Epiphytic lichen conservation in the Italian Alps: the role of forest type

Epiphytic lichens are a functionally important and species-rich component of Alpine forests, including several species of conservation concern. Their dependence on specific host trees predicts that forests with different tree species composition host different lichen communities, enhancing lichen diversity in forest landscapes. In this study, we tested for the first time the effect of forest type on patterns of epiphytic lichen diversity, in the Italian Alps. We sampled the main forest types of the South Tyrol, a typical Alpine region of Italy. We also assessed the influence of factors related to forest structure and climatic conditions. Our results demonstrate that different forest types host statistically different lichen communities, suggesting that the conservation of lichen diversity is entrusted to the maintenance of forest landscape heterogeneity, including forest types of minor economic value and rural habitats. The highest number of species was found in grazed larch forests and in high-elevation spruce forests, while the poorest pool was found in low-elevation spruce forests, beech forests and Scots pine (Pinus sylvestris) forests. High-elevation spruce forests also had the highest number of red-listed lichens, as the non-intensive management of these forest type allows the establishment of a rich lichen biota. Our results also emphasize the role for lichen conservation of some forest types that are of minor economic importance, such as oak (Quercus pubescens), riparian, and silver-fir (Abies alba) forests. This can also apply to grazed larch (Larix decidua) forests that are maintained by traditional farming, which shape one of the most pleasing aspects of the Italian Alpine landscapes.