Diamondback Terrapin Research

Kiawah Island, South Carolina

Diamondback terrapins are North America's only exclusively estuarine turtle. They inhabit tidal creeks of the Eastern and Gulf Coasts where they have experienced range-wide declines due to a variety of activities associated with coastal development. Historically, this species was overharvested, but today, terrapin populations have experienced declines from the development of nesting beaches, road mortality, and accidental drowning in blue crab fisheries equipment. Consequently, diamondback terrapins have received international attention from conservation organizations and have been identified as a priority species throughout their range.

Since 1998, the Davidson College Herpetology Lab has collected data on a population of diamondback terrapins on Kiawah Island, South Carolina. Initiated by Whit Gibbons (UGA's Savannah River Ecology Lab) in 1983, this long-term capture-mark-recapture study has documented a significant decline and even local extirpation from the first creek ever sampled by Whit Gibbons and his children. Our work at Kiawah Island continues to seek to understand the causes behind this decline in efforts to reverse this trend. We also seek to use this long-term data in addition to new data collection to understand more about the basic ecology of diamondback terrapins.

Current Projects

The role of bait and bycatch reduction device orientation on blue crab and diamondback terrapin catch. – Rebecca McKee, Kristen Cecala, Mike Dorcas, Whit Gibbons, Kelly Thorvalson

Mercury concentrations in diamondback terrapins (Malaclemys terrapin) from coastal South Carolina. – Thomas Rainwater, Kiefer Hazard, Matthew Chumchal, Louis Guillette Jr., Whit Gibbons, Mike Dorcas

Effects of environmental temperature variation on body temperatures and habitat use in free-ranging diamondback terrapins (Malaclemys terrapin). – Chance Ruder, Tia Akins, Steve Price, Leigh Anne Harden, Whit Gibbons, Mike Dorcas

Creek-specific variation in survivorship and recruitment of Malaclemys terrapin over three decades. – Lynea Witczak, Jackie Guzy, Steve Price, Whit Gibbons, Mike Dorcas


Kern, M. M., J. C. Guzy, J. E. Lovich, J. W. Gibbons, and M. E. Dorcas. In review. Factors causing deviation from optimal egg size theory in the diamondback terrapin (Malaclemys terrapin). Copeia.

Underwood, E. B., S. Bowers, J. C. Guzy, J. E. Lovich, C. A. Taylor, J. W. Gibbons, and M. E. Dorcas. In press. Sexual dimorphism and feeding ecology of diamondback terrapins (Malaclemys terrapin). Herpetologica.

Harden, L. A., S. E. Pittman, J. W. Gibbons, and M. E. Dorcas.2009. Development of a rapid assessment technique for diamondback terrapin (Malaclemys terrapin) populations using head-count surveys. Applied Herpetology 6:237-245. pdf

Cecala, K. K., J. W. Gibbons, and M. E. Dorcas. 2008. Ecological effects of major injuries in diamondback terrapins: Implications for conservation and management. Aquatic Conservation 18:421-427 pdf

Harden, L. A., N. A. DiLuzio, J. W. Gibbons, and M. E. Dorcas. 2007. Spatial and thermal ecology of diamondback terrapins (Malaclemys terrapin) in a South Carolina salt marsh. Journal of the North Carolina Academy of Science 123: 154-162. pdf

Dorcas, M. E., J. D. Willson, and J. W. Gibbons. 2007. Crab trapping causes population decline and demographic changes in diamondback terrapins over two decades. Biological Conservation 137: 334-340. pdf

Gibbons, J. W., J. E. Lovich, A. D. Tucker, N. N. Fitzsimmons and J. L. Greene. 2001. Demographic and ecological factors affecting conservation and management of the Diamondback Terrapin (Malaclemys terrapin) in South Carolina. Chelonian Conservation and Biology. 4:66-74. pdf

Hoyle, M. E. and J. W. Gibbons. 2000. Use of marked population of diamondback terrapins (Malaclemys terrapin) to determine impacts of recreational crab pots. Chelonian Conservation and Biology 3:735-737. pdf

Lovich, J. E. and J. W. Gibbons. 1990. Age at maturity influences adult sex ratio in the turtle Malaclemys terrapin. Oikos 59:126-134. pdf

Lovich, J. E., A. D. Tucker, D. E. Kling, J. W. Gibbons, and T. D. Zimmerman. 1991. Behavior of hatchling Diamondback Terrapins (Malaclemys terrapin) released in a South Carolina salt marsh. Herpetological Review 22:81-83. pdf

Seigel, R. A. and J. W. Gibbons. 1995. Workshop on the ecology, status, and management of the diamondback terrapin (Malaclemys terrapin), Savannah River Ecology Laboratory, 2 August 1994: Final results and recommendations. Chelonian Conservation and Biology 1:240-243. pdf

Tucker, A. D., N. FitzSimmons and J. W. Gibbons.1995. Resource partitioning by the estuarine turtle, Malaclemys terrapin: trophic, spatial, and temporal foraging constraints. Herpetologica 51:167-181. pdf

Tucker, A. D., J. W. Gibbons and J. L. Greene. 2001. Estimates of adult survival and migration for diamondback terrapins: conservation insight from local extirpation within a metapopulation. Canadian Journal of Zoology 79:2199-2209. pdf

Tucker, A.D., S.R. Yeomans, and J.W. Gibbons. 1997. Shell strength of mud snails (Ilyanassa obsoleta) may deter foraging by diamondback terrapins (Malaclemys terrapin). American Midland Naturalist 138:224-229. pdf

Support and Acknowledgements

This website created by Leigh Anne Harden and Kristen Cecala.
Some photos taken by Jackie Guzy, J.D. Willson, Tom Luhring, and Cris Hagen.

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Questions? Contact Michael Dorcas