Wood turtle population dynamics in northern Wisconsin


The wood turtle (Glyptemys insculpta) is a threatened in Wisconsin with the major threats being habitat degradation and fragmentation, road mortality, and nest predation. Nesting habitat degradation is of particular concern because adult female wood turtles are unable to find suitable natural nesting areas and are forced to nest on road shoulders. This enhances their risk to road mortality and may also attract nest predators especially raccoons and skunks. This combination of increased nest predation and adult mortality is likely driving population declines across the wood turtle range.

Management has focused on nest protection to decrease nest predation, head-starting to increase hatchling survival rates, nest site creation to prevent females from nesting on roads, and road barriers to prevent turtles from crossing roads. Although these conservation actions have been widely used for many freshwater turtle species, their relative effectiveness and feasibility has not been explored for wood turtle populations.

To explore the relative effectiveness of these conservation actions, we are creating a demographic model involving three wood turtle populations in northern Wisconsin. We are quantifying nest success that accounts for abiotic and habitat factors as well as management actions. Additionally, we are using telemetry to quantify wood turtle hatchling survival in northern Wisconsin. We will use these vital rates estimates as well as those previously estimated for adult turtles within our study site to create a regional wood turtle population viability analysis and assess strategies to stabilize wood turtle populations in northern Wisconsin.

This work is funded by the Wisconsin Department of Natural Resources.