Purdue University Graduate School
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posted on 2021-12-08, 20:57 authored by Daniel James GuintoDaniel James Guinto

The Blanding’s Turtle (Emydoidea blandingii) is considered a species of conservation need across much of its range. A key aspect to conserving a species is understanding the genetic diversity and population structure across the landscape. Several researchers have focused on E. blandingii genetic diversity in the northeastern United States, Canada, and the Midwest. However, little investigation has been done on localities within the Great Lakes region of Indiana, Michigan, and Ohio. Here 14 microsatellite loci are utilized to characterize the genetic diversity of E. blandingii in Indiana, Ohio, and Michigan. Understanding genetic trends within this region will allow for the defining of management units through genetic clustering, investigation of historic and recent migration between clusters, investigation of drivers of genetic differentiation, checks for bottlenecks, estimations of effective population size (Ne), and optimization of landscape resistance surfaces. Overall, little differentiation is observed between localities and within locality diversity tended to be high. A minimum of four clusters were identified and as many as seven clusters were detected in a hierarchical manner using three grouping methods (STRUCTURE, Tes3r, and DAPC). Historical migration between clusters was relatively low, and recent migration appears to be absent. Significant correlations between geographic distance and genetic differentiation (IBD), as well as watershed and genetic differentiation were observed. Optimized landscape resistance layers provided poor models and distance was maintained as the best driver of differentiation. No bottlenecking was detected, and Ne estimates were generally high, but likely biased by sample size. The long lifespan and delayed genetic differentiation of E. blandingii is likely responsible for the observed diversity and lack of differentiation between localities. This does not mean they are secure in the Great Lakes Region. Bottlesim analysis looking at the effects of population reduction and subsequent loss of genetic diversity indicates that many localities within the study area are likely vulnerable to genetic loss in the next 200 years, which can be rapid and drastic in long-lived species.


Degree Type

  • Master of Science


  • Biological Sciences

Campus location

  • Fort Wayne

Advisor/Supervisor/Committee Chair

Mark A. Jordan

Additional Committee Member 2

Bruce A. Kingsbury

Additional Committee Member 3

Rebecca A.S. Palu

Additional Committee Member 4

Matthew D. Cross

Additional Committee Member 5

Gregory J. Lipps, Jr.