Gopher Tortoise Ecology in Coastal Upland and Beach Dune Habitats in Northeast Florida

Abstract

Considered a keystone species in the southeastern US coastal plain, gopher tortoises occupy a variety of upland habitat types. Although upland pine-dominated habitats have received much attention, few studies have examined tortoises in nearby coastal beach dune habitats. To examine the distribution and abundance of gopher tortoises in northeast Florida coastal habitats, comprehensive burrow surveys were conducted 3 times during the last 8 yrs on 2 separate gopher tortoise populations near St. Augustine, Florida. The objectives for these surveys were to 1) examine changes in population size and structure in representative upland and coastal dune habitats and 2) describe the response of gopher tortoises to land management practices (i.e., prescribed fire). Total burrow density within the upland population remained stable over the 3 surveys (0.68 burrows/ha in 2005, 0.66 burrows/ha in 2007, and 0.64 burrows/ha in 2011). Burrow densities in the burned areas of the upland habitat increased in areas that were burned at least once since the time of the first survey in 2005 but decreased in areas that were infrequently burned or remained unburned. Burrow density on the beach dunes, however, greatly increased between the most recent 2 surveys (3.63 burrows/ha in 2007 and 8.95 burrows/ha in 2011), possibly attributable to an increased use of a relatively confined habitat, or sampling biases by surveyors. Three different correction factor methods were used to determine gopher tortoise population estimates for each of the surveys, providing a range of estimates. The results of this study and the few others focused on coastal beach dunes suggest that this vulnerable, yet important, habitat should receive more attention because some of the highest gopher tortoise burrow densities have been observed there.