<p>Maintaining high genetic diversity within and among wildlife populations is an important component to the management of threatened species. Population genomics utilizes recent advancements in high-throughput next-generation sequencing to obtain genome-wide data that can yield deeper perspectives on intraspecific genetic variation and elucidate evolutionary significant units that may require conservation management or augmentation. The semi-aquatic Blanding’s Turtle (<i>Emydoidea blandingii</i>) has experienced drastic population declines in North America due in large part to anthropogenic activities. This species is listed as threatened or endangered across most of its range. A population genomic study can help to understand the status of this species and guide future management practices. Hence, a population genomic analysis was conducted using 3RAD to discover and analyze SNPs across the range using samples from Nebraska, Indiana, Michigan, Ohio, and Nova Scotia,. Range-wide analysis used 8,602 SNPs while analysis within the Great Lakes region used 7,893 SNPs. High amounts of missing data were found across all individuals and loci. Low levels of genetic variation relative to other turtle species were detected both across the range and within the Great Lakes region. Minimal population structure was detected range-wide via clustering and admixture analyses; however, a signal of population differentiation was detected among Nebraska, Nova Scotia, and the Great Lakes. Clustering and differentiation analyses focused on the Great Lakes region found a signal of population structure and differences between the Lake Michigan and Lake Erie watershed. These results may prove useful for conservation management of Blanding’s Turtle populations, particularly related to efforts using translocation or head-starting practices.</p>

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<p>  </p> <p>Many species of turtle are facing serious declines from multiple anthropogenic causes. One such turtle native to the United States, the Blanding’s Turtle (<em>Emydoidea blandingii</em>), 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.</p>

<p>Understanding and adequately protecting habitat is at the forefront of modern conservation concerns. Turtles are especially vulnerable to habitat loss, and are therefore a top priority for habitat research. To help meet this need, I used radio telemetry to collect microhabitat data from two imperiled species of turtles that occupy a military base in Michigan. Preliminary data exploration was carried out with principal components analysis (PCA). Microhabitat use was then modeled for each species using conditional logistic regression (CLR), with a generalized estimating equation (GEE) element to limit bias due to individual variation. Finally, I compared habitat use between sympatric Blanding’s and Wood Turtles using Mann-Whitney U tests and Mood’s median tests to investigate the degree of overlap in microhabitat use when these species occur in sympatry. Evidence for microhabitat selection in Blanding’s Turtles was weak, suggesting that they likely do not make habitat decisions at this level. Wood Turtles selected sites that were farther from water and had fewer trees, less overstory canopy cover, and more ground cover. Additionally, the two species differed in several aspects of microhabitat use; Wood Turtles were more terrestrial and more tolerant of tree cover than Blanding’s Turtles. Patterns of microhabitat use found in this study match previously observed behavior of turtles in high quality habitat, suggesting that managers should work to maintain the habitat currently available at Camp Grayling. Additionally, because both turtle species were associated with open canopy, selective logging could benefit turtles provided care is given to timing and methods. </p>

<p>  </p> <p>Blanding’s Turtle populations face direct threats to their survival. To help protect populations, habitats that can best support Blanding’s Turtle populations need to be identified across their range. Blanding’s Turtles have been a difficult to detect species and may be present at a site even if not detected during targeted surveys. Additionally, Blanding’s Turtles may be present at a site but may have little to no recruitment so additional measures of site suitability beyond species presence are needed to determine more suitable or higher quality habitats. In my research, I attempt to determine suitability of sites for Blanding’s Turtles across Michigan and Ohio using data collected from rapid assessment protocols fit into single season occupancy models with wetland and upland landcover types as co-variates of occupancy. To further determine the suitability of sites based on these data, I created single season occupancy models for juvenile Blanding’s Turtles and used N-mixture abundance modelling to determine relative abundance of Blanding’s Turtles at a site using the same landcovers as covariates of occupancy and abundance. Both modelling frameworks also allowed me to include detection covariates that could increase Blanding’s Turtle detection in future surveys. </p> <p>Detection was largely influenced by Julian date with the highest probability of detection occurring from mid-May through late June. Length of trapping surveys was also found to influence Blanding’s Turtle detection with a substantial decrease in daily trap capture rates by the fourth trap night of a survey. Michigan occupancy and abundance models found that the most suitable sites in Michigan would have high percentages of high-quality upland forest and woody wetland landcovers, with the percentage of open water supporting the occupancy of turtles but having no discernable effect on abundance. Total upland forest also significantly increased the probability of juvenile occupancy in Michigan. In Michigan, I also observed that survey method can greatly influence the estimates of occupancy and abundance, and I determined that visual surveys cannot accurately determine these estimates. The heavily disturbed nature of Ohio’s landscape took away from the predictive power of landcovers used in my research for Blanding’s Turtle occupancy and abundance. The vast difference between occupied habitats in Michigan and Ohio also takes away from the predictive power of the regional level model and relative abundance of Blanding’s Turtle populations cannot be accurately determined at this scale using the spatial covariates I included. However, total undisturbed forest and total wetland proved to be positive covariates of Blanding’s Turtle abundance and occupancy for adult and juvenile turtles across both states, but the habitats used in each state vary greatly so future conservation decisions should be made on the state level as largest spatial scale. Using my models for Michigan suitable sites can be determined within the state and compare relative abundance between sites to determine healthier populations. For future analysis in Ohio, different, smaller scales spatial covariates should be used to explain differences in occupancy and abundance between sites.</p>

<p>The distribution of Blanding’s turtles in North America is centered on the Great Lakes region, where the impacts from high levels of development have reduced and isolated populations. They are particularly sensitive to habitat loss and fragmentation because of their broad habitat requirements, migratory behaviour, and relatively large seasonal movements and home ranges. Consequently, Blanding’s turtles have been designated a species at-risk throughout the majority of their geographic range. In 2011 we conducted a radio-tracking program to compare the home ranges and movement patterns of Blanding’s turtles in two eco-regions of Ontario that have contrasting habitat and landscape characteristics: Georgian Bay Islands National Park and Rondeau Provincial Park. We also used GPS loggers to supplement data collection by radio-tracking and to evaluate the effectiveness of GPS loggers in tracking the movements of a semi-aquatic species. We found differences in home range between our two study populations that may be linked to landscape features and seasonal differences in movement within the population in Georgian Bay Islands National Park. We also determined that GPS loggers, when used in combination with radio-tracking, can effectively track the movements of Blanding’s turtles with a higher temporal and spatial resolution than by radio-tracking alone. This study highlights the importance of developing management strategies that are tailored to the spatial requirements of distinct populations, and the need for conservation measures that protect aquatic and terrestrial habitat surrounding the main activity centres of Blanding’s turtles.</p> / Master of Science (MSc)