Environmental DNA detection of endangered and invasive species in Kejimkujik National Park and Historic Site.

The use of environmental DNA (eDNA) allows the early detection of aquatic species at low densities (e.g. elusive and invasive species), which otherwise could be challenging to monitor using conventional techniques. Here, we assess the ability of eDNA sampling to detect the presence/absence of one species-at-risk (Blanding's Turtle) and two invasive species (Chain Pickerel and Smallmouth Bass) in Kejimkujik National Park and National Historic site, Nova Scotia, where the aquatic system is highly acidic and rich in organic compounds. Five replicates of 1L water samples were taken per sampling site. Water filtration and eDNA extractions were performed on-site, while qPCR reactions were performed in the laboratory using species-specific assays. Samples were treated with an inhibition removal kit and analyzed pre- and post-inhibition removal. Despite the low pH and PCR inhibitors in water samples, our results showed positive eDNA detections in almost all expected positive sites (except in one site for Blanding's Turtle). Detections of the target species were also observed at sites where their presence was previously unknown. Our study supports the advantage of eDNA to monitor species at low densities, revealing new distributions or recently invaded areas. We also demonstrate how eDNA can directly instruct management strategies in Kejimkujik.