Landscape Ecology

, Volume 25, Issue 5, pp 791–801 | Cite as

Population structure and movements of freshwater turtles across a road-density gradient

  • David A. Patrick
  • James P. Gibbs
Research Article


Understanding interactions between roadways and population structure and movements of wildlife is key to mitigating “road effects” associated with increasing urbanization of the landscape. Aquatic turtles are a useful focal group because (1) population persistence is sensitive to mortality of individuals upon roads; (2) turtles frequently move among wetlands and encounter roads, and (3) turtles are an important component of vertebrate biomass in aquatic ecosystems. From 2005 to 2007, we examined the effects of urbanization on local- and landscape-scale populations of turtles. To do so, we sampled and marked turtles in 15 ponds arranged along a steep, urban–rural gradient in central New York State. We captured 494 turtles, representing 327 individuals, the majority of which were common snapping turtles Chelydra serpentina (n = 191) and eastern painted turtles Chrysemys picta picta (n = 122). At the local population (pond) scale, a higher proportion of female snapping turtles in ponds was associated with lower road densities within 500 m of ponds. The mean size of both species of turtle increased in ponds with a lower density of roads within 100 m. At the landscape-level, we observed fewer turtles dispersing through urbanized habitat than forested, and fewer movements through areas with a higher density of roads. Our study suggests that roads alter both local- and landscape-level turtle populations through a loss of female turtles, and by reducing movement between ponds. By extension, the study targets key landscape features upon which to focus mitigation efforts.


Interpond movement Road density Habitat resistance Urbanization Sex ratio 



We would like to thank Brett Jesmer, Kevin Shoemaker, Alex Krofta, Oscar Pineda, and Casey Tompkins for their help in the field, and Viorel Popescu for advice on the use of GIS. The Radisson Community Association and Radisson Greens Golf Course in Baldwinsville generously provided access to field-sites and help with transporting field equipment. We would also like to thank the New York State Department of Environmental Conservation, particularly Gary Pratt) and New York State Department of Transportation (NSYDOT), particularly Debra Nelson, for their help and support. An earlier draft of this manuscript was greatly improved by suggestions from an anonymous reviewer. Funding for the study was provided by the NYSDOT contract C-04-02.


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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Department of Environmental and Forest BiologyState University of New York College of Environmental Science and ForestrySyracuseUSA

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