Картографирование динамики растительного покрова Саяно-Шушенского заповедника

Abstract

The character of forest dynamics in the last century may be traced on the key area of the Altai-Sayan mountain country — the Sayan-Shushensky Biosphere Reserve of total area 389 000 ha. It is situated at the border of humid mountain region of South Siberia and the arid areas of Tuva. The basement for creation of prognosis map of potential state of the Reserve vegetation cover for 2050 year includes: 1) the data on inventory, ages structure, and conditions of forests; 2) the results of the earlier studies of dynamics of mountain open woodlands; 3) materials of dendroclimatic investigations at the upper and lower forest boundaries in the Sayan Mts.; 4) prognosis of climatologists. While classifying the Reserve vegetation, 1500 biogeocoenoses have been united into 362 types of biogeocoenoses which have been included into 112 groups of associations identified in altitudinal vegetation belts: goltsy, meadows and shrub thickets; high elevation open woodlands; mountain taiga; subtaiga—forest- steppe complexes. Local expansion of forest boundaries, at the expense of forming the 40— 80 years old forest stands in goltsy and open woodlands, testifies to climate warming, and a rise of the subtaiga—forest-steppe pine and larch forests of the 40—80 years old is the evidence of climate humification in this region during the last century. According to the prognoses of climatologists this tendency will continue in the future 50 years. On the territory of the Sayan-Shushensky Reserve, within the strip of 200 m width at the age of steppefied forests as well as within the steppes with shrubs, mesophilous species will be developed in the shrub, herb-dwarf shrub and moss cover. Under protection of shrubs, young open stands of larch and pine will spring up (on the area of 200 ha) and in subtaiga forests Abies sibirica and Pinus sibirica will appear among the regrowth. Under canopy of the mountain taiga and the subtaiga larch forests, the second layer of dark needle-leaved species will be formed. In the places of present pyrogenic derivatives — birch and aspen forests — the fir forest with admixture of Pinus sibirica and Picea obovata will be restored. On the area of 49 322 ha, occupied by mountain woodlands (87% of the total area), the closed mountain taiga forest of Pinus sibirica will spread. The area of goltsy and shrub thickets will decrease by 44.4% (19 214 ha), being replaced by the high elevation open woodlands of Pinus sibirica and Larix sibirica. In accordance with changes in vegetation cover the boundary between the Altai-Sayan and the Central-Asian forest areas within the Reserve's territory will deviate from the modern one approximately by 25 km.