Freshwater Lichens, Including New Species in the Genera and , Associated with (Poelt & Nimis) Sohrabi & Nimis from Watercourses of Sardinia.

This work summarizes the results of the exploration of freshwater lichen biota on the island of Sardinia associated with the regional flagship species , a large-sized crustose lichen from the splash zone along mountain streams, so far known from Sardinia only. Molecular data were used to confirm its distinctiveness from other taxa and its systematic placement and to identify critical taxa among its associated lichen biota. We found 25 species of lichenized fungi, including three species new to science in the genera , and , and seven species new to Sardinia (, , , , , ), or new to Southern Europe (). Specific traits for the freshwater lichen biota of Sardinia were identified and compared to those reported from freshwater sites in the Alps and Carpathian mountains, e.g., a relative scarcity of subgelatinous lichens. Parasitic or epilichenic interactions were found frequently but only in the splash zone and not in the permanently submerged zone, i.e., two parasitic species, and clearly lichenicolous thalli of and . Due to its specific trait profile and the great potential for the discovery of new species, we recommend the inclusion of Sardinian and further Mediterranean sites in continental-scale monitoring programs for freshwater lichens.