Abstract：
Environmental DNA (eDNA) is a technique increasingly used for monitoring organisms in the natural environment including riverine macroinvertebrates. However, the effectiveness of eDNA for monitoring riverine macroinvertebrates compared with the more traditional method of sampling the organisms directly and identifying them via morphological analysis, has not been well established. Furthermore, the ability of the various gene markers and PCR primer sets to detect the full range of riverine invertebrate taxa has not been quantified. Here we conducted a meta-analysis of the available literature, to assess the effectiveness of eDNA sampling for detecting riverine macroinvertebrates compared with sampling for the organisms directly and applying morphological analysis. We found, on average, eDNA sampling, irrespective of the gene marker used, detected fewer riverine invertebrates than morphological sampling. The most effective PCR primer set for identifying taxa was mlCOIintF/jgHCO2198, (mlCOIintF- forward primer, jgHCO2198, - reverse primer). Regardless of the gene marker or primer sets used, however, many taxa were not detected by eDNA metabarcoding that were detected by sampling directly for these invertebrates, including over 100 members of Arthropoda. eDNA sampling failed to detect any species belonging to Nematoda, Platyhelminthes, Cnidaria or Nematomorpha and these markers applied for eDNA sampling in terrestrial systems also do not detect members of Nematoda. In addition to these issues, uncertainties relating to false positives from upstream DNA sources, the stability of DNA from different species, differences in the propensity for DNA release into the environment for different organisms, and lack of available sequence information for numerous taxa illustrates the use of eDNA is not yet applicable as a robust stand-alone method for the monitoring of riverine invertebrates. As a primary consideration, further methodological developments are needed to ensure eDNA captures some of the key freshwater taxa, notably taxa belonging to the phyla Arthropoda, Nematoda, Platyhelminthes, Cnidaria and Nematomorpha.
摘要：
环境DNA（eDNA）是一种越来越多地用于监测自然环境中的生物的技术，包括河流大型无脊椎动物。然而,eDNA监测河流大型无脊椎动物的有效性，与更传统的直接采样生物并通过形态学分析鉴定它们的方法相比，还没有得到很好的确立。此外，各种基因标记和PCR引物组检测河流无脊椎动物分类群的能力尚未量化。在这里，我们对现有文献进行了荟萃分析，评估eDNA采样检测河流大型无脊椎动物的有效性，与直接采样生物和应用形态学分析进行比较。我们发现,平均而言,eDNA采样,不管使用的基因标记，检测到的河流无脊椎动物比形态学采样少。用于识别分类单元的最有效的PCR引物组是mlCOIintF/jgHCO2198，（mlCOIintF-正向引物，jgHCO2198，-反向引物）。不管使用的基因标记或引物集，然而,通过直接对这些无脊椎动物进行采样而检测到的eDNA元编码没有检测到许多分类单元，包括100多名节肢动物。eDNA采样未能检测到属于Nematoda的任何物种，桔梗，Cnidaria或Nematomorpha以及这些用于陆地系统中eDNA采样的标记也无法检测到Nematoda的成员。除了这些问题,与上游DNA来源的假阳性相关的不确定性，来自不同物种的DNA的稳定性，不同生物的DNA释放到环境中的倾向差异，并且缺乏许多分类单元的可用序列信息表明，eDNA的使用尚不能作为一种可靠的独立方法来监测河流无脊椎动物。作为首要考虑,需要进一步的方法发展，以确保eDNA捕获一些关键的淡水类群，特别是属于节肢动物门的类群，线虫,桔梗，雀巢和线虫。
