SECONDARY SUCCESSIONS ON ABANDONED CULTIVATION TERRACES IN CALCAREOUS PROVENCE .1. VEGETATION AND SOIL

Changes in cultivation terraces after land abandonment are studied from a synchronic approach with two main descriptors: vegetation and soil. Dynamic patterns are shown up with a Correspondence Analysis conducted on the floristic data. Changes in vegetation features (species richness, growth forms, dynamic indices and biogeographic types) and in pedological factors are studied along the main dynamic gradient in order to characterize the succession patterns. Without disturbance, abandoned terraces are quickly recolonized by vegetation that follows a forest dynamics. The characteristics of dynamics patterns agree with the results already obtained in many studies on secondary successions. Concerning the soil, in the upper horizon, the organic matter contents increase along the old field succession. However, wild fires can lead to the occurrence of low open shrublands, as well as soil alteration, notably sensitive in the lower horizon and concerning the granulometry. On the whole, this study leads to an approach of the ecological patterns of secondary and regenerative successions in the French mediterranean region.