Biodiversity, grazing, wildfires and management ofQuercus suberforest in the mountain of Bitti-Buddusò (NE Sardinia)

Quercus suberspecies grows in a narrow region bordering the western Mediterranean. The importance of cork oak lies in the fact that cork material constitutes a valuable sustainable source of income. Nevertheless, anthropic activities have strongly affected these landscapes i.e. fires, overgrazing and inappropriate cork harvesting.This thesis describes cork oak forest situation in the Mountain of Bitti-Buddusò, using data from five different floristic composition studies and the economical plan of silvo-pastoral goods of Buddusò, in addition to the phytosociological study that we conducted in 2015. Overall, 362 species were encountered with the dominance of therophytes (44.5%) followed by hemicryptophytes (32%), which presence indicates a high period of summer aridity and the inclusion of areas related to grazing. The chorological spectrum showed the prevalence of Steno and Euri-Mediterranean species (34.1 and 26.9%, respectively) revealing thus the Mediterranean character in which cork oak forests insure an optimum vegetative growth. Moreover, we gathered data from two wildfires that occurred between 2012 and 2014 to examine the post-fire tree responses. The most common response type was crown and basal resprouting (71.8%). Vulnerability to fire was higher in older and stripped trees. Additionally, stocking rate registered a lower density (0.62 heads/ha) than that observed 50 years earlier, which shows the importance of grazing management in multi-ownership lands.