Bryophytes as indicators of environmental gradients between forested and non-forested peatlands communities

Abstract Bryophytes are among the most sensitive bioindicators of environmental changes. In peatland ecosystems, however, their response to hydrological and trophic gradients in forested and open peatlands remains poorly understood. The aim of this study was to assess the bioindicative potential of moss species in relation to habitat moisture and the availability of mineral forms of nitrogen in bogs and transitional fens of north-western Poland. In the studied phytocoenoses, 36 moss species were recorded, with the genus Sphagnum being dominant. Forest phytocoenoses were characterized by greater species richness and a higher proportion of exclusive species than open communities. Multivariate analyses (PCoA, db-RDA, PERMANOVA) revealed a distinct differentiation of moss communities along habitat gradients. Species composition was most strongly determined by habitat moisture and the concentration of nitrate nitrogen (N–NO₃⁻). Differences were also demonstrated between peatlands situated in forested and agricultural surroundings, despite similar chemical conditions of the substrate. The IndVal analysis allowed for the identification of species strongly associated with specific hydrological and trophic conditions, including selected Sphagnum species and Warnstorfia fluitans . The obtained results demonstrate the high bioindicative value of bryophytes and their usefulness in monitoring hydrological and trophic changes in peatlands. Thus, it can be clearly stated that the species composition of the bryoflora can serve as a sensitive indicator of early environmental changes occurring in peatland ecosystems.