Home Range, Habitat Selection, and Diet of the Diamondback Terrapin
(Malaclemys terrapin) in a North Carolina Estuary
Phil Spivey
Georgia Department of Natural Resources Nongame Wildlife Section
We used radio telemetry to track 29 adult diamondback terrapins to estimate home range and examine habitat selection in a ditched North Carolina estuary (Carteret Co.). Pooled telemetry observations revealed terrapins selected areas of low, frequently flooded marsh over high, infrequently flooded marsh habitats. Overall, natural creeks in the study area were not used as often as areas of ditched marsh, possibly a result of intensive commercial crabbing efforts in the creeks. Eighty-six percent of all telemetry locations were within ditched marsh. Average home range was 257.7 ha (range 50.6-427.7 ha) as calculated by the adaptive kernel method.
We investigated the diet of the diamondback terrapin during the spring and summer of 1997. Large-sized (>30mm head width; n=14) terrapins consumed 75% blue crabs (Callinectes sapidus) consisting of whole juvenile crabs (60%) and cropped limbs (15%) of larger crabs. For medium-sized terrapins (20-30mm head width; n=20), 31% of their diet was fiddler crabs (Uca pugnax) in addition to 62% juvenile blue crabs. The diet of small sized terrapins (<20mm head width; n=34) consisted of 68% eastern melampus snails (Melampus bidentatus). Significant dietary overlap existed between medium and large terrapins. Large terrapins had the most diverse diet being comprised of 11 prey species. Small terrapins were most specialized, with only 4 prey species.
2nd Terrapin Workshop, October 6–8, 2000
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Thermal ecology and habitat utilization of diamondback terrapins
UNCW Southwood
The diamondback terrapin (Malaclemys terrapin) is the only estuarine species of turtle, and generally inhabits the shallow brackish waters of coastal marshes and creeks. Diamondback terrapin populations have decreased throughout their range over the past couple of decades, and this reptile is currently listed as a “Species of Concern” in North Carolina. Factors contributing to population decline are habitat loss, road and boat mortality, nest predation, and mortality due to incidental bycatch in fishing gear. The North Carolina Blue Crab Fishery Management Plan (NC Division of Marine Fisheries, 2004) states that research to determine the distribution of diamondback terrapins, particularly areas of overlap with blue crab habitat, is necessary in order to devise proper regulations and management strategies to minimize interactions between terrapins and crab pots (Blue Crab FMP, Section 10.3.5.4), thereby reducing fisheries-related mortality for terrapins. We have initiated surveys to assess relative abundance and distribution of diamondback terrapins in waters utilized by commercial and/or recreational crab fisheries in the marshes of southeastern North Carolina. We are also using radiotelemetry and micro-dataloggers to assess home range, diving and basking patterns, seasonal movements, and habitat utilization. Tissue samples collected from terrapins are used to determine thermal dependence of metabolic enzymes and seasonal changes in metabolic biochemistry.
Leigh Anne Harden - Leigh Anne is a 2007 graduate of Davidson College, NC where she received a BS in Biology. While attaining her undergraduate degree, she worked in the Davidson College Herpetology Laboratory where she focused her research on semi-aquatic turtles. She gained experience using several field/sampling techniques such as radio tracking, seining, hoop-net trapping, temperature data-loggers, and mark-recapture. For the past three years, she has been involved with a long-term mark-recapture study in Kiawah, SC on diamondback terrapins (Malaclemys terrapin) conducted by researchers from Davidson College and UGA’s Savannah River Ecology Lab. She plans to take her experience from this study and apply it to salt marshes in southeastern NC to learn more about terrapin ecology, physiology, and behavior in this region. Her MSc will focus on the spatial ecology and thermal biology of diamondback terrapins in Middle Sound using radio-telemetry in conjunction with and temperature micro-dataloggers.
