Fig. 3From: Understanding livestock production and sustainability of grassland ecosystems in the Asian Dryland BeltThe changes in forage proxies (or total amount of green biomass) during 1981–2013 based on Advanced Very High Resolution Radiometer (AVHRR) satellites. a is the trend of mean NDVI (Normalized Difference Vegetation Index), which may indicate forage, whereas b is the change in maximum NDVI over timeBack to article page