SREL Reprint #2587




Terrestrial habitat use by aquatic turtles from a seasonally fluctuating wetland: implications for wetland conservation boundaries

Kurt A. Buhlmann and J. Whitfield Gibbons

University of Georgia, Savannah River Ecology Laboratory, South Carolina 29802 USA

Abstract: Terrestrial habitat use by eight sympatric species of aquatic turtles was monitored at Dry Bay, a Carolina bay wetland on the Upper Coastal Plain of South Carolina, USA. During a three-year study, a total of 1446 captures and recaptures, averaging 1.2 turtles/d, was made at a drift fence that completely encircled the wetland. Emigrations (defined as movements away from Dry Bay to other water bodies) totaled 152 (10.5%), whereas immigrations (defined as arrivals from other water bodies) totaled 99 (6.8%). Hatchlings arriving at Dry Bay from nests accounted for 409 captures (28.3%). Gravid females exiting the bay on nesting forays accounted for 271 captures (18.7%). Turtles exiting Dry Bay to seek terrestrial refugia within the adjacent upland habitat (and later returning) accounted for 515 captures (35.6%). Five species of turtles used adjacent upland terrestrial habitats for refugia. Deirochelys reticularia and Kinosternon subrubrum were found commonly in refugia during late summer through winter at distances up to 165 m and 135 m, respectively, from the delineated wetland boundary. Some Sternotherus odoratus, Chelydra serpentine, and Kinosternon baurii also used terrestrial refugia. The average duration in refugia was 185 d for Deirochelys and 170 d for Kinosternon. A majority of turtles selected a closed-canopy pine-oak forest, but some entered a recently clearcut (4-8 year-old), open-canopy pine plantation. Most turtles in the closed-canopy forest remained inactive until they returned to the water in March, while many in the clearcut changed their location one or more times. Individual turtles demonstrated site fidelity to refugia in successive years. Trachemys scripta and Pseudemys floridana did not use upland refugia but emigrated directly towards other bodies of permanent water, demonstrating the need for movement corridors. Nests were clustered in specific open-canopy upland areas, whereas terrestrial refugia were dispersed throughout the forest that surrounded the wetlands. Adjacent upland terrestrial habitats, as used by turtles, are critical components of the wetland ecosystem. Because upland habitats are used for seasonal refugia, nesting, and as corridors to other water bodies, human alteration of such habitats will affect the survival of individuals and the long-term persistence of turtle populations.

Keywords: Reptilia; Testudines; Emydidae; Kinosternidae; Chelydridae; Deirochelys reticularia; Kinosternon subrubrum; Kinosternon baurii; Sternotherus odoratus; Chelydra serpentina; Trachemys scripta; Pseudemys floridana; Clemmys guttata; turtle; ecology; conservation; buffers; Carolina bays; critical upland habitats; corridors; landscape management; site fidelity; survivorship; terrestrial refugia; wetlands delineation; South Carolina; USA

SREL Reprint #2587

2587 Buhlmann, K. A. and J. W. Gibbons. 2001. Terrestrial habitat use by aquatic turtles from a seasonally fluctuating wetland: implications for wetland conservation boundaries. Chelonian Conservation and Biology. 4:115-127.

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