Vertebrate Use of Gopher Tortoise Burrows and Aprons

Gopher Tortoise (Gopherus polyphemus) burrows are used by more than 60 vertebrate species, but the frequency with which species use burrows and the extent to which other vertebrates use the mound of sand at the burrow entrance, called the burrow apron, has not been quantitatively assessed. Between 2 June and 9 October 2014, we monitored active and inactive adult Gopher Tortoise burrows with motion-triggered trail cameras to identify and enumerate vertebrate burrow visitors. We recorded 12,238 video clips during 2299 trap nights, of which 10,151 (83%) contained a Gopher Tortoise and 1732 (14%) contained other vertebrate species. We reduced multiple videos of a single burrow visitation to 1 observation, resulting in 929 observations of 14 vertebrate species (not including the Gopher Tortoise) using tortoise burrows and 34 species on burrow aprons. Mammals were the most commonly recorded taxa (54%), followed by birds (32%), amphibians (9%), and reptiles (5%). Active burrows were visited more frequently than inactive burrows across all taxa, and burrow aprons were used more frequently than the burrow tunnel. Although active and inactive Gopher Tortoise burrows provide refuge for some vertebrate species, active burrows may provide additional resources, such as increased prey for insectivorous species. More species were found to be present on burrow aprons than within burrows, indicating the apron may be an important microhabitat for species, including those not known to use burrows.