Low gene flow but high genetic diversity in the threatened Mallorcan midwife toad Alytes muletensis

Authors

  • F. J. L. KRAAIJEVELD-SMIT,

    Corresponding author
    1. The Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, Kent, CT2 7NS, UK,
    2. School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK,
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  • T. J. C. BEEBEE,

    1. School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK,
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  • R. A. GRIFFITHS,

    1. The Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, Kent, CT2 7NS, UK,
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  • R. D. MOORE,

    1. The Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, Kent, CT2 7NS, UK,
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  • L. SCHLEY

    1. The Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, Kent, CT2 7NS, UK,
    2. Service de la Conservation de la Nature, Direction des Eaux et Forêts, 16 rue Eugène Ruppert, L-2453 Luxembourg
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Femmie J. L. Kraaijeveld-Smit, Animal Ecology Section, IBL, Leiden University, Postbus 9516, Leiden, The Netherlands. Fax: 0031 (0)71 5274900; E-mail: kraaijeveldf@rulsfb.leidenuniv.nl

Abstract

We investigated fine-scale genetic structuring in the rare and vulnerable Mallorcan midwife toad Alytes muletensis using eight polymorphic microsatellite markers. The current range of this amphibian is restricted to some 19 sites of which six are derived from reintroductions, all located in the mountain ranges of Mallorca. We sampled tadpoles from 14 pools covering 10 natural sites and two reintroduction sites for microsatellite DNA analyses. Relatively high levels of genetic variation were found in most pools (HE = 0.38–0.71, allelic richness = 2.6–6.2). Only at one pool has the population recently gone through a bottleneck. Dispersal between pools in different torrents does not occur whereas downstream dispersal between pools within the same torrent does happen at low frequencies. This occasional exchange of individuals does not lead to neighbouring pools in the same torrent being panmictic. This can be concluded because all FST values (0.12–0.53) differ significantly from zero and structure analyses identified neighbouring pools as separate populations. Furthermore, assignment and migration tests showed little exchange between neighbouring pools. If upstream locations or complete torrents go extinct, they are unlikely to be recolonized naturally. For conservation purposes, reintroductions of tadpoles to sites where local extinctions have occurred may therefore be advisable.

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