Alpine plants are considered to be sensitive to global warming. This assumption is supported by an increasing number of observational studies. To obtain early-warning signals of vegetation changes on high alpine ecosystem of Japan, we started the vegetation investigation at Mt. Koma and Mt. Sannosawa in central Japan. This study reported vegetation changes between 2008 and 2011.

We set 4 permanent quadrats of 1m×1m at 14 sites on 6 regions and divided the each quadrat into 100 small grids (0.1 m×0.1m). All vascular plant species were recorded each grids. Soil surface temperature (at depth of 0.5–1 cm) was automatically recorded with data loggers at 1-h intervals to determine the timing of snowmelt.

Species richness per quadrats slightly increased during three years. Total number of emerged species in 100 small grids significantly increased. These results are seen to be primarily caused by the recent warming in the region. Unusually high summer temperatures, which were 1.5 degrees higher than usual, have recorded in 2010. Vegetation cover of shrub species, such as Pinus pumila, increased in some quadrats. Because species richness tended to decrease at the quadrats that shrub species were dominant, species composition would be changed if these trends continue. However, longer term trends should be evaluated before I come to any firm conclusion.