Follow-Up Demographic Survey of a Florida Gopher Tortoise Population

Cowboy_Ken

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Southeastern Naturalist 13(4):639-648. 2014
Joan E. Diemer Berish1,2,* and Erin Hoerl Leone1

1 Florida Fish and Wildlife Conservation Commission, 1105 SW Williston Road, Gainesville, FL 32601.

2 Current address - 20 Kiva Court, Sandia Park, NM 87047.

* Corresponding author - [email protected].

Manuscript Editor: Max Nickerson

Abstract

In 1995, we surveyed a previously studied (1982–1986) northern Florida population of Gopherus polyphemus (Gopher Tortoise) to document demographic changes that may have occurred over time. The sandhill study site had been unburned for approximately 8 years, resulting in increased woody midstory and decreased herbaceous groundcover. We captured 88 Gopher Tortoises in pitfall traps during May—June 1995. Eighteen (20%) of the tortoises had been previously mSarked; only 11% of 169 marked tortoises were recaptured. Gopher Tortoise distribution appeared to be more clumped in 1995, and density had declined by about half, likely due to habitat degradation associated with fire exclusion. Size- and sex-class distribution and clutch size were not significantly different between the two study periods. In 1995, the smallest female with detected shelled eggs had 11 plastral annuli and a carapace length of 225 mm. Habitat degradation, whether on private or public lands, is an ongoing problem for this species.

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Factors Influencing Reproductive Output and Egg Size in a Southern Population of Gopher Tortoises

Southeastern Naturalist 13(4):705-720. 2014
Betsie B. Rothermel1,* and Traci D. Castellón1

1 Archbold Biological Station, Venus, FL 33960.

* Corresponding author - [email protected].

Manuscript Editor: Will Selman

Abstract

Comparative life-history data are needed to develop effective conservation plans for Gopherus polyphemus (Gopher Tortoise), a threatened species that inhabits diverse ecosystems throughout its range. In 2010–2011, we measured and radiographed 27 female Gopher Tortoises occupying Florida scrub and mesic flatwoods habitats at Avon Park Air Force Range in south-central Florida. Counter to predictions of optimal egg size theory, both clutch size and mean egg width (measured via x-rays) increased significantly with body size. Furthermore, our data suggest the presence of a non-pelvic constraint on egg size in this species. Despite greater cover of grasses and forbs in flatwoods, clutch size, egg width, and female body condition were similar in flatwoods and scrub. Thus, the relatively low density of juvenile-sized burrows in flatwoods is not a result of low fecundity. Body condition tended to be higher in the wetter spring of 2010, although seasonal differences were not statistically significant. Clutch sizes at Avon Park Air Force Range (range = 4–9 eggs; overall mean = 5.8 ± 1.2) were comparable to other populations, but lower than reported for some peninsular Florida populations. Further research is needed to explain variation in reproductive output among individuals and populations in the southern part of the species' range.
 

ZEROPILOT

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They aren't as common here in south Florida as in the middle of the state. Likely because of the land situation. Lots of houses and lots of swamp here. Recently I saw dozens near Cape Canaveral and on the west central coast area. The last wild Gopher tortoise I saw near here was about three years ago. Florida is finally beginning to make it more difficult for developers to just build a shopping center on top of them........
 
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