Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 6 1st Alexander von Humboldt International Conference 2006 10.5194/adgeo-6-273-2006 http://www.adv-geosci.net/6/273/2006/ http://www.adv-geosci.net/6/273/2006/adgeo-6-273-2006.html http://www.adv-geosci.net/6/273/2006/adgeo-6-273-2006.pdf 273 277 2006-03-03 ENSO effects on primary productivity in Southern Atacama desert F. A. Squeo Y. Tracol D. López J. R. Gutiérrez A. M. Cordova J. R. Ehleringer Departamento de Biología, Facultad de Ciencias, Universidad de La Serena, Casilla 599, La Serena, Chile Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Casilla 599, La Serena, Chile Instituto de Ecología y Biodiversidad (IEB), Universidad de Chile, Casilla 653, Santiago, Chile Department of Biology, University of Utah, USA In the winter-rain southern Atacama Desert of the Coquimbo Region of Chile, El Niño - Southern Oscillation (ENSO) events modulate primary productivity. In this region, there are important changes in water availability between La Niña (dry) and El Niño (rainy) years. Using inter-annual comparisons of LANDSAT images from 30° to 31° S latitude, we observed changes in primary productivity between dry and rainy years at the regional level. There were also significant, negative correlations between productivity and elevation, with changes occurring first at low elevation during rainy years. The limiting factors to dryland vegetation primary productivity is different in regard to elevation. Rain during an El Niño year is the main factor that explains the increase in primary productivity at low elevation, while lower temperatures reduce and delay the net primary productivity at mid elevation.