Temporal variations on NDVI predict temporal changes in vegetation cover across Patagonian drylands (Argentina)

Abstract

Temporal variations on NDVI predict temporal changes in vegetation cover across Patagonian drylands (Argentina). In drylands, natural vegetation is an important source of livelihood as they provide food, fuel and forage for livestock. In addition to the provision of goods and services, dryland vegetation also plays an important role in many ecological processes, such as recycling nutrients or protecting the soil from erosion. Long-term monitoring of vegetation cover is therefore key for decision-making and management of these regions. In this study, we analyze the variation of vegetation cover in 239 sites of a long-term monitoring network (MARAS network), in one of the largest dryland biomes in the world: the argentine patagonian steppe. Then we relate it to the variation of different periods of the Normalized Difference Vegetation Index (NDVI), obtained from the MODIS sensor, which serve as a predictor variable. The adjusted empirical model explained up to 40% of the variation in the vegetation cover measured in the field. With this simple empirical model we have estimated and mapped temporal changes in the vegetation cover of a large dryland biome at low cost.