Monitoring of alien aquatic plants in the inland waters of Sicily (Italy)

Updated and reliable data on the presence and distribution of alien aquatic plant species in Sicily are lacking, and there is a need to fill this gap for a proper and efficient management of freshwater ecosystems and biodiversity. This paper reviews the available knowledge about alien aquatic vascular plants in the inland waters of Sicily (Italy). The aim is to provide an updated checklist, as a first step in the study of the impact of those plants on the native species and ecosystems of this Mediterranean island. The paper focuses on the strictly aquatic species (hydrophytes), excluding emergent macrophytes. Four species were listed, all of them free-floating and with American origin. Most of them occur within protected areas, and their introduction in the island appears to be anthropogenic. A set of functional traits of the alien species, such as relative growth rate, leaf mass per area, nitrogen and carbon content, were screened. These traits are useful for assessing the species invasive potential compared to native ones.