Blackman Rosetta C, Ling Kar Keun Sean, Harper Lynsey R, Shum Peter, Hänfling Bernd, Lawson-Handley Lori
Department of Aquatic Ecology Eawag Swiss Federal Institute of Aquatic Science and Technology Dübendorf Switzerland.
Department of Evolutionary Biology and Environmental Studies University of Zurich Zürich Switzerland.
Ecol Evol. 2020 Oct 29;10(23):13248-13259. doi: 10.1002/ece3.6921. eCollection 2020 Dec.
The early detection of invasive non-native species (INNS) is important for informing management actions. Established monitoring methods require the collection or observation of specimens, which is unlikely at the beginning of an invasion when densities are likely to be low. Environmental DNA (eDNA) analysis is a highly promising technique for the detection of INNS-particularly during the early stages of an invasion.Here, we compared the use of traditional kick-net sampling with two eDNA approaches (targeted detection using both conventional and quantitative PCR and passive detection via metabarcoding with conserved primers) for detection of quagga mussel, a high priority INNS, along a density gradient on the River Wraysbury, UK.All three molecular tools outperformed traditional sampling in terms of detection. Conventional PCR and qPCR both had 100% detection rate in all samples and outperformed metabarcoding when the target species was at low densities. Additionally, quagga mussel DNA copy number (qPCR) and relative read count (metabarcoding) were significantly influenced by both mussel density and distance from source population, with distance being the most significant predictor. . All three molecular approaches were more sensitive than traditional kick-net sampling for the detection of the quagga mussel in flowing water, and both qPCR and metabarcoding enabled estimates of relative abundance. Targeted approaches were more sensitive than metabarcoding, but metabarcoding has the advantage of providing information on the wider community and consequently the impacts of INNS.
入侵性非本地物种（INNS）的早期检测对于指导管理行动至关重要。既定的监测方法需要采集或观察样本，而在入侵初期，当物种密度可能较低时，这是不太可能实现的。环境DNA（eDNA）分析是一种极具前景的检测INNS的技术，尤其是在入侵的早期阶段。在此，我们将传统踢网采样与两种eDNA方法（使用常规PCR和定量PCR的靶向检测以及通过保守引物进行宏条形码分析的被动检测）进行了比较，以检测斑马贻贝（一种高度优先的INNS），该物种在英国雷兹伯里河沿密度梯度分布。在检测方面，所有三种分子工具都优于传统采样。常规PCR和qPCR在所有样本中的检测率均为100%，并且当目标物种密度较低时，其表现优于宏条形码分析。此外，斑马贻贝的DNA拷贝数（qPCR）和相对读数计数（宏条形码分析）均受到贻贝密度和与源种群距离的显著影响，其中距离是最显著的预测因子。对于在流动水中检测斑马贻贝，所有三种分子方法都比传统踢网采样更敏感，并且qPCR和宏条形码分析都能够估计相对丰度。靶向方法比宏条形码分析更敏感，但宏条形码分析的优势在于能够提供更广泛群落的信息，从而了解INNS的影响。
