Limiti altimetrici delle formazioni a lentisco (Pistacia lentiscusL.) e oleastro (Olea europaeavar.sylvestris(Miller) Lehr) in Sardegna in relazione al cambio climatico

The aim of this research is to provide a database through phytoclimatic-indicators such as wild olive and mastic tree, to define a tested starting condition, structured on the basis of ecological and geopedological parameters and climate. Climate change leads to an alteration in the balance of ecosystems resulting in increased vulnerability and a consequent loss of biodiversity (Bullocket al., 1996).The lack of data sometimes leads to use of theoretical models that are checked as to compliance with the actual field conditions and the resulting management actions. Because of this it is necessary to identify the species of reference. Wild olive and mastic tree (Pistacia lentiscusandOlea europaeavar.sylvestris) are characteristic indicators of the thermophilic range of Mediterranean plants (Arrigoni, 1968) and are closely associated with each other; these species are representative in function of environmental parameters such as geological substrate and soil, climatic factors and human impact. Sample areas have been identified for research purposes, according to specific criteria selected to determine the altitudinal limits of both species and their distribution. The results provide indications on the distribution of mastic tree and wild olive and the relationship that exists with the geopedological, climatic and anthropogenic characteristics and ecology. Assuming an increase of 2°C, the mastic tree and the wild olive would expand to most of Sardinian territories up to 900 m in elevation, possibly 1100 m in the southern slopes of sandstone areas. Thus, the vegetation takes in general a thermoxerophilic characters, while the mesophilic vetetation that nowadays occupies the 600-900 altitude belt. Important consequences are also expected on human activities.