Abstract
Reptiles are increasingly of conservation concern due to their susceptibility to habitat loss, emerging disease, and harvest in the wildlife trade. However, reptile populations are often difficult to monitor given the frequency of crypsis in their life history. This difficulty has left uncertain the true conservation status of many species, and the efficacy of conservation actions unknown. Environmental DNA (eDNA) surveys have consistently elevated the detection rate of species they are designed to monitor, and while promising for terrestrial reptile conservation, successes in developing such surveys to date have been sparse. We tested the degree to which inclusion of surface and soil eDNA sampling into conventional artificial cover object methods can elevate the detection probability of a small and cryptic terrestrial lizard, Scincella lateralis. We found that performing eDNA sampling of cover object surfaces using commercially-available paint rollers elevated per sample detection probabilities for this species 4-16x compared with visual surveys alone. We readily detected S. lateralis eDNA underneath cover objects up to 2 weeks after the last visual detection, and at some cover objects where no S. lateralis were visually observed in prior months. With sufficient sampling intensity, eDNA testing of soil underneath cover objects produced comparable per sample detection probabilities as roller surface methods. Our results suggest that combining eDNA and cover object methods can considerably increase the detection power of reptile monitoring programs allowing more accurate estimates of population size, detection of temporal and spatial changes in habitat use, and tracking success of restoration efforts. Further research into the deposition and decay rates of reptile eDNA under cover objects, as well as tailored protocols for different species and habitats, are needed to bring the technique into widespread usage. Article impact statement: Surveys for eDAN can be a critical tool for improving global reptile monitoring to aid conservation and recovery efforts. This article is protected by copyright. All rights reserved.