Invasive woody legumes: Climatic range shifts and their relationships to functional traits

Abstract Aim Analysis of the shifts in the climatic space for invasive species between native and introduced areas is a powerful tool for understanding their distribution patterns and the factors influencing their spread into new areas. In this study, we explored the shift in climatic distribution between ranges for invasive woody legumes and how the functional traits of these species are associated with their climatic distribution. Location Global. Time period Present. Major taxa studied Invasive woody legumes. Methods We evaluated the global patterns of occupation of the climatic space for 107 invasive woody legumes in their native and introduced distribution ranges, in addition to the differences in six key functional traits. We used the trait probability density (TPD) function to estimate species probabilistic niches. We then classified species into four groups according to the climatic differences between the distribution ranges. The comparisons between the climate shift groups and the distribution ranges were evaluated with mixed linear models. Additionally, we compared the functional traits between species groups using ANOVA. Results Overall, we found that invasive species exhibited low to moderate climatic overlap between their native and introduced distribution ranges. However, climatic conditions in the introduced range were different from those in the native range. Invasive legumes were clustered in four groups (conserved, expansion, dissociation and unfilling), with dissociation between climate niches being the most common one. In terms of functional traits, the most relevant finding was that the species in the expansion group had larger leaves than species in the dissociation group. Main conclusions Our results showed no consistent climatic range shift across all invasive woody legume species from their native to their introduced distribution. However, some species tended to invade climatic conditions that were different from those in their native range, supporting the hypothesis that some invasive species are able to adapt to novel environmental conditions. Finally, functional traits might be a good predictor of how these species modify their climatic spaces.