摘要
基于2000—2008年的MODIS影像,通过归一化植被指数(NDVI)像元二分模型对退耕还林(草)、水土流失综合治理等生态恢复措施驱动下陕北黄土高原生态脆弱区的植被覆盖度进行了动态评估.结果表明:2000—2008年,陕北地区植被覆盖度年内呈波动趋势,3月的植被覆盖度最差,8月最好;植被覆盖度空间分布的总体趋势是从西北向东南逐渐增加;年最大植被覆盖度在研究期间表现为明显增加;植被覆盖度组成中,低等植被覆盖度面积减少,中等植被覆盖度面积增加;植被覆盖度增加地区的面积占全区一半以上,以研究区东北部尤为明显.研究区植被覆盖度的显著增加是气候和人为因素综合作用的结果,一定程度上反映了生态恢复重建措施的有效性.像元二分模型可以准确模拟区域尺度上植被覆盖度的时空变化趋势,在区域植被恢复效果定量监测与评估方面具有适用性.
Based on the 2000-2008 MODIS-NDVI images and using dimidiate pixel model,a dynamic evaluation was made on the vegetation coverage in northern Shaanxi Province,one of the ecologically fragile area in China,under the backgrounds of returning farmland to forestland and grassland and of the integrated management of soil and water loss.In 2000-2008,the vegetation coverage in the study area fluctuated within a year,being the highest in August and the lowest in March,and showed an increasing trend from the northwest to the southeast.The annual maximum vegetation coverage had a pronounced increase,but the area of medium and high coverage increased while that of low coverage decreased.The increased area of vegetation coverage occupied more than half of the study area,especially in the northeast.Climate features and human activities were the main causes inducing the pronounced increase of vegetation coverage,reflecting to a certain extent the effectiveness of ecological restoration efforts.The dimidiate pixel model based on the MODIS-NDVI images could well and truly simulate the spatiotemporal variation trend of the vegetation cover in northern Shaanxi,and be applicable to quantitatively estimate and evaluate the effectiveness of vegetation restoration at regional scale.
出处
《应用生态学报》
CAS
CSCD
北大核心
2010年第8期2109-2116,共8页
Chinese Journal of Applied Ecology
基金
国家重点基础研究发展计划项目(2009CB421104)
国家科技支撑计划项目(2006BAD09B10)
国家自然科学基金项目(40871085)资助
关键词
植被覆盖度
像元二分模型
时空变化
遥感
生态恢复
陕北
vegetation coverage
dimidiate pixel model
spatiotemporal variation
remote sensing
ecological restoration
northern Shaanxi Province.
