Species attributes and invasion success by alien plants on Mediterranean islands

Authors

  • FRANCISCO LLORET,

    Corresponding author
    1. Center for Ecological Research and Forestry Applications (CREAF) and U. Ecologia, Department Biologia Animal, Biologia Vegetal i Ecologia, Fac. Ciències, Universitat Autònoma Barcelona, 08193 Bellaterra, Barcelona, Spain,
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  • FRÉDÉRIC MÉDAIL,

    1. Center for Ecological Research and Forestry Applications (CREAF) and U. Ecologia, Department Biologia Animal, Biologia Vegetal i Ecologia, Fac. Ciències, Universitat Autònoma Barcelona, 08193 Bellaterra, Barcelona, Spain,
    2. Institut Méditerranéen d’Ecologie et de Paléoécologie (IMEP, CNRS UMR 6116), Université Paul Cézanne/Aix-Marseille III, Europôle Méditerranéen de l’Arbois, BP 80, 13545 Aix-en-Provence cedex 04, France,
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  • GIUSEPPE BRUNDU,

    1. Center for Ecological Research and Forestry Applications (CREAF) and U. Ecologia, Department Biologia Animal, Biologia Vegetal i Ecologia, Fac. Ciències, Universitat Autònoma Barcelona, 08193 Bellaterra, Barcelona, Spain,
    2. Dipartimento di Botanica ed Ecologia vegetale, Università degli Studi di Sassari, Via F. Muroni 25, 07100 Sassari, Italy,
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  • IGNAZIO CAMARDA,

    1. Center for Ecological Research and Forestry Applications (CREAF) and U. Ecologia, Department Biologia Animal, Biologia Vegetal i Ecologia, Fac. Ciències, Universitat Autònoma Barcelona, 08193 Bellaterra, Barcelona, Spain,
    2. Dipartimento di Botanica ed Ecologia vegetale, Università degli Studi di Sassari, Via F. Muroni 25, 07100 Sassari, Italy,
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  • EVA MORAGUES,

    1. Center for Ecological Research and Forestry Applications (CREAF) and U. Ecologia, Department Biologia Animal, Biologia Vegetal i Ecologia, Fac. Ciències, Universitat Autònoma Barcelona, 08193 Bellaterra, Barcelona, Spain,
    2. Institut Mediterrani d’Estudis Avançats (CSIC-UIB), c. Miquel Marqués 21, 07190 Esporles, Majorca, Spain,
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  • JUAN RITA,

    1. Center for Ecological Research and Forestry Applications (CREAF) and U. Ecologia, Department Biologia Animal, Biologia Vegetal i Ecologia, Fac. Ciències, Universitat Autònoma Barcelona, 08193 Bellaterra, Barcelona, Spain,
    2. Departamento de Biología, Universidad de las Islas Baleares, Ctra Valldemossa km 7, 5. 07071 Palma de Mallorca, Majorca, Spain, and
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  • PHILIP LAMBDON,

    1. Center for Ecological Research and Forestry Applications (CREAF) and U. Ecologia, Department Biologia Animal, Biologia Vegetal i Ecologia, Fac. Ciències, Universitat Autònoma Barcelona, 08193 Bellaterra, Barcelona, Spain,
    2. NERC Centre for Ecology and Hydrology, Banchory, Aberdeenshire AB31 4BW, Great Britain
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  • PHILIP E. HULME

    1. Center for Ecological Research and Forestry Applications (CREAF) and U. Ecologia, Department Biologia Animal, Biologia Vegetal i Ecologia, Fac. Ciències, Universitat Autònoma Barcelona, 08193 Bellaterra, Barcelona, Spain,
    2. NERC Centre for Ecology and Hydrology, Banchory, Aberdeenshire AB31 4BW, Great Britain
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F. Lloret (e-mail francisco.lloret@uab.es).

Summary

  • 1Species attributes have been used to explain invasion patterns assuming the prevalence of biological mechanisms, although this approach often suffers several methodological and conceptual limitations, such as local idiosyncrasies, differences among habitats, phylogenetic constraints and insufficient sample size.
  • 2The relative importance of 15 species traits for explaining the abundance over 350 naturalized alien plant species was assessed across five Mediterranean islands (Corsica, Crete, Majorca, Malta and Sardinia). A comparative analysis accounting for phylogeny was used to examine variation in semi-quantitative estimates of species abundance in comparable habitats across the five island floras.
  • 3Species were divided into those with affinity for semi-natural, agricultural and ruderal habitats. Both vegetative and reproductive attributes were evaluated for individual islands and averaged across all islands.
  • 4Vegetative propagation, large leaf size, summer flowering, long flowering period and dispersal by wind or vertebrates were positively associated with average alien abundance across all five islands. Fewer significant trends were found in island-specific patterns.
  • 5The relative importance of a few reproductive traits is reflected in over-representation of Caryophyllales, Asterales and Poales (late flowering, large seed size and anemochory). Although significant covariation in traits was found there was no evidence for well-defined invasive syndromes.
  • 6Succulence was important in ruderal habitats, long flowering period in agricultural habitats and vertebrate seed dispersal in semi-natural habitats, suggesting that empty niches, avoidance of competitors and exploitation of mutualists, respectively, are important.
  • 7The study highlights the importance of estimating invasion success across a wide region, but analyses of specific invasion stages are also needed. Reproductive traits, which may be more relevant for long-distance colonization, and vegetative traits, which determine local dominance and persistence, were, nevertheless, both related to abundance within islands.

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