SREL Reprint #3241
Density and size class distribution of Yellow-bellied Sliders (Trachemys scripta scripta) inhabiting two barrier island wetlands
Brett A. Degregorio, Andrew M. Grosse, and J. Whitfield Gibbons
Savannah River Ecology Lab, University of Georgia, Drawer E, Aiken, South Carolina 29802, USA
Abstract: An abundance of physical barriers and physiological challenges often prevent reptile and amphibian species from arriving at, and subsequently colonizing, barrier islands. Despite the high diversity of herpetofauna in the southeastern United States, only a small subset of those species persist on the myriad of barrier islands present just offshore. The Yellow-bellied Slider (Trachemys scripta scripta) is a versatile habitat generalist that can often be found in freshwater wetlands on barrier islands. We used a mark-recapture approach to study the population size and demographics of two populations of Yellow-bellied Sliders on two barrier islands. The estimated turtle density of 2,200/ha on Bald Head Island, North Carolina, USA is the highest yet reported in the literature and is much higher than that of Capers Island, South Carolina, USA (387/ha). Furthermore, turtles of both sexes captured on Bald Head constituted a wide range of size classes; whereas, those on Capers Island were mostly female (3f:1m) and were significantly larger (plastron length). Selective predation between size classes or sexes can be an important driver of turtle population dynamics and behavior and we suggest that the abundance of large American Alligators (Alligator mississippiensis), an important turtle predator, present on Capers Island is likely responsible for the absence of small size classes of Yellow-bellied Sliders from this wetland.
Keywords: barrier islands; demographics; freshwater turtles; predation pressure; population density
SREL Reprint #3241
DeGregorio, B. A., A. M. Grosse, and J. W. Gibbons. 2012. Density and size class distribution of Yellow-bellied Sliders (Trachemys scripta scripta) inhabiting two barrier island wetlands. Herptological Conservation and Biology 7(3): 306-312.