Tree canopy effects on the functional structure of herbaceous communities typical of savanna-like ecosystems

Abstract: The increasing aridity due to climate change is considered a threat for biodiversity conservation and for the provision of ecosystem services, especially in savanna-like ecosystems (dehesas). We carried out a field experiment combining rainfall exclusion and warming in dehesas of southwestern Spain, using 36 experimental plots equally distributed between two habitat types – open grasslands and under tree canopy – with the aim of analyzing the effect of tree canopy as potential buffer of the impact of climate change in community functional structure. Leaf Area, Specific Leaf Area (SLA), Leaf Dry Matter Content (LDMC) and plant height were quantified in the most dominant herbaceous species in spring 2017 and 2018. Herbaceous communities located beneath tree canopies were mainly constituted by plants with big-sized leaves and higher SLA values for maximizing light uptake. The scattered trees played a potential mitigating role as buffers of climate-change effects. Our community-level approach helps us to predict the plant communities’ responses to biotic and abiotic changes.