科尔泌地区流动沙地景观破碎化与沙漠化过程分析

借助RS和GIS技术提取了科尔泌沙地典型地区不同时期流动沙丘的空间分布信息,通过对景观数量和形状破碎化指数的计算分析,探讨了科尔泌沙地的主景观要素流动沙丘在时间尺度上的变化趋势和及其对沙漠化过程的响应．结果表明:流动沙丘景观数量破碎化在时间尺度上的变化趋势呈波动下降趋势,其中 1974年在破碎化程度最高,1958年和1998年相对最低,这一变化趋势与同期的沙漠化过程呈线性正相关．流动沙丘景观形状破碎化指数在时间尺度上的变化呈直线型逐渐增加的趋势,表明科尔泌沙地近40年来的各种土地利用过程的变化对流动沙丘斑块形状的影响都起促进作用．从形状破碎化与沙漠化的相互关系来看,随沙漠化程度的增加将导致形状破碎化指数的降低．总的来看,在科尔泌沙地景观中,干扰过程的交替使流动沙丘景观数量破碎化指数呈下降趋势,使形状破碎化的程度呈增加的趋势．

Analysis of the Landscape Fragmentation of Mobile Dune and the Desertification Process in Horqin Sandy Land Region

In this paper, by means of RS and GIS from the typical area in Korqin Sandy Land, the spatial distribution information of mobile dunes were obtained to analyze the changing trends of landscape fragmentation of the mobile dunes and to discuss the relationships between the fragmentation and desertification process by using the number and shape of fragmentation indices. The results showed that the number fragmentation index decreased from 1958 to 1998 period, and the maximum fragmentation index occurred in 1974 and relative minimum fragmentation indices emerged in 1958 and 1998 during past four decades. There was a significant positive lineal relation between the numbers of fragmentation and the desertification process. In addition, findings also illustrated that fragmentation index assumed straight lineal shape changing at same temporal scale, which indicated that different land use processes promoted the shape change of mobile dune in recent decades. The regression outputs showed that the shape fragmentation decreased with the increase of desertification degree. In a word, the alternate disturbances that destroyed vegetation or rehabilitated vegetation by human activity brought about the decrease of the number fragmentation indices and the increase of shape fragmentation index of the mobile dune landscape in Horqin sandy land.