Seasonal snow cover patterns explain alpine treeline elevation better than temperature at regional scale  

作　　者：Mengyue Huang Guoyan Wang Xiaojuan Bie Yunqing Jiang Xiyue Huang Jing-Ji Li Songlin Shi Tingbin Zhang Pei-Hao Peng 

机构地区：[1]State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Sichuan,610059,China [2]Institute of Ecological Resources and Landscape,Chengdu University of Technology,Sichuan,610059,China [3]College of Tourism and Urban‒Rural Planning,Chengdu University of Technology,Sichuan,610059,China [4]College of Earth Science,Chengdu University of Technology,Sichuan,610059,China

出　　处：《Forest Ecosystems》2023年第2期227-237,共11页森林生态系统（英文版）

基　　金：supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program of China(No.2019QZKK0301);the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA26010101);the National Natural Science Foundation of China(Nos.31860123,31560153)。

摘　　要：Unprecedented modern rates of warming are expected to advance alpine treelines to higher elevations,but global evidence suggests that current treeline dynamics are influenced by a variety of factors.Seasonal snow cover has an essential impact on tree recruitment and growth in alpine regions,which may in turn influence current treeline elevation;however,little research has been conducted on its role in regional treeline formation.Based on 11,804treeline locations in the eastern Himalayas,we extracted elevation,climate,and topographic data for treeline and snowline.Specifically,we used linear and structural equation modelling to assess the relationship between these environmental factors and treeline elevation,and the climate-snow-treeline interaction mechanism.The results showed that the treeline elevation increased with summer temperature and permanent or seasonal snowline elevation,but decreased with snow cover days and spring temperature at the treeline positions(P<0.001).Importantly,spring snowline elevation(33.4%)and seasonal snow cover days(21.1%)contributed the most to treeline elevation,outperforming the permanent snowline,temperature,precipitation,and light.Our results support the assertion that the temperature-moisture interaction affects treeline elevation in the eastern Himalayas,but we also found that the effects were strongly mediated by seasonal snow cover patterns.The increasing tendency of snow cover governed by climate humidification observed in the eastern Himalayas,is likely to limit future treeline advancement and may even cause treeline decline due to the mortality of the remaining old trees.Together,our findings highlight the role of seasonal snow cover patterns in determining treeline elevation in the eastern Himalayas,which should be considered when assessing the potential for treeline ascent in snow-mediated alpine systems elsewhere.

关 键 词：Eastern Himalayas Global change Permanent snowline Seasonal snow cover Treeline elevation 

分 类 号：S718.5[农业科学—林学]