Vegetation-environment relationships in the ultramafic area of Monte Ferrato, Italy

Relationships between some environmental features and species composition a nd abundance of grassland and dwarf shrub vegetation were investigated on M onte Ferrato, one of the best known ultramafic (serpentine) sites of Italy. The main aim was to test the importance of the available fraction of soil metals in causing the typical infertility of ultramafic soils. The physical and chemical features of soil were determined for each plot in which speci es composition and cover were recorded. The plots were classified by cluste r analysis and ANOVA was applied to compare the environmental Variables of groups of plots. Canonical Correspondence Analysis (CCA) was used to detect the principle factors related to the gradient of species composition withi n the plant communities. It was found that the grassland and dwarf vegetati on of Monte Ferrato is not negatively influenced by soil content of nickel and other metals. Pine canopy cover, which provides additional nutrient inp ut and protects against erosion, was found to be important for evolution of the garigues into grasslands. The evolution of grassland turf induced the retention of higher levels of exchangeable cations, including potentially t oxic metals, in the evolved soil.