THE GOPHER TORTOISE:
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Transcript of THE GOPHER TORTOISE:
THE GOPHER TORTOISE:THE GOPHER TORTOISE:A SPECIES IN DECLINEA SPECIES IN DECLINE
“working to conserve the gopher tortoise and the fascinating world in which it lives”
A presentation by the Gopher Tortoise Council modified by Nora Demers for the Nature Place, City of
Bonita Springs onMay 11, 2009
This program was partially funded with grants from the Georgia Department of Natural Resources and the League of Environmental Educators in Florida
AcknowledgmentsAcknowledgmentsThe following people generously The following people generously donated photographs or slides for this donated photographs or slides for this presentation: presentation: Joan D. Berish, C. Kenneth Dodd, Jr., George L. Joan D. Berish, C. Kenneth Dodd, Jr., George L. Heinrich, Sharon Hermann, Joseph W. Jones Heinrich, Sharon Hermann, Joseph W. Jones Ecological Research Center, Lee County Parks & Ecological Research Center, Lee County Parks & Recreation, Barry Mansell, Henry Mushinsky, Recreation, Barry Mansell, Henry Mushinsky, Lora L. Smith, Jill Kusba, and Nora Demers Lora L. Smith, Jill Kusba, and Nora Demers Developed by Laura Wewerka and Lora L. Developed by Laura Wewerka and Lora L. SmithSmith
The Gopher TortoiseThe Gopher Tortoise((Gopherus polyphemusGopherus polyphemus))
Gopherus polyphemusGopherus polyphemus
Chordata- spinal cord and bony Chordata- spinal cord and bony vertebrae vertebrae
Reptilia- scales, amniotic eggs, Reptilia- scales, amniotic eggs, ectothermicectothermic
Testudines- flattened fused bones, ribs Testudines- flattened fused bones, ribs and vertebraeand vertebrae
Testidinoidea- clawed elephantine hind Testidinoidea- clawed elephantine hind feet, no webbingfeet, no webbing
Gopherus- burrowerGopherus- burrower Polyphemus- lives in cave (Greek)Polyphemus- lives in cave (Greek)
EvolutionEvolution
Tortoiselike fossils found from early Tortoiselike fossils found from early Triassic (250 mya)Triassic (250 mya)
originating in North America over 60 originating in North America over 60 million years agomillion years ago
Gophers first seen during Pleistocene Gophers first seen during Pleistocene (500,000 to 2 mya)(500,000 to 2 mya)
Only land turtle remaining in SE USOnly land turtle remaining in SE US (also only burrowing tortoise – is there a (also only burrowing tortoise – is there a
relationship?)relationship?)
Geographic Range of theGeographic Range of theGopher TortoiseGopher Tortoise
Legal StatusLegal Status AlabamaAlabama- state listed as - state listed as ProtectedProtected; federally listed ; federally listed
as as ThreatenedThreatened west of the Tombigbee and Mobile west of the Tombigbee and Mobile Rivers.Rivers.
FloridaFlorida- state listed as - state listed as ThreatenedThreatened (“harm” enters (“harm” enters protection terminology) protection terminology)
GeorgiaGeorgia- state listed as - state listed as ThreatenedThreatened..
LouisianaLouisiana- state and federally listed as - state and federally listed as ThreatenedThreatened..
MississippiMississippi- state listed as - state listed as EndangeredEndangered; federally ; federally listed as listed as ThreatenedThreatened..
South CarolinaSouth Carolina- state listed as - state listed as EndangeredEndangered..
Longleaf Pine SandhillLongleaf Pine Sandhill
ScrubScrub
Pine FlatwoodsPine Flatwoods
Coastal DunesCoastal Dunes
Disturbed SitesDisturbed Sites
The Ecological Role of FireThe Ecological Role of Fire
Regeneration after fire(tender vittles)
Promotes diversity
Cycles nutrients
Alleviates risk of wildfire
Keystone And Indicator SpeciesKeystone And Indicator Species
Gopher tortoises are keystone species. Gopher tortoises are keystone species. They alter the habitat by constructing and They alter the habitat by constructing and maintaining their burrows, which have over maintaining their burrows, which have over 350 commensals and associates. 350 commensals and associates.
