Amphibian Monitoring using Environmental DNA (eDNA)

This study aimed to improve monitoring of amphibian populations by using environmental DNA (eDNA) as a potentially more effective alternative to traditional detection methods. It aimed to identify the most efficient, reliable, and cost-effective approaches for eDNA monitoring of 10 resident amphibian species occurring in Alberta, Canada. The researcher tested various eDNA sampling strategies and detection platforms, including different primer sets and PCR methods on water and sediment samples collected from 39 wetlands known to contain one to four species of amphibians. The researcher investigated how sample dilution, detection platform type, sample medium, and seasonal timing influenced eDNA detection rates.

The species-specific primer set paired with two-step PCR produced the most accurate eDNA detections and minimized false positives, especially for wood frog (Lithobates sylvaticus), while detection rates for western toad (Anaxyrus boreas) and boreal chorus frog (Pseudacris maculata) remained low. Sample dilution improved detection in previously negative samples but decreased it in those initially positive, and duplicate qPCR testing outperformed single-run Ion Torrent PGM. Sediment samples yielded higher detection rates than water samples on the Ion Torrent platform, though this pattern was not seen with qPCR, and detection rates generally declined later in the season. Despite these insights, the researcher was unable to develop a consistently reliable protocol for detecting all 10 amphibian species in Alberta and recommends further refinement of methods.