Enrique G. de la Riva1 2, Oscar Godoy3, Pilar Castro-Díez4, Cayetano Gutiérrez-Cánovas5 and Montserrat Vilà1
1Estación Biológica de Doñana (EBD-CSIC), Avd. Américo Vespucio 26, Isla de la Cartuja, 41092 Sevilla, Spain
2Department of Ecology, Brandenburg University of Technology, Cottbus, Germany
3Departamento de Biología, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Puerto Real, 11510, Spain
4Departamento de Ciencias de la Vida. Universidad de Alcalá. Campus Universitario. Ctra. Madrid-Barcelona km 33.6. 28805 Alcalá de Henares, Madrid, Spain
5Freshwater Ecology, Hydrology and Management Group (FEHM Lab), Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia – Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Diagonal, 643, 08028 Barcelona, Spain
Do invasions by alien plant species with contrasting trait profiles (Arctotheca calendula, Carpobrotus spp., Conyza bonariensis and Opuntia dillenii) change the functional and phylogenetic structure of coastal plant communities? To answer this question, we identified species diversity and composition in 220 paired (invaded and non-invaded) plots along coastal habitats in Huelva (Spain). We measured nine functional traits for each native and invasive species, namely, specific leaf area (SLA), specific root length (SRL), leaf and root dry mass content (LDMC and RDMC) or carbon isotope fraction (δ13C). We calculated at the plot scale, community means (CMs) for each trait, functional richness, Faith’s phylogenetic diversity and functional and phylogenetic mean pairwise dissimilarities.
Three out the four species showed rather extreme trait values compared to the native flora with greater impact on invaded communities. In plots invaded by A. calendula the values of the native communities of SLA and SRL increased, while LDMC, RDMC and δ13C decreased showing CMs more similar to its functional profile. Additionally, these plots showed lower functional and phylogenetic diversity in the native component of the community. In plots invaded by Carpobrotus spp. and O. dillenii, the CMs values for LDMC and δ13C increased, but had little effect on the functional and phylogenetic structure of the native communities, while no differences were observed for the communities invaded by C. bonariensis (most functionally similar to the native species).
Our study highlights that inferring community assembly rules from the exploration of functional and phylogenetic differences between invaded and non-invaded plots is not straightforward. By considering invaders with different functional profiles, we have shown that species with different mechanisms of invasion have contrasting impacts on the community. Consequently, the effect of plant invaders differed depending on their functional distinction from the recipient community, rather than its phylogenetic origin.