Biomass partitioning in response to resources availability: a comparison between native and invaded ranges in the clonal invader Carpobrotus edulis.
Identifying the mechanism underlying plant invasiveness is a fast-moving research topic in current ecology. Phenotypic plasticity has been pointed out as a trait that can contribute to plant invasiveness. This experiment examines the presence of rapid adaptive evolution favoring plastic biomass partitioning during the invasion process. With that aim, we tested differences in patterns of biomass allocation between populations of Carpobrotus edulis from South Africa (native area) and the Iberian Peninsula (invaded area) growing under different nutrient, water and light availabilities in a common garden experiment. Here we demonstrate that biomass partitioning in response to nutrient availability in C. edulis differs between populations from native and invaded ranges, indicating that this trait could be under selection during the invasion process. Thus, nutrient shortage significantly increased the proportional production of roots in populations from the invaded range, but not in populations from the native area. This plastic root-foraging response may contribute to the optimization of nutrient uptake by plants, and therefore could be considered as an adaptive strategy. Understanding the ecological implications of rapid evolution for plastic biomass partitioning is important in determining processes of plant adaptation to new environments, and contributes to disentangling the mechanisms underlying plant invasiveness.