Abstract: Litter decomposition is an important part of the carbon cycle in terrestrial ecosystems, and temperature is a key determining factor of litter decomposition rate. This research explored the effects of warming on the decomposition of plant litter from alpine meadow grasslands in Northwestern Sichuan, using open-top chambers (OTCs) and the decomposition-bag method, to study the effects of warming on the litter decomposition rate of dominant species: Elymus nutans, Deschampsia caespitosa, Foeniculum vulgare, Potentilla anserine, Artemisia mongolica, Saussurea stella, and Saussurea nigrescens. The decomposition bags in this experiment contained mixed aboveground litter and community root litter from the dominant plant species. It was found that: 1) Warming did not significantly change the decomposition cycle of mixed aboveground litter, but significantly improved the decomposition efficiency of root litter. The decomposition-cycle responses of aboveground and underground litter to temperature changesdiffered. 2) Although there were significant differences in nutrient content and stoichiometric characteristics of litter from different plant species (P<0.05), compared with natural decomposition conditions, warming had no significant effect on the decomposition efficiency and the decomposition and release process of litter from individual plant species. In summary, the decomposition process of aboveground litter in the alpine meadow ecosystem in Northwestern Sichuan did not respond significantly to simulated warming, but simulated warming significantly affected the decomposition process of underground litter.

Key words: warming, litter, alpine meadow, Tibetan Plateau