1. Instituto de Ciencias Agrarias – Consejo Superior de Investigaciones Científicas, C/ Serrano 115 dpdo, Madrid 28006, Spain
2. INRA, UMR 0385 BGPI, CIRAD-INRA-Montpellier SupAgro, TA-A54/K, Campus International de Baillarguet, 34394 Montpellier Cedex 05, France
3. Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA