Mediterranean Taxus baccata woodlands in Sardinia: a characterization of the EU priority habitat 9580

The results of a field investigation on the structure and species composition of Taxus baccata L. forests in Sardinia (Italy) is given. The species, that occupies a wide range of altitudes from 50 to 1550 m a.s.l., but prefers to live from 800 to 1200 m a.s.l., was found to be the dominating tree in mesophylous forests, here described as new associations: 1) Cyclamino repandi-Taxetum baccatae ass. nova, at the top of Sardinian mountains, with 4 subassociations corresponding to local variation of geological substratum; 2) Polysticho setiferi-Taxetum baccatae ass. nova, at intermediate altitudes, near streams, in northern slopes of central Sardinian mountains. Moreover, in contact with mountain oak forests, the new sub-associations Saniculo europaeae-Quercetum ilicis taxetosum baccatae subass. nova and Glechomo sardoae-Quercetum congestae taxetosum baccatae subass. nova have been described. The multivariate analysis of plant assemblages showed a significant separation among the four different communities. Contrary to previous studies, our findings support the evidence for the presence of pure or yew-dominated woods in Sardinia. In particular, the Cyclamino repandi-Taxetum baccatae, has a relic character and a great biogeographic importance. The scattered distribution of the two habitats suitable for the yew in Sardinia can be considered the main current ecological trait that plays a fundamental role in the process of population isolation. To preserve the existing Mediterranean yew woods, we recommend not only measures directed to the species conservation, but also actions that should accomplish the phytocoenotic diversity highlighted by this investigation.