Vegetation evolution in a reclaimed area contaminated with dioxin

The results of a study on the evolution of the vegetation in a reclaimed area contaminated with dioxin are presented. Phytosociological relevés were carried out in 1992-1993 and in 1998 in 25 easily recognizable points. Elaborations on the species number, life forms, chorological types, vertical structure and ecological indicator values were realized. The most outstanding results regard the biodiversity, with floristic changes; the ecology, with increase in the ecological diversity, and the structure, with increase in the cover and complexity. The increase in the shrub layer is a clear indication of structural evolution. If, on the one hand, the vegetation structure indicates evolution of the system, on the other, the present floristic composition is still the result of the starting conditions. The observed floristic changes arise from autogenic floristic readjustments because there are no allogenic floristic increases. This is due to the isolation of the area which is completely surrounded by human sites, mostly of an urban type.