大興安嶺におけるオロチョンの生態(二)

抄録

(1) The northern Great Khingan is almost entirely covered with larch forest which is an extention of the dry taiga of eastern Siberia. Between this forest and the adjacent Mongolian steppe there is a transitional zone, the so-called forest-steppe. In the southern part of this region, it penetrates deeply into the forest area along the valleys of big rivers. The white birch is usually found there in open formation or in small groves. A large area in the wide valley floors is occupied by meadows and reed-swamps. (2) In the forest area, meadows and reed-swamps are replaced by sedge swamps, shrub swamps (shrub tundra) and also bog moss swamps (moss tundra). Together with barren grounds covered by lichen (lichen tundra), they represent a miniature of the forest-tundra landscape of northern Siberia. Distribution of such tundra elements in this region is unquestionably due to its high elevation. So they are distributed more abundantly in the central part of this region.