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Lecture 6 Vegetation of the Altai Region

The characteristics of the vegetation of the Altai region arise from its geo­graphical location, its complicated geographical history, and the variety of present environmental conditions, especially in the mountainous part. Being surrounded by the West Siberian and the Kazakhstan steppes in the south and west, by the vast forested areas of the Salair and the western Sayan mountains in the east, and by de- sert-steppe landscapes of Central Asia in the south-east, the vegetation comprises many different elements of the flora of adjacent regions. Endemic and relic plants give one more peculiarity of the floristic composition of the region.

The steppes of the Altai arc similar to the adjacent plains. Differences arise mostly from the more humid climate of the region, which supports the growth of a more mesophilic flora.

Meadows of the Altai region are mostly used as pastures. The species num­ber is rather low in comparison with meadows of other regions and comprise usu­ally 30-40 species.

In the southern steppe zone the amount of xerophytic plants increases whereas the role of mesophytic herbs decreases. __

The xcerophytic desert steppes occur mostly in the Chuyskaya depression. In the other mountain regions steppes may be observed only as more or less iso­lated islands. In the south-east of Altai the steppes merge directly in the high- mountain vegetation.

A great diversity of plant communities can be met on steppe soils of differ­ent degree of alkalinity' and on salt licks (sodic soil, white alkali). These communi­ties cover large areas on the slopes of lake depressions. The holophytic vegetation d

is characterized by a low species number and the low abundance of grass species. Currently these areas are mostly used for pastures.

Pine Forests

Pine forests are characteristic for Altai region. They are mostly composed of Scotch pine. Pines can be found in the Altai up to an altitude of 1570 m.

Pines in the region suffer from frequent fires and a great amount of fimgi dis­eases as well as entomo-pests - silk-worms, homtails, moths, and inch-worms. Belts of pine forests stretch from north-east to south-west in the valleys of the Ob and Irtysh rivers. These areas are from 3 to 12 km wide and about 400 km long. Those forests are composed of pine birch, aspen, fern, grasses and a high number of herbs.

In the vicinity of the Altai pine forests can be found in the northern parts. During the Tertiary the Altai was covered to a large extent by broad-leaved forest containing beech, sequoia, maple, lime, ash and others.

Taiga with islands of lime (Tilia cordata) trees can still be found in the Salairsky mountain chain and in the Lebed river basin in North-Eastern Altai. Ad­ditionally the forests comprising Tilia are also characterized by a high number of herbacens species occurring in the European and Asian broad-leaved forests. In Si­beria those plants show a disjunctive distribution pattern and occupy an isolated distribution range. Due to the fact these forests are affiliated with European and East-Asian forests and.are considered to be relicts of tertiary broad-leaved forests.

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