Is Moss Stoichiometry Influenced by Microtopography in a Boreal Peatland of Northeast China?

To examine the effects of microtopography on the stoichiometry of carbon (C), nitrogen (N) and phosphorus (P) in mosses along the hummock-hollow gradient in boreal peatlands, we investigated species-level C:N, C:P and N:P ratios of five mosses (Sphagnum magellanicum, S. perichaetiale, S. palustre, S. girgensohnii and Aulacomnium palustre) in the hummocks, hollows and their intermediate zones, and then assessed community-level spatial patterns in a boreal ombrotrophic peatland of north of the Great Xing'an Mountain, Northeast China. The results show that at the species level, C:N, C:P and N:P ratios of the selected Sphagnum mosses remained stable in the hummock-hollow complexes due to unchanged C, N and P concentrations, whereas the non-Sphagnum moss (A. palustre) in the hummocks and intermediate zones had lower P concentrations and thus greater C:P ratios than that in the hollows. At the community level, moss N concentration and C:N ratio remained constant along the hummock-hollow gradient, whereas hummocks and intermediate zones had higher community-level moss C:P and N:P ratios than hollows because of greater C and lower P concentrations. These findings imply that the effects of microtopography on moss C:N:P stoichiometry are scale-dependent and reveal spatial heterogeneity in C and nutrient dynamics. These results provide a more comprehensive understanding of biogeochemical cycles in boreal peatlands.