Biological invasions in Marine Protected Areas (MPAs): trends in non- indigenous macrophytes in Italian MPAs

Abstract

Non-indigenous species (NIS), widely recognized as one of the main drivers of global change, may in time become invasive, determining significant environmental impacts, such as biodiversity loss and ecosystem services degradation. The impact of NIS on marine habitats within Marine Protected Areas (MPAs), whose major aim is biodiversity conservation, can be significant even highly detrimental. Therefore, monitoring NIS distribution is crucial in these areas for planning effective conservation strategies. Currently, in Italy have been established 29 MPAs that are mainly concentrated in the two great islands, Sicily (7) and Sardinia (6). In Italy, 73 alien macrophytes (10 Chlorophyta, 16 Ochrophyta, 46 Rhodophyta, 1 Tracheophyta) is currently reported. Our research revealed differences among the MPAs with respect to the number of marine alien macrophytes, which could be linked to different reasons such as differences in the number of conducted studies or differences in geographical position. Despite their fundamental role in the conservation of marine biodiversity, MPAs are not immune to biological invasions, evidencing that protection does not hinder the introduction and spreading of NIS. Management actions within MPAs should include the planning of regular monitoring activities which will allow early detections and to follow the spread of species already present. This work represents an important starting point for the creation of a regularly updated list of alien macrophytes within the Italian MPAs.