论冰缘寒区景观生态与景观演变过程的基本特征

冰缘区复杂多样的地域环境和分异显著的生物带谱特征，形成了高寒环境条件下特有的景观生态格局和结构。景观异质镶嵌具有三向性带谱规律，并表现出不同方向上景观过渡的渐变和突变差异，在空间上形成４种基本景观结构类型。景观嵌块以环境和干扰类型为主，景观结构简单、粗粒化。景观格局变化速度快、范围大，气候条件变化、各类冰缘作用尤其是冻土冻融条件的改变。是景观生态过程的驱动力，形成特有的冻融生态过程。

The Features of Landscape Ecology and the Landscape Ecological Process in High-Asia Periglacial Regions

In the periglacial regions, owing to the varied spatial environment and biological type zones the special landscape structure and pattern is formed under the high-cold environment. With the law of three orientation type zones, landscape heterogeneity exhibits gradual change and sudden change in landscape types at different orientation. In the Tibetan plateau. the landscape varies in space as the following model from southeast to northwest: forest -high -cold bush -high -cold meadow- high-cold steppe -high-cold desert. Besides the horizontal variation of landscape. the vertical variation of landsca pe is also marked with the following model : the high-cold steppe (or high-cold meadow, desert) high-cold bush (or high-cold steppe) hig mountain meadowglacier-snow, bore rock. The forest matrix with high-cold bush and meadow mosaics, high-cold meadow matrix with high-cold bush. cold-warm forest and bare rock patches and river corridor mosaics, high-cold steppe matrix with high-cold meadow, swamp, lakes, bare rock and desert patches and river corridor mosaics, high-cold desert matrix with high-cold steppe, meadow, desert and bare rock patches are the four main types of landscape. There are mainly environmental patch and disturbance patches as land scape mosaics, with simple landscape structure and coarse grain. The landscape pattern change is fast in time and large in space. Climate change. all types of periglacial activities, specially the change of freeze - thaw condition of frozen soil are the main driving forces of landscape ecological processes, forming a special freeze-thaw ecological process. It is important to understand the landscape ecology on the periglacial regions for protection and improvement of the ecological environment.