Purdue University Graduate School
Michael Rohde Thesis.pdf (1.57 MB)

Michael Rohde Thesis.pdf

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posted on 2023-04-27, 20:37 authored by Michael L RohdeMichael L Rohde


Many species of turtle are facing serious declines from multiple anthropogenic causes. One such turtle native to the United States, the Blanding’s Turtle (Emydoidea blandingii), has faced declines in nearly every sector of their range, yet few populations have known recorded demographics, such as abundance, density, sex ratio, and body sizes. To inform managers of these crucial demographic measures of three spatially adjacent populations on Camp Grayling, MI, I implemented a capture-mark-recapture study from 2021 to 2022. I calculated Lincoln-Petersen Index and ran constant, time-varying, and behavioral response models for both full and conditional likelihoods in Program MARK. All best fit models estimated populations ≥30. The three populations sampled at Camp Grayling were low in abundance, densities, and biomass compared to some more well-known populations. Adult body weight means were 1456 g and 1223 g for males and females, respectively. Mean carapace lengths for males was 22.42 cm and females were 20.11 cm. The males of these populations were significantly larger than the mean found across the Blanding’ Turtles range. There is evidence of recruitment within these populations. A long-term research plan should be implemented and focus on investigating connectedness of these populations, as well as building data for population viability analyses. Additionally, immediate conservation action should take place to protect this vulnerable species.


Degree Type

  • Master of Science


  • Biological Sciences

Campus location

  • Fort Wayne

Advisor/Supervisor/Committee Chair

Dr. Bruce Kingsbury

Additional Committee Member 2

Dr. Jordan Marshall

Additional Committee Member 3

Dr. Mark Jordan

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