干旱区生态环境知识资源中心

The purpose was to determine the extent to which the relatively sparse lichen flora on the trunks of Scots pines (Pinus sylvestris L.) can serve as an indicator of air purity. The percentage cover and condition of the lichens were recorded in sample plots from which lichens (Hypogymnia physodes) and pine needles were collected for chemical analysis. Clear differences in pollution tolerance were found between the species, Platismatia glauca and H. tubulosa being the most sensitive of the macrolichens and H. physodes and Parmeliopsis ambigua the most tolerant. With decreasing distance from the city centre the numbers of macrolichen species and their size and percentage cover diminished, changes in their external appearance became more marked and the concentrations of impurities in the lichens and pine needles increased. Pendulous lichens of the genus Bryoria occurred on fairly polluted plots, but their maximum lengths remained small. No actual ’lichen desert’ could be discerned, however. The interaction of air pollutants with other environmental factors is discussed.