CURRENT VEGETATION COVER OF THE CASPIAN LOWLAND IN THE SOUTH-EAST OF EUROPEAN RUSSIA
The distribution of steppe and desert vegetation is typical for the Caspian Lowland. There are two subzones of the steppe zone of Eurasia (the Middle subzone with dry steppes and the Southern subzone with desert steppes) and one subzone of the desert zone of the Pre-Caspian and Turan (the Northern subzone with dwarf semishrub and shrub deserts). At present, natural regularities are invisible because of the results of human impact. Natural dry bunch-grass steppes have completely disappeared to the East from the Volga River. The vegetation cover is mostly represented by fallow lands of various ages, whose common features are the high general projective cover (80 - 85%), the fairly high specific diversity, with the presence of many perennial herbs typical of dry steppes. The specific feature of the desert steppes is the heterogeneity of the vegetation cover in the region under survey. Both complexes with a predominance of grass steppe communities and also with a predominance of dwarf semishrub wormwood communities (which make steppes look like deserts) are widespread. Secondary communities and primitive plant aggregation play an important role in forming the structure of the vegetation cover in the desert zone. The main dominants now are not only dwarf semishrubs, but also bunch grasses, perennial plants, annual and biennial herbaceous plants. Communities of Artemisia lerchiana predominate among dwarf semishrub communities. On pastures with sandy loam soils, Artemisia lerchiana is completely disappeared and anthropogenic communities of Poa bulbosa, Alchagi pseudalchagi, and Anabasis aphylla appear, sometimes Sporobolus cryptandrus predominates, communities of Leymus ramosus are formed on light loamy saline soils. Bunch grasses take a great part in the composition of the natural desert communities of Artemisia lerchiana on sandy soils in the Caspian Lowland. After strong grazing, haymaking, fires the fraction of Artemisia lerchiana becomes lower or it is almost destroyed to form anthropogenic communities with the abundance of grasses (Stipa lessingiana and S. sareptana), where annual plants have a continuous cover.
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