Selecting suitable moss indicators for routine bioindication of roadside air pollution

In the context of accelerating urbanization, industrial development, and climate change, accurate and cost-effective methods for monitoring air pollution are increasingly needed. Among biological tools, cryptogams—particularly mosses—have attracted considerable attention due to their physiological traits and wide distribution. Seeking effective indicator species, this study evaluates the bioindication potential of five common pleurocarpous mosses (Plagiomnium affine, Climacium dendroides, Hypnum cupressiforme, Pseudoscleropodium purum, and Thuidium tamariscinum) for monitoring air pollution using moss bags and a rapid, non-invasive method of magnetic susceptibility measurements. We focused on traffic-related heavy metals, including zinc (Zn), lead (Pb), cadmium (Cd), manganese (Mn), copper (Cu), chromium (Cr), nickel (Ni), and iron (Fe), quantified by Inductively Coupled Plasma Optical Emission Spectrometry. The results revealed clear interspecific differences in pollutant accumulation, with Plagiomnium affine and Climacium dendroides performing best, likely due to favorable morphological and physiological traits such as high specific leaf area and open leaf architecture. All tested species are widespread and easily accessible, enabling efficient biomass collection for field applications. By linking functional traits with pollutant retention capacity, this study provides evidence-based recommendations for species selection in routine biomonitoring protocols across temperate habitats.