The Gopher Tortoise by yurtgc548


									     THE GOPHER TORTOISE:
              A SPECIES IN DECLINE
         A presentation by the Gopher Tortoise Council
      modified by Nora Demers for the Nature Place, City of
                       Bonita Springs on
                         May 11, 2009

“working to conserve the gopher tortoise and the fascinating world in which it lives”

                      This program was partially funded with grants from
                      the Georgia Department of Natural Resources and
                      the League of Environmental Educators in Florida
The following people generously
donated photographs or slides for this
Joan D. Berish, C. Kenneth Dodd, Jr., George L.
Heinrich, Sharon Hermann, Joseph W. Jones
Ecological Research Center, Lee County Parks &
Recreation, Barry Mansell, Henry Mushinsky,
Lora L. Smith, Jill Kusba, and Nora Demers
Developed by Laura Wewerka and Lora L.
The Gopher Tortoise
(Gopherus polyphemus)
         Gopherus polyphemus
   Chordata- spinal cord and bony
   Reptilia- scales, amniotic eggs,
   Testudines- flattened fused bones, ribs
    and vertebrae
   Testidinoidea- clawed elephantine hind
    feet, no webbing
   Gopherus- burrower
   Polyphemus- lives in cave (Greek)
 Tortoiselike fossils found from early
  Triassic (250 mya)
 originating in North America over 60
  million years ago
 Gophers first seen during Pleistocene
  (500,000 to 2 mya)
 Only land turtle remaining in SE US
 (also only burrowing tortoise – is there a
Geographic Range of the
   Gopher Tortoise
                  Legal Status
   Alabama- state listed as Protected; federally
    listed as Threatened west of the Tombigbee and
    Mobile Rivers.
   Florida- state listed as Threatened (“harm”
    enters protection terminology)
   Georgia- state listed as Threatened.
   Louisiana- state and federally listed as
   Mississippi- state listed as Endangered;
    federally listed as Threatened.
   South Carolina- state listed as Endangered.
Longleaf Pine Sandhill
Pine Flatwoods
Coastal Dunes
Disturbed Sites
    The Ecological Role of Fire
                          Promotes diversity

                          Cycles nutrients

                          Alleviates risk of wildfire

Regeneration after fire
(tender vittles)
Keystone And Indicator Species
 Gopher tortoises are keystone species.
  They alter the habitat by constructing and
  maintaining their burrows, which have over
  350 commensals and associates.
 Tortoises are also considered “indicator”
  species, used as an indicator of ecosystem
The Gopher Tortoise Burrow
           Burrow details
 Protect from temperature extremes and
 One opening
 Max. length 13 m (40 feet), depth 3m (10’)
 Burrow has ledge at end where tortoise
  rests, nice humidity
 In SW Florida burrows are usually shorter
  and shallower (water table primary
    Adaptations for Burrowing

                         Hind foot

Burrow Associates
               Gopher Frog
                 (Rana capito)
Spend most of their time in burrows,
  -species of special concern in FL
Eastern Diamondback Rattlesnake
           (Crotalus adamanteus)

  there can be venomous snakes in those burrows!
Eastern Indigo Snake
(Drymarchon corais couperi)

     Largest (indigenous) snake in N.A.
     -glassy black with red head and chin
    Federally protected threatened species
Florida Mouse
(Podomys floridana)

        Occurs only in peninsular Fl.
           -Excavates side tunnels
       Species of special concern in Fl.
               Life History of the
                Gopher Tortoise
   Average length: 10-12 inches (25-30 cm)

Average    weight 4 kg (9 lbs)

Females slightly larger than males- sexually mature
when 15-20 years old

 Slow growing
(depending on environment)

   Can live more than 60 years
 Growth in Gopher Tortoises
Each annuli represents about 1 year
Rates vary by location and environmental conditions
       Sexual Dimorphism
       in Gopher Tortoises
                          concave lower plastron
                           thick gular projection
Female- slightly larger

Typically breed April to June
Lots of head bobbing and nose rubbing

                              Lay eggs May to June
  Average 6 eggs, up to 25!   in apron or sunny sand nearby
   Size of ping pong balls    Single clutch per year
Incubation time 80-110 days   (or not at all)
    (S to Northern range)
         Sex Determination
 The incubation temperature of the nest
  determines sex
 If over 30 degrees Celsius, female (80
  degrees F); if under 30 degrees, male.
 Difficult to determine sex of juveniles and
 Males apparently mature sooner than
      Nest Predation
A female may produce a successful nest
     no more than every 10 years
   Nest Predation

Also foxes, skunks, fire ants
Hatchling Gopher Tortoises

 Hatchlings are 1-2 inches long (25-30 cm)

   Use adult burrows or excavate their own

 Soft shell renders them
  vulnerable to predators
for first 7 years
Hatchling predators
         Domestic dogs, Fire ants,
         ‘coons, snakes, hawks
                  Food Plants

Stinging nettle                Prickly pear cactus

            Home Range Size
Range depends on habitat
usually stay near a burrow
 Adult Females:
   0.2 – 1.4 ac (0.1 – 0.6 ha)
(house lot size)
 Adult Males:
   1.1 – 3.2 ac (0.4 – 1.3 ha)
 Juveniles (<4 yrs):
   0.02 – 0.9 ac (0.01 – 0.4 ha)
Most have more than one burrow to call home-
  structure of burrow unique (left or right turn)
          Why Gopher Tortoise
        Populations are in Decline:
         Problems and a Few Solutions

                                         Mechanical tortoises
                                          in San Antonio Fl.

