Primary production dynamics and climate variability: ecological consequences in semiarid Chile

摘要: Increase in rainfall variability has important consequences for organisms arid and semiarid regions around the world. In South American Australian deserts, El Nino/Southern Oscillation (ENSO) phenomenon greatly influences patterns, therefore dynamics of plant communities. However, field data needed to assess effect climate change on vegetational patterns is difficult obtain because large spatial scale required such studies. Normalized Difference Vegetation Index (NDVI) characteristics allow use several indexes related structure. Due its direct relationship with primary productivity, it possible measures annual productivity. These include yield, maximum onset 'greening-up' senescence phases, length 'green' season, vegetation peak, therefore, periods when more or less food available herbivores. After verification ground-truth measures, we used NDVI from two localities north-central Chile (Fray Jorge Auco ´ ) determine relation- ship between cover productivity Nino phenomenon. With this information gauge influence climatic processes western America, an area subject strong variability. We predict significant variation Chilean due change, affecting mainly extent timing growth season vegetation, also including a shorter delayed greening-up season. Also, that decreases levels will not have effects production these ecosystems.