Literaturdatenbank
Literaturdatenbank |
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Ballou, A. R. (2013). Aspects of gopher tortoise (gopherus polyphemus) populations in georgia: Status, landscape predictors, juvenile movements and burrow use. Unpublished thesis , University of Georgia.
Added by: Admin (06 Jan 2014 18:24:01 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: anon2013m View all bibliographic details  |
Categories: General Keywords: Gopherus polyphemus, Habitat - habitat, Nordamerika - North America, Schildkröten - turtles + tortoises, Testudinidae Creators: Ballou Publisher: University of Georgia |
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| Abstract |
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Testudinidae Gopherus polyphemus I estimated gopher tortoise population sizes using line transect distance sampling on 17 sites in Georgia, and studied whether burrow width affects detection probability. I used tortoise density data to determine which site and landscape variables affect tortoise population density. I also studied a juvenile tortoise population in southwestern Georgia to test the accuracy of juvenile gopher tortoise burrow scopes, compare juvenile and adult tortoise burrow occupancy and evaluate a new method for tracking juvenile tortoises. Population size estimates among sites ranged from 89 (95% CI: 61-129) to 1877 (95% CI: 1485-2372). I found that detection probability decreased with decreasing burrow width, from 0.78 for burrows > 23 cm to 0.67 for burrows < 12 cm in width. The best model to predict tortoise densities was the model that included evergreen and mixed forest within sites and road density in the surrounding landscape. The juvenile burrow scope was highly accurate (occupancy of 96.7% of burrows was determined correctly), and juveniles had a significantly higher burrow occupancy rate (77%) than adults (40%). Finally, I found that fluorescent powder tracking was a simple and inexpensive method for tracking juvenile gopher tortoises.
Added by: Admin |