Responses of Targeted Herpetological Communities to Fire Management Practices in Pine-Oak Forests of the Great Smoky Mountains National Park

Fouts, Kevin; Maerz, John; Johnson, Kristine

SUMMARY: During the last two decades, managers at the Great Smoky Mountains National Park have instituted a formal program of scheduled, prescribed burning in the western section of the park. The program was established to pursue various ecological objectives, but as prescribed burning is not a widespread practice in the southern Appalachians, managers are uncertain about the effects of burning on some taxa and communities. Over the summers of 2012‐2014, we conducted a retrospective study on sites that had or had not experienced recent burning to estimate effects of burning on species of herpetofauna. On a series of matched control‐treatment sites, we counted salamanders caught in leaflitter traps placed in a network of monitored streams, and we counted reptiles encountered on hiking trails through upland habitats. On study plots established around the monitoring trails, we collected a time and spatial series of environmental data to characterize microclimate characteristics of the plot and model habitat suitability for a focal reptile species. Salamander surveys were conducted in 2012 and were repeated in 2014. We built models relating abundance of salamanders to type of site (burned or non‐burned reference) and time since last burn for each of four most often‐captured species. We fit the same models to data on four salamander guilds. Desmognathus quadramaculatus and the associated guild of large desmognathids were more abundant on reference sites than on burned sites, and greater abundances were associated with increasing time since last burn. For all other species analyzed (Desmognathus conanti, Pseudotriton ruber, and Eurycea wilderae) and their associated guilds (small desmognathids, large spelerpinids, small spelerpinids), abundances were greater on burned sites than on reference sites, and smaller abundances were associated with increasing time since last burn. The surveys conducted in 2014 largely reinforced the relationships observed in 2012 (see Supplement). In the summer of 2013, we identified a section of hiking trail occurring within each of 12 matched control‐treatment sites, and we located a single 10.1‐ha circular plot centered on one point of the trail. Within the plot, we continuously sampled temperature and humidity across an array of sensors. From the microclimate data, we built models of operative temperature for northern fence lizards (Sceloporus undulatus hyacinthinus) to investigate differences in predicted activity time budgets between burned and unburned sites. Burned forest stands had microclimates that resulted in longer modeled daily activity periods under most conditions during summer. We also conducted surveys for basking reptiles along the hiking trail sections. For two commonly‐encountered lizards (S. undulatus and skinks in the genus Plestiodon), we fit the count data to N‐mixture models of abundance. For both lizards, model results indicated that greater abundance per unit of trail occurred on burned sites than on unburned sites, and there was some evidence that smaller abundances were associated with increasing time since last burn.