Ecology of Chicken Turtles (Deirochelys reticularia) in a Seasonal Wetland Ecosystem: Exploiting Resource and Refuge Environments

Kurt A. Buhlmann^1,2, Justin D. Congdon¹, J.Whitfield Gibbons¹, and Judith L. Greene¹

¹University of Georgia, Savannah River Ecology Laboratory, Drawer E, Aiken, SC, 29802 USA
²University of Georgia, Odum School of Ecology, Athens, GA, 30602 USA

Abstract: Chicken turtles (Deirochelys reticularia) were studied at Dry Bay, a Carolina bay wetland in South Carolina, USA, between 1994 and 2005. A total of 461 individual turtles was marked from 1993–1998. Minimum ages at maturity for males and females were 2 and 5 yr, respectively. All females reproduced each year, and 60% of reproductive females produced two clutches per season. Clutch size averaged 9.8 eggs, and both clutch and egg size increased with body size. Hatchlings averaged 29.2 mm PL, and body sizes were similar among years. Yearling survivorship varied from 7.0–43.0% (mean=20.4%) among years. The highest survivorship of a hatchling cohort to age 5 was 0.21. Survivorships of juveniles and adults while in terrestrial refugia were higher than survivorships while in aquatic habitats. No adult females survived a 2-yr drought (2001–2003), and the bay was repopulated by mature males and juvenile females (most from the 1998 hatchling cohort) that had survived the extended drought in terrestrial refugia. Three of those juvenile females matured and produced eggs in 2004. The traits of early maturity, high susceptibility to predation, and shortened longevity characteristic of chicken turtles are consistent with predictions for species that live in seasonally fluctuating and highly unpredictable aquatic habitats.