Abstract

Italian coastal regions are heavily urbanized and, actually, exposed to a marked risk of coastal erosion. To control and counteract this negative trend the submerged meadows of Posidonia oceanica species could play an important functional role limiting sea swells and wave motions for the protection of national coastline from erosive processes. In this way, at the base of the meadows, there are sedimentary textures, made of intertwined rhizomes, roots and sediments, named “mattes”, representing a special kind of strenghening lands able to oppose against hydrodynamic forces. This study was conducted on a submerged beach of Cavo bay, in Elba island (North-Western Italy). The experimental trial showed the functional effect of the “matte” against coastal erosion based on the high resistance of the whole root system of Posidonia meadow able to compact mobile substrata as a reinforced soil in coastal seawaters. In conclusion, Posidonia “mattes” are very important to stabilize littoral seabeds for the protection of Italian sandy beaches against coastal erosion.

Keywords:Italian coastline; Coastal erosion; Elba island; Posidonia oceanica “matte”; Shear resistance