Bridging Knowledge Gaps for Protection and Recovery: Habitat Use and Threats of Blanding’s Turtles in an Understudied Region of The Great Lakes

Abstract

Ontario is home to 8 species of freshwater turtles, all of which are federally at-risk of extirpation. To conserve declining populations, the government turns to recovery strategies for each species that are listed as threatened, endangered, or extirpated. These recovery strategies require previous field studies to identify critical habitats to be protected and threats that need to be mitigated. Because the majority of this information relies on field studies, there are still many knowledge gaps that need to be investigated, particularly in regions such as eastern Georgian Bay of the Laurentian Great Lakes, where little research has been done. This region contains relatively abundant populations of 6 species of freshwater turtle, including the federally endangered Blanding’s turtle (Emydoidea blandingii), which acts as an umbrella species for the conservation of other species that share its habitat. This thesis aims to fill knowledge gaps related to the critical habitat that needs to be protected in this region, as well as potential threats to Blanding’s turtles that may require mitigation efforts, such as human development or climate change. In the first chapter, we determine the habitats used by 22 Blanding’s turtles over the active, nesting, and overwintering seasons among coastal and inland wetlands. We also identify site-specific threats due to preferences for nesting near built-up areas rather than rock barrens. In the second chapter, we determine a significant loss in functional aquatic wetland habitat for Blanding’s turtles due to changes in annual water levels and infer associated impacts due to climate change. This was achieved by classifying satellite imagery between 2002 (lower water level) and 2019 (higher water level) and conducting change detection analyses. This research is the first to occur along the eastern coast of Georgian Bay and will advance our understanding of the threats and habitat requirements of freshwater turtles. The findings will be used to implement recovery strategies aimed at protecting and mitigating threats to imperiled freshwater turtles.