STATUS: Species of Special Concern
The gopher tortoise is a terrestrial turtle characterized by an oblong carapace, large head with integumentary glands under the chin, stumpy elephantine hind feet and flattened, shovel-like forelimbs adapted for digging. The carapace is domed and averages 23 to 28 cm. in length; coloration is generally tan, brown, or gray. The plastron is dull yellowish-brown and has gular scutes which project anteriorly. The concavity of the plastron is usually greater in males than in females, and the length of the anal notch on the shell is also generally greater in males. Growth annule may be conspicuous, particularly in juveniles. Females reach sexual maturity at 10 to 20 years of age, depending on latitude.
HABITAT AND DISTRIBUTION:
Three environmental conditions are especially important: 1) well-drained loose soil in which to burrow; 2) adequate low-growing herbs for food; and 3) open sunlit sites for nesting. The gopher tortoise is primarily associated with xeric scrub oak, coastal strand and dune, live oak hammocks, dry prairie, pine flatwoods, and mixed hardwood-pine communities. Disturbed habitats, such as roadsides, fencerows, clearings, and old fields, often support relatively high densities. Their range includes areas in south and west Florida, and extends northward to South Carolina and westward to Louisiana. The species has been severely reduced in southern Alabama and Mississippi, southern southeastern Louisiana, southeastern South Carolina, and along south Florida's coasts and throughout much of the Florida Panhandle. In Florida, alone, gopher tortoise populations have dwindled to an estimated 30 percent of their original numbers.
LIFE HISTORY AND ECOLOGY:
Gopher tortoises excavate burrows, averaging 6 m. in length and 2 m. in depth and wide enough to allow them to turn around at any point. These burrows provide protection from temperature extremes, desiccation, and predators, and serve as refuges for a variety of other animals. Numerous species of animals, including Eastern indigo snakes (Drymarchon corais couperi), gopher frogs (Rana capito), Florida mice (Podomys floridanus), skunks, opposums, rabbits, quail, armadillos, burrowing owls, snakes, lizards, frogs, toads, and many invertebrates. Burrows also return leached nutrients to the surface. The placement and depth of burrows vary with the soil type, geographic location, and ground water levels. An individual tortoise may use more than one burrow and may excavate new burrows at any time during its life. Tortoises exhibit a strong tendency for colony formation; average number of
individuals in a colony is 10 to 12. The nesting season is generally considered to be from April to June. Several weeks after mating, female tortoises lay 3 to 15 eggs, usually in the sand mounds in front of their burrows or in some other, nearby sunny place. The incubation period varies latitudinally from about 65 to 110 days. Predation on nests and hatchlings is heavy. Armadillos, raccoons, foxes, skunks, alligators, fire ants, and other predators destroy more than 80 percent of gopher tortoise nests. After hatching, young tortoises either live in their mother's burrow or dig a small tunnel near her burrow. Many hatchlings are eaten by predators. Once they are too big to be swallowed easily, gopher tortoises have few enemies other than man, dogs, and raccoons. Estimated life expectancy is 40 to 60 years. Gopher tortoise densities and movements are affected by the amount of herbaceous ground cover. Principal foods include grasses, legumes, and grass-like plants of the sedge and aster families. When in season, fruits such as blackberries, pawpaws, gopher apples, and saw palmetto berries are also consumed. Tortoises are important seed dispersers.
BASIS OF STATUS CLASSIFICATION:
At one time gopher tortoises were hunted intensively for food. Although less frequent now, hunting still accounts for some losses. More immediate to the recent decline of the gopher tortoise population, however, is the increasing loss of habitat. Urbanization has severely fragmented the populations on the southern coasts. In order to protect the gopher tortoise populations from further decline, the Florida Game and Fresh Water Fish Commission classified the gopher tortoise as a "species of special concern" in 1986 and it is being reviewed for federal listing as an endangered species in the western portions of its range by the U.S. Fish and Wildlife Service. Also, collection of gopher tortoises in Florida was prohibited in 1988, and the practice of racing tortoises was banned in 1989.
The gopher tortoise is crucial to the survival of a number of other listed species in Collier County because its burrows provide important refuges for a much larger wildlife community (Speake 1981, Franz 1986). As gopher tortoise habitat decreases, so do many of the species that utilize their burrows. The eastern indigo snake and gopher frog are all listed species that occur within Collier County and prefer xeric habitat with gopher tortoise burrows.
The preservation strategy for the above listed species is to follow the management guidelines outlined for gopher tortoises with the following modifications to address the additional habitat needs; a viable population is 25-30 which translates to 75-90 active and inactive burrows, with 25 or more acres depending on the suitability of habitat size, shape, type and adjacent environs and maintaining habitat area with a canopy cover <25%. Management for gopher tortoise habitat should consider and/or maintain: (1) the presence of well-drained, sandy soils which allow easy burrowing, (2) an abundance of herbaceous ground cover, and (3) an open canopy (<25%) with sparse shrub cover to allow sunlight to reach the ground layer.
Conservation measures for this species should include establishment of preserves, prescribed burning, protection from illegal harvest, public education, identification of restocking sites, and stronger legislation to protect upland habitats in Florida. Additional studies are needed regarding tortoise use of pine flatwoods and dry prairies.
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Cox, J., D. Inkley, and R. Kautz. 1987. Ecology and habitat protection needs of gopher tortoise (Gopherus polyphemus) populations found on lands slated for large-scale development in Florida. Florida Game and Fresh Water Fish Commission. Nongame Wildlife Program Technical Report No. 4. Tallahassee, FL. 75pp.
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Diemer, J.E. 1991. Identification of critical gopher tortoise habitat in South Florida. Final Report, Study Number: 7539, Study Period: 1 July 1990 - 30 June 1991. Florida Game and Fresh Water Fish Commission. Tallahassee, FL. 23pp.
Diemer, J.E. 1986. The ecology and management of the gopher tortoise in the southeastern U.S. in Herpetologica 42:125-133.
Diemer, J.E. 1987. The status of the Gopher Tortoise in Florida. Pp. 72-83. In R. Odom, K. Riddleberger and J. Ozier (eds.), Proceedings from the Third Southeast Nongame and
Endangered Species Symposium. Georgia Department of Natural Resources Game and Fish Division. Atlanta, GA.
Gopher Tortoise Council. 1988. The gopher tortoise: A species in decline. Florida Museum of Natural History, University of Florida. Gainesville, FL. Brochure.
Jackson, D.R. and E.G. Milstrey. 1989. The fauna of gopher tortoise burrows. Pages 86-98 in Diemer, J., D. Jackson, J. Landers, J. Layne and D. Wood (eds.). Proceedings: Gopher tortoise relocation symposium. Nongame Wildlife Program Technical Report No. 5. Florida Game and Fresh Water Fish Commission. Tallahassee, FL.
Content updated Date March 4, 2005