ORIGINAL ARTICLE: The biogeography of avian extinctions on oceanic islands

Authors

  • Tim J. Karels,

    1. Department of Biology, 18111 Nordhoff Street, California State University, Northridge, CA 91330, USA
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  • F. Stephen Dobson,

    Corresponding author
    1. Department of Biological Sciences, 331 Funchess Hall, Auburn University, Auburn, AL 36849, USA
      F. Stephen Dobson, Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA. E-mail: fsdobson@msn.com
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    • Present address: Centre d'Écologie Functionelle et Evolutive, UMR 5175 du CNRS, 1919 route de Mende, F-34293 Montpellier Cedex 5, France.

  • Heather S. Trevino,

    1. Department of Biological Sciences, 331 Funchess Hall, Auburn University, Auburn, AL 36849, USA
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  • Amy L. Skibiel

    1. Department of Biological Sciences, 331 Funchess Hall, Auburn University, Auburn, AL 36849, USA
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F. Stephen Dobson, Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA. E-mail: fsdobson@msn.com

Abstract

Aim  To test the influences of island area, island isolation, and human-introduced mammalian predators on avian extinctions that have occurred on oceanic islands worldwide.

Location  The oceanic islands of the world.

Methods  We augmented and re-examined an existing data set for 218 oceanic islands by means of causal modelling using path analysis (a form of structural equation modelling) and a null model.

Results  The number of extinctions was not a simple function of the number of bird species on the various islands. Whereas introduced mammalian predators had an influence on the number of extinctions, island area (via indirect influences) and isolation (via direct influences) were equally or more important.

Main conclusions  The multiple influences of physical and biotic factors on past extinctions can be revealed through modelling the causal influences of physical attributes of islands on biological characteristics, and the causal influences of both physical and biological characteristics on extinctions.

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