呼伦贝尔草原植被覆盖时空动态变化监测定量方法研究

开展植被动态监测与评价,是评估生态保护措施、环境管理政策和全球变化研究的重要基础。论文以呼伦贝尔草原为例,基于1998—2008年间SPOT_VGT NDVI旬数据,通过分析生长期间的植被年均NDVI值、年NDVI最大值、年NDVI最小值、季节性动态性与物候的变化状况及其趋势,反映研究区植被覆盖空间特征,监测植被覆盖动态变化情况。结果表明:研究区植被覆盖区域特征为:以林地为主的区域草地-耕地-林地过渡区以耕地为主的区域以草地为主的区域;11 a来,研究区植被覆盖呈减弱趋势,植被覆盖最佳期提前,以林地为主的区域、草地-耕地-林地过渡区和以耕地为主的区域植被覆盖季节性动态变化较小,植被覆盖稳定性较强,而以草地为主的地区植被覆盖最小值日期推后,其季节性动态变化较大,生态环境稳定性较差。

Study on Quantitative Method of Spatial and Temporal Dynamic Monitoring of Vegetation Cover in Hulun Buir Grassland

Monitoring and assessment for vegetation cover is the foundation for evaluating protection measures, environmental management and global changes. Having taken Hulun Buir grassland for example, we used SPOT_VGT NDVI data from 1998-2008 to reflect the spatial and temporal characteristics of vegetation and its dynamic changes by analyzing average annual NDVI, annual maximum and minimum NDVI(MAX, MIN), the annual relative range RREL, and the date of maximum and minimum NDVI(DMAX, DMIN). The results showed that the relationship of different regions’ vegetation cover in the study area is as follows: main woodland region>grassland-arable land-forest transition>main farmland region>main grassland region, the study area vegetation cover was weakening, the best period vegetation cover was advancing during these years, vegetation cover of grassland-arable land-forest transition and main farmland region had less seasonal changes, vegetation cover trend to be stable, whereas, the main grassland area’s DMIN pushed back and had more seasonal changes in vegetation cover, its ecological environment becomes less stable.