植被覆盖动态变化是土地资源和环境变化研究的重要内容。本文基于长时间序列的SPOT/NDVI数据,通过研究乌江流域植被覆盖变化的总体特征、空间格局的变化趋势和程度、不同植被覆盖与NDVI的相互关系,分析了乌江流域1998-2006年期间的植被覆盖动态变化。研究结果显示:(1)乌江流域植被覆盖在近10 a内总体呈现改善和增加的趋势,年均增长率约为0.009/a,特别是流域的西南地区(水城县东北部、六枝特区北部和普定县)植被覆盖增长趋势和增加程度都特别显著,仅局部区域(东北部地区、遵义市和贵阳市周边地区)的植被覆盖呈退化和减少趋势;(2)乌江流域的森林和灌木林地植被覆盖较为稳定,而草地和耕地的植被覆盖生长却相对差异较大。上述结论为乌江流域土地资源管理和生态修复提供了参考依据。
Monitoring and assessing vegetative land cover change is important to resources management and environmental change study.This paper,using the 1 km SPOT Normalized Difference Vegetation Index(SPOT/NDVI)(1998-2006) data in growing seasons(April-September),assessed the vegetative land cover change in Wujiang River Basin(WRB),Southwest China from 1998 to 2006.The final results demonstrate that vegetative land cover show slight trend of amelioration in general during the past years,while in some areas(Guiyang,Zunyi) vegetative land cover degrade or decrease because of over grazing/farming or urbanization.Cropland and grassland are also found easily degraded than forest and shrubs in this area.All these finding may serve as a strong basis for decision making in regard to land resource management and environmental rehabilitation.