陇东黄土高原土地覆被变化的驱动力及生态环境效应

通过G IS空间分析,揭示了黄土高原生态脆弱区土地覆被和水土流失的时空分异特征。陇东地区土地覆被动态变化表现为丘陵区耕地、林地与草地的大互换,和在塬区建设用地大量占用优质耕地、林草地等土地覆被类型,这种变化使区域生态环境系统的功能发生退化。分析发现,该区土地覆被变化的驱动力主要有:脆弱的生态环境是生态环境恶化的自然环境背景;人口压力和经济发展落后是生态环境系统安全状态恶化的社会经济背景因素;对自然资源的不合理利用是生态环境恶化的直接人为因素。

Land-cover Changes as Related to Ecological and Environmental Effects in Longdong Loess Plateau

The eco-environment was sensitive and fragile in Longdong Loess Plateau,which was closely influenced by the special natural environment of this area.GIS presented the temporal and spatial features of land-cover in Longdong.The ecoenvironmental effects caused by the land-cover changed in Longdong loess plateau were included: The cultivated-land was in exchange with the forest-land largely at the high-land;Lots of high quality cultivated-land and forest-land were occupied by construction land at the low-land such as small plain and basin;The emergence of the soil erosion was not correlated closely with the slopes of landform but the altitudes and sloping dry-land.These changes led to the deterioration of regional eco-environment system.It was found that the driving factors of land-cover changes were as the following: 1) Population pressure and underdevelopment economics were the social economic background factors.2) Excessive use and unreasonable development of the natural resources were the direct human factors.3) Fragile ecological environment was the natural environmental background factor.Therefore,it was necessary to take some measures,including ecological immigration,construction and protection to prevent the regional ecological deterioration in Longdong loess plateau.