Vulnerability and resilience of forest ecosystems to extreme drought episodes

Abstract

Lloret,  F.  (2012).  Vulnerability  and  resilience  of  forest  ecosystems  to  extreme  drought  episodes.  Ecosistemas  21(3):85-90.  Doi.:10.7818/ECOS.2012.21-3.11

Drought-induced forest die-off has been recently reported in many locations abroad, and also in some shrublands. The phenomena show recognizable spatial patterns and it is not homogenous in localities with similar climatic characteristics. Therefore, we can identify different drivers contributing to die-off, for instance soil properties related soil availability, but also the existence of a remarkable resilience in these ecosystems. In fact, population decline would occur as a result of the unbalance between mortality and recruitment. Any factor contributing to diminish mortality or favouring recruitment would enhance resilience, and shifts in community composition would occur when the balance between mortality and recruitment will be different across species. Also, the impacts of these events would be intensified by the synergy with other disturbances, such as wildfires in Mediterranean-type ecosystems, particularly if these disturbance generate conditions similar to those resulting from the climatic anomaly. The die-off events can help to incorporate climate change context to forest management. Particularly, a pro-active approach by favouring the mechanisms contributing to forest resilience would be desirable. These actions include species and genotypes selection, forest structure adequate to optimize resource use in the oncoming climatic conditions, and distribution of these elements at landscape level.