Vernal Pool Amphibian Inventories in the Temperate Forests of Eastern North America: Can Environmental DNA Replace the Traditional Methods?

Abstract

Amphibian populations have been globally declining since at least 1990. In the temperate forests of eastern North America, vernal pools offer important breeding habitats to many amphibians but are usually not considered for forest management because of their small size and temporary status. The effective monitoring and management of amphibians rely on accurate knowledge of their spatiotemporal distributions, which is often expensive to collect due to the amount of fieldwork required. In this study, we tested whether eDNA metabarcoding could identify the same amphibian communities as the traditional inventory protocols. We collected eDNA samples in twelve vernal pools in the spring of 2019 and identified their communities via metabarcoding. At each pool, three traditional amphibian inventory methods were used: call surveys, trapping, and active search surveys. In total, 13 amphibian species were detected, with most of them being detected using both eDNA and the traditional methods. When comparing the results of eDNA with the traditional methods, we found that species ecology and behavior are key factors of its detectability via a specific method. With its higher taxonomical precision and repeatability, eDNA metabarcoding allows for the inventorying of amphibian species living and reproducing in vernal pools and their vicinity with accuracy. As eDNA metabarcoding is inexpensive compared to the traditional methods, we conclude that eDNA sampling should be considered for integration as a standard monitoring tool, after an initial assessment of amphibian diversity.