Research

►　  Carbon balance of alpine grassland ecosystem carbon

Despite the large difference in time between carbon uptake and release (carbon uptake < release time), the Kobresia humilis meadow and shrub meadow were carbon sink (78.5～192.5gCm-2yr-1and 58.5～75.5gCm-2yr-1, respectively), while swamp meadow’s annual atmospheric release is16.10～76.73gCm-2yr-1. This is probably because the ecosystem respiration at our site was confined significantly by low temperature and small biomass and usually soil moisture was not limiting factor for carbon uptake. This proves that the Kobresia humilis meadow and the shrub meadow have relatively low potential for CO₂ uptake and release compared to C4 grasslands, a number of lowland grasslands, and forests. Moreover, swamp meadow has relatively high release potential.