Data from: Environmental DNA reveals quantitative patterns of fish biodiversity in large rivers despite its downstream transportation

Despite the ecological and societal importance of large rivers, fish sampling remains costly and limited to specific habitats (e.g., river banks). Using an eDNA metabarcoding approach, we regularly sampled 500 km of a large river (Rhône River). Comparisons with long-term electrofishing surveys demonstrated the ability of eDNA metabarcoding to qualitatively and quantitatively reveal fish assemblage structures (relative species abundance) but integrated a larger space than the classical sampling location. Combination of a literature review and field data showed that eDNA behaves in the water column like fine particulate organic matter. Its detection distance varied from a few km in a small stream to more than 100 km in a large river. To our knowledge, our results are the first demonstration of the capacity of eDNA metabarcoding to describe longitudinal fish assemblage patterns in a large river, and metabarcoding appears to be a reliable, cost-effective method for future monitoring.

尽管大型河流在生态与社会层面均具有重要意义，但鱼类采样工作仍存在成本高昂、且仅能覆盖特定生境（例如河岸）的局限。本研究采用环境DNA（environmental DNA, eDNA）宏条形码（metabarcoding）技术，对大型河流——罗讷河（Rhône River）的500公里河段开展了常态化采样。通过与长期电捕鱼调查结果的对比分析，本研究证实环境DNA宏条形码技术可定性、定量揭示鱼类群落结构（即物种相对丰度），且其采样覆盖的空间范围远超传统采样点位。结合文献综述与野外实测数据的分析可知，环境DNA在水体中的行为模式与细颗粒有机质高度相似，其检测距离跨度较大：在小型溪流中仅为数公里，而在大型河流中则可超过100公里。据我们所知，本研究结果首次证明了环境DNA宏条形码技术可用于刻画大型河流的纵向鱼类群落分布模式，且该技术有望成为未来鱼类监测中可靠且高性价比的监测手段。