Shrub cover and soil moisture affect Taxus baccata L. regeneration at its southern range

The effect of key ecological and anthropic factors on recruitment of the common yew ( Taxus baccata ) in Sardinia (Italy) has been analysed. After a bibliographic and cartographic research, followed by field surveys, we found 232 sites where T. baccata grows in Sardinia (opposed to 69 previously reported in literature). Among them, we selected 40 sites, distributed in 14 different mountain chains, characterised by a number of individuals ranging from 11 to 836 adult yews with average Diameter at Breast Height (DBH) from 13 to 130 cm. By means of generalised linear modelling, we investigated and weighted the effect of ecological, structural, and anthropic factors on amount of T. baccata recruitment. Stand recruitment was positively correlated to shrub cover and soil moisture, and was negatively correlated to browsing (both from livestock and wild animals). Our data confirm that the presence of a protective layer of bushy and/or spiny shrubs is a crucial factor for seedling and sapling survival, mostly in relation to protection from summer drought and browsing of large herbivores. Finally, guidelines for conservation and restoration of T. baccata communities, referred to the EU priority habitat 9580* (Mediterranean Taxus baccata woods), have been outlined.