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Abstract

The study presents an analysis of bryophyte species diversity and distribution along the Pasaphu-Mochhu river in Trashigang district. For this study, the river was stratified into three different zones on which a systematic random sampling was carried out. A total of 156 plots with dimension of 1 m x 1 m were studied with plot-to-plot distance of 50 m x 10 m. The study documented 28 bryophyte species, comprising 19 moss species, 8 liverworts, and 1 hornwort. The highest diversity was observed in the lower part of river (H'=3.317). Brachythecium sp. was found to be the most dominant species with an important index value (IVI) of 34.40. There was a significant difference in diversity between the strata. Bryophyte species diversity fluctuated with increasing altitude (p=0.94) and no significant relationship between canopy closure and bryophyte coverage was observed (p=0.61). In terms of substrate, bryophyte species were predominantly distributed on silt and rock. Specifically, mosses were mainly found on rock substrates, liverworts on silt, and hornworts exclusively on silt substrate. Mosses were present across a range of canopy closures, while liverworts and hornworts were located in areas with partial to dense canopy coverage. The study underscores the need for more comprehensive investigations to fully understand the effect of changing environments on the conservation of bryophyte habitats and species, thus safeguarding them from degradation. Extensive degradation of habitat could threaten and lead to the disappearance of sensitive species and thus more comprehensive study is recommended.