Abstract:This study used a field sampling survey and laboratory analysis to investigate the different characteristics of community structure, above/belowground biomass, plant composition and diversity, root proportions in different soil layers, and soil physiochemical properties between alpine steppes and alpine meadows in the Qinghai-Tibetan Plateau. Five degradation stages were identified including non-degradation (ND), light degradation (LD), moderate degradation (MD), severe degradation (SD), and extreme degradation (ED). The results are as follows:(1) as degradation level increased, graminoid dominance in alpine steppes remained unchanged, but sedges in alpine meadows were gradually replaced by the subdominant forb species. (2) With increased alpine steppe degradation, there was a significant decrease in aboveground biomass (P<0.05). The grassland degradation did not affect significantly aboveground biomass with the exception of ED alpine meadows (P<0.05). The response of underground biomass to degradation in alpine meadows was more sensitive compared with alpine steppes. (3) The aboveground sedge biomass exhibited invisible trends with the increase of alpine steppe degradation. The proportion of aboveground graminoid biomass decreased from 88.12% (ND) to 53.54% (ED), while that of forbs increased from 0.08% (ND) to 42.81% (ED). In the process of the ecological succession of alpine meadow degradation, the aboveground graminoid and forb biomass significantly increased except a decrease in ED areas. The contribution of aboveground sedge biomass decreased from 69.15% (ND) to 0.04% (ED), while that of forbs increased from 12.56% (ND) to 92.61% (ED). (4) The alpine steppe root systems showed the increased shallowness as degradation levels increased. However, the alpine meadows showed an opposite trend. (5) The study determined that soil water content (θ), soil organic carbon (SOC), total nitrogen (TN), and bulk density (BD) of alpine meadows were more intensively influenced by degradation compared to those of alpine steppes. The results could provide a valuable reference for the restoration of the degraded grassland in the Qinghai-Tibetan Plateau.