Distribution, genetic structure, and wetland characteristics of four-toed salamanders (Hemidactylium scutatum) in Catoosa Wildlife Management Area

Abstract

The four-toed salamander (Hemidactylium scutatum) is a small, wetland-breeding amphibian that is patchily distributed and listed as a species of conservation concern across much of its range. Despite ranging throughout Tennessee, little is known about its ecology or distribution in the state. We conducted four-toed salamander surveys across 45 wetlands in Catoosa Wildlife Management Area (WMA) on the Cumberland Plateau to assess distribution, genetic structure, and habitat use. Four-toed salamanders were detected at 19 wetlands (42.2%) across the eastern two-thirds of Catoosa WMA and Lone Mountain State Forest. Population genetic analyses revealed spatial genetic structure and were largely congruent to previous genetic clustering analyses within the WMA. Using high-resolution geospatial data, we compared characteristics between wetlands where we detected four-toed salamanders and wetlands where we did not and found that wetlands where we detected four-toed salamanders had significantly greater within-wetland variation in slope and lower average solar radiance. This indicates that topographic complexity and natural shade could promote microhabitats that are suitable for nesting. These findings demonstrate that four-toed salamanders are more widespread within Catoosa WMA than previously documented and promoting future surveys and protecting small, topographically variable wetlands will be critical for conserving this species in Tennessee.