基于地形梯度的淇河流域土地利用时空变异分析

Analysis of spatial-temporal variability of land use with terrain gradient in Qi River Basin

地形作为最基本的自然地理要素,在一定程度上影响着土地利用变化,对土地利用空间格局的形成具有重要影响。以太行山淇河流域为例,借助DEM提取高程、坡度信息,采用转移矩阵、区域统计分析和地形分布指数系统分析淇河流域1990—2015年间土地利用时空变异特征,定量分析了地形梯度上土地利用变化。结果表明:25年来变化最大的土地利用类型为耕地和草地,耕地面积净减少量最大,林地次之;草地面积净增加最多,建设用地面积净增加次之,未利用地面积变化不大。耕地、建设用地、草地生态系统集中于低地形梯度区,而林地集中于高地形梯度区;耕地、林地在低海拔区域面积呈减少趋势,水域和建设用地增加集中在低海拔地区;耕地在低坡度区域内呈现减少趋势,建设用地在低坡度地区增加集中。

As the most basic natural geographical factor, topography affects land use change to a certain extent and has an important impact on the formation of spatial pattern of land use. Taking the Qi River Basin in Taihang Mountain as an example, DEM was used to extract elevation and slope information, and the transfer matrix, regional statistical analysis and terrain distribution index system were used to analyze the temporal and spatial variability of land use in the Qi River Basin from 1990 to 2015, and the land use status on the topographic gradient is quantitatively analyzed. The results showed that the largest change in the past 25 years was cultivated land and grassland. The largest net reduction of area occured in the cultivated land, followed by the forest land. However, the grassland showed the greatest increase of area, followed by the construction land. The area of unused land did not changed obviously. Cultivated land, construction land and grassland ecosystems were concentrated in the low-terrain gradient region, but forest land was concentrated in the high-terrain gradient region. Cultivated land and forest land were decreased in the low-altitude region, whereas water area and construction land were increased in the low-altitude region. Cultivated land was decreased in the low slope region, and construction land was increased centrally in the low-slope region.