Participation and Diagnostic Role of Epigeic Bryophytes in Forest Alliances in Central Poland

Epigeic bryophytes represent an important but often overlooked component of forest biodiversity, closely linked to fine-scale habitat heterogeneity. The conducted research revealed clear differences in both species richness and composition between phytocoenoses and substrates. Mineral soil was the most species-rich substrate, hosting 90 taxa, whereas litter supported the lowest diversity, with only 33 species, emphasising the role of substrate stability and microhabitat availability in shaping bryophyte assemblages. Although forest ecosystems and forest roads exhibited comparable overall species richness, their bryophyte floras differed markedly in species composition, indicating that non-forest habitats provide distinct ecological niches and function as refugia for rare and restricted taxa. Analyses demonstrated that substrates with similar properties often formed coherent species groups across different phytocoenoses and may play a more important role than forest type in structuring epigeic bryophyte communities. On the other hand, species with broad ecological amplitudes were widespread and structurally dominant, whereas taxa restricted to single phytocoenoses showed high bioindicative value. These restricted species proved particularly useful for differentiating phytocoenoses despite their limited spatial extent. Overall, the results highlight bryophytes’ sensitivity to microhabitat variation and underscore their value as effective indicators of habitat differentiation in forest ecosystems.