Functional trait scaling relationships across 13 temperate mosses growing in wintertime

Mosses growing in wintertime exert important ecosystem function, but we know little about their fundamental functional trait levels and scaling relationships across species. Thus the present study chose 13 common mosses growing under a temperate deciduous forest in wintertime to measure their light-saturated assimilation rate (A_mass), dark respiration rate (Rd_mass), major element concentrations and stoichiometric ratios (C_mass, N_mass, P_mass, C:P, C:P and N:P) and the shoot mass per area (SMA). Their bivariate log–log scaling relationships were determined by standardized major axes approach. We confirmed that except C_mass, the nutrient concentrations and metabolic rates of our mosses were higher than that of mosses growing at warmer sites but the SMA was lower than for Sphagnum species. Furthermore, the functional trait levels were totally lower than those of vascular plant leaves except P_mass. Besides, we found the N_mass and P_mass were significantly positively related to A_mass and Rd_mass but negatively associated with SMA. The C:P and N:P were also closely linked with A_mass, Rd_mass and SMA. The SMA was significantly related to Rd_mass but not to A_mass. Functional trait relationships across the current species deviated from previous studies of mosses but were generally analogous to those of vascular plant leaves only with different scaling. The findings suggest that mosses allocated a greater proportion of nutrients to metabolic components rather than to the non-photosynthetic tissues. In addition, phosphorus was associated more closely with other functional traits than was nitrogen and might play a greater role to withstand the cold temperatures in wintertime for mosses.