Graduation Year
1986
Document Type
Thesis
Degree
M.S.
Degree Name
Master of Science (M.S.)
Department
Biology
Degree Granting Department
Biology
Major Professor
Henry R. Mushinsky, Ph.D.
Committee Member
Earl D. McCoy, Ph.D.
Committee Member
Glen E. Woolfenden, Ph.D.
Committee Member
Richard P. Wunderlin, Ph.D.
Abstract
Scat analysis and foraging observations were used to determine the diet of a gopher tortoise, Gopherus polyphemus, population in a sandhill community in west central Florida. Live vegetation was assessed to determine plant availability. The bulk of the gopher tortoise diet was composed of the dominant plant species in the habitat while the tortoises were selective with respect to most plant genera. Tortoises ingested many plant taxa with Poaceae, Asteraceae, Fabaceae, Pinaceae and Fagaceae being the most frequent components of the diet. Sixty-eight genera from 26 families were identified in the tortoise diet. In the scat the most common genus identified was Aristida and the most common family was Poaceae. Other common genera were Pinus, Quercus, Galactia, Cnidoscolus, Tillandsia, Pityopsis, and Richardia. Insects and charcoal were often present in scats. Although plant availability differed between seasons, the gopher tortoise diet did not change significantly. The proportions of plants in the diet differed from the proportions of plants available in the spring but no significant difference was indicated between diet and availability in the fall. Comparing the overall diet indicated no difference between sexes or age groups. Comparing diet with respect to individual plant taxa indicated young tortoises ingested significantly less Poaceae and some plants with external defense mechanisms (Rubus, Cnidoscolus) than did adults. Nonplant items may be a significant source of nutrients. Jacobs Electivity Index indicated the tortoises preferred Galactia, Cnidoscolus, Pinus, Quercus, and the Rubiaceae. Poaceae, Aristida, Asteraceae, and Pityopsis, the most common plants in the habitat, were selected at or below the proportions at which they were available. Feinsinger's Proportional Similarity Index indicated gopher tortoise foraging behavior lies midway between a specialist and generalist.
Scholar Commons Citation
Macdonald, Laurie Ann, "THE DIET OF THE GOPHER TORTOISE, Gopherus polyphemus, IN A SANDHILL HABITAT IN CENTRAL FLORIDA" (1986). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/8709
