山西省不同地貌形态类型区土地覆被变化的GIS分析

基于全国1:100万数字地貌数据库,全国2000、2005、2010年土地覆被数据和山西省行政区边界数据,采用土地覆被动态度、转移概率矩阵和地貌面积频度方法,分析了2000-2010年山西省基本地貌形态类型下的土地覆被变化。结果表明：（1）山西省的土地覆被类型以耕地、林地和草地为主,面积总和占省域面积的95%以上。面积变化的总体趋势是耕地和草地缩减,林地和建设用地持续增加。通过分析转移概率矩阵,表明2000-2005年和2005-2010年2个时段内,土地利用的主要转化趋势相似,即林地与草地之间大面积的相互转化,耕地、草地分别与建设用地之间的相互转化。（2）耕地和建设用地的分布,随着起伏度的增大而逐渐减小。林地分布随着起伏度的增加而逐步增大。从面积变化来看,耕地、林地和草地变化主要位于中起伏山地;水域变化主要集中在大起伏山地;建设用地变化主要分布于平原和台地;未利用地变化主要在小起伏山地。从动态度来看,耕地、草地和水域动态度,在大起伏山地地区最大;林地动态度在平原区最大;建设用地的动态度最大位于丘陵;未利用地在小起伏山地地区最大。（3）土地覆被类型之间的主要转化在地貌上也存着差异。平原地区林地的增加主要来自草地转化。台地和丘陵地区3个主要转化类型相似,2000-2005年主要是林地向草地退化,2005-2010年主要是林地和草地的相互转化。在小起伏山地地区,主要是草地和林地之间的相互转化,但草地转化为林地的面积较林地向草地的转化多。中起伏和大起伏山地地区主要以草地和耕地向林地的转化为主,也有较高比例的建设用地转化为林地。封山育林和退耕还林主要是在起伏较大的山地地区,毁林主要发生在地形平缓地区。

Analysis of Land Cover Change on Basic Geomorphic Types in Shanxi Province

Based on the land cover data in 2000, 2005 and 2010, we used the Shanxi Province administrative boundary and the digital geomorphic database of China at a scale of 1:1 000 000, the methods of the dynamic degree analysis, the transformation probability matrix and the frequency distribution of area in different land cover types to analyze the land cover dynamic change from 2000 to 2010 on basic geomorphic types in Shanxi Province. The results were indicated as follows: (1) The main types of land cover were arable land, woodland and grassland, which accounted for over 95% of the area in Shanxi Province. The woodland and construction land revealed an increasing tendency; however, the arable land and grassland indicatd the opposite tendency. The primary change tendency of land cover types was similar for the two periods of 2000-2005 and 2005-2010, which were resulting from the mutual transformation between woodland and grassland, arable land and construction land, as well as grassland and construction land. (2) The percentages of arable land and construction land gradually reduced with the increase of relief amplitude. Inversely, the percentage of woodland increased as the relief amplitude increased. In terms of the area change, the main changes of arable land, woodland and grassland occurred in the medium relief mountains; change of water area mainly occurred in high relief mountains; change of construction land area mainly occurred in plains and tablelands; and change of unused land area primarily occurred in small relief mountains. In the view of dynamic degree, arable land, grassland and water area exhibited the greatest changes in high relief mountains. And the most evident changes of woodland, construction land and unused land occurred in plains, hills and small relief mountains respectively. (3) The major transformations between land cover types were different with respect to basic geomorphic types. In the plains, the main occurrence was that the grassland evolved into woodland. The major transformations of tablelands were similar to that of the hills. Between 2000 and 2005, woodland was mainly degraded to grassland, while between 2005 and 2010, there was a mutual transition between grassland and woodland. In the small relief mountains, the dominating change trend was the mutual transition between grassland and woodland. However, the proportion of the grassland converted into woodland was much higher than that from the woodland into grassland. While in the medium relief and high relief mountains, the main transitions were that other land cover types transformed into woodland. It can be noted that the National Grain for Green Project and Afforestation Policy mainly occurred in the mountain area, while deforestation occurred in the gentle relief area.