SREL Reprint #3324

Head-starting as a management component for Gopher Tortoises (Gopherus polyphemus)

Tracey D. Tuberville1, Terry M. Norton2,3, Kurt A. Buhlmann1, and Veronica Greco2

1University of Georgia’s Savannah River Ecology Lab, Drawer E, Aiken, South Carolina, 29802, USA
2St. Catherines Island Foundation, 182 Camellia Road, Midway, Georgia, 31320, USA
3Georgia Sea Turtle Center, 214 Stable Road, Jekyll Island, Georgia, 31527, USA

Abstract: Viability models of turtle populations have shown that after adult survivorship, juvenile survivorship is the most influential parameter affecting population persistence. This suggests that increasing juvenile survivorship, such as through head-starting, might be a useful management strategy. Little is known about survivorship and ecology of juveniles of most turtle species, including even wellstudied species such as the Gopher Tortoise (Gopherus polyphemus). Limited data on the fate of headstarted tortoises further constrains attempts to evaluate head-starting as a management tool. We summarize our experiences head-starting Gopher Tortoise hatchlings as part of reintroduction efforts at Savannah River Site (SRS), South Carolina, USA, and St. Catherines Island (SCI), Georgia, USA, and compare survivorship of head-started hatchlings with juveniles manipulated using other techniques. Hatchlings exhibited nearly 100% survivorship during the captive head-start period, but survivorship during the first year post-release varied among cohorts: 17 of 32 (53.1%) 2001 SRS hatchlings, seven of seven (100%) 2005 SCI hatchlings, and one of 32 (3.1%) 2006 SCI hatchlings. For two cohorts, head-started hatchlings performed as well as older non-head-started juvenile tortoises. At least 20.0% of St. Catherines Island neonates that we released into temporary predator-proof cages shortly after hatching (i.e., without head-starting) were known to have survived through their first winter dormancy. Survivorship for all manipulated hatchlings (regardless of treatment) was lowest during the first year post-release. The potential role of head-starting as a management tool merits further investigation. We recommend that future studies include an experimental component to allow critical evaluation of the techniques implemented.

Keywords: direct-release; Gopherus polyphemus; Gopher Tortoise; hatchling; head-start; juvenile; survivorship; translocation

SREL Reprint #3324

Tuberville, T. D., T. M. Norton, K. A. Buhlmann, and V. Greco. 2015. Head-starting as a management component for Gopher Tortoises (Gopherus polyphemus). Herpetological Conservation and Biology 10(Symposium): 455-471.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).