Effects of new forestry practices on rare epiphytic macrolichens

The preservation of key habitats is included in modern forest-management practices as one of the main means to preserve biodiversity in northern European production forests. I examined the distribution patterns and persistence of occurrence of rare epiphytic macrolichens in a predominantly unprotected forest landscape with an area of 278 km(2) in southern Finland. Occurrence data of macrolichens in two key habitats, rock outcrops and mires, were compared with data from production forests. The density of populations of rare macrolichens was 50-fold higher on rock outcrops and 25-fold higher on mires than in production forests. Most rare species of epiphytic macrolichens were found only in key habitats. In modern, intensively managed forest landscapes, rock outcrops appeared to represent the main habitats for rare macrolichens as a result of the long-term continuity of old trees. Most macrolichen occurrences represented very small populations with a high extinction risk. Of the populations found in 1989-1995 in key habitats, 51% had disappeared, by 2000-2001, mainly as a result of forestry activities. The disappearance of populations significantly exceeded the rate of establishment of new populations. My results emphasize the guidelines for delimiting and managing key habitats in order to halt the continued decline of epiphytic macrolichens.