Analysis of the vertical distribution of epiphytic lichens on Pinus nigra (Mount Olympos,Greece) along an altitudinal gradient

Epiphytic lichen vegetation was studied in 10 sites along an altitude gradient from 750 to 1510 m on NW-facing slopes of Mount Olympos, Greece to assess the main spatial heterogeneity of microhabitats affecting communities and species composition. Community structure along the gradient was studied by using multivariate techniques. The critical factor for spatial heterogeneity seems to be the height at which the lichen community develops on the tree trunks. Changes in the community structure of the epiphytic lichen vegetation were also detected along the altitudinal gradient and the altitude of 1200 m is considered to be an ecotone. A comparative study of epiphytic lichen communities on Mt. Olympos and in the Thessaloniki area revealed species indicators of air pollution.