基于地形梯度的纯喀斯特和非喀斯特及亚喀斯特区土地利用格局分析

Analysis of Land Use Patterns in Pure Karst, Non-karst and Subkarst Areas Based on Terrain Gradient

以黔中地区为研究区,利用地形位指数和分布指数,探究其纯喀斯特、亚喀斯特及非喀斯特地貌类型区土地利用的地形梯度空间分布特征。结果表明:(1)研究区土地利用类型整体上有相似的地形梯度特征,农村居民点、水田、园地、道路、基础设施用地、城镇建设用地、水浇地和水域等在1~3地形梯度优势分布显著,有林地、灌木和草地及未利用地在7~10地形位有分布优势,而旱地的优势分布主要集中于低和一般地形位。(2)不同地貌类型区相同景观类型地形梯度特征差异显著,非喀区有林地地形分布范围最广(地形位5~9范围)、纯喀区次之(4~8),亚喀区较窄(4~7);草地在纯喀区和非喀区均分布于地形位5~10范围,亚喀区最差(4~9);纯喀区水田对地形选择性最强(1~3),亚喀和非喀区选择性较弱(1~4);农村居民点在纯喀与非喀区均为单调递减趋势,而亚喀区则是呈先增后减;旱地和未利用地在非喀区的优势分布变化速率低于亚喀区,更远低于纯喀区,而水域却恰恰与之相反。不同喀斯特地貌区相同土地利用类型在优势分布范围和变化趋势及速率上有差异,土地利用具有显著的地形梯度特征。

To explore the spatial distribution characteristics of topographic gradient of land use in pure karst, semi-karst and non-karst, Qianzhong area was taken as the research area, and opographic position index and distribution index were used. The results show that:(1) the land use types in the research area have similar topographical gradient characteristics on the whole;rural residential areas, paddy fields, gardens, roads, infrastructure land, urban construction land, irrigated land and water areas are in 1~3 terrain gradients;the distribution of advantages is significant, with woodland, shrubs and grassland and unused land having distribution advantages in topographical positions 7~10, while the distribution of advantages in dry land mainly concentrates in low and general topographical positions;(2) there are significant differences in topographic gradient characteristics of the same landscape type in different landform types;the non-karst area has the widest distribution of woodland topography(topography range 5~9), followed by the pure karst area(topography range 4~8), and the semi-karst area is more narrow(topography range 4~7);grassland distributes in the topography range of 5~10 in both pure karst and non-karst, semi-karst is the worst(topography range 4~9);pure karst paddy field has the strongest topography selectivity(topography range 1~3), the selectivity of the subkarst and non-karst areas is weak(topography range 1~4);the rural settlements in pure karst and non-karst areas are monotonously decreasing, while in the semi-karst areas, they increase first and then decrease;the rate of change of the dominant distribution of dry land and unused land in the non-karst area is lower than that in semi-karst area, and much lower than that in the pure karst area, while the water area is just the opposite. The different karst landforms with the same land use types have differences in the dominant distribution range, change trend and rate, and land use has significant topographic gradient characteristics.