Home – Home – Jornals – Contemporary Problems of Ecology 2018 number 4

A new method of approach to the determination of "upper forest border" (UFB) as the border of the "rootclosed" stand and regrowth ones as its potential vaniguard is suggested. The mass scale of Pinus sibirica populations dispersal by the nutcracker (Nucifraga caryocatactes) in the UFB ecotone in the Northern Urals (Pavdinskii Kamen and Third Hillock mountains) from the middle-mountain taiga to the mountain forest-tundra and tundra at distance up to 1 km has been established. It was performed on the basis of original reconstruction method of the number dynamics of P. sibirica annua seedlings and the analysis of the relations with the dynamics of the seedbearing and population number of the nutcracker. The trustworthy consortive relations of the generations number of Pinus sibirica in the mountain fortundra and tundra zones with its seedbearing and the nutcracker number in the previous year in the middle-mountain taiga zone have been revealed. A trustworthy increase (2.6 times) of seedling generations number during the last 49 years has been established in connection with the increase of the summer air temperature in Subarctic up to 2.0 ^oC. A hypothesis of the formation of the united genetical metapopulation of P. sibirica in the mountain ecotone zone "forest - tundra" in consequence of its seed ornitochory from the high-different populations has been formulated. A prognosis of the mosaical formation of the vaniguardal "thin forests" in 20-25 years and the rootclosed curtains of the "forest" in 40-50 years in the mountain tundra in the Northern Urals by current speed of the rise in temperature is made.