Unexpected phenological responses of butterflies to the interaction of urbanization and geographic temperature

Authors

  • Sarah E. Diamond,

    Corresponding author
    1. Department of Biology, Case Western Reserve University, Cleveland, Ohio 44106 USA
    2. Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27695 USA
    3. W.M. Keck Center for Behavioral Biology, Raleigh, North Carolina 27695 USA
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  • Heather Cayton,

    1. Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27695 USA
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  • Tyson Wepprich,

    1. Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27695 USA
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  • Clinton N. Jenkins,

    1. Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27695 USA
    2. Instituto de Pesquisas Ecológicas, Nazaré Paulista, São Paulo 12960 000 Brazil
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  • Robert R. Dunn,

    1. Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27695 USA
    2. W.M. Keck Center for Behavioral Biology, Raleigh, North Carolina 27695 USA
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  • Nick M. Haddad,

    1. Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27695 USA
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  • Leslie Ries

    1. National Socio-Environmental Synthesis Center, Annapolis, Maryland 21401 USA
    2. Biology Department, University of Maryland, College Park, Maryland 20742 USA
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  • Corresponding Editor: J. T. Cronin.

Abstract

Urbanization and global climate change can profoundly alter biological systems, yet scientists often analyze their effects separately. We test how the timing of life cycle events (phenology) is jointly influenced by these two components of global change. To do so, we use a long-term phenological data set of 20 common butterfly species from 83 sites across the state of Ohio, USA, with sites that range from rural undeveloped areas to moderately sized cities. These sites span a latitudinal gradient in mean temperature of several °C, mimicking the range of projected global climate warming effects through the end of the century. Although shifts toward earlier phenology are typical of species' responses to either global climate change or urbanization, we found that their interaction delayed several Ohio butterfly species' first appearance and peak abundance phenology. Exploitative species exhibited smaller delays in first appearance and peak abundance phenology in areas that were urbanized and geographically warm. Our results show that phenological responses to urbanization are contingent upon geographic variation in temperature, and that the impacts of urbanization and global climate change should be considered simultaneously when developing forecasts of biological responses to environmental change.

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