长白山苔原是亚洲最为典型的山地苔原。在当前气候变暖的背景下，低海拔草本植物沿海拔向上不断侵入到苔原生态系统，威胁典型苔原植物的生存。本研究基于植物上侵的迁移、定植、扩散三个关键过程开展观测和控制实验，通过多坡向样带调查方法，确定长白山苔原带上侵草本植物的种类、数量及分布格局，对比分析上侵植物的性状优势；提出在当前气候变暖的背景下，雪被覆盖能够帮助上侵植物度过严酷的低温冻害期从而完成定植的假说，并设计了雪被覆盖和定植控制实验予以验证。通过开展跨海拔移栽和扩张实验，研究上侵草本植物在应对高海拔恶劣环境的同时，逐渐取代本地植物的机制。为揭示气候变化背景下长白山苔原带植被变化的格局、过程与机理，预测未来长白山苔原带植被变化趋势提供科学依据，同时也为国际高山地区植物垂直分布格局变化研究提供实证参考。

The tundra of the Changbai Mountains is typical temperate alpine tundra in Asia. Herbaceous plant species from low elevations have shifted their distribution ranges and encroached the tundra ecosystem in high elevations under climate warming, which threatened the survival of indigenous tundra species. By focusing on three critical processes (transport, establishment, spread) of the upward shift process of herbs, this research aims to 1) reveal the demography, plant traits, quantity, and distribution pattern of upward shift herbs in tundra zone based on multi-regions and transects field survey, 2) verify the hypothesis that upward shift herbs could take advantage of the superior environment under snow patches to avoid frost damage and establish, using our seed germination experiments, and 3) investigate the mechanisms linking expansion of herbs by conducting transplant and control experiments. We aimed to prove the process that after establishment, encroaching herbs would cope with the harsh environment and compete with local tundra shrubs simultaneously. Our results could help to reveal the pattern, process and mechanisms linking vegetation change in the context of climate warming, predict the future change of tundra vegetation in Changbai Mountains, and supply the positive reference for the research on upward shift of plant species in mountain regions at global scale.