【摘要】 我国东北地区位于中高纬度欧亚大陆东缘,大、小兴安岭多年冻土区是欧亚大陆高纬冻土区向南最突出的部位,属于高纬山地冻土.东北多年冻土区是我国,乃至全球范围内,受气候变暖和人为活动影响最显著的冻土区之一.过去40 a来该区冻土显著退化,主要表现在:1)冻土南界及不连续多年冻土各分区边界北移而导致总面积减小、空间分布破碎化;2)活动层加深,融区扩大,局地冻土岛消失;3)冻土温度升高、厚度减薄、热稳定性降低等.由于各种因素的共同影响,寒区生态环境也发生了一系列变化.这具体表现为以兴安落叶松占绝对优势的天然林带锐减,整个北方森林带北移,沼泽湿地面积减小等,寒区生态系统和环境已出现恶性循环.关注、研究、整治和管护寒区环境对区域社会、经济和生态可持续发展不可或缺.更多还原

【Abstract】 The Northeastern China is located on the eastern margin of the Eurasian Continent in the mid-to high-latitudes.The permafrost in the Da and Xiao Xing’anling Mountains lies at the southernmost parts of the Eurasian latitudinal permafrost zone.The permafrost region in Northeastern China has been the very area in China,or even in the world,most severely impacted by climate warming and anthropogenic activities.During the last four decades,permafrost has been in rapid degradation as evidenced by: 1) Northward shifts of the southern limit of permafrost and the boundaries of discontinuous permafrost zones,and resultant shrinkage of the areal extents of permafrost and fragmentation in the spatial distribution of permafrost;2) The deepening active layer,and expanding taliks,and disappearing patches of permafrost,and;3) Rising ground temperatures,thinning permafrost,and destabilizing thermal regimes.Due to the combined impacts of climate change and increasing intensity of human activities,cold regions ecological environments have changed noticeably.These changes include sharp reduction in areal extent of the naturally grown forests dominated by Larix gemillnii and northward shifts of the boreal forest belts,and the shrinkage of wetlands.A vicious circle of permafrost degradation and deteriorating cold regions ecological environments has been formed.Urgent attention,adequate research,practical mitigation and prudent management/protection of cold regions environments are deemed indispensable for regional socio-economical and ecological sustainable development.更多还原