Bioclimate and zonal vegetation in Northeast Asia: first approximation to an integrated study
Nakamura, Yukito; Krestov, Pavel V.; Omelko, Alexander M.
This study focused on indication of climatic factors that act at local and regional scales in Northeast Asia by the phytosociological classification using the bioclimatic tools of Rivas-Martínez at the phytogeographical zones of Northeast Asia. More than 5000 phytosociological relevés from different parts of Northeast Asia and climatic records from 1802 stations were involved in an analysis designed to quantify the relationships between climatic variables and zonal vegetation units. The development of the vegetation cover of Northeast Asia is controlled by polar, boreal and temperate macroclimates that differentiate vegetation into Arctic tundra, subarctic woodlands boreal (with northern, middle and southern subzones) and temperate (with northern, middle and southern subzones) forest zones. Basic changes of vegetation along the gradient of continentality depend on the variations of the seasonal temperature and precipitation distribution and caused the differentiation of 6 continentality sectors: oceanic, suboceanic, maritime, continental, subcontinental and ultracontinental. Climatic factors, especially the accumulated temperature and its relation to growing season expressed through the Kira's warmth and coldness indices, continentality, availability of moisture during the growing season expressed through the evapo-transpirational index, and the accumulated precipitation and its distribution over the growing season appear to be major factors for the zonal and sectoral differentiation of vegetation complexes. The use of the world-wide bioclimatic classification of Rivas-Martínez et al. (1999), that suggests three-dimensional vegetation distribution by zones, continentality sectors and elevation belts, allowed identification of the major climatic ranges of vegetation units and determined a core zonal association that indicates major thermo- and ombrotypes of bioclimates of Northeast Asia.