Date of Award

Spring 5-2013

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Committee Chair

Brian Kreiser

Committee Chair Department

Biological Sciences

Committee Member 2

Carl Qualls

Committee Member 2 Department

Biological Sciences

Committee Member 3

Mark Welch

Committee Member 3 Department

Biological Sciences

Abstract

Despite the protection of gopher tortoises, Gopherus polyphemus, in the western portion of their range for over twenty years, populations of the De Soto National Forest (DNF) in southern Mississippi experience low recruitment and lower hatching success than populations in the eastern portion of the range, and the causes of this are unknown. Previous work has shown that Mississippi populations of the DNF have lower levels of genetic diversity than eastern populations, which prompted the suggestion that reduced levels of genetic variation may play a part in low hatching success. Small populations can become more susceptible to the effects of inbreeding which can have negative effects on fitness of offspring. Using a microsatellite-based approach, I assessed genetic variation at two sites in south Mississippi that have different levels of recruitment to test for a correlation between genetic variation and survivorship. T44 at Camp Shelby is a low recruitment site, and Hillsdale is a high recruitment site. I found evidence of a heterozygosity fitness correlation among tortoises belonging to different age classes in the Hillsdale population. Multilocus genotypic data was also used to perform parentage assessments to characterize the mating systems and movements of both populations. Both populations demonstrated unequal reproductive success among adult tortoises, and spatial analyses revealed strong colony fidelity within populations even across several years.

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