Sulphur isotope composition of epiphytic and terricolous lichens and pine bark in Finland

The sulphur isotope composition of the epiphytic lichens, Hypogymnia physodes (L.) Nyl and Pseudevernia furfuracea (L.) Zopf, of the terricolous lichens, Cladina sp. and Peltigera aphthosa (L.) Willd., and of pine bark, at 31 sites in Finland, appeared to be dependent on lichen and tree species. The negative correlation of sulphur isotope composition with sulphur content was highly significant (P<0.001) in H. physodes and significant (P<0.01) in Pseudevernia furfuracea and Peltigera aphthosa. No correlation between the sulphur isotope composition and sulphur content was found for Cladina sp. and pine bark. The sulphur isotope compositions displayed statistically significant regional variation from south to north. Microenvironmental factors were considered, including phorophyte species and the chemical form of sulphur.