱼类种群表现出物种小型化的趋势，土著鱼类受到严重威胁。此外,通过eDNA方法监测的鱼类组成被发现接近乌江历史信息的鱼类组成，这表明eDNA方法可以作为该盆地常规方法的补充工具。
