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RESEARCH PRODUCT

Indagine fitosociologica sulle praterie a Brachypodium retusum (Pers.) Beauv. della Sardegna.

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The grasslands characterized by the dominance of Brachypodium retusum occurring in Sardinia are examined. These communities, belonging to the Thero-Brachypodion ramosi alliance (Lygeo-Stipetea class), are quite widespread in the Island, where they usually grow on carbonate substrata from the sea level up to 1300 m of altitude. On the basis of several phytosociological relevés, it has been possible to recognize six associations well-differentiated from the floristic, ecological and syndynamic point of view. The autonomy of these associations is also supported by a numerical multivariate analysis based on quantitative data (dendrogram and P.C.A.). The associations surveyed are the following: Dorycnio suffruticosi-Stipetum offneri ass. nova, localized on summit plateaux at an altitude of 700-1200 m (CE Sardinia), Stipo bromoidis-Astragaletum verrucosi ass. nova, very rare and circumscribed to the coastal hills (W Sardinia), Triseto splendentis-Brachypodietum retusi ass. nova, colonizing more or less stabilized screes at 200-900 m of altitude (NE Sardinia), Asphodelo africani-Brachypodietum ramosi Biondi & Mossa 1992 corr., thermo-xerophilous community linked to coastal stands (S Sardinia), Ranunculo graminei-Brachypodietum retusi ass. nova, orophilous community growing on jointed rocky places at an altitude of 1100-1300 m (CE Sardinia), Melico ciliatae-Brachypodietum retusi ass. nova, found on the coastal screes of Figarolo islet (NE Sardinia). Besides, a floristic comparison among the hitherto known associations belonging to this alliance is given.