An example of the distribution maps and potential occurrence in Europe – Ambrosia confertiflora. A Global occurrence locations were obtained from the Global Biodiversity Information Facility B The global climate was summarised as two principal components analysis (PCA) axes on the 19 WorldClim layers (Hijmans et al. 2005). Species occurrences were plotted in this climate space and a bivariate normal kernel density model (Calenge 2006) was used to estimate ‘climate envelopes’ at different percentiles C These envelopes were then projected onto geographic space in the EU. Shading indicates these percentiles, with smaller numbers indicating higher density of occurrences.