Summary
Using coverboards to monitor herpetofauna is common practice, yet few studies have formally tested the efficacy of using coverboards. We tested whether using coverboards on survey plots increased the number of small snakes detected in eastern Ontario, Canada. We set up twenty 2500 m2 plots in field and forest habitat, ten with plywood coverboards and ten without coverboards. We sampled these twenty plots systematically for small snakes, and compared the number of snakes detected on plots with coverboards to the number detected on plots without coverboards. The number of snakes detected was always higher on plots with coverboards than on plots without coverboards, to the extent that we only detected the smallest snake species on plots with coverboards. We then examined whether Storeria occipitomaculata in western Québec, Canada prefer plywood or tin coverboards. We set up pairs of plywood and tin coverboards along transects, and monitored the use of these coverboards throughout the active season. Storeria occipitomaculata preferred tin over plywood coverboards. We confirmed that coverboards are indeed a useful tool for monitoring small snakes, and that some snakes show preferences for specific types of coverboards. We therefore suggest that researchers use an array of different types of coverboards when attempting to monitor small snake communities, or determine which coverboards are preferred by their target species in a pilot study.
Methodology
We sampled snakes at the Queen’s University Biological Station (QUBS; 44.5488 N, 76.3668 W; Figure 1) in eastern Ontario, Canada. Although QUBS is home to nine species of snakes, we limited our data analyses to three species with adequate sample sizes: Thamnophis sirtalis (Linnaeus 1758; Common Gartersnake), Storeria dekayi (Holbrook 1836; Dekay’s Brownsnake), and S. occipitomaculata (Storer 1839; Red-bellied Snake). We set up 10 study plots in field habitat matched with 10 adjacent study plots in forest habitat (Figure 1). All of the fields were cut once per year, and were thereby maintained as a mixed grass (Poa spp.) and forb (Trifolium spp. and Viccia spp.) community. All forests were composed mostly of Acer saccharum, Ostrya virginiana, Fagus grandifolia, and Betula papyrifera. All of our plots had an area of 2500 m2 . Whenever possible, we attempted to create plots that were 50 × 50 m; however, not all fields were large enough to contain a 50 × 50 m plot, but could instead contain a 25 × 100 m plot. We matched the shape of all forest plots to the shape of their adjacent field plot. We placed eight uniformly spaced plywood coverboards (60 × 60 cm pieces of 0.64 cm plywood) per plot in half of our plots (5 field and 5 forest plots).