XVI International Botanical Congess

Ninety-seven plots of eight stands of secondary vegetation from abandoned grassland in upland S.W. Honshu, Japan, were surveyed in summer 1998 to investigate secondary succession. Dominance degree of 255 common species and basal area of 124 wood species were employed. The eight stands were divided into five groups by TWINSPAN: grassland, shrub land, young secondary-, mature secondary- and climax-forest. Grassland succeeded significantly as age of abandonment increased and as altitude decreased. Both species richness and species diversity peaked at intermediate stage of succession. Two shrublands had the highest similarity, while grassland in use shared little in common with mature secondary forest or climax. Average turnover rate was 0.060 yr-1 for community coefficient, or 0.065 yr-1 for dominant similarity. Species turnover at the early succession stage was much faster than the late stage. At least 283 yr were needed for climax forest to succeed to grassland.