SREL Reprint #3690

Metabolic responses to increased temperatures in three semi-aquatic turtle species from the southeastern United States

David L. Haskins1,2,3 and Tracey D. Tuberville1

1Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA
2Interdisciplinary Toxicology Program, University of Georgia, Athens, GA, 30605, USA
3Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30605, USA

Abstract: Physiological maintenance of ectotherms is largely dependent on temperature. Abrupt changes in environmental conditions can cause shifts in energy budgets, with higher temperatures requiring more energy be devoted to maintenance functions, making less energy available for other activities. As a group, freshwater turtles are of conservation concern; thus, it is important to understand their physiological responses to temperature shifts, particularly given current climate change predictions. We quantified metabolic rates (MR) for three species of semi-aquatic turtles that vary in their degree of terrestriality and propensity to aestivate: chicken turtles (Deirochelys reticularia), eastern mud turtles (Kinosternon subrubrum), and eastern musk turtles (Sternotherus odoratus). Metabolic trials were performed using a flow-through respirometer at three environmentally-relevant temperatures: 25°C, 30°C, and 35°C. As expected, MRs of turtles were significantly and positively associated with increases in mass and temperature. Pairwise comparisons revealed that D. reticularia exhibited significantly higher oxygen consumption rates (VO2) relative to K. subrubrum, which had significantly higher VO2 than S. odoratus. The combination of higher metabolic rates, the tendency to terrestrially aestivate, and declining quantity of high quality thermal habitats may place some semi-aquatic turtles at a disadvantage when considering future climate scenarios. Our findings, when combined with knowledge of other ecological traits, may be a useful tool for predicting relative sensitivities of turtle species to predicted climate change, particularly those species inhabiting seasonal wetlands.

Keywords: Metabolic rate; Aestivation; Deirochelys reticularia; Kinosternon subrubrum; Sternotherus odoratus; Seasonal wetlands

SREL Reprint #3690

Haskins, D. L. and T. D. Tuberville. 2022. Metabolic responses to increased temperatures in three semi-aquatic turtle species from the southeastern United States. Journal of Thermal Biology 109(2022): 103331.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).