Improving the containment of a freshwater invader using environmental DNA (eDNA) based monitoring

Abstract

On-ground management actions targeting invasive and/or native species are often undertaken based on incomplete and biased distribution data for the species of interest. Once an invasive species becomes established, containment can provide an effective management option to conserve native biodiversity only if it is implemented beyond the outer distribution limits of the species of interest. Determining these outer distribution limits is currently difficult for freshwater fish species because of the low sensitivity and biases associated with conventional monitoring methods. The improved sensitivity of environmental DNA-based surveys makes them particularly useful to determine these outer distribution limits. In this study, we used conventional monitoring methods and eDNA-based monitoring using real-time PCR to determine the spread of the invasive redfin perch (Perca fluviatilis) in an intermittent river system. This voracious predatory fish is responsible for the continued decline of several threatened and vulnerable species within Australia. We found that eDNA detection rates were high in our study system, when redfin perch presence was confirmed by conventional monitoring, compared to previously published works. Additionally we describe how the combination of conventional and eDNAbased monitoring can improve redfin perch distribution data compared to conventional monitoring alone. This improvement has subsequently been used to inform management and determine the optimal location for the construction of an exclusion barrier.

An environmental DNA‐based method for monitoring spawning activity: a case study, using the endangered Macquarie perch (Macquaria australasica)

“…; Laramie, Pilliod & Goldberg ; Bylemans et al . ). Furthermore, it has been suggested that the absolute abundance of mitochondrial (mt‐) eDNA fragments can be used to determine the reproductive status of populations (Spear et al .…”

“…Environmental DNA-based species detection is a relatively new technique which is particularly useful for detecting aquatic species at low densities (Ficetola et al 2008;Thomsen et al 2012a). The sensitivity of this technology can be used to improve presence/absence data for cryptic species (Dejean et al 2012;Thomsen et al 2012b;Sigsgaard et al 2015) and accurately delineate the distribution of species (Jerde et al 2011;Laramie, Pilliod & Goldberg 2014;Bylemans et al 2016a). Furthermore, it has been suggested that the absolute abundance of mitochondrial (mt-) eDNA fragments can be used to determine the reproductive status of populations (Spear et al 2014).…”

Application of environmental DNA analysis to inform invasive fish eradication operations

“…bluegill sunfish ( Lepomis macrochirus ) (Takahara et al 2013). This increased effectiveness, combined with relatively low financial costs and reduced impact on the environment, demonstrates that eDNA methodologies have high potential for enhancing the management of invasive fish species (Rees et al 2014; Bylemans et al 2016). Applications so far have included distribution assessments (Takahara et al 2013; Keskin 2014), monitoring surveys on invasion fronts (Jerde et al 2013; Adrian-Kalchhauser and Burkhardt-Holm 2016) and the evaluation of population eradication attempts (Dunker et al 2016).…”

Monitoring the eradication of the highly invasive topmouth gudgeon (Pseudorasbora parva) using a novel eDNA assay

“…The use of eDNA to detect and monitor invasive species at low densities has numerous advantages over traditional techniques, Sampling point 1 2 3 4 5 6 7 8 9 10 P1 PCR 0 0 0 0 3 0 0 0 0 0 P1 qPCR1 2 3 3 2 3 3 2 1 0 3 P1 qPCR2 0 0 0 2 0 0 1 0 0 1 P2 PCR 0 1 0 1 0 0 1 1 1 1 P2 qPCR1 1 3 0 2 0 3 2 1 3 3 P2 qPCR2 1 0 0 2 0 1 0 0 0 0 P3 PCR 0 1 0 2 1 1 0 0 0 1 P3 qPCR1 0 2 0 3 3 3 0 (Evans, Shirey, Wieringa, Mahon, & Lamberti, 2017;Jones, 2013;Tucker et al, 2016). For example, eDNA from European weather loach (Misgurnus fossilis) and redfin perch (Perca fluviatilis) was detected at sites where fishing had previously failed to find these species (Bylemans, Furlan, Pearce, Daly, & Gleeson, 2016;Sigsgaard, Carl, Møller, & Thomsen, 2015). P. parva has a small size, and trapping can on occasions be unsuccessful, particularly during the early life stages…”