Hibernation Ecology of an Isolated Population of Bog Turtles,Glyptemys muhlenbergii

Abstract

Information on the hibernation ecology of Bog Turtles (Glyptemys muhlenbergii) throughout their range is limited. Few studies have identified suitable hibernacula or documented behavior during hibernation including site fidelity, communal hibernation, and entrance and emergence times. Our study presents long-term documentation of hibernation in a relatively understudied portion of the species' range. From fall 2005 to spring 2014, we observed the hibernation of 13 marked turtles in an isolated population located in the southern Appalachian Mountains of North Carolina. During the course of our study, nine turtles were radio-tracked for 1-5 y. Turtles spent about six months in hibernation, usually entering the hibernaculum in late September into October and emerging in mid-April. Using radiotelemetry, we identified 11 hibernacula of three types: root masses of trees/shrubs, root masses of cinnamon ferns (Osmundastrum cinnamomeum), and sedge (Carex stricta) clumps. Site fidelity and communal use were common in our study. Ten turtles located in multiple winters repeated their use of a hibernaculum in at least two of those winters. Twelve turtles hibernated communally in at least one year. No mortality was observed at the hibernacula. Our study demonstrates the importance of root masses with soft deep substrate for survival in long, harsh winter conditions. Bog Turtles spend about half of every year, and therefore half of their lives, in hibernation, making the identification and protection of suitable habitat for hibernation imperative for successful management to ensure the long-term viability of the species.