Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Gopher Tortoise Gopherus polyphemus Photo courtesy of Joan Berish •Identification •Natural History •Habitat •Status •Threats to Species •Importance of Species •Management and Conservation Photo courtesy of Camp Blanding Identification • Domed shell and stumpy feet • Shovel like front feet adapted for digging Photo courtesy of Joan Berish • Long-lived • Average adult size is 9-11 inches • Related species in U.S.: Texas tortoise and desert tortoise, both in genus Gopherus Identification • Gopher tortoise has unhinged plastron and carapace is generally unmarked • Gopher tortoise lives in dry upland habitats Photo courtesy of Joan Berish Gopher Tortoise Florida Box Turtle Photo from Jamie Barichivich Hatchling Identification Photo courtesy of Lora Smith Yellowish orange in color Approximately 1.7 inches in length Age Determination in Tortoises Photo courtesy of Lora Smith Close up of adult scute Hatchling tortoise without growth rings Sexual Dimorphism Males: – slightly smaller than females – have projection on plastron (underside of shell) – plastron is concave (indented) Photo courtesy of Joan Berish Natural History •Distribution •Diet •Activity •Reproduction •Hatchling Growth & Survival •Burrows Distribution photo from Joan Berish Diet • Grasses and other grass-like plants • Legumes (plants with beans or pods) • Fruits, including blackberries and fruit of the prickly pear cactus • Legumes seem to be a favorite of juveniles photo from Joan Berish Activity Photo courtesy of Camp Blanding • Active during warmest part of day, except in summer • Spends most of its time in burrow, however most of its time above ground is spent basking, followed by walking and feeding • Activity reduced during winter, especially in northern parts of range Reproduction • Female tortoises take 10-21 years to reach reproductive maturity, males take about 9-16 years. • Mating occurs in early spring and nesting occurs in summer. • Females lay clutch of about 6 eggs. photo from Joan Berish Reproduction Photo courtesy of Lora Smith Photo courtesy of Lora Smith • Nests are sometimes dug in apron of burrow. The nest site must be in a sunny area. • Predation on eggs is high, especially during first week of deposition. • Predators on nest are raccoons, opossums, and armadillos. Photo courtesy of Lora Smith Hatchling Growth & Survival Photo courtesy of Joan Berish • Incubation time depends on climate; eggs take longer to hatch in northern part of range • Eggs hatch in about 80-90 days Photo courtesy of Lora Smith Young may construct small burrows, or bury themselves in leaf litter or sand Hatchling Growth & Survival The lowest survival rate of a gopher tortoise’s life occurs during the first few months Photo courtesy of Lora Smith Growth & Survival • Only predators on adult tortoises are humans and dogs • Defensive position • Expulsion of waste Photo courtesy of Joan Berish Burrows • Average 15 feet long and 6.5 feet deep • Provide refuge from weather, predators, environmental disturbances • Apron makes burrow easily recognizable Photo courtesy of Joan Berish Burrows • Remain at relatively constant temperature and humidity year-round • Burrows are at center of home range activity • One tortoise may use more than one burrow during the active season Photo courtesy of Lora Smith Habitat Photo courtesy of Joan Berish Habitat Photo courtesy of Lora Smith Necessary Components • Well drained loose soils • Sufficient low-lying herbaceous vegetation • Sunlit sites Sandhill Habitat Habitat • Primarily inhabit sandhills • Sand pine scrub, live oak hammocks, dry prairies, and mixed hardwood pine communities photo courtesy of Joan Berish Coastal Strand • Disturbed areas, such as roadsides and old fields • Also found in coastal dunes Status • Species of Special Concern in FL • Protected to some extent across all its range • Unlawful to take, harm, harass or possess tortoises photo from Joan Berish Threats • Direct threats from humans • Habitat destruction • Fire suppression • Road mortality • Disease Photo courtesy of Mark Hostetler Direct Threats • Molestation from humans • Predation from dogs is common, but its effects on tortoise populations unknown photo courtesy of Lora Smith Direct Threats • Major food source during the Depression • Collection for tortoise races Photo courtesy of Lora Smith Habitat destruction Loss and/or destruction of upland habitat caused by: Photo courtesy of Camp Blanding • urbanization • mining activities • pine plantations Tortoise Habitat Habitat Destruction Why aren’t sand pine plantations suitable tortoise habitat? • Pine plantations are monocultures dominated by pine trees with low plant diversity • Monocultures prevent: –Growth of low-lying food plants, such as legumes and cacti –Adequate sunlight for nesting sites • Some clear-cutting and site prep practices may harm tortoises Fires • Fires are a natural part of sandhill community • They keep the habitat suitable