Transcript Revised for the Nature Place

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
Acknowledgments
The following people generously
donated photographs or slides for this
presentation:
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.
Smith
The Gopher Tortoise
(Gopherus polyphemus)
Gopherus polyphemus




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Chordata- spinal cord and bony
vertebrae
Reptilia- scales, amniotic eggs,
ectothermic
Testudines- flattened fused bones, ribs
and vertebrae
Testidinoidea- clawed elephantine hind
feet, no webbing
Gopherus- burrower
Polyphemus- lives in cave (Greek)
Evolution
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
relationship?)

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
Threatened.

Mississippi- state listed as Endangered;
federally listed as Threatened.

South Carolina- state listed as Endangered.
Longleaf Pine Sandhill
Scrub
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
health.

The Gopher Tortoise Burrow
Burrow details
Protect from temperature extremes and
predators
 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
influence)

Adaptations for Burrowing
Hind foot
Forefoot
Burrow Associates
Gopher Frog
(Rana capito)
Spend most of their time in burrows,
-species of special concern in FL
Eastern Diamondback Rattlesnake
(Crotalus adamanteus)
CAREFULthere 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)
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
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
Maleconcave lower plastron
thick gular projection
Female- slightly larger
Courtship
Typically breed April to June
Lots of head bobbing and nose rubbing
Nesting
Average 6 eggs, up to 25!
Size of ping pong balls
Incubation time 80-110 days
(S to Northern range)
Lay eggs May to June
in apron or sunny sand nearby
Single clutch per year
(or not at all)
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
sub-adults
 Males apparently mature sooner than
females

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
Wiregrass
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 homestructure of burrow unique (left or right turn)
Why Gopher Tortoise
Populations are in Decline:
Problems and a Few Solutions
Races
Mechanical tortoises
in San Antonio Fl.
Food
“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
Tortoises
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
enjoy
surroundings
with needs of
native species
Habitat Degradation
Mitigation Options in Florida
 Avoid
impacting burrows
 Set
aside on-site preserves/on-site
relocation
 Relocate
tortoises off-site
 Incidental
Take/ Mitigation Banking
• Protect (and manage) habitat off-site
Gopher Tortoise Relocation
 THE
GOOD
• Saves individuals
• Restocking
• Increased knowledge of tortoise movements
Gopher Tortoise Relocation
 THE
•
•
•
•
•
•
BAD… AND THE UGLY
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

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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
range
Studies of other upland species: southern hognose
snake; eastern indigo snake; red-cockaded
woodpecker
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
 The
Nature Conservancy- habitat
acquisition and land stewardship
 Mitigation
Banking
 County-wide
 Gopher
land conservation measures
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
contact
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
management

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!
 If
injured, contact your local Game
Commission or Department of Natural
Resources
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:
www.gophertortoisecouncil.org
Now a short quiz
images courtesy of Jill Kusba
Can you find
the tortoise?
How big is this tortoise?

HINT: It is a one-year
old hatchling
Can you find the burrow?
The Future