土地利用时空变化对宁夏盐池县沙区人居环境的影响

中国北方地区的沙害严重威胁着当地的生态安全、社会经济发展和人民的生命财产安全。以地处毛乌素沙地南缘的宁夏盐池县北部风沙区为案例,研究其近20 a以来的土地沙化、建设用地、植被变化等土地利用/覆被变化的时空特征,分析了其对人居环境的影响。结果表明:土地沙化加大了该区人居环境改善的难度;路网密度增加为人们出行提供便捷;公共用地布局合理与否很大程度上影响着人居环境改善的进程及成果;植被变化特别是天然植被的变化也是影响人居环境安全不可忽视的重要因子。

The impact of land use/land cover changes on human settlements in sandylands

Sandstorm is a serious threat to the local ecology，socio-economic development，and property in China’s northern region. Clear perception of land use history and its main driving factors is crucial step to understand regional living environment，including its pattern, evolution and trends. The study was conducted in the northern sandy areas of Yanchi County，which was located on the southern edge of the Mu Us Sandyland. Spatial and temporal land use/land cover changes，such as land desertificationroad, residential land，and vegetation, were quantified from 1989－2007 using GIS and RS technology. The impact of these changes on the environment of human settlements was also analyzed. Results showed that: 1）the most serious land desertification occurred around 1995，which accounted for 16.05% of  the total area. Land desertification made the local living environment more difficult to improve. 2）road density doubled during study period, but there was a significant difference of road density in residential area varying from 2 to 6 km road buffer zones. 3) food security issues were highlightened because lots of farmland （around 49%）was developed into construction land. Overall population shifted towards northeast, but trend of green space，infrastructure construction are not well reflect this trend. Reasonable public land layout greatly influenced the process and achievements toward improving the living environment. 4）vegetation area showed a decreasing trend until 1995，followed by a significant increase； but“high coverage grassland” area continuous decreased. Vegetation change particularly changes in natural vegetation which was an important factor for a safe living environment should not be ignored. Our findings implied that there was a complex balance between land cover change and living environment. We strongly suggested the clear perception of spatial and temporal land use/land cover changes which would be helpful in guiding regional human settlement construction. ［Ch，2 fig. 3 tab. 18 ref.］