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An increase in the nitrogen (N) content in coarse woody debris (CWD) facilitates its decomposition, affecting the cycling of N and other nutrients in forest ecosystems. Bryophytes may increase the N content by transferring the N in bryophyte tissues to the underlying CWD. This study examined whether and how bryophytes increase N content in the underlying CWD using N‐stable isotope ratios (δ15N) as tracers for N sources. The N content and δ15N values in CWD with bryophytes were significantly higher than those in CWD without bryophytes. However, the δ15N values in CWD with bryophytes differed significantly from those in bryophytes on CWD, demonstrating that the N in bryophytes did not cause the increase in N content in CWD. The analyses using δ15N further indicated that the high N content in CWD with bryophytes may be attributed to increased N supply from wood‐decomposing fungi and N‐fixing bacteria. This increase in N content may result from the enhanced moisture content in CWD beneath bryophytes, which facilitates the activity of wood‐decomposing fungi and N‐fixing bacteria. Notably, the influence of bryophytes on the N content in CWD differed between bryophyte life forms: bryophytes that form dense mats increased the N content in CWD, whereas those with loose mats decreased the N content. This difference can be explained by the greater humidity experienced by CWD with bryophytes forming dense mats than that experienced by CWD with bryophytes forming loose mats. Given that the N content in CWD affects the decay processes, the results highlight the importance of biological interactions associated with bryophytes in forest ecosystems. [ABSTRACT FROM AUTHOR]

Paddy-field landscapes play an important role in conservation of plant diversity. However, in only a few studies has bryophyte diversity been investigated in these landscapes. Therefore, we examined the characteristics and factors that determine bryophyte diversity in paddy fields. Three approaches were used in this study: plant taxa, life form, and habitat type. Our aim in using the plant-taxa approach was to reveal differences between bryophytes and vascular plants in terms of landscape elements that are significant for species richness. The life-form and habitat-type approaches were used to elucidate how landscape elements determined bryophyte diversity. Generalised linear models and non-metric multidimensional scaling were used for these analyses. The landscape elements influencing species richness differed between vascular plants and bryophytes. Specifically, the forest area emerged as a crucial factor for bryophyte richness. Moreover, the species composition of bryophytes was determined by the forest area, influencing the prevalence of hydrophilic life forms and presence of forest-associated bryophyte species. These results can be attributed to two key functions of forest areas: supplying forest species to adjacent paddy fields, and alleviating heat and drought stress. Bryophyte diversity in paddy fields was influenced more strongly by the surrounding forest areas than by the vascular plant diversity, owing to the vulnerability of bryophytes to drought stress. These results highlight the importance of forest–paddy mosaics for conservation of bryophyte diversity in paddy fields. Furthermore, the species composition results suggest that paddy fields can serve as suitable habitats for flood-plain bryophytes. [ABSTRACT FROM AUTHOR]