Date of Award

5-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Forestry and Environmental Conservation

Committee Chair/Advisor

Kyle Barrett

Committee Member

Robert Baldwin

Committee Member

Catherine M. Bodinof Jachowski

Abstract

Urbanization poses a significant threat to wildlife through fragmentation, degradation, and loss of habitats. Species response to urban development is variable, from species that thrive in urban areas to those that avoid them. Eastern box turtles (Terrapene carolina carolina) can live and reproduce in urban areas; however, reports of population decline throughout the species’ range have raised concerns. The objective of this study was to compare home range size and composition, as well as the microhabitat selection of the Eastern box turtle across a developmental gradient in Clemson, SC. We tracked 14 individuals in habitats along a developmental gradient ranging from residential neighborhoods to the protected habitat of the Clemson Experimental Forest. Individuals were relocated at a frequency of once weekly during the active season (April to November) of 2022, twice weekly during the active season of 2023, and once every other week in the winter. Each time a telemetered turtle was located we recorded the coordinates and various habitat parameter (e.g., humidity, vegetation cover) at the used and two associated random locations 5-10 and 50-60 meters. We generated 95% autocorrelated kernel density estimates to represent home range size and minimum convex polygons to determine home range composition. A discrete choice framework was used to compare various habitat parameters hypothesized to influence microhabitat selection. Our results indicated turtles in small forest patches within the suburban landscape had smaller home ranges and reduced average weekly displacement compared to individuals in continuous forest areas. The increased presence of edge habitat could act as an ecological trap by encouraging behavior specific to that ecotone (e.g., nesting or thermoregulation). Our results also indicated that microhabitat selection varied across levels of development. In habitats with no development selection was influenced by vegetation cover composition (i.e., turtles selected for areas with foraging potential and woody debris). In contrast in habitats with moderate and high development, turtles selected areas with greater leaf litter depth and vegetation > 15 cm in height. Our results highlight the importance of large continuous forest patches for maintaining unrestricted home range area and movement, as well as reducing opportunities for human-caused mortality. We also call attention to the importance of a complex understory that includes deep leaf litter depth, vegetation greater than 15 cm in height, and the presence of woody debris. The results from this study help to further our understanding of how development affects the movement and behavior of the Eastern box turtle, and the results provide a means to improve backyard habitat management for this species.

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