“…5), more likely due to changes in leaf area rather than changes in leaf chlorophyll content, since the latter would have an opposite effect on C: leaves with higher photosynthetic activity would show higher water-use efficiency and, thus, lower 13 C (Farquhar and Richards 1984;Cernusak et al 2013). Still, both chlorophyll content and leaf area tend to decrease under drought conditions in P. halepensis (Baquedano and Castillo 2006) and, thus, NDVI might hold a signal from both variables, particularly in drought-prone environments (Pasquato 2013). Hence, the poor agreement between 13 C and NDVI at the temporal scale in the driest sites could be the result of a greater relevance of the chlorophyll content signal controlling NDVI in water-limited environments.…”