PLANT GEOGRAPHICAL PECULIARITIES OF THE FLORISTIC COMPOSITION OF BIRCH-PINE (BETULA PUBESCENS VAR. LITWINOWII, PINUS SYLVESTRIS VAR. HAMATA) GRASS FORESTS FROM THE NORTH-WESTERN CAUCASUS
Nikolai B. Ermakov1,2,3,4, Yulia S. Akatova5, Mariya A. Polyakova4
1Nikita Botanical Garden - National Scienti c Center of Russian Academy of Sciences, Yalta, Russia
2Maykop State Technological University, Maykop, Russia
3Khakass State University N. Katanov, Abakan, Russia
4Central Siberian Botanical Garden SB RAS, Novosibirsk, Russia
5Caucasian State Nature Biosphere Reserve named after H.G. Shaposhnikov, Maykop, Russia
Keywords: cenoflora, hemiboreal forests, Braun-Blanquet, Brachypodio-Betuletea, Caucasus
Abstract
The pine and small-leaved pine grass forests of the North-Western Caucasus are proposed to be considered as part of a special subzonal geographical type - the European-Siberian hemiboreal forests. The results of the analysis of the spectrum of phytocenotic groups demonstrated the highest importance of light-depending mesophilous species of subalpine-forest and “betular” (related to birch forests) phyto-cenoenotic elements, as well as the important role of subalpine species along with the weak participation of shade-tolerant nemoral plant species. The results of the geographical analysis of the floristic composition revealed the predominance of widespread species (of Eurasian, European-Siberian and West Palearctic chorological groups), as well as endemic Caucasian taxa. According to the proposed concept of the genesis of the Caucasian hemiboreal forests, the high level of endemism is a consequence of their autochthonous floro-genesis at the upper boundary of the forest belt in the Pliocene. At the same time, the significant participation of European-Siberian, Western Palearctic and Eurasian chorological groups is the result of active migrations of plant species in hemiboreal forests predominated during the Quaternary period in forest and forest-steppe zones of Northern Eurasia.
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