Multiple lines of evidence for demographic and range expansion of a temperate species (Hyla sarda) during the last glaciation

Authors

  • ROBERTA BISCONTI,

    1. Dipartimento di Scienze Ecologiche e Biologiche, Università della Tuscia, Largo dell’Università s.n.c., I-01100 Viterbo, Italy
    Search for more papers by this author
    • These authors contributed equally to this work.

  • DANIELE CANESTRELLI,

    1. Dipartimento di Scienze Ecologiche e Biologiche, Università della Tuscia, Largo dell’Università s.n.c., I-01100 Viterbo, Italy
    Search for more papers by this author
    • These authors contributed equally to this work.

  • PAOLO COLANGELO,

    1. Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Università“La Sapienza”, Via Borelli 50, I-00161 Roma, Italy
    2. Centro Nazionale per lo Studio e la Conservazione della Biodiversità Forestale “Bosco Fontana”, Strada Mantova 29, I-46045 Marmirolo, Italy
    Search for more papers by this author
  • GIUSEPPE NASCETTI

    1. Dipartimento di Scienze Ecologiche e Biologiche, Università della Tuscia, Largo dell’Università s.n.c., I-01100 Viterbo, Italy
    Search for more papers by this author

Daniele Canestrelli, Fax: 0039761357751; E-mail: canestrelli@unitus.it

Abstract

Many temperate species experienced demographic and range contractions in response to climatic changes during Pleistocene glaciations. In this study, we investigate the evolutionary history of the Tyrrhenian tree frog Hyla sarda, a species inhabiting the Corsica–Sardinia island system (Western Mediterranean basin). We used sequence analysis of two mitochondrial (overall 1229 bp) and three nuclear (overall 1692 bp) gene fragments to assess the phylogeography and demographic history of this species, and species distribution modelling (SDM) to predict its range variation over time. Phylogeographic, historical demographic and SDM analyses consistently indicate that H. sarda does not conform to the scenario generally expected for temperate species but rather underwent demographic and range expansion mostly during the last glacial phase. Palaeogeographic data and SDM analyses suggest that such expansion was driven by the glaciation-induced increase in lowland areas during marine regression. This unusual scenario suggests that at least some temperate species may not have suffered the adverse effects of glacial climate on their population size and range extent, owing to the mitigating effects of other glaciations-induced palaeoenvironmental changes. We discuss previous clues for the occurrence of such a scenario in other species and some possible challenges with its identification. Early phylogeographic literature suggested that responses to the Pleistocene glacial–interglacial cycles were expected to vary among species and regions. Our results point out that such variation may have been greater than previously thought.

Ancillary