SECONDARY SUCCESSION OF HERBACEOUS COMMUNITIES IN JAPAN : A CASE STUDY IN SUGADAIRA, CENTRAL JAPAN

Changes of floristic composition were observed for 7 years in an experimental field of secondary succession. In the 1-year-old stand, Echinochloa crus-galli var. crus-galli was the dominant species, and Chenopodium album and Digilaria violascens were important constituent. The sequence of dominant species during the succession was Erigeron spp. (Erigeron annuus, and E. canadensis) in 2-year-old stands, and Artemisia princeps in 3-year-old stands. A. princeps maintained its dominance from 4-year-old to 7-year-old stands. Miscanthus sinensis was established in the 3-year-old stands and increased in later stages. Rumex acetosella and Oenothera parviflora were important constituent species during succession, Four stages of secondary succession were recognized in herbaceous stages by different life-forms : summer annual, biennial (winter annual), perannial herb and perennial grass. Comparing secondary succession in various sites in temoerate regions, the dominant species of each stage was similar in their life form. Raunkiaer\u27s life-form spectra change from the therophyte type in the 1-and 2-year-old stands to hemicryptophytes and chamaephytes in later stages of succession. The dominant disseminule form in the 1-year-old stand was clitochore, and anemochore increased in the later three stages. The type of life history of the dominants was the same in the same seral stage among the sites in temperate regions. Key words ; Secondary succession, Experiment, Mechanis