Title: THE GOPHER TORTOISE:
1THE GOPHER TORTOISE
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
2Acknowledgments
- 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
3The Gopher Tortoise(Gopherus polyphemus)
4Gopherus polyphemus
- 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)
5Evolution
- 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?)
6Geographic Range of theGopher Tortoise
7Legal 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.
8Longleaf Pine Sandhill
9Scrub
10Pine Flatwoods
11Coastal Dunes
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13Disturbed Sites
14The Ecological Role of Fire
Promotes diversity Cycles nutrients Alleviates
risk of wildfire
Regeneration after fire (tender vittles)
15Keystone 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.
16The Gopher Tortoise Burrow
17Burrow 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)
18Adaptations for Burrowing
Hind foot
Forefoot
19Burrow Associates
20Gopher Frog (Rana capito)
Spend most of their time in burrows, -species of
special concern in FL
21Eastern Diamondback Rattlesnake(Crotalus
adamanteus)
CAREFUL- there can be venomous snakes in those
burrows!
22Eastern Indigo Snake (Drymarchon corais couperi)
Largest (indigenous) snake in N.A. -glassy black
with red head and chin Federally protected
threatened species
23Florida Mouse(Podomys floridana)
Occurs only in peninsular Fl. -Excavates side
tunnels Species of special concern in Fl.
24Life History of theGopher 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
25Growth in Gopher Tortoises
Each annuli represents about 1 year Rates vary by
location and environmental conditions
26Sexual Dimorphismin Gopher Tortoises
Male- concave lower plastron thick gular
projection
Female- slightly larger
27Courtship
Typically breed April to June Lots of head
bobbing and nose rubbing
28Nesting
Lay eggs May to June in apron or sunny sand
nearby Single clutch per year (or not at all)
Average 6 eggs, up to 25! Size of ping pong
balls Incubation time 80-110 days (S to Northern
range)
29Sex 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
30Nest Predation
A female may produce a successful nest no more
than every 10 years
31Nest Predation
Also foxes, skunks, fire ants
32Hatchling 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
33Hatchling predators
Domestic dogs, Fire ants, coons, snakes, hawks
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35Food Plants
Stinging nettle
Prickly pear cactus
Wiregrass
36Home 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 (lt4 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)
37Why Gopher Tortoise Populations are in
DeclineProblems and a Few Solutions
Races
Mechanical tortoises in San Antonio Fl.
Food Hoover Chickens (GTC helped end legal
harvest in 1988)
38Upper RespiratoryTract 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
39The Danger Asymptomatic Tortoises
Or is it a danger? Regulations for testing under
review
40Habitat Loss
Forestry Practices
Development
Mining
Agriculture
41Habitat loss
- Housing other developments
- Citrus groves give way to development in Estero
(NDN 3/6/06)
Photo by M Forter Daily News
42Invasive Species
43Gopher Tortoises and Roads
- Direct effects
- habitat loss
- mortality
- Indirect effects
- habitat fragmentation
- artificial habitat
-
44Roads and Parking lots
- Balance desire of humans to enjoy surroundings
with needs of native species
45Habitat Degradation
46Mitigation 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
47Gopher Tortoise Relocation
- THE GOOD
- Saves individuals
- Restocking
- Increased knowledge of tortoise movements
48Gopher 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
49The Future
50Current 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 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)
51Land Managementthe Use of Prescribed Fire
52Creative Conservation at Work
- The Nature Conservancy- habitat acquisition and
land stewardship - Mitigation Banking
- County-wide land conservation measures
- Gopher Tortoise Conservation Initiative
- Tortoise Reserve Program
53Local Mitigation options
- Lee County
- Hickeys 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
54What 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!
55Listing 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 1990s - pre-European settlement estimate of habitat 10
million acres, today 1.7 million acre - Meets criteria for classification as Threatened
- FWC requesting input
56What 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
57The Mission of the Gopher Tortoise Council
- Education
- Habitat protection
- Research
58For 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
59Now a short quiz-
- Can you find the tortoise?
images courtesy of Jill Kusba
60How big is this tortoise?
- HINT It is a one-year old hatchling
61Can you find the burrow?
62The Future