Vegetation succession was studied for 12 years on an abandoned nutrient-poor small field surrounded by a strip of natural grassland. No fertilizers or herbicides were applied. Few weeds or annuals were present during this period. Only two plants, i.e. Agrostis capillaris and Festuca rubra, dominated during the 12 years. At two spatial scales (0.04 and 0.4 m2 ) a dramatic increase in species richness was recorded during the first two years. However, no further trend in species richness occurred after the sixth year of succession. Successional changes were directed and continuous. The rate of succession depended on the distance from the neighbouring meadow. Vegetation at the margins of the transect developed more slowly and diverged from the middle during the succession.
We assessed vegetation changes on acidic sandy soils in permanent plots to follow secondary succession after cessation of intensive goose breeding in E Hungary. We also aimed to estimate the time required for vegetation regeneration and indicate differences in secondary succession patterns at different altitudes in sand dunes. Two sites in the low and two in the high parts of the dunes were chosen and sampled for twelve years. The initial stages are characterized by ruderal communities dominated by nitrophilous annual weeds. Ruderal vegetation was soon replaced by nutrient-poor communities dominated by short-lived pioneer dicotyledonous plants and grasses. In the last few years of the study, coinciding with a rainy period, the low sites were dominated by the perennial grasses, Poa angustifolia, P. pratensis and Cynodon dactylon. In contrast, in the high sites a less dense cover of perennials developed. The influence of initial composition on vegetation development decreased with time and the influence of altitude increased during succession. The altitude of the site had a significant effect on regeneration. Species richness and Shannon diversity of the high sites increased during vegetation development and that of the lowsites decreased. Most annuals persisted in the high sites but became extinct in the low sites. The mean species turnover rate, irrespective of altitude, decreased during the study.