Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Global Change Biology 2163-2175 drought ecohydrology hydraulic conductance leaf area index leaf water potential Mediterranean evergreen forest Quercus ilex throughfall exclusion transpiration 2009 fdi:010046254 ENG Global Change Biology 1354-1013 ISI:000268684200006 9 10.1111/j.1365-2486.2009.01852.x https://www.documentation.ird.fr/hor/fdi:010046254 https://www.documentation.ird.fr/intranet/publi/2009/08/010046254.pdf 15 Horizon (IRD) In the Mediterranean basin, precipitation is expected to decline as a consequence of climate change. The response of a Quercus ilex forest in southern France to such a decline in water availability was studied using a 4-year throughfall exclusion experiment. Seasonal courses of sap flow and leaf water potential were obtained from 2004 to 2007 and used to characterize tree water relations in a control and a dry treatment. The experiment reduced the average precipitation input to the soil by 29%, and resulted in a 23% reduction in annual transpiration. Soil water potential was significantly lower in the dry treatment only during summer drought, but transpiration was reduced all year round even during well-watered periods. Despite a tight stomatal control over transpiration, whole-tree hydraulic conductance was found to be lower in the trees growing in the driest conditions. This reduction in water transport capacity was observed jointly with a reduction in leaf transpiring area. Canopy leaf area decreased by 18% in the dry treatment as a consequence of the throughfall exclusion, which was found to validate the ecohydrological equilibrium theory. 072 UR060