Headstarting Eastern Box Turtles in Southwest Michigan: Implications for Growth, Survival, and Spatial Ecology

Author

Faith C. KuzmaFollow

Date Approved

1-4-2024

Graduate Degree Type

Thesis

Degree Name

Biology (M.S.)

Degree Program

Biology

First Advisor

Jennifer Moore

Second Advisor

Paul Keenlance

Third Advisor

Alexandra Locher

Fourth Advisor

William P. Flanagan III

Academic Year

2023/2024

Abstract

Turtles and tortoises are one of the most endangered groups of animals in the world as anthropogenic activities like overexploitation, collection for the pet trade, and habitat loss and fragmentation have caused dramatic population declines in recent years. As a result, proactive conservation techniques are being increasingly implemented to facilitate population recovery. Headstarting is a popular chelonian conservation technique that aims to reduce vulnerability and increase survival of juvenile turtles. While headstarting has been a valuable tool for many species, there is increasing evidence that species-specific influences impact its success. In this study, we headstarted four annual cohorts of eastern box turtles (Terrapene carolina carolina) for nine months from 2019 – 2023. Following their release at Pierce Cedar Creek Institute in Barry County, Michigan, we tracked the turtles using radio telemetry and examined their growth, survival, and spatial ecology in comparison to a cohort of wild (non-headstarted) hatchlings. Headstarted turtles were larger than their wild conspecifics (50.73 g vs. 8.75 g) and had a higher survival probability (0.62 vs. 0.44). Captive growth was influenced by initial weight, time (duration in captivity), cohort, and maternal identity. Headstarts and wild hatchlings both used mesic forest habitats the most and displayed seasonal variation in their habitat use. Headstarted turtles had larger home range sizes (mean MCP = 1.11 ha, mean AKDE_c = 4.35 ha) than wild hatchlings (mean MCP = 0.14 ha, mean AKDE_c = 1.26 ha) and displayed annual variation in home range location which suggests they may undergo a settling period following release. This study reveals important information about the survival and spatial ecology of the understudied juvenile age class and identifies the direct impacts of headstarting on eastern box turtles. Overall, headstarting appears to be a promising conservation technique for eastern box turtles as it increases growth and survival rates without significantly affecting post-release behavior.

Comments

In collaboration with Pierce Cedar Creek Institute and John Ball Zoo.

ScholarWorks Citation

Kuzma, Faith C., "Headstarting Eastern Box Turtles in Southwest Michigan: Implications for Growth, Survival, and Spatial Ecology" (2024). Masters Theses. 1115.
https://scholarworks.gvsu.edu/theses/1115