for tortoises by: –stimulating higher yields of tortoise food plants –preventing community succession Photo courtesy of Joan Berish Photo courtesy of Camp Blanding Photo courtesy of Camp Blanding Road Mortality Photo courtesy of Lora Smith Tortoise road mortality is even high in rural areas. Disease Upper respiratory tract disease, (URTD), caused by a naturally occurring bacterium known as a mycoplasma infected healthy Photo courtesy of Joan Berish Photo courtesy of Joan Berish Disease • Disease probably made worse by stress put on tortoise populations by humans • Disease may be spread into uninfected population by tortoise pet releases and tortoise relocation • Spread by close contact • Seemingly healthy tortoise may be a carrier • Tortoise may get “sicker quicker” upon secondary infection Disease Complications of URTD: • Blood tests only report exposure, not infection of disease • Mycoplasmal infection known to cause die-offs in western Gopherus species • Effects on gopher tortoise not fully understood photo courtesy of Joan Berish • URTD may be spread through tortoise relocation projects Disease Currently populations of infected tortoises are being monitored to learn about URTD’s effects on the species Photo courtesy of Joan Berish Importance of Species Burrows are important refuges for many organisms in the tortoise’s community Gopher Frog Photo courtesy of Camp Blanding Importance of Species Burrow Occupants Gopher Frog Photo from Camp Blanding Hognose Snake Indigo Snake Photo from Camp Blanding Photo by Jamie Barichivich Importance of Species Photo courtesy of Camp Blanding • Keystone species: Removal of the species from its community would have a harmful effect on many other organisms in the community • Protection of tortoises and their burrows helps all organisms that use the tortoise burrows Importance of Species Gopher tortoises inhabit two declining ecosystems: • scrub habitat, home to the threatened scrub jay • old longleaf pine communities, home to the endangered red-cockaded woodpecker Photo courtesy of Camp Blanding Importance of Species • Tortoises are seed dispersers • Burrowing returns leached nutrients to the surface • Burrow mounds provide a foothold to young plants • Aprons provide suitable sand for “swimming” skinks Photo courtesy of Lora Smith Sand Skink photo by Jamie Barichivich Mitigation • Tortoise mitigation and conservation is a controversial issue between biologists and land developers photo courtesy of Camp Blanding • Developers have several options when building on land with active burrows Mitigation Developer’s Options • Do not develop on site with active burrows • Avoid burrows • Tortoise captured, released on-site • Mitigation banking • Tortoise relocation off-site photo courtesy of Joan Berish Mitigation banking • Highly controversial • Allows developer to entomb tortoises • Suitable habitat purchased elsewhere Photo courtesy of Lora Smith Relocation • An environmental consultant is hired to capture and relocate tortoises • Potentially harmful to existing population • Low site fidelity photo courtesy of Camp Blanding Conservation Strategies • Habitat management • Establishment of preserves • Protection from poaching • Public education photo courtesy of Alan Long Conservation Strategies photo courtesy of Camp Blanding • Restock populations in areas tortoises once lived • Nest enclosures to increase hatching rate and and provide head start for hatchlings Summary • Gopher tortoises are protected throughout their range, listed as Species of Special Concern in Florida • Must have well drained soil, low-lying herbacious plants, and enough sunlight for nests • Habitat loss is the major threat on tortoises today • URTD threat increased due to stress on populations Summary • Burrows provide refuge for over 350 animals • Protection of tortoise habitat provides protection for other listed species • Relocation option is least effective because it does not provide permanent solution • Controlled fires, habitat preservation, and plans to increase survivorship of eggs and young are all conservation strategies What you can do to help: • Notify Florida Fish and Wildlife Conservation Commission (FWC) if land with active burrows is slated for development. http://wld.fwc.state.fl.us/fwc_dir/offices.htm • Report harassing, collecting, or killing of tortoises to FWC. • Do not attempt to relocate tortoises yourself. • Join the Gopher Tortoise Council. Visit their website at • www.gophertortoisecouncil.org Photo courtesy of Camp Blanding For More Information To find out more about gopher tortoises in Florida, visit the UF/IFAS extension website at: www.ifas.ufl.edu/extension www.floridaconservation.org Acknowledgments • Created by Audrey Owens and Dr.Mark Hostetler, Department of Wildlife Ecology and Conservation, IFAS, University of Florida • In conjunction with: Joan Diemer-Berish, Florida Fish and Wildlife Conservation; Lora Smith, Gopher Tortoise Council • Photo credits: Camp Blanding