Por Maria C. Caldeira (Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa).

Woody shrub encroachment is increasing worldwide, including in the Mediterranean regions. Shrub encroachment affects the structure, functioning and resilience of ecosystems. Negative and positive effects of encroachment are expected. These mainly depend on environmental factors, cover and functional traits of shrubs. Most studies on encroachment have addressed species diversity and composition, soil carbon sequestration and fertility but only a few focused on water fluxes. In Mediterranean regions, where water is a determining resource driving ecosystem functioning and resilience, it is crucial to know the effects of encroachment on water fluxes. In addition, the frequency and intensity of droughts are projected to increase in these regions that can be synergistic with shrub encroachment, which makes even more pressing to understand this phenomenon. A case-study of cork oak ecosystems encroached by Cistus ladanifer L. will be presented.