Evaluation of Environmental DNA as a Surveillance Tool for Invasive House Mice (Mus musculus)

Abstract

Increasing the success of invasive species management depends on the development, testing, and deployment of new tools. Environmental DNA (eDNA) is an effective tool for monitoring invasive species that can help identify presence/absence, geographical boundaries of invasion, risk pathways, and population connectivity. In particular, understanding the sensitivity of eDNA detection rates to target species density allows calibration of sampling rates. In this study, we take a lab-validated eDNA assay for Mus musculus (house mouse) and test its detection rates at different populations densities for wild-caught, free-ranging M. musculus in a controlled laboratory and an outdoor mesocosm. The goal was to understand both eDNA accumulation after M. musculus is introduced and the persistence of the accumulated eDNA signal in the environment after animals were removed. We found that eDNA signal was detectable within 1 h of a single mouse being introduced and that the signal was detectable for months after in the controlled environment but largely undetectable after 4 days in an outdoor mesocosm. We suggest sampling strategies for post-eradication deployment of eDNA and highlight other uses for this assay, which are important to the deployment of this tool for invasive M. musculus management.