Effects of Nonnative Plants on Space-Use in Eastern Box Turtles

Author

Emily Ilene Crago, Winthrop University

Date of Award

Spring 5-1-2023

Document Type

Thesis

College

College of Arts and Sciences

Degree Program

Biology

Degree Name

Master of Science

Thesis Advisor

Kiyoshi Sasaki, Ph.D.

Committee Member

Jennifer Schafer, Ph.D.

Committee Member

Lauren Brasington

Keywords

Nonnative Plants, Space Use, Eastern Box Turtle, Movement Patterns, Density of Nonnative Plants

Committee Member

Salvatore Blair, Ph.D.

Abstract

Introduction of nonnative plants outside their natural range has caused widespread reduction in the abundance and diversity of native plant species. Nonnative plants typically form dense, often monotypic, thickets that affect the ability of animals to find food, reproduce, avoid predation risk, and thermoregulate. By doing so, nonnative plants have the potential to displace resident animals from areas otherwise suitable as animal habitat. However, limited studies have investigated whether resident animals avoid areas dominated by nonnative plants. This study investigated impacts of nonnative plants on eastern box turtles (Terrapene carolina carolina), a species that has been declining throughout their range. To determine if eastern box turtles avoid nonnative plants, I estimated habitat selection based on GPS fixes recorded for 16 individuals (6 males and 10 females) in an urban forest. Specifically, I determined if nonnative plants are avoided when turtles establish their home range (i.e., second order selection) and when they use their home ranges (i.e., third order selection). For females, the density of four of the six most common nonnative plant species was lower in turtle locations than available locations across the study area (i.e., second order selection) and those within home ranges (i.e., third order selection). For males, the density of only one nonnative plant species was lower in turtle locations than available locations across the study area (i.e., second order selection), and none of the species were different between turtle locations and available locations within their home ranges (i.e., third order selection). These results suggests that eastern box turtles avoid some (but not all) species of nonnative plants and that females are more sensitive to nonnative plants than males. The displacement of animals from highly invaded areas represents a functional loss of habitat. The reduction in available habitat area may lead to reduction in carrying capacity of invaded areas, and therefore, may have long-term impacts on population persistence.

Recommended Citation

Crago, Emily Ilene, "Effects of Nonnative Plants on Space-Use in Eastern Box Turtles" (2023). Graduate Theses. 148.
https://digitalcommons.winthrop.edu/graduatetheses/148