Urban environments present many challenges for aquatic turtle species. Here, we investigated whether the diets of Trachemys scripta (Red-eared Slider) and Graptemys geographica (Common Map Turtle) may help explain the spatial ecology of these 2 species in a pair of constructed aquatic habitats in Indianapolis, IN, USA. We conducted stomach flushings on 43 turtles from 2 sites (Central Canal, n = 33; IMA Lake, n = 10). Common Map Turtles from the Central Canal (n = 27) consumed mostly mollusks and crayfish, which comprised ~86% of the volume of stomach contents. We captured no adult Common Map Turtles at IMA Lake, likely due to the lack of mollusks within this habitat. There was considerable variability in the diet of Red-eared Sliders between the 2 habitats, with 98.8% of the diet contents comprised of plant material in the Central Canal (n = 6) and only 67% plant material in IMA Lake (n = 10). This difference in diet may have been due to the lower abundance of vegetation found in IMA Lake compared to the Central Canal, or possibly a diversification of diet in response to decreased interspecific competition in IMA Lake. Diet comparison between species in the Central Canal shows almost no overlap, which may partially explain habitat association and movement differences between the 2 species documented in a previous study. The descriptions of Red-eared Slider and Common Map Turtle diets presented here are the first to be described from an explicitly urban landscape. Further understanding of the ecology of these species in urban habitats can aid city planners and managers with the goal of maintaining species diversity in urban landscapes.
Ryan, Travis, "Diet of Trachemys scripta (Red-eared Slider) and Graptemys geographica (Common Map Turtle) in an Urban Landscape" Urban Naturalist 21/ (2019): 1-11.
Available at https://digitalcommons.butler.edu/facsch_papers/1331