论青藏高原苔原——成因、分布与分类的研究

通过分析青藏高原形成苔原的综合因素,论证了高原边缘高山和高原本体都发育有苔原,是全球中纬度独特的大陆苔原带.在划分高山苔原与山原苔原的基础上,将山原苔原进一步划分为湿地苔原、草甸苔原、草原苔原和荒漠苔原等4类,丰富了全球苔原结构.阐明青藏高原既有区域环境的独特性,也有适应全球地带性规律的统一性,使高原自然地带的定位更为准确,也有益于高原环境垂直带理论的完善.

Discussion on the Tundra in the Tibetan Plateau

There is no scientific research about the tundra in the Tibetan Plateau. In this paper, the synthetic factors for tundra formation in the plateau were analyzed: They are: a)Low temperature mean annual temperature is 0-8℃, the warmest monthly temperature is 0～10℃, and only about 3～4 months have the mean daily temperature {>0℃}; b)Less precipitation—mean annual precipitation is about 50～600 mm; c)Permafrost developing —there is permafrost, deep and continual, in most regions of the plateau; d)Strong freezing-thawing action with prevalent and typical periglacial landforms; e)No forest. These environment factors are very similar to the tundra in Polar Regions. The distribution of tundra soil is very wide in the sources of rivers, and the soil changes into forest steppe soil and prost desert soil in northeast due to humidity change. These soils develop on the base of permafrost, where the freeze-thawing effect is most important dynamics process. The biomes have the features suitable the cold habitats, although their seeds are not the same with the polar. Therefore it is considered that the plateau belongs to a tundra region in the middle latitude continent.Based on the inside difference of environment, the tundra of the plateau was classified into two types: alpine tundra and mountain-plateau tundra. The alpine tundra is only near the top of the mountains and the mountain-plateau tundra has large area on the plateau. The main types of mountain-plateau tundra are wetland tundra, meadow tundra, steppe tundra and desert tundra. It is important to study the tundra in the Tibetan Plateau. First, the plateau, as the Third Polar of the Earth, will fully display the polar features, because the tundra is a base feature in Polar Regions. Second, the vertical zonal law will fully display in the middle latitudes. Third, the tundra diversity will be fully displayed. Furthermore, it is possible to unite the unique environment of the plateau with the general zonal law of the global, favorable to study the unique law of the plateau.The tundra in high latitude polar is a display following the horizontal zone law of natural landscape and the tundra in the plateau is a display following the vertical zone law. Thus, they have different features, with identical essence, forming the diversity of the world tundra. On the earth, all the high mountains and high plateaus, no matter what climate zone they are located in, can form tundra if their altitudes are higher than the forest line and into the permafrost zone. There is no regular tundra line.