The paper provides original data on accumulation capabilities of bryophytes typical of peatland ecosystems with different degree of anthropogenic transformation occurring in the Kaliningrad Region of Russia. A key study area was the Vittgirrensky Peatland, abandoned after milled peat extraction in 1990s and designated as the Rossyanka Carbon Measurement Supersite in 2021. The accumulation of micro- and macroelements: Ca, Mn, Fe, Ni, Zn, Br, Rb, and Sr – was identified by means of X-ray fluorescence spectroscopy in 13 bryophyte species (Aulacomnium palustre, Campylopus introflexus, Polytrichum commune, P. strictum, Sphagnum capillifolium, S. centrale, S. cuspidatum, S. fuscum, S. magellanicum, S. riparium, S. squarrosum, S. teres) focusing on comparison with the reference species Pleurozium schreberi. The records of average element concentrations from the Vittgirrensky Peatland are shown to be distinctly lower than the regional background level. The accumulation of Mn, Ni, Br, Rb, and Sr varies significantly among disturbed and natural sites: the concentrations are comparable for Fe and Zn, while cut-over peatlands showed the level of Mn several times less than in undisturbed peat bogs. Aulacomnium palustre can be recommended for passive biomonitoring purposes on bog ecosystems as having most similar accumulation capability to the reference species Pleurozium schreberi that is widely recognized as indicator of atmospheric air pollution.