北京山区植被动态及生态恢复的遥感监测

基于北京地区1979、1988、1999、2005和2009年5期Landsat数据，利用基于植被指数的像元线性分解模型对植被覆盖度进行反演，分析了北京山区植被覆盖的时空动态，并通过提取植被退化和修复的区域，研究了海拔、坡度和土壤类型对生态修复的影响.结果表明：1979-1988年，北京山区植被覆盖基本稳定，其后由于社会经济的快速发展，1988-2000年北京山区植被严重退化，2000年以后由于采取多种保护措施，大部分区域生态恢复效果明显，2009年平均覆盖度达到72%，比1999年增加了13%.北京山区植被覆盖变化与地理特征密切相关，土壤贫瘠和坡度较大区域在自然状态下的退化比例相对较高，且退化后不易自然恢复，而低海拔区域受人为因素的影响更大.

Remote sensing based monitoring of vegetation dynamics and ecological restoration in Beijing mountainous area

By using the Landsat images in 1979, 1988, 1999, 2005, and 2009, and the linear unmixed model at pixel scale, this paper analyzed the spatiotemporal variation of vegetation coverage in Beijing mountainous area. After detecting the areas of vegetation degradation or restoration, the impacts of elevation, slope, and soil type on vegetation restoration were studied. From 1979 to 1988, the vegetation coverage in the study area had no obvious change, but in the following 12 years, the vegetation coverage was seriously destroyed due to the fast development of social economy. Fortunately, many protective measures were taken since 2000, which improved the vegetation coverage to 72% in 2009, with an increment of 13% compared to the vegetation coverage in 1999. A significant correlation was observed between the variations of vegetation coverage and territorial features. The areas with poor soil or large slope were more easily suffered from degradation than other places, and the flat regions with low elevation were more affected by human activities.