The increasing aridity due to climate change is considered a major threat for biodiversity conservation and provision of ecosystem services, especially in savanna-like systems (dehesas). To analyze the effects of these environmental changes on the herbaceous community, an experimental rainfall exclusion and warming was set up at three dehesas (differing in grazing intensity) located in southern Spain, equally distributed between grassland and under tree 1canopy. Four climatic scenarios were simulated in each of them (control, warming, drought and warming + drought), and quantified Leaf Area, Specific Leaf Area (SLA), Leaf Dry Matter Content (LDMC) and plant height in the most abundant herbaceous species during 2017 and 2018 springs. Species composition and frequency differed strongly among sites and habitats. Communities growing under high grazing intensity were mainly constituted by plants with lowcost leaves, likely as a strategy for maximizing regrowth after grazing. Herbaceous communities located beneath ree canopies were mainly constituted by taller plants with bigsized leaves and higher SLA values for maximizing light uptake. Plant communities subjected to warming increased their height, whereas those exposed to combined warming and drought reduced their SLA values, likely as a mechanism for reducing water loss by evapotranspiration. The scattered trees that are present in these landscapes (Quercus ilex subs. ballota) play a potential mitigating role as buffers of climate-change effects. Our community-level approach constitutes a useful tool to categorize plant communities based on their functional attributes, predicting their responses to biotic and abiotic changes as well as inferring ecosystem properties of ecological and agricultural importance. Finally, the preservation of dehesas is of great importance due to the high amount of ecosystem services they provide and their high animal and plant biodiversity.

Póster presentado en el 9th Meeting of the IOBC-WPRS working group “INTEGRATED PROTECTION IN OAK FORESTS”. Del 7 al 11 de octubre. Oeiras (Portugal)