LAUSR

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.