         “Hoover Chickens”
(GTC helped end legal harvest in 1988)
       Upper Respiratory
      Tract Disease (URTD)
 Caused  by mycoplasm (obligate
  intracellular pathogen like t.b.)
 Transmission by nose rubbing etc
 Symptoms
  • Clear or white
  nasal discharge
  • Watery eyes
  • Swollen eyelids
The Danger: Asymptomatic

  Or is it a danger?
  Regulations for testing under review
           Habitat Loss
Development          Forestry Practices

  Mining               Agriculture
                         Habitat loss
   Housing & other developments
   Citrus groves give way to development in Estero (NDN 3/6/06)

                                             Photo by M Forter Daily News
Invasive Species
    Gopher Tortoises and Roads

   Direct effects:
• habitat loss
• mortality

   Indirect effects:
• habitat fragmentation
• artificial habitat
Roads and Parking lots
                   Balance desire
                    of humans to
                    with needs of
                    native species
Habitat Degradation
 Mitigation Options in Florida
 Avoid   impacting burrows
 Setaside on-site preserves/on-site
 Relocate   tortoises off-site
 Incidental   Take/ Mitigation Banking
  • Protect (and manage) habitat off-site
 Gopher Tortoise Relocation
 • Saves individuals
 • Restocking
 • Increased knowledge of tortoise movements
 Gopher Tortoise Relocation

 •   Net loss of habitat
 •   Tortoises often leave relocation site
 •   Disruption of resident populations
 •   Labor intensive/costly
 •   Transmission of disease
 •   Diverts conservation funds
The Future
             Current Research
   Upper Respiratory Tract Disease- distribution and
    impacts- now believed to have co-evolved with tortoises
   Investigations into impacts of fire ants on gopher
    tortoise populations in Federally threatened part of
   Studies of other upland species: southern hognose
    snake; eastern indigo snake; red-cockaded
   Summer of ’04 first low frequency sound
    communications (Eliz. von Miggenthaler- Prez. of
    Fauna Communication Society)
   Land Management:
the Use of Prescribed Fire
Creative Conservation at Work

 TheNature Conservancy- habitat
 acquisition and land stewardship
 Mitigation   Banking
 County-wide   land conservation measures
 Gopher   Tortoise Conservation Initiative
 Tortoise   Reserve Program
       Local Mitigation options
   Lee County
    – Hickey’s Creek Mitigation Park--NOT a
      relocation center
    – Persimmon Ridge, Caloosahatchee Regional
      Park, 10-mile Canal Park relocation for private
      (developers) mitigation
    – Gator Hole -20/20 lands (off Corkscrew Rd.)
      for public improvement (3-oaks expansion)
   Collier County- Maureen Bonness good
            What You Can Do
   Landscape with native plant species (many are
    food plants of gopher tortoises)
   Become active in conservation organizations
    that promote habitat protection and
   Be a watch dog for tortoises
   Write to your local politicians about issues that
    affect tortoises and their habitat
   Vote!
               Listing in Florida
    FWC Draft Biological Status Report (Nov. ’05)
    Criteria for State Listing (Rule 68A-1.00 F.A.C.)
    Population size reduction due to habitat loss –note that
        human population has increased 2,161% since 1910
        (2003 figure) and has been doubling every 20 years
        during the 1990’s
    - pre-European settlement estimate of habitat: 10
        million acres, today: 1.7 million acre
    Meets criteria for classification as Threatened
    FWC requesting input
         What to do if You Find a
             Stray Tortoise
“Hands off” unless:
   On roads, move tortoise to nearest
    habitat (preferably in direction it was
    heading) - BEWARE OF TRAFFIC!
   Ifinjured, contact your local Game
    Commission or Department of Natural
  The Mission of the Gopher
      Tortoise Council

 Education

 Habitat   protection

 Research
      For More Information:
 Write    to us at the following address:
  Gopher Tortoise Council
  c/o Florida Museum of Natural History
  P.O. Box 117800
  University of Florida
  Gainesville, FL 32611-7800

 Visit   our web site:

Now a short quiz-
                                 Can you find
                                  the tortoise?

  images courtesy of Jill Kusba
How big is this tortoise?

                 HINT: It is a one-year
                  old hatchling
Can you find the burrow?
The Future

To top