Vegetation and pastoral traits of wood pastures in the eastern Italian Pre-Alps

After being long contrasted owing to alleged damages to forest regeneration, traditional semi-natural wood pastures (WPs) have recently regained interest for their biodiversity and cultural heritage. To support public policies and actual management aiming at conserving or restoring them, ground cover, vegetation and pastoral traits of Alpine WPs with increasing tree cover (TC) were studied at 99 sampling plots distributed in three altitudinal belts (montane, high montane and subalpine). In the tree-cover gradient from open pasture (TC 0%–5%: OP) and the very high-density WP (TC 75%–100%: VHDWP), the number of grassland and forest species decreased and increased, respectively, resulting in a bell-shaped relation with the highest species richness in the low- and middle-density WPs (TC 5%–25% and 25%–50%: LDWP and MDWP). In the same gradient, the pastoral value decreased linearly, particularly from the high-density WP (TC 50%–75%: HDWP). This decline occurred as the growth and abundance of grassland species significantly diminished when light availability dropped below 50% of full sun. Consequently, the herbaceous vegetation cover became less complete (more bare soil and moss cover), and the abundance of distasteful or poisonous forest species increased. Compared with OP, the decrease in pastoral value in the different WP types was particularly important in the lower altitudinal belt, especially due to the higher abundance of poisonous species. LDWP and MDWP are important for their high biodiversity and relatively high pastoral value. HDWP has lower pastoral value and species richness, but it also deserves conservation as a source from which high-value LDWP or MDWP can be restored. The conservation and restoration of WP types should be legal and financially viable when site and livestock-utilisation requirements still exist.