Temporal and spatial characteristics of the composition of Hypogymnia physodes (Monk’s-hood lichen) from the Niepołomice Forest in Poland

The Niepołomice Forest, though relatively natural, is affected by air pollutants transported from nearby urban areas. To assess this impact, we examined the bioaccumulation of elements (Ca, Cd, Cu, Fe, Hg, Pb, S, Zn) in thalli of Hypogymnia physodes (L.) Nyl., together with oxidative stress biomarkers (SOD, TBARS) and thallus condition, at 15 sites. Samples were collected during both heating and non-heating seasons. Seasonal variability was observed: Cd, SOD, and TBARS were higher in the non-heating season, while S increased during the heating season, reflecting emissions from fuel combustion. Spatial differences were most pronounced for Cd, Zn, and TBARS. In the western part of the forest, H. physodes was absent at some sites, and lichens showed elevated Pb and Cu concentrations with increased SOD activity, indicating strong traffic-related pollution. In the east, thalli contained a high proportion of degenerated algae, associated with elevated Cd, Hg, and S, as well as other stressors. Overall, element concentrations were similar to those reported from other regions of Poland. The study highlights that even seemingly natural forests are subject to significant pollution pressure. Combining chemical data with biomarkers offers deeper insight into the effects of toxic elements on lichen bioindicators.