Lichens as indicators of ecological continuity in subalpine forests case studies in the Paneveggio Forest (NE Italy)

In the Italian Alps subalpine forests are still intensively managed for timber production. The increasing interest on near-to-nature silvicolture has favoured a scientific-based and multi-purpose management approach whose models are often developed on the basis of ecological studies in the remnant near-natural sites. This could apply also to lichens, whose role in biodiversity conservation in subalpine coniferous forests of the Italian Alps is still largely unknown. Thus, testing the relations between tree parameters, the availability of different types of Coarse Woody Debris (CWD) in different decay stages and the richness and composition of lichen communities in near-natural stands could be a first step to gather information for forest managers interested in conservation and in biodiversity assessment and monitoring. This thesis summarize the results of four case studies, carried out in near-natural sites in the Paneveggio Forest (NE Italy). They were focused on the evaluation of the influence of tree age and age-related parameters and CWD in shaping species richness and composition of lichen communities. In two complemetary sections the influence of forest management on epiphytic lichens and the suitability of a standard assessment of lichen diversity to predict total species richness are also evaluated. Tree-level lichen diversity and composition proved to be related to the main features of the trees such as age and size. Several lichens, including nationally rare species, are related to old trees (more than 200 years old), which are normally absent in managed forests. The macrolichen Letharia vulpina, which is a relatively dispersal limited species related to old-trees is suggested as a potential indicator of tree growth continuity. Its use as an indicator species is strongly enhanced since it is easily identifiable by non-specialists. Also CWD has an important role for lichen diversity in subalpine forests. Stumps, which are the main type of available CWD in managed stands, host several nationally rare species, which are related to different stages of wood decay. However, the presence of different types of CWD in different decay stages proved to enhance several nationally rare species, indicating that the retention of logs, snags and stumps should be included in management plans aiming at improving naturalistic silvicolture in the Alps. The relations between lichen communities and some structural features of mature forests such as over-mature trees and different types of CWD in different decay stages suggest their suitability for evaluating tree growth- and forest continuity, and conservation importance of subalpine forests of the Alps. Lichens should be therefore included in the framework of indicators which are used to evaluate the effectiveness of forest management for biodiversity conservation in the Alps.