Lobaria pulmonaria (L.) Hoffm.: The Multifaceted Suitability of the Lung Lichen to Monitor Forest Ecosystems

Lobaria pulmonaria (L.) Hoffm. is a tripartite, broad-lobed foliose lichen usually found on bark and on epiphytic and epilithic mosses in humid forests. Currently, the species is threatened in most European countries because of its sensitivity to environmental alterations. In this paper, a total of 107 previous studies across more than 50 years were analysed to gain insight into the multiple roles that L. pulmonaria plays in forest habitats, specifically relating to ecosystem services and as environmental bioindicator. Content analysis was employed to systematically characterise and classify the existing papers on the functions performed by L. pulmonaria into several groups mostly based on research topic and scope. Two main types of ecosystem services (N2 fixation and feeding) offered by L. pulmonaria have been identified, with varying research aims and types of parameters measured in the studies. Two aspects of current biomonitoring applications using L. pulmonaria in forest habitats (concerning atmospheric pollution and forest management) were analysed, and it was found that the number of related studies increased significantly in recent years. Finally, the current practices of monitoring using L. pulmonaria as a biological indicator are discussed, and recommendations are provided.