绿洲景观若干理论问题的探讨

APPROACH TO SOME THEORETICAL PROBLEMS ON OASIS LANDSCAPE

本文应用近年来日益活跃的景观生态学研究成果．对绿洲的概念、基本特征、分布、景观类型、景观命名等理论问题进行了探讨．

Oasis is one kind of the landscapes in small or medium scale. It has a relatively high primary productive forces, is formed under dry climate and is accompained by desert. It relies on surface runoff develops in two orientations and different stages, and has the azonal vegetation. In China, oases distribute from Helan Mountain and Usaoling Mountain westward including Junggar Basin, Tarim Basin, Caidam Basin, Hexi corridor and Alashan Plateau. Finally, an oasis classification system is presented according to the fol1owing four different hierarchy critcrions: Firstly, oasis 1andscapes can be divided into temperate zone oases and tropical or subtropical oases. Secondly, it can be divided into natural oases, artificial oases and potential oases according to the human disturbance. Because the vegetation is the most remarkable surface indicator, it can be taken as the third criterion. Natural oases here include four types: desert-riverbank forest oases, swamp meadow oases, saline meadow oases and flood meadow oases. Artifidal oases and potenhal oases have agricultural vegetation and desert vegetahon seperately. Fourth, oasis landscape can be divided according to their landforms. Because landforms is revea1ed by the natural vegetation in some degrees in natural oases, the artificial oases and potential oases can be dishnguished easily. The results are consisted of sit types: valley oases, dried delta oases, a1luvial fan oases, alluvial plain oascs, lakeside delta oases and riverbank oases.