Mediterranean Quercus suber wooded grasslands risk disappearance: New evidences from Sardinia (Italy)

Wooded grasslands are the most widespread agro-forestry systems in Europe, and are included in the Natura 2000 network due to their importance in biodiversity conservation. Similar to many man-made systems, long-term wooded grasslands conservation depends on sustainable use practices. Regeneration of the tree layer is indispensable to assure wooded grassland maintenance. Several studies in Spanish dehesas and Portuguese montados generated concerns regarding the long-term conservation of these agro-silvo-pastoral systems. In the present study, we tested if tree regeneration issues documented for the Iberian Peninsula also affected wooded grasslands located in another Mediterranean area inside and outside Natura 2000 network. The size structure of Quercus suber L. stands, and the abundance and height of seedlings and saplings were determined at farm and landscape scales, in grazed, grazed and tilled wooded grasslands, and non-grazed woodlands to test the compatibility of management type for tree regeneration. A frequency model of size structure was calculated to estimate the probability of cork oak stand survival in a medium and long term time period. New evidences of a generalised absence of regeneration in grazed wooded grasslands emerged from all the study sites. Some management practices are indicated for the long-term conservation of the habitat.