image: Relationships with climatic and atmospheric factors (MAT, MAP, VPD, UVB, and N deposition), overstory covers (tree, shrub, herb, and litter), and soil nutrients (C, N, and P) as predictors and the response variable being biomass of forest floor bryophytes. The red and orange letters indicate the p-values of the bivariate relationships using the data from all study sites or only the sites with forest floor bryophytes, respectively. The red solid lines indicate significant relationships based on the data from all study sites (p < 0.05), with the grey bands representing the 95% confidence intervals.
Credit: Zhe Wang; Defeng Feng; Yanqiang Jin; Mijun Zou; Beibei Gao; Xin Liu; Weikai Bao
A large cross-regional study has shown that temperature is the dominant factor controlling the biomass of forest floor bryophytes (mosses and liverworts).
Researchers from the Chengdu Institute of Biology, Chinese Academy of Sciences, surveyed 413 forest sites across Sichuan Province, China, spanning a wide range of elevations, climates, and forest types, to understand what determines how much bryophyte biomass accumulates on the forest floor. Their findings, published in Forest Ecosystems, reveal that colder forests have more bryophyte biomass, while warmer conditions strongly limit their growth.
Bryophytes were most abundant in forests with lower temperatures, lower nitrogen deposition, lower vapor pressure deficit, and more open canopies that allow light to reach the forest floor. Among all environmental factors tested, mean annual temperature stood out as the strongest factor.
Soil conditions also played a role. Bryophyte biomass was positively associated with soil carbon and nitrogen content, highlighting a close connection between moss communities and forest nutrient cycling.
Despite these clear trends, the researchers emphasize that bryophyte biomass is shaped by multiple interacting factors, many of which are strongly correlated across landscapes. Forest type and soil nutrients contributed to biomass variation, but their effects were secondary to temperature. This finding underscores the importance of climate as a large-scale constraint on bryophyte distribution and productivity.
The study also highlights a modeling challenge. Although temperature strongly influences bryophyte biomass, commonly used environmental variables explained only a portion of the observed variation. The authors suggest that fine-scale microclimates, short-term weather extremes, forest age, species composition, and biological traits of bryophytes may further shape biomass patterns and should be incorporated into future research.
Journal
Forest Ecosystems
Article Title
Temperature determines the biomass of forest floor bryophytes: A cross-regional investigation in 413 sites
Article Publication Date
25-Nov-2025