高台绿洲边界变化及其生态系统分析

The Analyses of the Changes in Gaotai Oasis Boundary and its Ecosystem

绿洲是干旱区人民赖以生存的一片沃野。由于人类的强度作用，绿洲向复杂方向演变发展。本文以高台绿洲为例，以地下水位为指标确定了绿洲边界范围，进而研究了绿洲从１９５８年至１９８５年边界的变化，并分析高台绿洲农田和草地生态系统功能，指出草地生态系统的恶化是绿洲边界变化的重要原因，应当加强对草地的投入与管理。

asis is a fertile land on which people in arid zone have to rely. Because of human excessive utilization of resources,oasis is changing in complex direction. In this paper ,the author pays attention to its boundary and thinks of that the boundary is the external reflection of an oasis in an inner transient balance state.Gaotai Oasis lies in Hexi Corridor,an arid zone in our country, which has something in common with oases. Based on the research result which ground water is linear to vegetation in oasis,the auther chooses 4. 5-5.0m as an index of ground water, which defines boundary of oasis and in further, draws the map of the change in oasis boundary from 1958-1985. The map shows an important feature that changes happen in grassland, not in farmland, small oases disappeared, but big oases were connected into a bigger one.Obviously, it is necessary to analysize the function of Gaotai oasis ecosystem. By studying matter and energy flow balance in both farmland and grassland ecosystem, the author finds that grassland ecosystem is weak very much, which causes constant changes in oasis boundary,while farmland is still stable, but in low efficiency. Based on this study,the author puts forward some thoughts as follows:(1)Make full use of solar energy so as to relax the tention to grassland.(2)Strengthen management of grassland.(3)Develope oasis ecoagriculture and readjust the industrial struture.