THE GEOBOTANICAL MAP OF THE ALTAI-SAYAN MOUNTAINOUS REGION: ECOLOGO-GEOGRAPHICAL REGULARITIES OF VEGETATION COVER FORMATION
N.B. Ermakov1,2,3
1Nikita Botanical Garden - National Scientific Center, Russian Academy of Sciences, Yalta, Russia
2N.F. Katanov Khakassian State University, Abakan, Russia
3Maikop State Technological University, Maikop, Russia
Keywords: vegetation, phytocenochors, geobotanical mapping, bioclimatic regularities, plant geography, Southern Siberia
Abstract
The system of higher spatial categories of vegetation cover of the Altai-Sayan mountainous region has been developed and presented on a small-scale geobotanical map at a scale of 1:1 000 000. The study is based on V.B. Sochava’s methodology of the dimensionality of vegetation cover and the hierarchy of leading ecological and geographical factors as well as on results of classification of plant communities using the Brown-Blanquet method. The hierarchy of the map legend reflects four levels of spatial units. The first level represents the main patterns of vegetation of mountainous areas, i. e. altitudinal belts. The second belt includes the largest phytogeographic subdivisions: phytochors (combinations of vegetation classes), dominated by Euro-Siberian and North Asian types and phytochors with a predominance of East Siberian-Central Asian types. The ecological content of these phytochors in the Altai-Sayan mountain region is conditioned by the interaction of orography and the leading climatic processes: westerly moisture transport and the Asian anticyclone, leading to the effects of the “rain barrier” and “rain shadow” as well as the oceanic-continental climate gradient. The latter factor, along with the conditions of humidity-aridity of the climate, determined the allocation of four phytochors of bioclimatic content: vegetation of cyclonic excessively humid, cyclonic humid, anticyclonic insufficiently humid, and anticyclonic dry bioclimatic sectors. Each sector corresponds to a characteristic combination of alliances of different vegetation types: steppe, forest, and highland. The third level of the map legend reflects intra-belt differences within each bioclimatic sector. The fourth level characterizes different regional geographical combinations of units (mesocombinations) of the rank of vegetation associations within each sub-belt. As an example of the implementation of the regularities described above, an abbreviated fragment of the legend (limited to the four highest hierarchical categories) characterizing the forest belt of the Altai mountain system and reflected on the map-scheme (1:1 000 000) of this region is presented.
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