Altered spring phenology of North American freshwater turtles and the importance of representative populations |
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Authors: | Fredric J Janzen Luke A Hoekstra Ronald J Brooks David M Carroll J Whitfield Gibbons Judith L Greene John B Iverson Jacqueline D Litzgus Edwin D Michael Steven G Parren Willem M Roosenburg Gabriel F Strain John K Tucker Gordon R Ultsch |
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Institution: | 1. Department of Ecology, Evolution & Organismal Biology, Iowa State University, Ames, Iowa;2. Department of Integrative Biology, University of Guelph, Guelph, ON, Canada;3. , Warner, New Hampshire;4. Savannah River Ecology Laboratory, Aiken, South Carolina;5. Department of Biology, Earlham College, Richmond, Indiana;6. Department of Biology, Laurentian University, Sudbury, ON, Canada;7. Division of Forestry and Natural Resources, West Virginia University, Morgantown, West Virginia;8. , Hinesburg, Vermont;9. Department of Biological Sciences, Ohio University, Athens, Ohio;10. GAI Consultants, Inc., Bridgeport, West Virginia;11. Jerry F. Costello National Great Rivers Research and Education Center Confluence Field Station, East Alton, Illinois;12. Department of Biology, University of Florida, Gainesville, Florida |
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Abstract: | Globally, populations of diverse taxa have altered phenology in response to climate change. However, most research has focused on a single population of a given taxon, which may be unrepresentative for comparative analyses, and few long‐term studies of phenology in ectothermic amniotes have been published. We test for climate‐altered phenology using long‐term studies (10–36 years) of nesting behavior in 14 populations representing six genera of freshwater turtles (Chelydra, Chrysemys, Kinosternon, Malaclemys, Sternotherus, and Trachemys). Nesting season initiation occurs earlier in more recent years, with 11 of the populations advancing phenology. The onset of nesting for nearly all populations correlated well with temperatures during the month preceding nesting. Still, certain populations of some species have not advanced phenology as might be expected from global patterns of climate change. This collection of findings suggests a proximate link between local climate and reproduction that is potentially caused by variation in spring emergence from hibernation, ability to process food, and thermoregulatory opportunities prior to nesting. However, even though all species had populations with at least some evidence of phenological advancement, geographic variation in phenology within and among turtle species underscores the critical importance of representative data for accurate comprehensive assessments of the biotic impacts of climate change. |
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Keywords: | advancing phenology climate nesting phenotypic plasticity representative population reptile |
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