The anagenetic world of spore-producing land plants

Authors

  • Jairo Patiño,

    Corresponding author
    1. Institute of Botany, University of Liège, Liège, Belgium
    2. Departmento de Ciências Agrárias, Azorean Biodiversity Group (CITA-A) and Platform for Enhancing Ecological Research & Sustainability (PEERS), Universidade dos Açores, Terceira, Açores, Portugal
    3. Departmento de Biología Vegetal, Universidad de La Laguna, Tenerife, Spain
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  • Mark Carine,

    1. Department of Life Sciences, The Natural History Museum, London, UK
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  • José María Fernández-Palacios,

    1. Departamento de Ecología, Facultad de Biología, Universidad de La Laguna, Tenerife, Spain
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  • Rüdiger Otto,

    1. Departamento de Ecología, Facultad de Biología, Universidad de La Laguna, Tenerife, Spain
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  • Hanno Schaefer,

    1. Technische Universitaet Muenchen, Plant Biodiversity Research, Freising, Germany
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  • Alain Vanderpoorten

    1. Institute of Botany, University of Liège, Liège, Belgium
    2. Departmento de Ciências Agrárias, Azorean Biodiversity Group (CITA-A) and Platform for Enhancing Ecological Research & Sustainability (PEERS), Universidade dos Açores, Terceira, Açores, Portugal
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Summary

  • A fundamental challenge to our understanding of biodiversity is to explain why some groups of species diversify, whereas others do not. On islands, the gradual evolution of a new species from a founder event has been called ‘anagenetic speciation’. This process does not lead to rapid and extensive speciation within lineages and has received little attention.
  • Based on a survey of the endemic bryophyte, pteridophyte and spermatophyte floras of nine oceanic archipelagos, we show that anagenesis, as measured by the proportion of genera with single endemic species within a genus, is much higher in bryophytes (73%) and pteridophytes (65%) than in spermatophytes (55%).
  • Anagenesis contributed 49% of bryophyte and 40% of endemic pteridophyte species, but only 17% of spermatophytes. The vast majority of endemic bryophytes and pteridophytes are restricted to subtropical evergreen laurel forests and failed to diversify in more open environments, in contrast with the pattern exhibited by spermatophytes.
  • We propose that the dominance of anagenesis in island bryophytes and pteridophytes is a result of a mixture of intrinsic factors, notably their strong preference for (sub)tropical forest environments, and extrinsic factors, including the long-term macro-ecological stability of these habitats and the associated strong phylogenetic niche conservatism of their floras.

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