Get access

Replicated radiations of the alpine genus Androsace (Primulaceae) driven by range expansion and convergent key innovations

Authors

  • Cristina Roquet,

    Corresponding author
    • Laboratoire d'Écologie Alpine, CNRS UMR 5553, Université Joseph Fourier – Grenoble 1, Grenoble, France
    Search for more papers by this author
    • These authors contributed equally to this paper.

  • Florian C. Boucher,

    1. Laboratoire d'Écologie Alpine, CNRS UMR 5553, Université Joseph Fourier – Grenoble 1, Grenoble, France
    Search for more papers by this author
    • These authors contributed equally to this paper.

  • Wilfried Thuiller,

    1. Laboratoire d'Écologie Alpine, CNRS UMR 5553, Université Joseph Fourier – Grenoble 1, Grenoble, France
    Search for more papers by this author
  • Sébastien Lavergne

    1. Laboratoire d'Écologie Alpine, CNRS UMR 5553, Université Joseph Fourier – Grenoble 1, Grenoble, France
    Search for more papers by this author

Correspondence: Cristina Roquet, Laboratoire d'Écologie Alpine, CNRS UMR 5553, Université Joseph Fourier – Grenoble 1, BP 53, 38041 Grenoble Cedex 9, France.

E-mail: cristina.roquet@gmail.com

Abstract

Aim

We still have limited understanding of the contingent and deterministic factors that have fostered the evolutionary success of some species lineages over others. We investigated how the interplay of intercontinental migration and key innovations promoted diversification of the genus Androsace.

Location

Mountain ranges and cold steppes of the Northern Hemisphere.

Methods

We reconstructed ancestral biogeographical ranges at regional and continental scales by means of a dispersal–extinction–cladogenesis analysis using dated Bayesian phylogenies and contrasting two migration scenarios. Based on diversification analyses under two frameworks, we tested the influence of life form on speciation rates and whether diversification has been diversity-dependent.

Results

We found that three radiations occurred in this genus, at different periods and on different continents, and that life form played a critical role in the history of Androsace. Short-lived ancestors first facilitated the expansion of the genus' range from Asia to Europe, while cushions, which appeared independently in Asia and Europe, enhanced species diversification in alpine regions. One long-distance dispersal event from Europe to North America led to the diversification of the nested genus Douglasia. We found support for a model in which speciation of the North American–European clade is diversity-dependent and close to its carrying capacity, and that the diversification dynamics of the North American subclade are uncoupled from this and follow a pure birth process.

Main conclusions

The contingency of past biogeographical connections combined with the evolutionary determinism of convergent key innovations may have led to replicated radiations of Androsace in three mountain regions of the world. The repeated emergence of the cushion life form was a convergent key innovation that fostered radiation into alpine habitats. Given the large ecological similarity of Androsace species, allopatry may have been the main mode of speciation.

Get access to the full text of this article

Ancillary