Genetic attributes of midwife toad (Alytes obstetricans) populations do not correlate with degree of species decline

Authors

  • Ursina Tobler,

    Corresponding author
    1. Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
    2. KARCH, Neuchâtel, Switzerland
    • Correspondence

      Ursina Tobler, Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland. Tel: +41 (0)44 635 47 52; Fax: +41 (0)44 635 68 18; E-mail: ursina.tobler@ieu.uzh.ch

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  • Trenton W. J. Garner,

    1. Institute of Zoology, Zoological Society of London, London, U.K
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  • Benedikt R. Schmidt

    1. Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
    2. KARCH, Neuchâtel, Switzerland
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Abstract

Genetic diversity is crucial for long-term population persistence. Population loss and subsequent reduction in migration rate among the most important processes that are expected to lead to a reduction in genetic diversity and an increase in genetic differentiation. While the theory behind this is well-developed, empirical evidence from wild populations is inconsistent. Using microsatellite markers, we compared the genetic structure of populations of an amphibian species, the midwife toad (Alytes obstetricans), in four Swiss regions where the species has suffered variable levels of subpopulation extirpation. We also quantified the effects of several geographic factors on genetic structure and used a model selection approach to ascertain which of the variables were important for explaining genetic variation. Although subpopulation pairwise FST-values were highly significant even over small geographic scales, neither any of the geographic variables nor loss of subpopulations were important factors for predicting spatial genetic structure. The absence of a signature of subpopulation loss on genetic differentiation may suggest that midwife toad subpopulations function as relatively independent units.

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