科研之友
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摘要
Analysis of aquatic environmental DNA (eDNA) is a promising tool for monitoring invasive species, but application of this method is hindered by the inability to distinguish whether sources are alive or dead. We analyzed how the detection of eDNA from dead and live model organisms (Carassius auratus) differs depending on collection method and applied the resulting method in the field. We sampled 15 microcosms containing dead or live fish through time using different filter membrane types and pore sizes at varying depths. We detected DNA from dead individuals only at the bottom of the water column. We found that as pore size increased, the quantity of DNA captured decreased for both treatments, the quantity of DNA from dead individuals decreased over time, and dead individuals were associated with less DNA than their live counterparts. We then sampled restoration sites across National Parks where nonnative fish were being removed to create habitat for endangered frogs (Rana sierrae and Rana muscosa). We sampled completed restoration sites (sites containing only dead fish; n = 21) and active restoration sites (sites containing dead and live fish; n = 9) with 1.2-mu m polycarbonate track etch filters. Our field sampling accurately indicated the status of each site, except 1 probable false positive (low-level) and 1 false negative at a low-density site. Our results highlight that eDNA collection methods can be tailored to maximize the utility of eDNA techniques in aquatic habitat conservation. We recommend using eDNA techniques that maximize eDNA detection, sampling from water surfaces to avoid detection of dead individuals, and inferring presence of live individuals through the coupling of presence-only and quantification-based detections.
- 出版日期2018-9
