青藏高原东北边缘区不同草地类型碳密度及其影响因素研究OA

Carbon density varies among grassland types owing to differences in productivity and soil properties.This study focused on the northeastern marginal area of the Qinghai-Xizang Plateau.Based on systematic investigations at 108 sampling sites and laboratory analyses,this study aimed to reveal the carbon density patterns of different grassland types and their key influencing factors.The results indicate that within the study area,vegetation and soil carbon densities decreased significantly along a gradient from alpine meadow,mountain meadow,and temperate meadow steppe to temperate steppe.The alpine meadow exhibited the highest carbon density,whereas the temperate steppe displayed the lowest.Belowground root biomass constituted the predominant component of the ecosystem carbon pool,accounting for an average proportion exceeding 60%.Grassland types differed in the dominant component of their carbon density:Soil inorganic carbon dominated in the temperate steppe and temperate meadow steppe,while soil organic carbon prevailed in the alpine meadow and montane meadow,contributing 65.87%-91.34%of the soil carbon pool.The carbon density in alpine meadows was synergistically regulated by the slope aspect and plant species richness,whereas that in montane meadows was influenced by multiple factors including the grazing intensity,slope position,and vegetation coverage.In temperate steppes,the carbon density was primarily controlled by grazing management regimes,whereas in temperate meadow steppes,it was predominantly governed by altitudinal gradients.These findings provide a scientific basis for implementing"zoning-classification-grading"precision management for different grassland types in the northeastern margin of the Qinghai-Xizang Plateau and for enhancing regional carbon sink capacity.