SREL Reprint #3094

A Long-Term Study of Eastern Box Turtles (Terrapene c. carolina) in a Suburban Neighborhood: Survival Characteristics and Interactions with Humans and Conspecifics

I. Lehr Brisbin, Jr.1, Robert A. Kennamer1, Eric L. Peters2, and Deno J. Karapatakis1

1Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802, USA
2Chicago State University, 9501 S. King Dr., Chicago, Illinois 60425, USA

Abstract: We report findings from over 125 animal-yr of adult Eastern Box Turtle (Terrapene carolina carolina) radio tracking in an urban forest/suburban neighborhood ecotone in Aiken, South Carolina (USA). Data gathered from 23 radiotelemetered adults over 15.5 yr (1989-2004) documented 10 deaths (7 associated with human activities). Constant annual adult survival probability estimated for radiotelemetered turtles was 0.932 ± 0.021 (SE). Although a model of gender-specific adult survival was not as strongly supported as a constant survival model, evidence pointed to females experiencing lower survival than males. A model that included time spent in suburban neighborhoods also performed nearly as well as a constant survival model, suggesting that greater time spent in suburban habitats tended to reduce survival. In a separate analysis derived from opportunistic marking and recapture of 86 adult turtles not used in the radiotelemetry study, a model of constant survival and constant capture probability proved the most parsimonious, with annual apparent survival probability estimated as 0.954 ± 0.036. Estimated annual capture probability was low (0.085 ± 0.019), but a gender-specific capture probability model suggested that the encounter rate for females was higher than for males, even though the population was male-dominated (male:female = 2.1:1). Survival estimates indicated that average life-span (after attaining adulthood) ranged from 14 to 21 yr. Coincidental human encounters with radiotelemetered turtles took place mostly within developed suburban areas, peaking in June-July, and suggested that females may have been more attracted to developed habitats than males (e.g., females were more likely than males to be encountered crossing streets). In contrast, conspecific interactions among Box Turtles were reported more frequently in forest than in developed habitats. Our study suggests that adult Box Turtles can persist in urban forest/suburban neighborhood ecotones with survival rates not differing greatly from those of adults in more natural habitats. However, movements of adult females from forested habitat into adjacent suburban neighborhoods, especially during the nesting season, may result in these human-altered habitats acting as ecological traps, possibly impacting long-term population viability.

Keywords: Behavioral Interactions, Eastern Box Turtle, Habitat Use, Mortality Sources, Suburban Habitats, Survival Estimation, Terrapene c. carolina

SREL Reprint #3094

Brisbin, I. L., Jr., R. A. Kennamer, E. L. Peters, and D. J. Karapatakis. 2008. A Long-Term Study of Eastern Box Turtles (Terrapene c. carolina) in a Suburban Neighborhood: Survival Characteristics and Interactions with Humans and Conspecifics. In: J. C. Mitchell, R. E. Jung Brown, and B. Bartholomew (Eds.). Urban Herpetology. Society for the Study of Amphibians and Reptiles. Herpetological Conservation Number 3: 373-385.

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