Symbiosis of Marshes and Permafrost in Da and Xiao Hinggan Mountains in Northeastern China

摘要

Recently, the degradation of permafrost and marsh environments in the Da and Xiao Hinggan Mountainshas become a great concern as more human activities and pronounced climate warming were observed during the past30 years and projected for the near future. The distribution patterns and development mechanisms of the permafrostand marshes have been examined both in theories and in field observations, in order to better understand the symbiosisof permafrost and marshes. The permafrost and marshes in the Da and Xiao Hinggan Mountains display discerniblezonations in latitude and elevation. The marsh vegetation canopy, litter and peat soil have good thermal insulationproperties for the underlying permafrost, resulting in a thermal offset of 3℃ to 4℃ and subsequently suppressing soiltemperature, In addition, the much higher thermal conductivity of frozen and ice-rich peat in the active layer is condu-cive to the development or in favor of the protection of permafrost due to the semi-conductor properties of the soilsoverlying the permafrost. On the other hand, because permafrost is almost impervious, the osmosis of water in marshsoils can be effectively reduced, timely providing water supplies for helophytes growth or germination in spring. In theDa and Xiao Hinggan Mountains, the permafrost degradation has been accelerating due to the marked climate warming,ever increasing human activities, and the resultant eco-environmental changes. Since the permafrost and marsh envi-ronments are symbiotic and interdependent, they need to be managed or protected in a well-coordinated and integratedway.