Академическое издательство «Гео»

Key words: vegetation, steppe belt, forest-steppe belt, Khakasiya, Tuva.

Rastitel'nyj Mir Aziatskoj Rossii (Plant Life of Asian Russia), 2010, № 2, p. 50-57

The vegetation structure of steppe and forest-steppe altitudinal belts
of Khakassia and Tuva mountain basins

N.I. Makunina

Central Siberian Botanical Garden, SB RAS, 630090 Novosibirsk, Zolotodolinskaya str., 101,
e-mail: natali.makunina@mail.ru

The intermontane basins of Khakasiya and Tuva are situated in the eastern part of the Altai-Sayan Mountain Area. They are separated by sublatitudinal ranges and are located from north to south in the following order: North-Minusinskaya, South-Minusinskaya, Turano-Uyukskaya, Central-Tuvinian, and Uvs-Nuur. Climate changes and basin floor altitudes have the same trend: the climate of the North-Minusinskaya basin is milder than that of the Uvs-Nuur basin; the floors in the Khakasiyan basins are 300–500 m a. s. l., those in Tuvinian ones vary from 700 to 900 m a. s. l. The latitudinal position, mountain boundary peculiarities and basin floor height determine presence of a certain basic vegetation belt. It varies from the forest-steppe belt in the northern part of the North-Minusinskaya basin to the desert steppe belt in the Uvs-Nuur basin. The forest-steppe belt borders the steppe one. In the mountain basins the phenomena of rain shadow and foothills humidity are observed. The extent of the steppe and forest-steppe belts varies from north to south. In Khakasiyan basins the belt areas are comparable, in the Uvs-Nuur basin the forest-steppe belt forms a narrow strip and is much inferior to the steppe one in area. The vegetation cover of each of the basins has a unique composition, the degree of their similarity or distinctions can indicate difference in climatic condition complex.
The steppe, forest and meadow communities of the Khakasiyan and Tuvinian basins are represented by 6 classes, 8 orders, 12 alliances and 27 associations.

Key words: vegetation, steppe belt, forest-steppe belt, Khakasiya, Tuva.