Pistia stratiotes L . and E ichhornia crassipes ( M art.) S olms.: emerging invasive alien hydrophytes in C ampania and S ardinia ( I taly)

This article provides general information on the distribution and presence of invasive macrophytes in Italy and describes and discusses two hydrophyte invasion case studies: Eichhornia crassipes in Sardinia and Pistia stratiotes in Campania. The two invasions took place in the same period, but mechanical removal intervention started only in Sardinia, even if costly and unsuccessful in the long term. Two main pathways are responsible for the presence of these two species in Italy, i.e. introduction as ornamentals and investigation and use for phytoremediation. The drafting of a national strategy on biological invasions is a priority for Italy and several specific action plans for species and habitats, as in the case of inland waters, are required. Furthermore, there is the need for regulations in the trade sector of invasive plant species and to evaluate the possibilities for biological control for established aquatic alien invaders.