The evolution of dispersal traits based on diaspore features in South American populations of Senecio madagascariensis (Asteraceae)

Plant invasion success is influenced by several driving factors such as the dispersal, environmental conditions and the species characteristics. In wind dispersed plants, the dispersal traits and the altitude are key for predicting dispersal ability. In this work, we estimated this feature in Senecio madagascariensis invasive populations from Argentina and Brazil using diaspore traits to understand its dynamics. Our results show that dispersal is strongly affected by the geographic conditions. We observed that in Argentinian populations growing at higher altitudes, selection favours larger seeds, which might favour seedling establishment over of longer dispersal distance. Conversely, populations grouped in lower altitudes show higher dispersal ability, probably due to the adaptation to environment and assortment of the better dispersal genotypes. In contrast, the Brazilian populations display rapid dispersal ability due to recent colonisation and multiple introductions. The variability in the gene pool could facilitate the occurrence of genotypes with greater dispersal, which could explain why these populations display greater dispersal ability than the Argentine ones. In conclusion, the phenotypic response to geographic conditions and the population density play an important role in the dispersion strategies in S. madagascariensis.