Vegetation and environmental factors during primary succession on glacier forelands: some outlines from the Italian Alps

Relationships between plant communities and the physical environment during primary succession on recently deglaciated glacier forelands were studied in 3 areas of the Italian Alps. The aim of the research was to relate traditional phytosociological data with environmental variables. Twenty-eight phytosociological relevés were performed, each associated with twenty-six environmental variables; quantitative parameters of richness and diversity were also calculated. Species/relevés, environmental variables/relevés and species/environmental variables matrices were analyzed by cluster analysis, PCA and Spearman correlation coefficient. Three main stages of succession were identified by floristic composition and confirmed by environmental parameter evaluation. A complex of environmental variables seems to be closely correlated with terrain age and richness/diversity parameters, even though diversity decreases in late successional stages. The phytosociological significance of species is in accordance with their position in the context of succession.