三工河流域绿洲景观格局的定量分析

Quantitative Analysis of Landscape Pattern of Oasis in Sangong River Basin

荒漠绿洲景观格局是不同类型、不同大小、不同形状和不同开发程度的地块 (生态系统 )在空间上构成的镶嵌体。景观镶嵌结构的差异反映出不同的功能 ,通过计算一些景观指数 ,对荒漠绿洲景观格局作出定量分析。人类活动强烈的景观要素或纯粹的人工景观中 ,表征复杂的景观指数往往高于人类活动较轻的景观要素 ,而表征稳定性的指数正好相反 ;处在干旱内陆荒漠中的绿洲景观 ,其抵抗外来干扰的能力低 ,恢复力弱 ,人类不合理的活动极易破坏其稳定状态 ,从而导致荒漠化发生。

Oasis is a patch which has a higher productive force of plants comparatively based on desert. Human being can live on it and be engaged in every social economy activities because of its regular water resource. The oasis ecosystem is a component of desert ecosystem and an important part which can control the structure and function of desert ecosystem, in the meantime, it also is the most susceptible part in arid land. Oasis landscape pattern has a marked change for peoples action. Taking Sangong river basin as a case, 13 kinds landscape elements were classified according to land using type, soil type and vegetable etc. to quantitative analysis the landscape pattern of oasis, and seven landscape indexes such as diversity, dominance, fragmentation, separation, even, separation and fractal indexes were calculated. Some useful conclusions were analyzed through this indexes: the formation and evolution of oasis landscape pattern was controlled by natural environmental process and human activities; the landscape elements which disturbed by man or artificial elements appeared complicated and unstable (for instance, cultivated land, residential area, reservoir etc.); natural elements has a simple and stable state frequently (for example, desert, grassland and alkali saline land); the arrange in stability of each type patch is :desert>sandy land>urban>pond>paddy field>grass land>vegetable plot>woodland>residential area>saline alkali land>wasteland>farming land>orchard.