山区景观镶嵌体的数量特征分析与分形结构模型——以兰州山区西固区为例

Quantity Character Analysis and Fractal Model Study on the Mosaic Structure of the Landscape in a Mountaionous Area——A Case Study in Xigu District of Lanzhou City

利用RS与GIS相结合的技术和景观生态学方法研究了作为西北干旱城乡结合部的兰州市西固区在不同地貌形态上景观镶嵌体的数量特征变化特点。结果显示 :随着海拔高度的增加 ,景观镶嵌体的多样性指数和破碎度先增加后减小 ,优势度先减小后增加 ,海拔越高变化率越大 ;利用效率高的景观类型在河谷川区集中度高 ,在高海拔地区利用程度低的类型分离度指数小。应用分形结构模型模拟结果显示 :人类影响较小的自然景观类型的复杂性远高于人工景观类型 ,而稳定性后者高于前者 ;在川区自然景观的复杂性较大 ,而在高海拔的山区人工景观的复杂性较大。由此得出以下结论 :(1)山区景观镶嵌体系统是一个多因子共同作用下的复合生态系统 ;(2 )在低海拔地区景观镶嵌体结构主要受人类活动的影响为主 ,高海拔地区主要受自然———垂直地带性影响为主 ;(3)人类活动通过其复杂的内部机制影响着景观镶嵌体的稳定性 。

Based on RS?&?GIS technique and landscape ecology methods,the mountaionous landscape at different physignomy areas in Xigu district of Lanzhou city was analyzed by changing of quantity character,the result shows that the landscape diversity and the landscape fragmentation increase at first,then reduce along with increasing of altitude,but the landscape dominance is reverse,the landscapes which are used sufficiently have bigger landscape convergence in valley-basin,but the condition is reverse in mountaionous area.The simulative result by fractal model shows that the nature landscapes influenced lower by humankind have more complexity than man-power landscapes,the stability is reverse,the complexity of human landscapes is greater in mountainous area than in valley-basin,the complexity of nature landscapes in valley-basin is greater than man-power landscapes.So we can conclude that:(1)the mosaic structure of the landscape of a mountainous area is a compound ecosystem effected by lots of factors together;(2)the mosaic structure of the landscape at low altitude has been influenced mainly by human being activities,at high altitude it has been influenced mainly by natureal factors;(3)human being have influenced nature ecosystem by changing stability of the mosaic structure of the landscape.