Landscape-level Factors Influencing Bog Turtle Persistence and Distribution in Southeastern New York State

The bog turtle Glyptemys muhlenbergii is a highly endangered species inhabiting freshwater wetlands of the eastern United States. Habitat degradation is considered one of the chief causes of bog turtle declines. Most of the studies investigating habitat requirements of bog turtles focus on intrawetland influences on bog turtle habitat, but few have explored landscape-level drivers of bog turtle distribution. To better understand causes of bog turtle declines, we combined bog turtle occurrence records with geographic data to contrast 12 landscape variables among wetlands containing extant populations of bog turtles (n = 65) and 500 nearby and 500 distant, randomly located wetlands in southeastern New York State. In contrast to randomly chosen wetlands, bog turtles have persisted in relatively large, open-canopy wetlands (typically >0.42 ha) within large watersheds (typically >13.54 ha), in wetlands with more numerous stream connections, and more often in wetlands positioned atop carbonaceous rock types. Wetlands occurring within carbonaceous surficial geological settings may be more resistant to bog turtle habitat degradation and hence likely to support more persistent populations of bog turtles. Our findings that geomorphic features and intrawetland vegetation are the most useful predictors of bog turtle occurrence and persistence in southeastern New York State are important for generating more detailed hypotheses regarding drivers of bog turtle declines and are also helpful for prioritizing sites for bog turtle conservation and guiding surveys to discover new populations.