Epiphytic lichen distribution and plant leaf heavy metal concentrations in Russian–Norwegian boreal forests influenced by air pollution from nickel-copper smelters

The Norwegian–Russian border area is exposed to air pollution from Russian nickel-copper smelters at Kola Peninsula. An attempt was made to relate distribution and abundance of epiphytic lichens to concentrations of sulphur, nickel and copper in birch and bilberry foliage and soil. Lichen cover showed significant correlation with Ni and Cu concentrations. However, since the deposition patterns of airborne heavy metals and sulphur dioxide (SO2) around the smelters differ, some plots experience low lichen cover, despite low heavy metal concentrations. These plots are affected by relatively high SO2 emissions. Climatic variability within the study area may also play a role in explaining variation in lichen cover. For areas with uniform climate and physiognomy nearer than ca. 20 km from the smelters, Ni concentrations in birch leaves may prove useful for estimating the likelihood for recolonization to take place. The area closest to the smelters presently is much too polluted for lichen recolonization to occur.