Abstract: Global warming is profoundly affecting litter decomposition in plateau ecosystems. We evaluated the impacts of warming on the litter decomposition rate in a Zoige alpine marsh on the Tibetan Plateau. Based on the field manipulative experiments and laboratory incubation experiments, we analyzed the effects of warming on litter decomposition rates of Carex muliensis, the contents of carbon (C), nitrogen (N) and phosphorus (P) of decomposing litter, and CO₂ flux during one-year decomposition. The results showed that: (1) Warming significantly increased the soluble sugar content in the litter of C. muliensis (P<0.05), while significantly decreased lignin content and C/N ratio (P<0.05). (2) After one-year decomposition, warming resulted in a decrease of 33.98% in litter mass, being significantly greater than that of 28.84% in the control (P<0.05). (3) The contents of C, N, and P in the litter all showed a decreasing trend during decomposition, with the decline being much greater in summer than that in spring and autumn. (4) During the rapid decomposition phase, CO₂ flux under warming treatment was significantly higher than that in the control (P<0.01). CO₂ flux had a significant positive correlation with surface temperature (r=0.82, P<0.05) and litter mass loss (r=0.77, P<0.01). Our results help elucidate litter decomposition dynamics and its environmental effects in highaltitude marshes under warming conditions.

Key words: warming, litter decomposition, Qinghai Tibet Plateau, alpine swamp