Alpine ecotone in the Siberian Mountains:vegetation response to warming  

作　　者：KHARUK Viacheslav I. IM Sergei T. PETROV Il’ya A. 

机构地区：[1]Sukachev Institute of Forest,Federal Scientific Center,Russian Academy of Science,Siberian Branch,Academgorodok 50/28,Krasnoyarsk 660036,Russia [2]Siberian Federal University,Svobodny str.79,Krasnoyarsk 660041,Russia [3]Reshetnev Siberian State University of Science and Technology,Krasnoyarsky rabochy str.31,Krasnoyarsk 660014,Russia

出　　处：《Journal of Mountain Science》2021年第12期3099-3108,共10页山地科学学报（英文）

基　　金：The research was funded by Russian Foundation for Basic Research,Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science,project number 20-44-240007.

摘　　要：Birch(Betula tortuosa)is one of the treeline forming species within the Siberian Mountains.We analysed the area dynamics of birch stands and the upslope climb of birch treeline based on the Landsat time series scenes and on-ground data.We found that since the warming onset(1970th)birch area increased by 10%,birch stands and treeline boundary were moving upslope with a rate of 1.4 m/yr and 4.0 m/yr.Birch upslope shift correlated with air temperatures at the beginning(May-June)and the end(August-October)of the growth period.Meanwhile,no correlation was found between birch upslope migration and precipitation.Winds negatively influenced both birch area growth and birch upslope climb during spring,fall,and wintertime.In the windy habitats,birch,together with larch and Siberian pine,formed clusters(hedges)which mitigated the influence of adverse winds.These clusters are the adaptive pattern for trees’upslope climb within windward slopes.The other adaptation to the harsh alpine ecotone habitat is non-leaf(bark)photosynthesis which supports tree survival.Thereby,Betula tortuosa upslope climb depends on the wind impact and warming in spring and fall that extended growth period.With ongoing warming and observed wind speed decrease on the background of sufficient precipitation,it is expected to further birch advance into alpine tundra in the Siberian Mountains.

关 键 词：Alpine biomes Treeline shift rate Treeline ecotone Siberian mountain forests Betula tortuosa Forest densification Tree clustering 

分 类 号：P467[天文地球—大气科学及气象学]