Oasi xeriche della Valle di Susa

The present work aimed at analyzing the dry grasslands of the lower Val di Susa, included within the SCI IT1110030 " Oasi xerotermiche della Valle di Susa-Orrido di Chianocco e Foresto ". The dry grasslands are among the most biodiverse plant communities in Europe, hosting many rare plant species and a key habitat for many animal species. In order to provide useful information to preserve this habitat, we analyzed and described the flora and vegetation of the area by carrying out261phytosociological surveys over the 1250 ha of the SCI. The data obtained from the surveys allowed the identification of the alliance Xerobromion for the first time in this area. It was also confirmed the presence of the alliance Stipo-Poion carniolicae. Through a t-tests and the implementation of Generalized Linear Models we investigated differences and similarities between the two different alliances. The Xerobromion proved to be slightly more mesophilic than the Stipo-Poion carniolicae. Xerobromion grasslands were threatened by shrub-encroachment. Conversely, the Stipo-Poion carniolicae grasslands were subject to a slower encroachment and this slowness was due to the drier microclimate and to the less fertile and thinner soil. The open areas located on steeper slopes were characterized by thin and loose soil and were hosted the most rare plant species of flora. After the introduction of sheep grazing, the monitoring of flora (especially Orchidaceae) will prosecute within the areas exploited by the flock, as the action exerted by sheep grazing could produce a positive effect on Orchidaceae and therophytes with high floristic value conservation.