Tortoises are also considered “indicator” Tortoises are also considered “indicator” species, used as an indicator of ecosystem species, used as an indicator of ecosystem health.health.
The Gopher Tortoise BurrowThe Gopher Tortoise Burrow
Burrow detailsBurrow details
Protect from temperature extremes and Protect from temperature extremes and predatorspredators
One openingOne opening Max. length 13 m (40 feet), depth 3m (10’)Max. length 13 m (40 feet), depth 3m (10’) Burrow has ledge at end where tortoise Burrow has ledge at end where tortoise
rests, nice humidityrests, nice humidity In SW Florida burrows are usually shorter In SW Florida burrows are usually shorter
and shallower (water table primary and shallower (water table primary influence)influence)
Adaptations for BurrowingAdaptations for Burrowing
Forefoot
Hind foot
Burrow AssociatesBurrow Associates
Gopher FrogGopher Frog((Rana capitoRana capito))
Spend most of their time in burrows, -species of special concern in FL
Eastern Diamondback RattlesnakeEastern Diamondback Rattlesnake((Crotalus adamanteusCrotalus adamanteus))
CAREFUL- there can be venomous snakes in those burrows!
Eastern Indigo SnakeEastern Indigo Snake((Drymarchon corais couperiDrymarchon corais couperi))
Largest (indigenous) snake in N.A. -glassy black with red head and chin
Federally protected threatened species
Florida MouseFlorida Mouse((Podomys floridanaPodomys floridana))
Occurs only in peninsular Fl. -Excavates side tunnels
Species of special concern in Fl.
Life History of theLife History of theGopher TortoiseGopher 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 TortoisesGrowth in Gopher Tortoises
Each annuli represents about 1 yearRates vary by location and environmental conditions
Sexual DimorphismSexual Dimorphismin Gopher Tortoisesin Gopher Tortoises
Female- slightly larger
Male- concave lower plastronthick gular projection
CourtshipCourtship
Typically breed April to JuneLots of head bobbing and nose rubbing
NestingNesting
Lay eggs May to June in apron or sunny sand nearbySingle 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)
Sex DeterminationSex Determination
The incubation temperature of the nest The incubation temperature of the nest determines sexdetermines sex
If over 30 degrees Celsius, female (80 If over 30 degrees Celsius, female (80 degrees F); if under 30 degrees, male.degrees F); if under 30 degrees, male.
Difficult to determine sex of juveniles and Difficult to determine sex of juveniles and sub-adultssub-adults
Males apparently mature sooner than Males apparently mature sooner than femalesfemales
Nest PredationNest Predation
A female may produce a successful nest no more than every 10 years
Nest PredationNest Predation
Also foxes, skunks, fire ants
Hatchling Gopher TortoisesHatchling 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 predatorsHatchling predators
Domestic dogs, Fire ants, ‘coons, snakes, hawks
Food PlantsFood Plants
Stinging nettle
Wiregrass
Prickly pear cactus
Home Range SizeHome Range Size
Range depends on habitat Range depends on habitat usually stay near a burrow usually stay near a burrow Adult Females: Adult Females: 0.2 – 1.4 ac (0.1 – 0.6 ha) 0.2 – 1.4 ac (0.1 – 0.6 ha) (house lot size)(house lot size) Adult Males: Adult Males: 1.1 – 3.2 ac (0.4 – 1.3 ha)1.1 – 3.2 ac (0.4 – 1.3 ha) Juveniles (<4 yrs): Juveniles (<4 yrs): 0.02 – 0.9 ac (0.01 – 0.4 ha)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 Most have more than one burrow to call home- structure of burrow unique (left or
right turn)right turn)
Why Gopher Tortoise Why Gopher Tortoise Populations are in Decline:Populations are in Decline:
Problems and a Few SolutionsProblems and a Few Solutions
Races
Food “Hoover Chickens”
(GTC helped end legal harvest in 1988)
Mechanical tortoises in San Antonio Fl.
