Abstract
The species composition, habitat condition, and geographical distribution pattern of the subalpine to alpine meadow （Trollio-Ranunculetalia acris japonici Ohba 1973） on the northern part of the Ushiro-tateyama mountain range were investigated. Based on species composition, the Trollio-Ranunculetalia acris japonici in this region was classified into 7 associations, 1 community, and 3 subassociations. In this area, with heavy snowy climate, variety of Trollio-Ranunculetalia acris japonici were found, depending on altitude, topography （slope type, slope inclination）, in sites with high snow accumulation such as avalanche slopes and concave slope. Characteristic association were found in serpentine areas. It suggests that the diversity of the Trollio-Ranunculetalia acris japonici in the northern part of the Ushiro-tateyama Mountain range is caused by the snowy environment and serpentine. Additionally, the proportions of the geographical distribution pattern of the species that constituted each vegetation unit differed as a function of altitude and topography. The Carici brevisquamae-Hedysaretum vicioidis established close to the ridgeline above the forest limit had a high proportion of circumpolar elements, while other vegetation units that were established above the forest limit tended to have a higher proportion of Pacific elements. Conversely, the vegetation units that were distributed below the forest limit had a higher proportion of lower montane elements and low-altitude species. This difference in the geographical distribution pattern as function of altitude and topography suggests that vegetation history resulting from climate change should be considered when discussing factors that affect the distribution of the subalpine to alpine meadow.
