Floristic composition and diversity of bryophytes along an elevation gradient in Kailali, Far West Nepal

Bryophytes were the first plants to colonize land. They are the most diverse group after angiosperms, but are a neglected group due to their small size. In Nepal, bryophyte-related studies have largely been confined to eastern and Central regions. Moreover, research focusing on species richness patterns and associated ecological parameters remains limited. To address these gaps, the present study employed a systematic random sampling method. Bryophyte sampling was conducted across six elevation zones ranging from 150-1600 m, with an interval of approximately 300 m (±75 m). A total of 150 small plots (1 m x 1 m) were established within 30 large circular plots (10 m radius) to record bryophytes and associated environmental variables. A total of 89 bryophyte taxa were documented, representing three lineages, 38 families, and 58 genera. Among them, 57 species were mosses, 27 were liverworts, and 5 were hornworts. Among the seven habitat types, bryophytes mostly preferred lithophyte+terrestrial (42%). Bioclimatic zone-wise distribution showed higher number of bryophytes in the subtropical zone (69 species). Multivariate analysis indicated elevation and shrub cover as the main environmental gradients shaping bryophyte species richness and distribution. A generalized linear model (GLM) showed that species richness increases with elevation and moisture, but decreases with total canopy cover, tree cover, herb cover, litter cover, and bare-ground. Despite dry conditions, the study area showed high bryophyte diversity. Overall, the finding emphasize the significant role of elevation and soil moisture in promoting bryophyte species richness, highlighting their importance in determining bryophyte diversity and distribution.