Significant differences in the characteristics were found between the communities dominated by annual herbs (Impatiens parviflora, I. noli-tangere) and those dominated by perennials (Parietaria officinalis, Petasites hybridus, Sambucus ebulus). The annual communities exhibited twice as low above ground phytomass and dominance, and about twice as high stem density and species diversity than the perennial ones. Phytomass and plant size of the dominant species varied according to stand density. Reproductive effort and leaf area of the dominants ranged from 0.5-26% and 157-242 cm2 per plant, respectively. Species diversity was largely a function of dominance of the most important species, rather than of stand phytomass.