The relative importance for plant invasiveness of trait means, and their plasticity and integration in a multivariate framework

Authors

  • Oscar Godoy,

    1. Laboratorio Internacional de Cambio Global, LINC-Global, Museo Nacional de Ciencias Naturales-CSIC, Serrano 115 dpdo, E-28006 Madrid, Spain
    2. Departamento de Ecología, Universidad de Alcalá, Ctra, Madrid-Barcelona Km.33.6 E-28871, Alcalá de Henares, Madrid, Spain
    3. Present address: Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA
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  • Fernando Valladares,

    1. Laboratorio Internacional de Cambio Global, LINC-Global, Museo Nacional de Ciencias Naturales-CSIC, Serrano 115 dpdo, E-28006 Madrid, Spain
    2. Departamento de Biología y Geología, Área de Biodiversidad & Conservación, Universidad Rey Juan Carlos, ESCET, Tulipán s/n E-28933, Móstoles, Madrid, Spain
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  • Pilar Castro-Díez

    1. Departamento de Ecología, Universidad de Alcalá, Ctra, Madrid-Barcelona Km.33.6 E-28871, Alcalá de Henares, Madrid, Spain
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Author for correspondence:
Oscar Godoy
Tel: +1 805 893 7415
Email: godoy@msi.ic.ucsb.edu

Summary

  • Functional traits, their plasticity and their integration in a phenotype have profound impacts on plant performance. We developed structural equation models (SEMs) to evaluate their relative contribution to promote invasiveness in plants along resource gradients.
  • We compared 20 invasive–native phylogenetically and ecologically related pairs. SEMs included one morphological (root-to-shoot ratio (R/S)) and one physiological (photosynthesis nitrogen-use efficiency (PNUE)) trait, their plasticities in response to nutrient and light variation, and phenotypic integration among 31 traits. Additionally, these components were related to two fitness estimators, biomass and survival.
  • The relative contributions of traits, plasticity and integration were similar in invasive and native species. Trait means were more important than plasticity and integration for fitness. Invasive species showed higher fitness than natives because: they had lower R/S and higher PNUE values across gradients; their higher PNUE plasticity positively influenced biomass and thus survival; and they offset more the cases where plasticity and integration had a negative direct effect on fitness.
  • Our results suggest that invasiveness is promoted by higher values in the fitness hierarchy -- trait means are more important than trait plasticity, and plasticity is similar to integration -- rather than by a specific combination of the three components of the functional strategy.

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