On the introduction history and plant ecology of the alien Salpichroa origanifolia in Tuscany (Italy)

Invasive alien species (IAS) are a major threat to biodiversity worldwide. The invasion of Salpichroa origanifolia (Lam.) Baillon (Solanaceae), an herbaceous climber native to South America, is recently rising concern in several Mediterranean countries. In North America, Australia, Japan, and New Zealand, where S. origanifolia has a longer history of introduction it already poses a threat to critical habitats and native species. We, therefore, recommend listing it as an invasive alien species of EU concern and include it in the EPPO list. In Tuscany (central Italy), S. origanifolia has successfully colonised a mesophile forest (San Rossore Regional Park), showing to be a strong competitor towards the resident understorey vegetation, which also led to the progressive depletion of the soil seed bank [1]. Although its first record in the Regional Park is from 1996, it is only in recent years that this species has massively spread. Giving insight into the spatio-temporal stages of alien invasion (transport, colonization, establishment, and spread) is important for planning targeted and effective conservation measures. Furthermore, explaining the arrival and spread of S. origanifolia within the Regional Park provides information to reduce the risk of introducing potential IAS. First aim of this research was to trace the history of introduction of S. origanifolia in Tuscany, and the invasion routes within the Regional Park. Moreover, we studied which environmental factors, primarily illumination and soil moisture, may have favoured the establishment at the current invasion spots, and the ecology (reproductive biology, functional traits) of this species in the introduced area. The invader S. origanifolia proved to adapt well to different light conditions, due to its ability to allocate resources differently between leaves and rhizomes.