SPECIES TURNOVER AND SEEDLING RECRUITMENT IN LIMESTONE GRASSLANDS

Species turnover and germination were analysed in the Veronica spicata - Avenula pratensis limestone grassland community. Species turnover was estimated on the basis of presence/absence of species in fifty 10 x 10 cm permanent plots during the period 1986 to 1989. The contribution made by reproduction by seeds to turnover was evaluated by recording newly-germinated seedlings on thirty-five 10 x 10 cm plots on three occasions during the growing season in each year from 1986 to 1989. Turnover, expressed as the sum of increase and decrease of individual species (when comparing subsequent years), varied much between species and remarkably much between years. Seedling recruitment varied widely amongst and within years, indicating the occurrence of non-synchronized regeneration occasions for different species. Species that showed high turnover were different in life-form. High turnover values are related to both reproduction by seeds and vegetative growth of species.