Field Assessment of Gopher Tortoise Habitat at Camp Shelby, MS. Phase II: Overstory and Combined Assessments
ENGINEER RESEARCH AND DEVELOPMENT CENTER CHAMPAIGN IL CONSTRUCTION ENGINEERING RESEARCH LAB
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The western population of the gopher tortoise Gopherus polyphemus is listed as Federally threatened its presence on the Camp Shelby, MS has resulted in training restrictions. To determine the specific habitat variables that influence gopher tortoise habitat selection, this research assessed overstory habitat conditions between active, recently active and randomly selected non-burrow locations at this site. Field surveys were completed in three study areas at the installation. On average, burrow sites had a much higher overall occurrence of longleaf pine and significantly lower total basal area as compared to non-burrow sites. Overstory mean height was significantly lower on burrow than non-burrow sites. When considering all variables understory, midstory, overstory, stepwise logistic regression identified seven significant explanatory variables. Burrow presence was positively correlated with understory legume cover,midstory woody cover, percentage of overstory pine, bare ground coverage, and debris coverage. Burrow presence was negatively correlated with overstory species richness and overstory percent open canopy. The strongest explanatory variable for predicting the occurrence of burrows was understory legume coverage. Within-model cross-validation correctly predicted the presence or absence of active burrows for 83.9 percent of the observed outcomes.
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