MODERN VEGETATION COVER OF THE NORTH-WESTERN CASPIAN SEA REGION AND ITS CARTOGRAPHIC REPRESENTATION
I.N. Safronova1, T.Y.U. Karimova2,3, N.Y.U. Stepanova4
1Komarov Botanical Institute, Russian Academy of Sciences, St. Petersburg, Russia
2A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
3Water Problems Institute, Russian Academy of Sciences, Moscow, Russia
4Tsitsin Main Botanical Garden, Russian Academy of Sciences, Moscow, Russia
Keywords: steppe and desert zones, vegetation dynamics, fallows, pastures, mapping units
Abstract
A map of modern vegetation at a scale of 1:200 000 was created in the ArcGIS program for the territory of the potential habitat of the Saiga tatarica tatarica population with an increase in its number in the North-Western Caspian Sea region. The mapped territory with an area of 220 × 145 km2 lies within the steppe and desert zones. The modern cover of the region is characterized by extreme heterogeneity which reflects both the natural complexity caused by the existence of solonetzes and solonchaks, and the dynamics of vegetation on fallows and pastures. In the steppe zone, dwarf semishrub communities occupy large areas along with feather-grasses and firm-bunch grass communities. They are either halophytic variants of steppes or one of the stages of overgrowth of fallows. They give the plains a “desert” view. In the desert zone, vegetation is represented by pastures with varying degrees of grazing intensity. In places on the sands, because of grazing, the feather-grasses create an aspect, and the plains have a “steppe” appearance. The dynamic processes of vegetation in the North-Western Caspian Sea region create great difficulties for mapping. In the map legend, the division of the territory into the steppe and desert zones is shown by the headings of the highest rank. The diversity of formations of steppe and desert vegetation and spatial heterogeneity of vegetation cover are reflected by the following hierarchical units. Five such units (I-V) characterize the steppe zone, and six units (VI-XI) correspond to the desert zone. They are arranged according to the degree of increase in soil salinity and the degree of grazing. Probably, the lowest mapped units of the legend should be considered as transformation series. However, for the series there is not enough data on the time of plowing and its existence, on the degree of pasture load, on the time of fires. Signs out of scale are used to show features that are not expressed at the map scale.
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