Causes of warm-edge range limits: systematic review, proximate factors and implications for climate change

Authors

  • Abigail E. Cahill,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
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    • These authors contributed equally to this manuscript.
  • Matthew E. Aiello-Lammens,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
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    • These authors contributed equally to this manuscript.
  • M. Caitlin Fisher-Reid,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
    2. Department of Biology, University of Richmond, Richmond, VA 23173  , USA
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  • Xia Hua,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
    2. Centre for Macroevolution and Macroecology, Division of Ecology, Evolution and Genetics, Research School of Biology, Australian National University, Canberra ACT 0200, Australia
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  • Caitlin J. Karanewsky,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
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  • Hae Yeong Ryu,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
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  • Gena C. Sbeglia,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
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  • Fabrizio Spagnolo,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
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  • John B. Waldron,

    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
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  • John J. Wiens

    Corresponding author
    1. Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
    2. Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721-0088, USA
    • Correspondence: John J. Wiens, Department of Ecology and Evolutionary Biology

      University of Arizona, Tucson, AZ 85721-0088, USA.

      E-mail: wiensj@email.arizona.edu

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Abstract

Aim

The factors that set species range limits underlie many patterns in ecology, evolution, biogeography and conservation. These factors have been the subject of several reviews, but there has been no systematic review of the causes of warm-edge limits (low elevations and latitudes). Understanding these causes is urgent, given that the factors that set these limits might also drive extinction at warm edges as global climate changes. Many authors have suggested that warm-edge limits are set by biotic factors (particularly competition) whereas others have stressed abiotic factors (particularly temperature). We synthesize the known causes of species' warm-edge range limits, with emphasis on the underlying mechanisms (proximate causes).

Location

Global.

Methods

We systematically searched the literature for studies testing the causes of warm-edge range limits.

Results

We found 125 studies that address the causes of warm-edge limits, from a search including > 4000 studies. Among the species in these studies, abiotic factors are supported more often than biotic factors in setting species range limits at warm edges, in contrast to the widely held view that biotic factors are more important. Studies that test both types of factors support abiotic factors significantly more frequently. In addition, only 23 studies (61 species) identified proximate causes of these limits, and these overwhelmingly support physiological tolerances to abiotic factors (primarily temperature). Only eight species with identified proximate causes were tested for both biotic and abiotic factors, but the majority support abiotic factors.

Main conclusions

Although it is often assumed that warm-edge limits are set by biotic factors, our review shows that abiotic factors are supported more often among the species in these 125 studies. However, few studies both identify proximate causes and test alternative mechanisms, or examine the interaction between biotic and abiotic factors. Filling these gaps should be a high priority as warm-edge populations are increasingly driven to extinction by climate change.

Ancillary