In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1.

The Japanese Rose (Rosa rugosa) is a perennial shrub belonging to the family Rosaceae. It was introduced in Europe from East Asia as an ornamental plant in the XIX century and is now considered an invasive species, especially in northern Europe, colonising the Atlantic and Baltic coastal dune habitats and threatening local biodiversity. However, little is known about its presence and invasion patterns in the Mediterranean area. In Italy, R. rugosa has been classified as naturalised and just a few observations have been recorded in dune habitats in the North Adriatic coast. Here, we review the published data on R. rugosa in Europe and present preliminary data on the invasive pattern of R. rugosa on the Italian North Adriatic coast. We surveyed the coastline in two locations (i.e., Brussa and Bibione, Italy) where we characterised the dimension and structure (i.e., number of ramets and stem height) of the R. rugosa populations and listed the associated floristic composition. No occurrence of R. rugosa was recorded in Bibione, probably due to the success of the restoration project carried out on that site. In contrast, several stands of R. rugosa were found in Brussa, where many other alien species were also found (accounting for 15.28% of the sampled species). Given the strong invasiveness of R. rugosa, it is important to keep data on its distribution up-to-date and investigate its ecology and physiology to promote appropriate management strategies to control its spread and anticipate its future potential distribution.

Biological invasions are deemed to be the second most important global driver of biodiversity loss, right behind habitat destruction and fragmentation. In this study, we aimed at testing if community invasibility, defined as the vulnerability to invasion of a community, could be associated with the characteristics of a given habitat, as described by the composition and structure of its native species. Based on a probabilistic sampling of the alien flora occurring in the temperate wetland Lake Doberdò (Friuli Venezia Giulia region, NE Italy) and using a null-model-based approach, the observed occurrence of Invasive Alien Species (IAS) within sampling units was randomized within habitats. While testing the degree of invasibility for each habitat within the wetland, our null hypothesis postulated that habitats are equally invaded by IAS, as IAS can spread homogeneously in the environment thanks to their plasticity in functional traits that makes them able to cope with different ecological conditions. The obtained results comparing observed IAS frequencies, abundance and richness to those obtained by the null model randomizations show that, for all habitats, invasion was selective. Specifically, a marked preference for habitats with an intermediate disturbance level, a high nutrients level and a medium-high light availability was observed, while an avoidance was detected for habitats characterized by lower levels of nutrients and light availability or extreme conditions caused by prolonged submersion. This method allows us to provide useful information using a simple-to-run simulation for the management of the IAS threat within protected areas. Moreover, the method allows us to infer important ecological characteristics leading to habitat invasion without sampling the environmental characteristic of the habitats, which is an expensive operation in terms of time and money.