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.