Upper RespiratoryUpper RespiratoryTract Disease (URTD)Tract Disease (URTD)
Caused by mycoplasm (obligate Caused by mycoplasm (obligate intracellular pathogen like t.b.)intracellular pathogen like t.b.)
Transmission by nose rubbing etcTransmission by nose rubbing etc SymptomsSymptoms
• Clear or white Clear or white
nasal dischargenasal discharge• Watery eyesWatery eyes• Swollen eyelidsSwollen eyelids
The Danger: Asymptomatic The Danger: Asymptomatic TortoisesTortoises
Or is it a danger? Regulations for testing under review
Habitat LossHabitat LossForestry Practices
Mining Agriculture
Development
Habitat lossHabitat loss Housing & other developments Housing & other developments Citrus groves give way to development in Estero (NDN 3/6/06)Citrus groves give way to development in Estero (NDN 3/6/06)
Photo by M Forter Daily News
Invasive SpeciesInvasive Species
Gopher Tortoises and RoadsGopher Tortoises and Roads
Direct effects: • habitat loss• mortality
Indirect effects:• habitat fragmentation• artificial habitat
Roads and Parking lotsRoads and Parking lots
Balance desire Balance desire of humans to of humans to enjoy enjoy surroundings surroundings with needs of with needs of native speciesnative species
Habitat DegradationHabitat Degradation
Mitigation Options in FloridaMitigation Options in Florida
Avoid impacting burrowsAvoid impacting burrows
Set aside on-site preserves/on-site Set aside on-site preserves/on-site relocationrelocation
Relocate tortoises off-siteRelocate tortoises off-site
Incidental Take/ Mitigation BankingIncidental Take/ Mitigation Banking
• Protect (and manage) habitat off-siteProtect (and manage) habitat off-site
Gopher Tortoise RelocationGopher Tortoise Relocation THE GOODTHE GOOD
• Saves individualsSaves individuals• RestockingRestocking• Increased knowledge of tortoise movementsIncreased knowledge of tortoise movements
Gopher Tortoise RelocationGopher Tortoise Relocation
THE BAD… AND THE UGLYTHE BAD… AND THE UGLY• Net loss of habitatNet loss of habitat• Tortoises often leave relocation siteTortoises often leave relocation site• Disruption of resident populationsDisruption of resident populations• Labor intensive/costlyLabor intensive/costly• Transmission of diseaseTransmission of disease• Diverts conservation fundsDiverts conservation funds
The FutureThe Future
Current ResearchCurrent Research
Upper Respiratory Tract Disease- distribution and Upper Respiratory Tract Disease- distribution and impacts- now believed to have co-evolved with tortoisesimpacts- now believed to have co-evolved with tortoises
Investigations into impacts of fire ants on gopher Investigations into impacts of fire ants on gopher tortoise populations in Federally threatened part of tortoise populations in Federally threatened part of rangerange
Studies of other upland species: southern hognose snake; Studies of other upland species: southern hognose snake; eastern indigo snake; red-cockaded woodpeckereastern indigo snake; red-cockaded woodpecker
Summer of ’04 first low frequency sound Summer of ’04 first low frequency sound communications (Eliz. von Miggenthaler- Prez. of Fauna communications (Eliz. von Miggenthaler- Prez. of Fauna Communication Society)Communication Society)
Land Management:Land Management:the Use of Prescribed Firethe Use of Prescribed Fire
Creative Conservation at WorkCreative Conservation at Work
The Nature Conservancy- habitat The Nature Conservancy- habitat acquisition and land stewardshipacquisition and land stewardship
Mitigation BankingMitigation Banking
County-wide land conservation measuresCounty-wide land conservation measures
Gopher Tortoise Conservation InitiativeGopher Tortoise Conservation Initiative
