Tracking an invasion front with environmental DNA

Abstract

Data from environmental DNA (eDNA) may revolutionize environmental monitoring and management, providing increased detection sensitivity at reduced cost and survey effort. However, eDNA data are rarely used in decision‐making contexts, mainly due to uncertainty around (1) data interpretation and (2) whether and how molecular tools dovetail with existing management efforts. We address these challenges by jointly modeling eDNA detection via qPCR and traditional trap data to estimate the density of invasive European green crab (Carcinus maenas), a species for which, historically, baited traps have been used for both detection and control. Our analytical framework simultaneously quantifies uncertainty in both detection methods and provides a robust way of integrating different data streams into management processes. Moreover, the joint model makes clear the marginal information benefit of adding eDNA (or any other) additional data type to an existing monitoring program, offering a path to optimizing sampling efforts for species of management interest. Here, we document green crab eDNA beyond the previously known invasion front and find that the value of eDNA data dramatically increases with low population densities and low traditional sampling effort, as is often the case at leading‐edge locations. We also highlight the detection limits of the molecular assay used in this study, as well as scenarios under which eDNA sampling is unlikely to improve existing management efforts.

Temperature Controls eDNA Persistence across Physicochemical Conditions in Seawater

“…Anthropogenic impacts are causing species extinctions and population declines globally. − Molecular biology methods accelerate the pace at which vulnerable biological communities are characterized to inform conservation and ecosystem restoration efforts. , Environmental DNA (eDNA) sequencing and quantification complement conventional methods for assessing biodiversity and the distribution of invasive and ecologically important species in marine habitats. − However, the utility of eDNA methods hinges on understanding the factors that control the distribution and abundance of eDNA across spatiotemporal scales …”

Integrating spatial stream network models and environmental DNA to estimate current and future distributions of nonnative Smallmouth Bass

“…Indeed, jointly modeling eDNA detection and traditional sampling techniques has led to advances integrating multiple data streams into nonnative species management (Keller et al. 2022).…”

“…Complementary information collected from traditional sampling, such as electrofishing, could aid in filling data gaps and developing management strategies with our data set. Indeed, jointly modeling eDNA detection and traditional sampling techniques has led to advances integrating multiple data streams into nonnative species management (Keller et al 2022).…”

How to barcode (almost all) freshwater biodiversity

“…The use of eDNA as a method for the cost-effective and non-intrusive monitoring and management of invasive species and species at risk has seen increasing attention and standardization in recent years (Abbott et al 2021; Fediajevaite et al 2021). The concomitant detection of invasive/native species can help to delineate the invasion front of an invasive species (Keller et al 2022) and capture shifting dynamics of the river ecosystem (Greenhalgh et al 2022), for example the increasing detection in time and space of dreissenid mussels to the detriment of local native species (Ricciardi, Whoriskey, and Rasmussen 1996).…”