Species living in harsh environments have low clade rank and are localized on former Laurasian continents: a case study of Willemia (Collembola)

Authors

  • Andreas Prinzing,

    Corresponding author
    1. Université de Rennes 1, CNRS UMR 6553 ECOBIO: Ecosystèmes, Biodiversité, Evolution, Rennes Cedex, France
    2. Alterra, Centre for Ecosystem Studies, Wageningen, The Netherlands
    • Correspondence: Andreas Prinzing, Université de Rennes 1, CNRS UMR 6553 ECOBIO: Ecosystèmes, Biodiversité, Evolution, Campus de Beaulieu, Bâtiment 14A, 263 Avenue du Général Leclerc, 35042 Rennes Cedex, France.

      E-mail: andreas.prinzing@univ-rennes1.fr

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  • Cyrille A. D'Haese,

    1. Muséum National d'Histoire Naturelle, Département Systématique et Évolution, Paris, France
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  • Sandrine Pavoine,

    1. Muséum National d'Histoire Naturelle, Département Écologie et Gestion de la Biodiversité, Paris, France
    2. Mathematical Ecology Research Group, Department of Zoology, University of Oxford, UK
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  • Jean-François Ponge

    1. Muséum National d'Histoire Naturelle, Département Écologie et Gestion de la Biodiversité, Brunoy, France
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Abstract

Aim

Certain species have few living relatives (i.e. they occupy low clade ranks) and hence they possess high conservation value and scientific interest as unique representatives of ancient lineages. However, we do not know whether particular environments favour the maintenance of low clade ranks or whether the distribution of environments across the globe affects the global distribution of clade ranks and, hence, evolutionary uniqueness. In this study, we tested whether and how harsh environments decrease the clade ranks of the species that inhabit them.

Location

Global.

Methods

We described the phylogeny of the collembolan genus Willemia by a parsimonious method based on 52 morphological characters and estimated the species' use of harsh environments (polar, high mountain, desert, polluted, waterlogged, saline and acidic) from 248 publications.

Results

We found that the use of different types of harsh environments is maintained among close relatives and has similar phylogenetic signals (except for the use of salinity). The use of harsh environments might therefore affect the diversification of lineages. Correcting for the phylogenetic non-independence of species, we found that species using harsh environments have comparatively low clade ranks. We also found that species using harsh environments occur almost exclusively on former Laurasian continents and that, as a statistical consequence, Laurasian species tend to have lower clade ranks.

Main conclusions

We suggest that harsh environments maintain low-clade-rank species by decreasing, simultaneoulsy or successively, extinction and speciation, which may eventually explain the major variation in clade rank across the globe.

Ancillary