Movement Ecology of the Imperiled Wood Turtle (Glyptemys insculpta) in a Lower Hudson River Watershed

Abstract

Knowledge of the spatial ecology of many turtle species is lacking or limited by small sample sizes of study animals, short study periods, or incomplete representation of the species' geographic range, all of which can present barriers to science-based management and conservation. The wood turtle (Glyptemys insculpta) is a declining North American freshwater turtle that is now listed as threatened or endangered in several US states and Canadian provinces. Local-scale knowledge of wood turtle movement patterns and home range sizes is needed for more effective management and regulatory protection, yet the spatial ecology of this species remains undescribed in large portions of its range. We radiotracked 31 wood turtles for 1–5 yrs each in a stream system along the border of New York and Connecticut to describe their movement behavior and inform management efforts in this previously unstudied region. Annual and multiyear 95% minimum convex polygon home range sizes averaged 2.8 (± 3.79 SD) ha and 5.2 (± 7.36 SD) ha, respectively. Males had significantly larger annual and multiyear home ranges than did females, often by severalfold. Overlap of home ranges from one year to the next ranged from 10.5% to 99.7% and averaged 62.6% (± 22.86% SD). Home range centroids shifted 3.8–328.1 m (x̄ = 70.3 ± 80.31 m SD) from year to year and averaged 41.2 m (± 40.56 m SD) from the stream and 138.4 m (± 70.66 m SD) from the nearest road across all individuals. Most turtles' home ranges spanned one or both of the major roads in our study area, illuminating the threat of vehicle collision mortality to the viability of this population. Hibernaculum fidelity was low, with only 15% of turtles hibernating in the same location as in the previous year. Our results suggest that management efforts for wood turtles in western Connecticut and the adjacent region of New York should consider that males (the wider-ranging sex) use an average of 5.3 ha to meet their resource requirements over the course of one annual cycle, buffers of at least 116 m surrounding streams should be protected, habitats that are distant from roads should be prioritized for conservation, and measures that facilitate safe passage beneath roads should be implemented whenever roads are present near occupied wood turtle habitat.