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Roberts HP, Willey LL, Jones MT, Akre TSB, King DI, Kleopfer J, Brown DJ, Buchanan SW, Chandler HC, deMaynadier P, Winters M, Erb L, Gipe KD, Johnson G, Lauer K, Liebgold EB, Mays JD, Meck JR, Megyesy J, Mota JL, Nazdrowicz NH, Oxenrider KJ, Parren M, Ransom TS, Rohrbaugh L, Smith S, Yorks D, Zarate B. Is the future female for turtles? Climate change and wetland configuration predict sex ratios of a freshwater species. GLOBAL CHANGE BIOLOGY 2023; 29:2643-2654. [PMID: 36723260 DOI: 10.1111/gcb.16625] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/15/2022] [Indexed: 05/31/2023]
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.
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Affiliation(s)
- H Patrick Roberts
- Department of Environmental Conservation, University of Massachusetts, Amherst, Massachusetts, USA
| | - Lisabeth L Willey
- Department of Environmental Studies, Antioch University New England, Keene, New Hampshire, USA
- American Turtle Observatory, New Salem, Massachusetts, USA
| | - Michael T Jones
- Natural Heritage and Endangered Species Program, Massachusetts Division of Fisheries and Wildlife, Westborough, Massachusetts, USA
| | - Thomas S B Akre
- Smithsonian Conservation Biology Institute, Front Royal, Virginia, USA
| | - David I King
- U.S. Forest Service, Northern Research Station, Department of Environmental Conservation, University of Massachusetts, Amherst, Massachusetts, USA
| | - John Kleopfer
- Virginia Department of Wildlife Resources, Charles City, Virginia, USA
| | - Donald J Brown
- U.S. Forest Service, Pacific Northwest Research Station, Amboy, Washington, USA
- School of Natural Resources, West Virginia University, Morgantown, West Virginia, USA
| | - Scott W Buchanan
- Division of Fish and Wildlife, Rhode Island Department of Environmental Management, West Kingston, Rhode Island, USA
| | - Houston C Chandler
- The Orianne Society, Tiger, Georgia, USA
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, USA
| | | | - Melissa Winters
- New Hampshire Fish and Game Department, Concord, New Hampshire, USA
| | - Lori Erb
- The Mid-Atlantic Center for Herpetology and Conservation, Oley, Pennsylvania, USA
| | - Katharine D Gipe
- Pennsylvania Fish and Boat Commission, Bellefonte, Pennsylvania, USA
| | - Glenn Johnson
- Biology Department, State University of New York, Potsdam, New York, USA
| | - Kathryn Lauer
- Department of Environmental Studies, Antioch University New England, Keene, New Hampshire, USA
- American Turtle Observatory, New Salem, Massachusetts, USA
| | - Eric B Liebgold
- Department of Biological Sciences, Salisbury University, Salisbury, Maryland, USA
| | - Jonathan D Mays
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Gainesville, Florida, USA
| | - Jessica R Meck
- Natural Heritage and Endangered Species Program, Massachusetts Division of Fisheries and Wildlife, Westborough, Massachusetts, USA
- Smithsonian Conservation Biology Institute, Front Royal, Virginia, USA
| | - Joshua Megyesy
- New Hampshire Fish and Game Department, Concord, New Hampshire, USA
| | - Joel L Mota
- U.S. Forest Service, Pacific Northwest Research Station, Amboy, Washington, USA
| | - Nathan H Nazdrowicz
- Species Conservation and Research Program, Delaware Division of Fish & Wildlife, Delaware, USA
| | - Kevin J Oxenrider
- West Virginia Division of Natural Resources, Romney, West Virginia, USA
| | - Molly Parren
- American Turtle Observatory, New Salem, Massachusetts, USA
| | - Tami S Ransom
- Environmental Studies Department, Salisbury University, Salisbury, Maryland, USA
| | - Lindsay Rohrbaugh
- District of Columbia Department of Energy & Environment, Washington, District of Columbia, USA
| | - Scott Smith
- Maryland Department of Natural Resources, Maryland, Wye Mills, USA
| | - Derek Yorks
- Maine Department of Inland Fisheries and Wildlife, Augusta, Maine, USA
| | - Brian Zarate
- New Jersey Division of Fish and Wildlife, Lebanon, New Jersey, USA
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Riparian Buffers as a Critical Landscape Feature: Insights for Riverscape Conservation and Policy Renovations. DIVERSITY 2022. [DOI: 10.3390/d14030172] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Riparian zones are critical for functional integrity of riverscapes and conservation of riverscape biodiversity. The synergism of intermediate flood-induced disturbances, moist microclimates, constant nutrient influx, high productivity, and resource heterogeneity make riparian zones disproportionately rich in biodiversity. Riparian vegetation intercepts surface-runoff, filters pollutants, and supplies woody debris as well as coarse particulate organic matter (e.g., leaf litter) to the stream channel. Riparian zones provide critical habitat and climatic refugia for wildlife. Numerous conservation applications have been implemented for riparian-buffer conservation. Although fixed-width buffers have been widely applied as a conservation measure, the effectiveness of these fixed buffer widths is debatable. As an alternative to fixed-width buffers, we suggest adoption of variable buffer widths, which include multiple tiers that vary in habitat structure and ecological function, with each tier subjected to variable management interventions and land-use restrictions. The riparian-buffer design we proposed can be delineated throughout the watershed, harmonizes with the riverscape concept, thus, a prudent approach to preserve biodiversity and ecosystem functions at variable spatial extents. We posit remodeling existing conservation policies to include riparian buffers into a broader conservation framework as a keystone structure of the riverscape. Watershed-scale riparian conservation is compatible with landscape-scale conservation of fluvial systems, freshwater protected-area networks, and aligns with enhancing environmental resilience to global change. Sustainable multiple-use strategies can be retrofitted into watershed-scale buffer reservations and may harmonize socio-economic goals with those of biodiversity conservation.
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