Fish diversity in Nanchang section of the lower Ganjiang River based on environmental DNA metabarcoding

随着人类活动对自然生态系统的负面影响不断加剧,无创性生物多样性评估变得越来越重要。本研究旨在利用环境DNA宏条形码技术研究赣江下游南昌段鱼类多样性,并从不同季节(春、夏、秋、冬)、不同水层(上层、中层和下层)和不同取样位置(近岸和离岸)比较鱼类环境DNA信息的物种组成和多样性。结果表明:利用环境DNA宏条形码技术在赣江下游南昌段检测到鱼类114种,其中83种为历史记录种。不同季节的鱼类环境DNA信息的多样性和组成显示出极显著差异。上层水检测到的鱼类物种数分别显著多于中层水和下层水,且中层水和下层水检测到的鱼类在上层水中绝大多数都被检测到。上层水、中层水和下层水的鱼类环境DNA信息的多样性和组成不具有显著性差异。近岸检测到鱼类物种数多于离岸的,鱼类多样性指数无显著性差异,但群落结构具有显著性差异。RDA分析表明,赣江下游鱼类环境DNA受温度和pH的影响较大。本研究能够为基于环境DNA宏条形码的赣江鱼类资源的调查提供基线数据,并对后续赣江鱼类资源环境DNA宏条形码监测实施不同目的的采样策略提供依据;可为使用环境DNA宏条形码技术研究流水系统鱼类多样性提供技术参考,为环境DNA宏条形码技术应用的标准化流程提供依据。;As the negative impacts of human activities on natural ecosystems continue to intensify, non-invasive biodiversity assessment is becoming more and more important. The purpose of this study was to study fish diversity in Nanchang section of the lower reaches of Ganjiang River using environmental DNA metabarcoding technology. It compared the species composition and diversity of fish environmental DNA information from different seasons (spring, summer, autumn and winter), different water layers (upper, middle and lower) and different sampling locations (nearshore and offshore). The results showed that 114 species of fish were detected, among which 83 species were recorded in history. The diversity and composition of fish environmental DNA information in different seasons showed significant differences. The number of fish species detected in upper water was significantly higher than that in middle water and lower water, respectively. Most of the fish detected in the middle and lower waters were also detected in the upper water, respectively. There were no significant differences in diversity and composition of fish environmental DNA information in upper water, middle water and lower water. More fish species were detected near shore than offshore. There was no significant difference in fish diversity index, but significant difference in community structure. RDA analysis showed that fish environmental DNA in the lower reaches of Ganjiang River were greatly affected by temperature and pH. This study can provide baseline data for the investigation of fish resources based on environmental DNA metabarcoding, and a basis for the implementation of different sampling strategies for the subsequent monitoring of environmental DNA metabarcoding, in Ganjiang River. This study can also provide a technical reference for studying fish diversity in flowing water system using environmental DNA metabarcoding technology, and a basis for standardization process of application of environmental DNA metabarcoding technology.