ANALYSIS OF THE VERTICAL-DISTRIBUTION OF EPIPHYTIC LICHENS ON PINUS-NIGRA (MOUNT-OLYMPUS, 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, Gree ce to assess the main spatial heterogeneity of microhabitats affecting communities and. species composition. Community structure along the g radient was studied by using multivariate techniques. The critical fac tor for spatial heterogeneity seems to be the height at which the lich en community develops on the tree trunks. Changes in the community str ucture of the epiphytic lichen vegetation were also detected along the altitudinal gradient and the altitude of 1200 m is considered to be a n ecotone. A comparative study of epiphytic lichen communities on Mt. Olympos and in the Thessaloniki area revealed species indicators of ai r pollution.