Abstract:

The nutrient uptake, requirement and releasing rates of bryophytes are very different from those of tracheophytes. However, it is difficult to make a quantitative evaluation of bryophytes’ roles in nutrient cycling and their specific eco-physiological adaptations due to lack of knowledge of their concentrations and stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P). To fill this gap, the present study aims to investigate: (i) what are the elevational trends of C, N and P concentrations and stoichiometric ratios of bryophytes? (ii) whether C, N and P concentrations and stoichiometric ratios of bryophytes differ between different bryophyte types (in terms of the growth form and living substrate)? and (iii) how do the exponent scalings of N and P of bryophytes change along the elevational gradient?

We measured and calculated the C, N, P concentrations and stoichiometric ratios of bryophytes from four elevations on the eastern slope of Gongga Mountain (22 species in total). Differences in these traits among elevations, and between different bryophyte types were compared. The log-log allometric regression parameters of N and P at each elevation were also determined and compared.

The C, N and P concentrations of bryophytes showed decreasing trends with increasing elevations. More specifically, erect bryophytes possessed higher C and N concentrations than those of prostrate species, and terricolous species had higher P concentration than that of corticolous and saxicolous species. Bryophytes from different elevations had an invariant allometric regression slope for P versus N. Future research at a larger scale is in need for a more generalized law of bryophytes.

Key words: allometric scaling, growth form, living substrate, stoichiometric ratio, subalpine