| To date, research aimed at identifying the effects of roads on freshwater turtle populations has been based primarily on anecdotal evidence and reports of site-specific mortality of individuals. To determine if road density and associated vehicle induced road mortality affects freshwater turtles at the population level, I trapped painted turtles, Chrysemys picta, and snapping turtles, Chelydra serpentina, in 35 wetlands surrounded by varying levels of road density within central New York. In both species, sex ratio was strongly male-biased at high road densities, a pattern likely due to the selective nature of road mortality for females. Examination of published sex ratios of turtle populations within North America revealed that the phenomenon may be widespread: the proportion of males in most species has increased substantially over the last century. This pattern is consistent with predictions associated with an increase in the road network. |
