During plant invasions, phylogenetic relatedness of alien species to existing community members may either facilitate or hinder successful establishment, depending on the scale. Biotic interactions with other existing alien species at different stages of invasion, however, may also play a role.
In this study, researchers sought to determine the variation of phylogenetic relatedness of alien species across spatial scales, and whether the different stages—introduction, naturalization and invasion—showed similar patterns.
Working from a comprehensive list of all alien plant species in China, the authors extracted species occurrences from GBIF and the National Specimen Information Infrastructure (NSII), resulting in more than 87,000 records across 706 angiosperm plant species.
Based on molecular sequence data from GenBank, they constructed a phylogenetic tree and assessed phylogenetic relatedness of the species at different invasion stages, as well as spatial and taxonomic scales, using two measures: net relatedness index (NRI) and nearest taxon index (NTI).
Overall, analyses of the phylogenetic relatedness scores suggested that the presence of a close relative in a community may facilitate successful naturalization of an alien species. At the same time, the phylogenetic spaces of invasive species differed significantly from that of naturalized and introduced species, suggesting a need to be phylogenetically different in order to become invasive.