Identification of Wood Turtle Nesting Areas
for Protection and Management


1 USDA Forest Service, Forestry Sciences Lab, 183 Highway 169 East,
Grand Rapids, MN 55744, USA / e-mail:
2 710 High St., Duluth, MN 55805-1135, USA
3 USDA, Forest Service, North Central Forest Experiment Station,
1992 Folwell Ave., St. Paul, Minnesota 55108, USA

        ABSTRACT:  The wood turtle, Clemmys insculpta, is a long-lived, semi-aquatic, riverine species that inhabits forested regions of the northcentral and northeastern United States and adjacent regions of Canada.  Many states list the wood turtle as “Endangered” or “Threatened” and it is now listed on Appendix II of the Convention on International Trade in Endangered Species (CITES).  In this paper, we examine the hypothesis that nesting areas are critical determinants of wood turtle occurrence in northern portions of its range.  We measured six habitat variables at 334 nesting sites and used those data to develop criteria that define suitable nesting areas.  Our study demonstrated that wood turtles in the Upper Great Lakes Region prefer nesting areas that are near water, very sandy, elevated, bare, and well exposed to solar radiation.  Using a geographic information system (GIS), we designed a model that used sandy soil and stream spatial data to locate potential wood turtle nesting areas.  The accuracy of the model was evaluated using three methods: aerial photographic interpretation, aerial survey, and ground survey.  The ground survey confirmed that all wood turtles and nearly all potential nesting areas meeting the criteria were located near river reaches predicted by the GIS to have potential for producing nesting areas.  Aerial photographic interpretation yielded unacceptably poor information, while the aerial survey was acceptable for identifying major nesting areas.
        Geologic factors most likely determine the local distribution of wood turtles.  In glaciated portions of their range, the historic distribution of wood turtles was probably correlated with the soils from glacial outwash plains.  Because these soils occur in isolated patches, wood turtle populations have probably always occurred in disjunct segments.  However, human activity has altered the availability of sand and gravel, which in turn may have altered the local distribution of wood turtles.  Wood turtles are vulnerable to loss or degradation of their nesting areas from streambank stabilization, channelization, damming, and dredging programs.  Thus, it is essential that resource managers identify and protect this element of critical habitat.  Because nesting areas are a landscape feature, a partnership of private and public entities is required to effectively manage wood turtles in entire watersheds.

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