Research Article

Is the future female for turtles? Climate change and wetland configuration predict sex ratios of a freshwater species

Published: 2023-5

Journal: Global Change Biology

DOI: 10.1111/gcb.16625

Abstract

Climate change and land‐use change are leading drivers of biodiversity decline, affecting demographic parameters that are important for population persistence. For example, scientists have speculated for decades that climate change may skew adult sex ratios in taxa that express temperature‐dependent sex determination (TSD), but limited evidence exists that this phenomenon is occurring in natural settings. For species that are vulnerable to anthropogenic land‐use practices, differential mortality among sexes may also skew sex ratios. We sampled the spotted turtle (Clemmys guttata), a freshwater species with TSD, across a large portion of its geographic range (Florida to Maine), to assess the environmental factors influencing adult sex ratios. We present evidence that suggests recent climate change has potentially skewed the adult sex ratio of spotted turtles, with samples following a pattern of increased proportions of females concomitant with warming trends, but only within the warmer areas sampled. At intermediate temperatures, there was no relationship with climate, while in the cooler areas we found the opposite pattern, with samples becoming more male biased with increasing temperatures. These patterns might be explained in part by variation in relative adaptive capacity via phenotypic plasticity in nest site selection. Our findings also suggest that spotted turtles have a context‐dependent and multi‐scale relationship with land use. We observed a negative relationship between male proportion and the amount of crop cover (within 300 m) when wetlands were less spatially aggregated. However, when wetlands were aggregated, sex ratios remained consistent. This pattern may reflect sex‐specific patterns in movement that render males more vulnerable to mortality from agricultural machinery and other threats. Our findings highlight the complexity of species' responses to both climate change and land use, and emphasize the role that landscape structure can play in shaping wildlife population demographics.

Faculty Members

  • Glenn Johnson - Biology Department State University of New York Potsdam New York USA
  • Eric B. Liebgold - Department of Biological Sciences Salisbury University Salisbury Maryland USA
  • Lori Erb - The Mid‐Atlantic Center for Herpetology and Conservation Oley Pennsylvania USA
  • Derek Yorks - Maine Department of Inland Fisheries and Wildlife Augusta Maine USA
  • Houston C. Chandler - The Orianne Society Tiger Georgia USADepartment of Fish and Wildlife Conservation Virginia Tech Blacksburg Virginia USA
  • Melissa Winters - New Hampshire Fish and Game Department Concord New Hampshire USA
  • Thomas S. B. Akre - Smithsonian Conservation Biology Institute Front Royal Virginia USA
  • Scott W. Buchanan - Division of Fish and Wildlife Rhode Island Department of Environmental Management West Kingston Rhode Island USA
  • Jessica R. Meck - Natural Heritage and Endangered Species Program Massachusetts Division of Fisheries and Wildlife Westborough Massachusetts USASmithsonian Conservation Biology Institute Front Royal Virginia USA
  • Kevin J. Oxenrider - West Virginia Division of Natural Resources Romney West Virginia USA
  • Jonathan D. Mays - Fish and Wildlife Research Institute Florida Fish and Wildlife Conservation Commission Gainesville Florida USA
  • Joshua Megyesy - New Hampshire Fish and Game Department Concord New Hampshire USA
  • Tami S. Ransom - Environmental Studies Department Salisbury University Salisbury Maryland USA
  • Phillip deMaynadier - Maine Department of Inland Fisheries and Wildlife Augusta Maine USA
  • Kathryn Lauer - Department of Environmental Studies Antioch University New England Keene New Hampshire USAAmerican Turtle Observatory New Salem Massachusetts USA
  • Joel L. Mota - U.S. Forest Service Pacific Northwest Research Station Amboy Washington USA
  • Molly Parren - American Turtle Observatory New Salem Massachusetts USA
  • David I. King - U.S. Forest Service, Northern Research Station, Department of Environmental Conservation University of Massachusetts Amherst Massachusetts USA
  • Donald J. Brown - U.S. Forest Service Pacific Northwest Research Station Amboy Washington USASchool of Natural Resources West Virginia University Morgantown West Virginia USA
  • Scott Smith - Maryland Department of Natural Resources Maryland Wye Mills USA
  • Nathan H. Nazdrowicz - Species Conservation and Research Program Delaware Division of Fish & Wildlife Delaware USA
  • John Kleopfer - Virginia Department of Wildlife Resources Charles City Virginia USA
  • Brian Zarate - New Jersey Division of Fish and Wildlife Lebanon New Jersey USA
  • Lisabeth L. Willey - Department of Environmental Studies Antioch University New England Keene New Hampshire USAAmerican Turtle Observatory New Salem Massachusetts USA
  • H. Patrick Roberts - Department of Environmental Conservation University of Massachusetts Amherst Massachusetts USA
  • Michael T. Jones - Natural Heritage and Endangered Species Program Massachusetts Division of Fisheries and Wildlife Westborough Massachusetts USA
  • Lindsay Rohrbaugh - District of Columbia Department of Energy & Environment Washington District of Columbia USA
  • Katharine D. Gipe - Pennsylvania Fish and Boat Commission Bellefonte Pennsylvania USA

Themes

  • effects of land-use change on demographic parameters
  • temperature-dependent sex determination
  • adaptive capacity and phenotypic plasticity in species
  • sex ratio dynamics in wildlife populations
  • climate change and its impact on biodiversity
  • relationship between landscape structure and wildlife demographics

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