Abstract
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 or 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.
Highlights
The introduction of non-native species into aquatic ecosystems is known to potentially have dramatic effects on ecosystem structure and function
We evaluated the fish community structure in lakes with and without pickerel to assess the effect of the presence of this predator
The chain pickerel (Esox niger) is an introduced fish species to Nova Scotia, initially planted in three lakes in 1945, whose distribution has spread to 95 known locations over time (Figure 1)
Summary
The introduction of non-native species into aquatic ecosystems is known to potentially have dramatic effects on ecosystem structure and function. The chain pickerel (Esox niger) is an introduced fish species to Nova Scotia, initially planted in three lakes in 1945, whose distribution has spread to 95 known locations over time (Figure 1). All of these introductions have been through additional illegal movements of live fish and/or subsequent dispersal within watersheds following initial introductions, contingent on connectivity of adjoining or adjacent waterways. There is evidence that introduction of littoral predators, such as chain pickerel, can change the fish assemblage structure of lakes, most notably the cyprinid community (Whittier et al, 1997; 1999). The purpose of the work described here was to compare fish community structure in lakes with and without chain pickerel
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