Environmental-lap analysis xerophytes flora of the Russian Caucasus

The objective of the research was the analysis of distribution of xerophytes of flora of the Russian Caucasus on high-rise belts. Direct long-term ob-servations were made on constant trial platforms or by comparison of the data obtained with use of re-mote methods (Alexandrova, Moiseev, Shiyatov, etc.). However, the lack of certain information on the trends of allogeneic shifts can be obtained based on indirect methods, in particular through analysis of plant populations in the border of their distribution (Alexandrova; Gorchakovsky, Shiyatov; Kharuk;. Leac, Craber results. The analysis of the obtained data shows that the largest number of species of xerophytes obligate, i.e. confined to a single high-altitude zones are found in the condi-tions of low mountains and plains (598 species, 58.7 %), and about the same number in the mid-lands and highlands (respectively 159 and 148 species, 15.6 % and 14.5 %). The total number of types of 905 (88.9 %) in view of hypsometrically plastic types that do not have affinity to the same level, but occurring in two, at least in ten levels, plains and low mountain species 678 (66. 6 %), medium-272 (26.7 %), high-189 (18.7 %). Taking into account hypsometric plastic types which do not have arrangement to one level, and found in two is more rare in three levels: flat and low-mountain types - 678 (66,6%); the mid-mountain - 272 (26.7 %); the mountainous - 189 (18.7 %). The overlapping makes 11.6 % that testifies about the vast majority of types dated for a certain high-rise belt. The types which are found in all three levels, only 8 (0.8 %). They are Juniperus oblonga, Stipa pulcherrima, S. capillata, Festuca ovina, F. valesiaca, Allium albidum, Holosteum umbellatum, Androsace elongata. The vast majority of xerophytes are dated for a steppe belt (63.3 %). Approximately identical quantity of types (from 112 to 137) meet in a subalpine belt, a belt of mountain xerophytes and the Alpine belt. The least of all xe-rophytes in a forest belt, single types live in subnival.