Plant Functional-Group Differentiation and Soil Property Variation Across Hummock–Hollow Microtopography in an Alpine Sedge Peatland on the Qinghai–Tibetan Plateau

Hummock–hollow microtopography is associated with fine-scale variation in vegetation and soil properties in alpine peatlands. In this study, we compared plant diversity, aboveground biomass of functional groups, and soil properties between hummocks and hollows in five paired plots in an alpine sedge peatland on the Qinghai–Tibetan Plateau. Total aboveground biomass averaged 286.38 g m−2 in hollows and 228.32 g m−2 on hummocks. Hollows had greater sedge and grass biomass, whereas hummocks had greater forb biomass and higher plant diversity. Soil water content, total carbon, total nitrogen, nitrate nitrogen, and ammonium nitrogen were higher in hollows, whereas soil pH was higher in hummocks. Soil C:N and C:P ratios were lower in hummocks, whereas Olsen-P and N:P did not differ significantly between microforms. Pooled associations of functional-group biomass with plant diversity and soil properties largely paralleled these microform contrasts. These findings indicate that total aboveground biomass alone does not fully characterize vegetation differences between microforms and suggest that microtopographic variation should be considered when assessing vegetation and soil conditions in alpine peatlands.