Diversity, Ecotopology and Hypsometric Distribution of the Endemic Flora in High- Mountain Phytolandscapes of the Caucasus

Abstract

The paper considers diversity, systematic-geographical, ecotopologic (biotopologic) structure and peculiarities of hypsometric distribution of the endemic flora in the high-mountain phytolandscapes in the western (Abkhazia, Samegrelo), central (Svaneti, Racha-Lechkhumi, Shida Kartli, Khevi) and eastern (Khevsureti, Tusheti, Mountainous Kakheti) parts of the Eucaucasus (Caucasus Mountains). Endemic calciphilous flora is especially characteristic of limestone lithological areas, which within the borders of Georgia are met only in Abkhazia, Samegrelo and Racha-Lechkhumi, whereas diversity of endemic flora of argillaceous slate and marly habitats is observed in Tusheti and Pirikita Khevsureti (the gorges of the rivers Pirikita, Gometsari Alazani and Arghuni-Andaki-Asa). These habitats are nowhere else met within the boundaries of Georgia. It should be noted that in the florogenesis of the high mountain endemism a significant role was played by orogenesis processes of the Caucasus, which was caused due to extinction of ancestral species at lower altitudes and resulted in their geographical isolation. This is proved by geographical and hypsometric vicarism of some species of generas Campanula, Cerastium, Silene, Erysimum, Pedicularis, Delphinium, and Jurinea. The western, central and eastern parts of the Caucasus are floristically different not only from each other, but also from neighboring mountain massifs. The above mentioned is conditioned by distinct geographic isolation of the mountain system of the Caucasus, different altitudes, petrology, and glaciogenic relief. Floristically, slate screes and rocky habitats are most diverse. The endemic species are unequally distributed in different mountain systems and phytolandscapes of the Eucaucasus. It again indicates to the significance of the phenomenon of the well expressed geographical isolation of the Caucasus Mountains.