The community classification is made on the Uryu-Numa mire vegetation situated at 43゜42´NL, 141゜37´ EL and 850 m above sea-level. In the present studies, the authors has applied the sociation-association system to the community classification. In the classification, sociations are first distinguished by the dominants or the constant species, or often by the combination of them with the habitat indicators. Then, the sociations distinguished are grouped into associations by the characteristic species or sometimes by their combination with the plants which are usually conspicuous physiognomically. In the classification, the authors stress that the sociation is the subunit of the association and that it is a basic unit available for field practice. As the higher hierarchical ranks above the association have not been identified in their classification, the authors do not refer to them in the present paper. The plant communities classified are as follows
Experiments were made to understand the movement of nitrogen, potassium and phosphorus in the Zoysia matrella sp. community. The standing crop of the whole plant was measured from March, 1966 through December, 1967. The decomposition rate of litter was estimated by the litter bag method from August, 1967 through August, 1968. The maximum standing crops were 2089g d.w./m^2 in 1967. The decomposition amounts of litter were 214g/m^2 ・yr and 529g in 1966 and 1967,respectively. In 1967. the amount of nitrogen absorbed in the community was 22.6g/m^2・yr, the amount lost from the plant was 9.2g and the amount that disappeared in the litter was 5.5g, and for potassium, 11.6g, 5.6g and 2.1g and for phosphorus, 3.1g, 1.5g and 0.7g, respectively.
The grassland vegetation of the Utsukushigahara Heights in Nagano Prefecture is developed in the subalpine zone from 1850 to 2000m in altitude and is almost used for pasture and meadow. Various grassland communities under artificial and natural conditions are physiognomically recognized as seral stages that will finally become the coniferous climax forest of Tsuga diversifolia and Abies veitchii. As the representative grassland communities in this area, the Festuca ovina community under grazing, the Calamagrostis longiseta community under cutting and the wind-swept herbaceous community without human interference were investigated as to the floristic composition and physiognomy based on the summed dominance ratio (SDR). The Festuca ovina community is a short-grass type from 10 to 35cm tall accompanied by Scabiosa japonica, Agrostis clabata, Carex oxyandra and so on. The Calamagrostis longiseta community is a tall-grass type about 65cm tall accompanied by Cirsium japonicum, Scabiosa japonica, Bupleurum longiradiatum form. elatius, Polygonum cuspidatum, Carex humilis var. nana and so on. The wind-swept herbaceous community mixed with herbs and shrubs is composed of Scabiosa japonica, Carex oxyandra, Rhododendron tschonoskii var. tetramerum, Cirsium japonicum and so on. Regarding the cological structure, the biological spectra based on the combination of lifeforms were studied. The dominant biological types of the three communities mentioned above are HD_4R_5e, HD_4R_3e and HD_4R_5e according to the number of species and HD_1R_5t, HD_4R_3e and HD_1R_5e according to the summed dominance ratio representing physiognomy. The grassland types used for grazing and mowing in Japan were classified by NUMATA^<9)17)16)>, and they are recognized mainly in the warm-and cool-temperate zones and the subarctic zone in Japan. But he pointed out that the data of grassland vegetation in the subarctic zone and the subalpine zone were insufficient. The subalpine grassland vegetation mentioned above in the Utsukushigahara Heights, though it is local, will be regarded as a new type in Japan and ecological studies of the grassland are now in progress.