Alien tree species invading European landscapes: the case of black locust in north-eastern Italy

Invasive alien species are well-known for expanding within different landscapes. Currently, in the EU a new regulation on invasive alien species entered in force on 1 January 2015 thus calling for a raise of awareness on such topic. Black locust (Robinia pseudoacacia L.), a nitrogen fixing species, is among the most widely spread alien tree species in Europe. In north-eastern Italy it invades forest and open habitats important for native biodiversity. The invasion of abandoned areas in hilly landscapes may lead to the homogenization of vascular plant communities of native secondary forests. Here we investigate relationships between black locust invasion, landscape mosaic, soil composition and vascular plant biodiversity. Finally, we recommend further research and management measures to limit black locust spread and impacts supporting the need of embedding these measures within forest landscape planning.