The maximum relative growth rate of common UK plant species is positively associated with their global invasiveness

Aim An emerging consensus in invasion ecology is that faster-growing alien plant species tend to be more invasive than slower-growing species. However, phylogenetic non-independence and the precision of growth-rate measures often remain unaccounted for in comparative studies. We tested whether global invasiveness was related to mean and maximum relative growth rate of 105 plant species (101 native and 4 introduced) commonly occurring in the UK. Location Global. Methods We combined a unique experimental dataset of relative growth rates (RGR) measured under standardized experimental conditions for plant species that occur widely in the UK with our global measures of invasiveness, which were the number of references in the Global Compendium of Weeds (GCW) and the number of world regions invaded. We weighted mean RGR measures per species by including variances of RGR in our analyses, and we also conducted analyses with and without phylogenetic structure, to account for potential phylogenetic non-independence in RGR. Results We found a positive association between global invasiveness and maximum RGR. In addition, this association was not confounded by phylogenetic correlation, or by species seed mass. Main conclusions The results from this study suggest that faster-growing species are more widespread at a global scale, adding support to other studies that suggest faster-growing alien plant species tend to be more invasive in the introduced range.