Bog Turtle Demographics within the Southern Population

Turtles are among the most vulnerable vertebrate group to declines, extirpations, and extinctions, especially those species with specific habitat requirements. The Bog Turtle (Glyptemys muhlenbergii) is listed as federally Threatened in the United States, but the southern population of the species does not receive full habitat protection under the Endangered Species Act. To understand Bog Turtle demographics within the southern population, we applied Cormack-Jolly-Seber and multistate models in program MARK and calculated annual adult, sex-specific, and juvenile survival for intensively sampled (19–180 sampling days) Bog Turtle populations in North Carolina. The most parsimonious model indicated that adult survival remained constant over time for all populations, but was relatively low when compared to other species of turtles. Adult survival estimates varied between 0.86 and 0.94 among the sites, all below the 0.96 adult survival estimate documented for northern Bog Turtle populations. To evaluate variation in juvenile survival, we focused on three populations: the two largest known populations and an intensely studied, but critically declining population. The two largest populations had a greater proportion of juveniles than other populations and higher juvenile survival (0.68 and 0.67) than the declining population (0.50). Thus, conservation efforts targeting juvenile survival and recruitment, such as nest protection and habitat enhancement, are important to ensure population stability. Furthermore, our estimates of adult and juvenile survival indicate that North Carolina populations are likely declining and without stronger protection measures, local and regional extirpations of the species may occur.