基于环境DNA宏条形码的太湖流域底栖动物监测与生态健康评价

大型底栖动物是生态环境监测和评估的主要目标生物类群之一。环境DNA宏条形码技术的发展为提高底栖动物多样性监测的通量、精准性、标准化程度提供了新的机遇,但该方法在我国尚未有流域尺度的应用先例,其结果的可靠性和对生态环境健康状况的指示性有待检验。率先将环境DNA宏条形码技术用于太湖流域65个点位的底栖动物监测和流域生态健康评价,并与同步进行的形态学监测结果进行了比较。结果表明:①环境DNA方法能检出更多的底栖动物类群,在科、属、种水平上检出的分类单元数分别是形态学监测结果的106%、132%、155%;②基于环境DNA技术的检测方法能够很好地识别形态学监测结果中的优势物种,检出的科级、属级分类阶元能够覆盖形态学监测结果中90%以上的生物量和个体数,同时包含60%以上的物种数;③两种方法对同一物种的检出频次显著相关(R²>0.7,P<0.0001),总体检出一致率达72.3%;④在底栖动物完整性指数(B-IBI)方面,环境DNA方法与形态学方法的计算结果显著相关(R²=0.235,P<0.0001),94%的点位的B-IBI等级划分误差在1级以内,且两种方法的计算结果在底栖动物完整性的流域空间格局描绘上高度重合。综上所述,环境DNA宏条形码技术在太湖流域底栖动物群落监测和评价中的整体应用结果表明,环境DNA监测方法结果可靠,将其进一步规模化应用有望显著提高我国水生态系统生物监测结果的准确性和生态健康评价的技术水平。

Benthic Macroinvertebrate Biomonitoring and Ecological Assessment in Taihu Lake Basin Based on Environmental DNA Metabarcoding

Benthic macroinvertebrate is one of the main target groups in biomonitoring and ecological assessment of aquatic environment.Recent advance in environmental DNA (eDNA) metabarcoding technology provides a unique opportunity to enhance the throughput,precision and standardization degree for biomonitoring of benthic macroinvertebrate.Up to now,however,there still lacks a basin scale validation to promote the application of the eDNA based benthic macroinvertebrate biomonitoring and ecological assessment in China.Here the reliability of the eDNA based biomonitoring results and its implications for ecological health assessment were evaluated.The eDNA metabarcoding technique was applied to the large-scale biological monitoring and ecological assessment of macroinvertebrate in Taihu Lake Basin,and the results were compared with the traditional monitoring methods.Firstly,more species were detected by eDNA method,and the number of taxa at the family,genus and species levels by eDNA method were 106%,132% and 155% of the morphological results,respectively.Secondly,the morphologically dominant species were well identified by the eDNA method.The families and genera detected by eDNA method represented the vast majority (over 90%) of the biomass and the number of individuals,which also represented the majority (over 60%) of the species by the morphological approaches.Thirdly,the detection frequency of the same species was significantly correlated between the two methods (R²>0.7,P<0.000 1),and the overall detection consistency was 72.3%.Finally,there was a significant correlation between the benthic-index of biotic integrity (B-IBI) calculated by eDNA and morphological methods (R²=0.235,P<0.000 1).Most of the sites (94%) had variance of B-IBI within one grade by the two approaches.Moreover,the spatial pattern of benthic integrity was highly coincident between the two methods.Overall,this study demonstrated that the eDNA metabarcoding provided reliable results for benthic macroinvertebrate biomonitoring and ecological assessment in Taihu Lake Basin.Further large-scale application of eDNA technologies could significantly improve the technical level and efficiency of biomonitoring and ecological health assessment of aquatic ecosystems in China.