滇池流域土地利用格局变化的地形梯度效应

目的]分析滇池流域的土地利用变化的总趋势和地形梯度格局及影响因素,为土地利用模式的优化配置和土地资源的可持续发展提供依据。方法]采用土地利用幅度和动态度分析了土地利用变化的总趋势,从地形因子(地形起伏度、坡度、坡向、地形位)角度用地形分布指数法分析了土地利用的地形梯度格局,用定性分析法分析了地形梯度效应的影响因素。结果](1)2000—2014年研究区土地利用类型以耕地、林地、草地和建设用地为主,建设用地增速最快,草地减速最快。(2)土地利用在不同地形梯度上有明显的层次分布格局和变化趋势。随着地形梯度的升高,水域、耕地和建设用地、草地和未利用地、林地的优势分布区逐渐升高,分别在最低、低和中低、中低、中高和高地形梯度上占绝对优势;水域、耕地和建设用地(除后两者最低一级梯度)分布指数随之减少,草地和未利用地分布指数变化不明显,林地分布指数则不断增加。(3)土地利用格局变化的地形梯度效应受基础的地形因素、起推动的社会经济因素和宏观调控的政策因素的共同影响。结论]滇池流域土地利用地形梯度格局变化明显,并受地形、社会经济和政策因素共同影响。

Terrain Gradient Effect of Land Use Pattern Change in Dianchi Watershed

Objective] General trend and terrain gradient distribution pattern and the influence factors of land use change in Dianchi watershed were analyzed to provide the optimal allocation of land use pattern and the reference for the sustainable development of land resources.Methods] We used range and dynamic degree of land use to analyze the general trend of land use change. The terrain distribution index method with respect to the terrain factors(landform relief, slope, aspect, terrain niche) was analyzed. Influence factors of the terrain gradient effect were analyzed by qualitative analysis method.Results] (1) The main land use types of the study region from 2000 to 2014 were cultivated land, forest land, grassland and construction land, among which, grassland had obviously decreased and construction land obviously increased. (2) The pattern of land use type in different terrain gradient has obvious level distribution and change trend. With the increase of topographic gradient, the proportional coverage by water area, cultivated land and construction land, grassland and unused land, woodland gradually increased. These land use types preponderated at lowest, low and mid-low, mid-low, mid-high and high terrain gradients, respectively. With the increase of topographic gradient, the distribution index of water area, cultivated land and construction land(except the lowest level gradient of cultivated land and construction) declined, the distribution index of grassland and unused land didn not change obviously, the distribution index of forest distribution increased. (3) Terrain gradient effect of land use pattern change is mutually influenced by basic terrain factors, promoted social and economic factors and control policy factors of macroeconomic regulation.Conclusion] The terrain gradient distribution pattern of land use in Dianchi watershed changed distinctly and was affected by terrain, social economy and policy.