Diversity and ecology of terricolous bryophyte and lichen communities in coastal areas of Sardinia (Italy)

A first characterization of soil-growing bryophyte and lichen communities along the coasts of Sardinia (Italy) is presented. The lichen Micarea melaenida is reported for the first time. Altogether, 5 different communities are reported: Group 1, dominated by Tortella flavovirens, Cladonia convoluta and Pleuroehaete squarrosa; Group 2, close to the Cladonietum mediterraneae; Group 3, with dominance of the bryophytes Tortella flavovirens, Rhynchostegium megapolitanum and Bryum capillare; and Group 4, characterized as a Tortella flavovirens fragment community. In many plots neither bryophytes nor lichens were recorded (Group 5). Bryophytes and lichens present different ecological requirements. The bryophytes are more tolerant of shaded conditions, eutrophication and higher soil pH, whereas lichens are more sensitive to man-made disturbance, especially trampling, fire and competition from exotic species. The highest diversity of both groups of organisms (lichens and bryophytes) is found in well-preserved native Juniperus woodlands, while no bryophytes or lichens are present in highly disturbed areas. Both are severely threatened by human activities and plant invasion, and require special protection through the forest management policies outlined here: thinning of exotic vegetation, removal of exotic species, and increased propagation of natural vegetation.