科尔沁沙地不同尺度上沙丘景观格局动态变化分析

Changes on Landscape Pattern of Sand Dunes at Different Scales in Horqin Sandy Land

研究了科尔沁沙地过去30 a不同尺度上沙丘景观格局及其动态变化。结果表明,大尺度研究区(892.74km2)从1975—1995年流动沙丘面积、斑块数、景观面积百分比和最大斑块指数逐渐增加;1995—2005年流动和半流动沙丘面积减小,半固定沙丘和固定沙丘面积增加。中尺度(110.42 km2)和小尺度(14.14 km2和14.10 km2)研究区从1975—1985年流动沙丘面积、斑块数增加,1985年后流沙面积减小。通过沙漠化过程指数计算表明,大尺度上沙漠化经历了发展(1975—1995年)—逆转(1995—2005年)的过程,中尺度和小尺度上,沙漠化经历了发展(1975—1985年)—逆转(1985—2005年)的过程。科尔沁沙地不同尺度上景观结构变化具有差异性,显示出景观空间格局变化存在尺度效应;景观格局变化主要受流动沙丘斑块变化的影响,而这一变化的主要原因是人类生产活动引起的。

The present study provides an analysis on landscape pattern changes of sand dunes at different scales in Horqin Sandy Land. The resulted showed that the areas, patch numbers, landscape area percent and largest patch index of mobile dune at larger scale （892.74 km^2） increased gradually from 1975 to 1995, but the areas of mobile dune and semi-mobile dune decreased after 1995. The areas and patch numbers of mobile dune at medium （110.42 km^2） and small scales （14. 14 km^2 or 14.10km^2） increased from 1975 to 1985, but they decreased after 1985. The analysis of the index and value of desertification process indicated that the desertified lands at larger scale are in the development process of desertification from 1975 to 1995 and are in the reversion process after 1995, and the desertified lands at medium and small scales, are in the development process of desertification from 1975 to 1985 and are in the reversion process after 1985. The study scales had an important effect on the changes of spatial landscape pattern in the sandy land. The changes of landscape pattern of Horqin Sandy Land are determined mainly by the changes of numbers and areas of mobile dunes resulted from the unsuitable human activities.