Format: ORAL

Alba Cuena-Lombraa1, Mauro Fois1, Lina Podda1, Gianluigi Bacchetta1

1 Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy.

Biodiversity is declining globally and invasion by alien plants is regarded as one of the most significant threats to ecosystems worldwide. Despite their great value in biodiversity conservation, wetlands are one of the most vulnerable environments to Invasive Alien Species (IAS). This is attributed to the anthropogenic pressure, especially eutrophication, which favours new invaders and variations of flooding pulses. IAS plants can cause radical changes in aquatic ecosystems with severe consequences, either through competition for resources with the native plants or by physically altering the habitat. Here are presented analyses on invasion by alien plants and how these affect the native flora. We monitored 500 wetlands around Sardinia (Italy), including different types. The field information was gathered following a rapid assessment protocol to provide a general overview of a maximum number of sites.Most of the wetlands investigated are threatened by biological invasion, a total of 128 alien plant species were found (ca. 1300 records), accounting for 8,5% of the total plant species. Furthermore, invasive plants were found in the 50.41% of the wetlands, while the naturalized in 30.89% and the casual ones in 18.70% sites. Asteraceae species had the highest frequency, followed by Poaceae, and Fabaceae. Among invasive hydrophytes, we recorded Lemna minuta, Hydrocotyle ranunculoides, Pontederia crassipes and Azolla filiculoides. Higher concentration of IAS was detected in coastal wetlands than in inland or human-made wetlands. These wetland types include lagoons, estuaries and salt marshes of different surface and catchment size, human population and touristic pressure. We detected that multiple activities around coastal wetlands and their catchments directly and indirectly promote IAS proliferation, especially in the most easily accessible areas. These results lead us to enhance multidisciplinary research on the ecology and functioning of wetlands, to plan more effective conservation actions based on plant communities knowledge.