REGENERATION WINDOW FOR FLESHY-FRUITED PLANTS DURING SCRUB DEVELOPMENT ON ABANDONED GRASSLAND

Successional patterns in seed rain, seed predation; seed bank, and the density and survival of seedlings were studied for fleshy-fruited plants in a patchy vegetation of dry grassland with interspersed scrub in central Europe. These hay meadows were abandoned 20-30 years ago. Three successional scrub stages (phases) and the adjacent mown and abandoned meadows were used for the investigation. Seeds of 29 fleshy-fruited species were collected in seed traps over two years. The spatial pattern of seed dispersal strongly depended on the successional stage: seed rain density was highest beneath the mature scrub phase and lowest in the grassland. This was also true for seed predation by rodents, and frequency of fleshy-fruited plants in the seed bank. The density of seedlings showed a different pattern; it was highest in the intermediate phase of scrub development. In this phase the seed rain was less abundant than under the mature phase, but the destructive influence of seed predation and the mortality of seedlings (particularly due to shading) were not as strong as beneath the mature phase. Therefore, it can be assumed that this intermediate phase is a regeneration window for fleshy-fruited scrub species.