Rediscovery of the endangered lichen Pseudocyphellaria aurata (Lobariaceae, Ascomycota) in mainland Spain

Lichens, as well as other organisms, should be considered important biodiversity components for the establishment of priorities in conservation biology. In this study, we report six new recent localities of the highly endangered, epiphytic macrolichen Pseudocyphellaria aurata in Spain: two in Navarra and four in A Coruna. Previous Spanish reports based on literature and herbarium specimens suggest a reduction of the distribution area of P. aurata and local extinction. Pseudocyphellaria aurata is known to be extinct in six localities, where it has not been observed since the middle of the 19th century (Cadiz, Pontevedra, Malaga). Four records reported for central Spain (Zaragoza, Salamanca, Teruel) are considered unplausible. The newly discovered populations are located in well-preserved patches of atlantic deciduous forest with strong oceanic influence, whose long-term ecological stability seems evident because of the presence of ancient trees. Nevertheless, these populations are small, fragmentary, and are threatened by habitat degradation, forestry and maybe fungal pathogens. Two populations, Intzola and Beba (Navarra and A Coruna, respectively), account for 75.7% of thalli. The localities with the highest number of trees colonized by P. aurata are Santa Leocadia and Beba in A Coruna. We reassessed the conservation status of this species concluding that conservation initiatives must be implemented to avoid its extinction in mainland Spain.