Colonization history of the Swiss Rhine basin by the bullhead (Cottus gobio): inference under a Bayesian spatially explicit framework

Authors

  • SAMUEL NEUENSCHWANDER,

    1. CMPG, Zoological Institute, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland,
    2. Department of Ecology and Evolution, Biophore, UNIL-Sorge, 1015 Lausanne, Switzerland,
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  • CARLO R. LARGIADÈR,

    1. CMPG, Zoological Institute, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland,
    2. Institute of Clinical Chemistry, University Hospital, University of Bern, Inselspital, 3010 Bern, Switzerland,
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  • NICOLAS RAY,

    1. CMPG, Zoological Institute, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland,
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  • MATHIAS CURRAT,

    1. CMPG, Zoological Institute, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland,
    2. Laboratory of Anthropology, Genetics and Peopling history (AGP), Department of Anthropology and Ecology, University of Geneva, 1227 Geneva, Switzerland,
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  • PASCAL VONLANTHEN,

    1. CMPG, Zoological Institute, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland,
    2. Aquatic Ecology, Zoological Institute, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland
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  • LAURENT EXCOFFIER

    1. CMPG, Zoological Institute, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland,
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Samuel Neuenschwander, Fax: +41 21 692 42 65; E-mail: samuel.neuenschwander@unil.ch

Abstract

The present distribution of freshwater fish in the Alpine region has been strongly affected by colonization events occurring after the last glacial maximum (LGM), some 20 000 years ago. We use here a spatially explicit simulation framework to model and better understand their colonization dynamics in the Swiss Rhine basin. This approach is applied to the European bullhead (Cottus gobio), which is an ideal model organism to study fish past demographic processes since it has not been managed by humans. The molecular diversity of eight sampled populations is simulated and compared to observed data at six microsatellite loci under an approximate Bayesian computation framework to estimate the parameters of the colonization process. Our demographic estimates fit well with current knowledge about the biology of this species, but they suggest that the Swiss Rhine basin was colonized very recently, after the Younger Dryas some 6600 years ago. We discuss the implication of this result, as well as the strengths and limits of the spatially explicit approach coupled to the approximate Bayesian computation framework.

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