基于RS和GIS的嫩江下游土地沙漠化景观格局变化特征分析

RS-and-GIS-Based Analysis of Variation of Landscape of Land Desertification in the Lower Reaches of Nenjiang River

以2004、2008年的MODIS数据为主要数据源,在ArcGIS 9.0、ERDAS IMAGE 9.0等软件支持下,利用FRAGSTATS软件分析土地沙漠化的景观格局变化。结果表明,研究区域沙漠化土地以轻度和中度沙漠化土地为主;各景观要素的边缘密度和斑块密度呈现一致性的减少,表明斑块形状趋向简单,景观整体破碎化程度降低,边缘效应影响减小;除水域景观外,其他景观要素的形状指数和分维数都呈现一致性的下降,表明整体景观的形状都向着简单化和稳定性方向发展,各景观要素的散布与并列指数和聚集度指数都呈现一致性的增加,反映出各要素斑块趋向大型化发展,景观整体连接度增强,破碎化程度降低,景观相互作用和空间关系增强。

Based on the MODIS data of 2004 and 2008, variation of the landscape of land desertification in the lower reaches of Nenjiang River was explored with the aid of ArcGIS 9.0, ERDAS IMAGE 9. 0, and FRAGSTATS. Results show that the desertified land in the studied area was dominated with light and moderate desertification. The edge density and patch density of various landscape elements decreased coincidentally, showing that patches were getting to be simpler in shape, the fragmentation degree of the landscape as a whole lowered and edge effect declined. Of all the landscape elements, except for water landscape, the shape index and the fractal dimension index both dropped, suggesting that the landscape as a whole developed towards simplicity and stability in shape. The interspersion juxtaposition index （IJI） and aggregation index （AI） of all the landscape elements showed a uniform rising trend, demonstrating that patches of the elements were turning to be larger, overall connectivity of the landscape higher, fragmentation degree lower, and interaction and spatial relationship of the landscapes have been strengthened.