VEGETAZIONE PRATO-PASCOLIVA INFRAFORESTALE E BIODIVERSITÀ DI UN'AREA ALPINA ORIENTALE

Actual pastoral activity reduction in many Alpine environments determined a gradual decrease of open grassland areas, caused by penetration and development of trees. Inside a wide complex of researches on sustainable forest management for biodiversity conservation, in the bottom of Val Visdende (BL), characterized by presence of pastoral surfaces inside forests of Picea abies, values of specific biodversity of close forest, pastoral areas and transition surfaces between forest and pastoral zones were determined, using vegetational analysis and synthetic indexes. The extreme variability and richness of canopy in transition areas, characterized by different illumination, stressed the biologic diversity of these little surfaces, whose survival, closely related to the maintaining of grazing activity, could determine important benefits for landscape value and, consequently, for tourist attraction. Great reduction of pastoral resources (from 160 ha to 122 ha) and decreasing of total length of the edge of glades (from 25.3 km to 24.2 km) in the bottom of Val Visdende in 35 years (from 1957 to 1992), creates problems about the conservation of these important niches and suggest more careful evaluations in forest management.