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WOOD TURTLE IN THE ST CROIX WATERSHED: ASSESSMENTS 2009
Kurt Miedtke, University of Wisconsin-Stevens Point
In our poster entitled above, we present our first year results of assessments of wood turtle habitat threats and public outreach. The wood turtle (Glyptemys insculpta syn. Clemmys insculpta), a threatened species in Minnesota, occurs in a limited range throughout the Eastern US and Canada. In Minnesota it is found in rivers and streams in the eastern part of the state, where it reaches the western edge of its range. Limited surveys of wood turtles in the 1980's and early 1990's established that the wood turtle occurs in the St Croix River watershed in Pine County. Baseline population size and distribution prior to land changes in the late 19th and early 20th century however are not known. In 2009, the MNDNR contracted out surveys for wood turtles in the Kettle River. Reconnaissance surveys were conducted in May when turtles are emerging from hibernation to identify potential nest sites and to capture and mark wood turtles found. Nesting surveys were conducted later in June by visiting potential nest sites between dusk and dawn. MNDNR staff was involved with assessing the current condition of potential nesting sites. MNDNR staff collected site access information and assessed the feasibility of including selected potential nest sites in a long range monitoring plan of wood turtle populations and habitat. We undertook some limited public outreach to assess public interest in and awareness of turtles in general and wood turtles specifically. During the field season many threats to the wood turtle were identified. An important mortality factor for young turtles is predation by raccoons and skunks. We found that 7 out of the 10 best nesting sites that had nesting signs of various turtle species also had tracks of predators or depredated nests. Wood turtle populations could be limited by the availability of nesting sites. Nesting sites are lost when they become overgrown with vegetation and the sun is not able to reach the soil and incubate the eggs. Our data show that 10 sites out of 19 had more than 50% vegetation cover. From our public outreach efforts along the Kettle River, Sand and Crooked Creek we conclude that overall, the public is very interested in turtles in general. Many landowners expressed concern that the overall turtle abundance seems to be decreasing while the human population and traffic along a major highway is increasing, a cause for higher roadside mortality. With a higher human population more people use rivers for recreation. We found 7 out of 19 potential nesting sites showed signs of human disturbance including ATV usage. Research has shown that with increased human disturbance, wood turtle abundance decreases. The scientific community should address threats to wood turtle before the species is extirpated from the St. Croix watershed.
Acknowledgements: Mentorship was received from Maya Hamady and Gaea Crozier, MNDNR/ Division of Ecological Resources. Assistance was received from Mary Armitage, retired engineer as MN DNR volunteer. Coordination and guidance were provided by Jason Naber, principal investigator, Emmons and Olivier Resources Inc.
Buech, R.R. 1992. Streambank stabilization can impact wood turtle nesting areas. 54th Midwest Fish and Wildlife Conference, Abstract 190, p.260. 6-9 December 1992, Toronto, Ontario.
Ewert, M.A. 1984,1985. Assessment of the current distribution and abundance of the wood turtle (Clemmys insculpta) in Minnesota and along the St. Croix Scenic Waterway in Wisconsin. First year report submitted to the Minnesota Department of Natural Resources.