httpswwwyoutubecomwatchvo5FwvUD2e94 https wwwyoutubecomwatchvGQSZjgl6Iss https wwwyoutubecomwatchvBF8UAEVWgwk Tortoise facts Gopherus polyphemus 1 of 4 tortoise species in North America ID: 542549
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Slide1
Gopher tortoisesSlide2
https://www.youtube.com/watch?v=o5FwvUD2e94
https://
www.youtube.com/watch?v=GQSZjgl6Iss
https://
www.youtube.com/watch?v=BF8UAEVWgwkSlide3
Tortoise facts
Gopherus
polyphemus
1 of 4 tortoise species in North America
Family TestudinidaeDesert tortoise Gopherus agassiziiTexas tortoise Gopherus berlandieri Sonoran Desert tortoise Gopherus morafkai Slide4
Gopher tortoise
Range: Slide5
Gopher tortoise ecology
Like other NA tortoises, inhabits relatively arid environments in its range (
sandhill
, scrub, coastal scrub primarily here in FL)
Often found in disturbed sites (retention ponds, roadsides)
Not often found in association with sites with standing water/high water tables, although they can swim.Limiting factors (other than standing water) include difficult soils (compacted, clays), unbroken canopy, dense ground-level shrubby vegetationSlide6
Gopher tortoise ecology
Primary remaining native grazer in FL grasslands
Higher densities often associated with higher density (ground cover) of herbaceous vegetation
Food items include broadleaf grasses, legumes, cacti (
Opuntia
), wiregrass (early spring), and opportunistic foraging (seeds, fruits, flowers)Potentially an important disperser for native grasses and other plantsSlide7
Gopher tortoise biology
Long-lived species (?)
Females reach sexual maturity after 12-15 years
Low fecundity (clutch size is ~ 5-6 eggs, single clutch per year)
Mating and nesting occurs in the spring
Eggs incubate over 100 days in the burrowsVast majority of eggs and young are killed (some reports estimate populations may only produce young that survive beyond the first year every 7 years or so.Racoons are primary nest predators, but lots of others Slide8
Gopher tortoise burrows
Burrow depth limited by the water table
Affect soil chemistry
Serve as sites for plant recruitment
Serve as key soil disturbance necessary for soil swimming vertebrates (e.g. sand skinks)
Serve as refuge for numerous species (indigo snakes, Florida mouse)Hundreds of commensal species (flies, beetles, etc.)Slide9
Reasons for decline/threats
Primary factors: habitat loss, habitat degradation (fire suppression), human predation
Habitat loss: urban development is generally incompatible with tortoise ecology
Habitat degradation: roads (roadkill), dense vegetation (due to lack of burning), loss of food plants (due to lack of burning) makes habitat unsuitable causing abandonment and/or death
Gopher tortoise has been a food item for over 4000 years for humans.
Until recently, regularly taken as food. Now illegal.Slide10
https://
www.youtube.com/watch?v=eNknz8hYTRs
Discuss issues of tortoise relocation (unexpected threats, problems)