榆林地区土地利用/覆被变化区域特征及其驱动机制分析

利用榆林地区1986、1995年土地利用现状图，在地理信息系统支持下建立土地利用变化转移矩阵，结合多年社会统计资料分析榆林地区10多年来的土地利用动态变化特征。研究结果表明：土地利用类型变化幅度大、流转方向较为集中，具体表现为农田总面积下降、耕地质量局部改善，林草覆盖面积增长、其它用地类型面积减少；从区域角度分析，南部黄土丘陵沟壑区耕地面积减少、成熟林地面积增加幅度大与西北部风沙区耕地面积轻微增加、天然草地优势地位增强形成鲜明对比，这种区域特征符合“因地制宜”规律，与“退耕还林还草”政策导向吻合。全区总人口及其区域分布、农民年均收入和农业人口比重为该区土地利用／覆被变化的主要驱动力，同时人们的环境保护意识和相应的土地政策也对该区土地利用／覆被变化产生较大影响。

Regional Characteristics and Driving Mechanism of Land use/Cover Change in Yulin Prefecture, Shaanxi

Based on the land-use map of Yulin prepared in 1986 and 1995, the conversion matrix of land-use change from the 1980s to the 1990s is acquired by using Geographic Information System (GIS). Then, the characteristics of land use/cover change in the corresponding period in Yulin Prefecture are further discussed with the help of statistic data. The results indicate that the range of land use/cover change was great and most land-use type went to the same direction. In detail, compared with the rapidly increasing area of woodland/grassland, the gross area of farmland and the others were decreasing, but the farmland quality in some areas was improved. On regional scale, the notable decrease of farmland and increase of woodland in the southern loess hilly region showed a striking contrast with the slightly rise of farmland and rapidly increase of grassland in the northwest sandy area, which was in accordance with the regional environmental characteristics and the land policy "returning farmland to woodland/grassland". And the main driving forces of land-use change are population growth, population ratio between peasant and citizen, and annual income of local farmers. Additionally, the land-use policy and the public awareness on environmental protection also play an important role in land use/cover change.