Tortoise Reserve ProgramTortoise Reserve Program
Local Mitigation optionsLocal Mitigation options
Lee County Lee County – Hickey’s Creek Mitigation Park--NOT a Hickey’s Creek Mitigation Park--NOT a
relocation centerrelocation center– Persimmon Ridge, Caloosahatchee Regional Persimmon Ridge, Caloosahatchee Regional
Park, 10-mile Canal Park relocation for private Park, 10-mile Canal Park relocation for private (developers) mitigation(developers) mitigation
– Gator Hole -20/20 lands (off Corkscrew Rd.) Gator Hole -20/20 lands (off Corkscrew Rd.) for public improvement (3-oaks expansion)for public improvement (3-oaks expansion)
Collier County- Maureen Bonness good Collier County- Maureen Bonness good contactcontact
What You Can DoWhat You Can Do
Landscape with native plant species (many are Landscape with native plant species (many are food plants of gopher tortoises)food plants of gopher tortoises)
Become active in conservation organizations Become active in conservation organizations that promote habitat protection and that promote habitat protection and managementmanagement
Be a watch dog for tortoisesBe a watch dog for tortoises
Write to your local politicians about issues that Write to your local politicians about issues that affect tortoises and their habitataffect tortoises and their habitat
Vote!Vote!
Listing in FloridaListing in Florida
FWC Draft Biological Status Report (Nov. ’05)FWC Draft Biological Status Report (Nov. ’05)Criteria for State Listing (Rule 68A-1.00 F.A.C.)Criteria for State Listing (Rule 68A-1.00 F.A.C.)
Population size reduction due to habitat loss –note that Population size reduction due to habitat loss –note that human population has increased 2,161% since 1910 human population has increased 2,161% since 1910 (2003 figure) and has been doubling every 20 years (2003 figure) and has been doubling every 20 years during the 1990’sduring the 1990’s
- pre-European settlement estimate of habitat: 10 pre-European settlement estimate of habitat: 10 million acres, today: 1.7 million acremillion acres, today: 1.7 million acre
Meets criteria for classification as Threatened Meets criteria for classification as Threatened
FWC requesting inputFWC requesting input
What to do if You Find aWhat to do if You Find a Stray Tortoise Stray Tortoise
On roads, move tortoise to nearest On roads, move tortoise to nearest habitat (preferably in direction it was habitat (preferably in direction it was heading) - BEWARE OF TRAFFIC!heading) - BEWARE OF TRAFFIC!
If injured, contact your local Game If injured, contact your local Game Commission or Department of Natural Commission or Department of Natural ResourcesResources
“Hands off” unless:
The Mission of the Gopher The Mission of the Gopher Tortoise CouncilTortoise Council
EducationEducation
Habitat protectionHabitat protection
ResearchResearch
For More Information:For More Information:
Write to us at the following address:Write to us at the following address:
Gopher Tortoise CouncilGopher Tortoise Council
c/o Florida Museum of Natural Historyc/o Florida Museum of Natural History
P.O. Box 117800P.O. Box 117800
University of FloridaUniversity of Florida
Gainesville, FL 32611-7800Gainesville, FL 32611-7800
Visit our web site:Visit our web site:
www.gophertortoisecouncil.orgwww.gophertortoisecouncil.org
Now a short quiz-Now a short quiz-
Can you find Can you find the tortoise?the tortoise?
images courtesy of Jill Kusbaimages courtesy of Jill Kusba
How big is this tortoise?How big is this tortoise?
HINT: It is a one-year HINT: It is a one-year old hatchlingold hatchling
Can you find the burrow?Can you find the burrow?
The FutureThe Future