Spatial differences in the evolution of NDVI in the high river basin of the Aragón : effects of the changes of land uses

Abstract

The vegetation cover evolution in the central Spanish Pyrenees is analysed from 1993 to 2000. The analysis has been achieved using one NDVI (Normalized Vegetation Index) temporal series obtained from NOAA-AVHRR images. A positive trend in NDVI data has been detected. However, the spatial differences in the magnitude and sign of NDVI trends are significant. An important increment of vegetation biomass is detected in most areas, particularly in those affected by field abandonment and extensive land use (shrublands and pine forests). Cultivated fields and pastures above timberline show a smaller increase in vegetation cover. The results indicate the important role of socio-economic transformations and land-use extensification in the vegetal biomass evolution.