绿洲景观格局动态及其梯度分析的遥感研究

以张掖绿洲为例,利用遥感与GIS技术提取了从1987年到2002年间张掖绿洲的景观格局动态变化信息,并使用FRAGSTAS移动窗技术获取了所选景观指数的梯度变化分布图。通过分析张掖绿洲内各景观类型的时空演变及景观指数的梯度差异,研究发现荒漠绿洲过渡带、人工防护林带、河流及灌溉渠系等廊道景观是景观指数梯度变化中的峰值或谷值所在,对绿洲生态安全格局起到了关键性的控制作用。利用廊道景观的空间特性和景观结构的梯度概念,本文对张掖绿洲景观生态安全状况进行了分析与评价,并验证了景观梯度理论与遥感技术相结合在绿洲植被景观格局动态及其生态安全分析中的适用性。

A Study on Dynamics of Oasis Landscape Pattern and its Gradient Analysis by Using Remote Sensing Techniques

The dynamic information was extracted from the landscape patterns of the Zhangye Oasis, as a case study, by means of remote sensing and GIS techniques. Thereafter, the gradient changes maps were acquired immediately with the FRAGSTATS moving-window technique. It was found from the spatio-temporal changes of the landscape structure and the gradient difference of landscape metrics that the ecological security pattern of the Zhangye Oasis had dominated by corridor landscapes, mainly including the transitional zone between oasis and desert, the man-made shelter belt and the irrigation channel network. These oasis corridor systems demonstrated the peak and valley values of the gradient changes of the oasis landscape pattern, and also controlled the key patterns of oasis ecological security. Therefore, the spatial characteristic of the corridor landscape and the concept of landscape gradient had been employed to analyze and evaluate the ecological security status of the Zhangye Oasis and also validate the applicability of integrating the theory and methodology of landscape gradient with remote sensing techniques on the landscape dynamic and ecological security of the Zhangye Oasis.