呼伦贝尔盟草原植被覆盖状况时空演变特征分析

以呼伦贝尔盟草原为研究对象,基于1998～2008年4～10月的SPOT_VGT数据、2000年土地利用数据,利用时间序列植被指数(NDVI)动态变化监测方法,分析了研究区植被覆盖的时空演变特征。结果表明:1998至2008年期间,呼伦贝尔盟草原以草地为主的地区、草地-耕地过渡区、草地-林地过渡区的草地覆盖状况呈现先减后增趋势,但草地-耕地、草地-林地过渡区的林地覆盖状况变化不大,研究区2008年植被覆盖要小于1998年;同时,低植被覆盖区域面积不断扩大。说明研究区存在大范围、严重的退化现象,尤以西部的新巴尔虎右旗、新巴尔虎左旗最为严重,研究区沙化面积增大,生态系统恶化,生态系统脆弱性更加突出。

Analysis of dynamic change of Hulunbeier grassland vegetation coverage

Taking Hulunbeier grassland as research object,we characterized the dynamic change of the study area,making use of time series NDVI method based on SPOT_VGT from April to October during 1998 ～ 2008. The results showed that grassland coverage of grassland area,grassland - farmland ecotone,grassland - woodland ecotone in Hulunbeier decreased firstly and then increased from 1998 to 2008 while woodland coverage changed slightly in grass - farmland and grass - woodland ecotone. The study area's vegetation coverage in 2008 was less than that in 1998 and low vegetation coverage area was extending to high coverage. These implied that grassland of study area degenerated widely and seriously,especially in Xinbaerhuzuoqi and Xinbaerhuyouqi. Besides,desertified area increased,ecosystem degraded and became more fragile.