Non-native species disrupt the worldwide patterns of freshwater fish body size: implications for Bergmann’s rule

Authors

  • Simon Blanchet,

    Corresponding author
    1. Station d’Ecologie Expérimentale du CNRS à Moulis, U.S.R 2936, Moulis, 09200 Moulis, France
    2. Laboratoire Evolution et Diversité Biologique, U.M.R 5174, C.N.R.S-Université Paul Sabatier, 118 Route de Narbonne, F-31062 Toulouse Cedex 4, France
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  • Gael Grenouillet,

    1. Laboratoire Evolution et Diversité Biologique, U.M.R 5174, C.N.R.S-Université Paul Sabatier, 118 Route de Narbonne, F-31062 Toulouse Cedex 4, France
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  • Olivier Beauchard,

    1. Department of Biology, Ecosystem Management Research Group, University of Antwerp, Faculty of Sciences, Universiteitsplein 1, BE-2610 Antwerpen (Wilrijk), Belgium
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  • Pablo A. Tedesco,

    1. UMR IRD 207 “BOREA”, DMPA, Muséum National d’Histoire Naturelle, 43 rue Cuvier, 75231 Paris Cedex, France
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  • Fabien Leprieur,

    1. UMR IRD 207 “BOREA”, DMPA, Muséum National d’Histoire Naturelle, 43 rue Cuvier, 75231 Paris Cedex, France
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  • Hans H. Dürr,

    1. Department of Physical Geography, Faculty of Geosciences, Heidelberglaan 2, PO Box 80.115, Utrecht University, NL 3508 TC Utrecht, The Netherlands
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  • Frederic Busson,

    1. UMR IRD 207 “BOREA”, DMPA, Muséum National d’Histoire Naturelle, 43 rue Cuvier, 75231 Paris Cedex, France
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  • Thierry Oberdorff,

    1. UMR IRD 207 “BOREA”, DMPA, Muséum National d’Histoire Naturelle, 43 rue Cuvier, 75231 Paris Cedex, France
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  • Sébastien Brosse

    1. Laboratoire d’Ecologie Fonctionnelle, U.M.R 5545, C.N.R.S-Université Paul Sabatier, 118 Route de Narbonne, F-31062 Toulouse Cedex 4, France
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* Correspondence: E-mail:blanchet@cict.fr

Abstract

Ecology Letters (2010) 13: 421–431

Abstract

In this study, we test whether established non-native species induce functional changes in natural assemblages. We combined data on the body size of freshwater fish species and a worldwide data set of native and non-native fish species for 1058 river basins. We show that non-native fish species are significantly larger than their native counterparts and are a non-random subset of the worldwide set of fish species. We further show that the median body size of fish assemblages increases in the course of introductions. These changes are the opposite of those expected under several null models. Introductions shift body size patterns related to several abiotic factors (e.g. glacier coverage and temperature) in a way that modifies latitudinal patterns (i.e. Bergmann’s rule), especially in the southern hemisphere. Together, these results show that over just the last two centuries human beings have induced changes in the global biogeography of freshwater fish body size, which could affect ecosystem properties.

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