Survivorship and Population Densities of Painted Turtles (Chrysemys picta) in Recently Modified Suburban Landscapes

Populations of long-lived animals, such as semi-aquatic turtles, that depend on high survivorship of reproductive adults, are particularly susceptible to the negative effects associated with habitat modification in suburban areas. Survivorship of semi-aquatic turtles in suburban landscapes may be reduced as a result of a number of factors, including the elimination of appropriate nesting habitat and the introduction of human-subsidized predators. Unfortunately, few studies on turtle populations in anthropogenically modified habitats estimate vital rates, and researchers are rarely able to study populations both before and after development. We studied painted turtle (Chrysemys picta) vital rates at 5 ponds in the Charlotte Metropolitan area of North Carolina; 2 ponds and their surrounding habitat underwent development after the first year of study, 1 pond was on a golf course, and 2 were farm ponds. We used Program MARK to generate open population models examining the effects of location and sex on turtle survivorship. Our results showed relatively stable population densities over 4 years across all ponds, with the largest density (approximately 100 turtles/ha) occurring at a recently developed site. Among ponds, turtles had variable annual adult survivorship (ca. 60%-95%), and males generally had lower survivorship than females. Our results emphasize the importance of site-specific habitat factors that influence turtle population demography and indicate that for long-lived species, whose population densities may not respond immediately to habitat change, long-term monitoring efforts examining population vital rates are needed to more fully evaluate the effects of anthropogenic modification.