Patterns of native and alien plant species occurrence on coastal dunes in Central Italy

Mediterranean coastal dunes are affected by high levels of human disturbance, particularly in thelast years. Disturbance not only promotes a physical alteration that increases the invasibility ofcoastal dunes, but also allows the arrival of new alien plant propagules. This study examined thecurrent distribution of the native and alien species growing on coastal dunes in central Italy, consideringalien origin, invasive status and growth form strategies. The floristic sampling was carriedout following the European Cartographic Project protocol. Major trends in wild plant distributionin coastal dunes were identified through Principal Coordinates Analysis (PCoA). High floristicdiversity was found with consistent numbers of alien species and clear differences between theTyrrhenian and the Adriatic coast. There was also a negative relationship between the total numberof alien species and the species richness of the plot, probably related to disturbance. Results showedthat the percentage of the total alien flora was related to species richness of the plot. Finally, invasivealiens appeared to be related to either annual or perennial evergreen strategies.