Dispersal, home range establishment, survival, and reproduction of translocated eastern box turtles, Terrapene c. carolina

Abstract

The feasibility of translocation to establish a population of the eastern box turtle ( Terrapene c.carolina) was studied at Floyd Bennett Field, Brooklyn, NewYork, USA. The 579 ha site,originally salt marsh, was e lled during the 1920' s to construct a now-abandoned airport. It consists primarily of grasslands, native shrub thickets and woodlands, and mixed stands dominated by giant reed (Phragmites australis ). These human-created uplands are managed by the U.S. National Park Service for recreation and ecological restoration. Prior to this work, the site did not support a population of this species, but it is historically native to adjacent uplands. T. c. carolina were collected from sites on Long Island, New York, that were undergoing development, and released after data on size, mass, age, and sex were recorded. From 1987 through 1990, 335 individuals were released into developing woodlands. To provide data on dispersal, home range establishment, and initial survival, e fty-three of these were radio-tracked for up to seven years. Though individually variable, the T. carolina dispersed homeward. Of the 53 radio-tagged individuals, 13 (24.6%) left the site, 25 (47.2%) established home ranges, and 15 (28.3%) died before determination of home range establishment could be made. Most individuals established home ranges within a kilometer of the release point. However, some dispersed greater distances. Of the 25 individuals that established home ranges, 17 (68%) did so in the release year, two (8%) in outyear 1, three (12%) in outyear 2, and three (12%) in outyear 3. Annual known survival over e ve years post-release was 71%. Though not statistically signie cant, annual survival was 64% over the e rst two years and 84% over the e nal three. Principal causes of mortality were dispersal from the site and pneumonia, both of which were greatest initially, plus winter kill, a random event. Patterns of growth, home range size, activity season, habitat use, annual reproductive output, and production of young were generally comparable to natural populations of T. carolina. These results suggest that translocation may have potential for establishing new populations of T. carolina, though long term viability is still uncertain. However, any contemplated translocation would need to address the initially high loss to dispersal and disease. Moreover, since there are few sites of adequate size and quality, at least 500 ha of predominantly woody habitat, lacking populations of this species, its appropriateness is very limited.