Evaluating Interannual Vegetation Change in Songnen Plain from SPOT/VEGETATION Imagery

The temporal evolution of decadal NDVI composition is regarded as an effective time window which is able to show the natural seasonal variations. In this study, a time series of SPOT-VEGETATION Normalized Difference Vegetation Index (NDVI) data with 1×1 km² spatial resolution are used to detect the vegetation cover change in west Songnen plain, Northeast China during the period of 1998 to 2006. Our findings suggest that the yearly average Maximum Value Composite NDVI (MNDVI) over the study area decreased from 0.41 in 1998 to 0.39 in 2006, and the annual average NDVI value dropped by 0.015, which indicated the decreasing trend of vegetation activity. The degraded regions occupied 57.33% of the study area. Results can provide valuable information for environmental management policies involving biodiversity preservation and rational exploitation of natural and agricultural resources in this vulnerable ecotone.