Resource overlap and the potential for competition between invasive red-eared slider turtles and native red-bellied turtles

Background/Question/Methods

Invasive species have affected populations and communities worldwide through predation and competition for limited resources. Globally, the invasive red-eared slider turtle (Trachemys scripta elegans) is hypothesized to compete with native turtles for limited food and spatial resources. In the Mid-Atlantic region of the United States the red-bellied turtle (Pseudemys rubriventris) has undergone population declines where red-eared slider turtles have been introduced. Using bio-telemetry and dietary analysis our research quantifies the extent of overlap for spatial and nutritional resources between sympatric red-eared slider turtles and red-bellied turtles in Pennsylvania.

Results/Conclusions

Radio tracking and trapping data suggest extensive overlap of habitat use by both species. Stomach flushing, fecal analysis and stable isotope data show that diets of red-eared slider turtles overlap extensively with those of red-bellied turtles in smaller, anthropogenically altered wetlands. In larger, less altered wetlands, turtle species exhibit partitioning of food resources. Our research shows that wetland characteristics may play a key role in determining the extent of competition between invasive red-eared slider turtles and declining native turtle species. These findings have fundamentally important implications to conservation and management of declining turtles world-wide.