Aims Few comparative studies have been conducted on the decomposition of the plant litters from different geographical sources in the same site.We aimed to understand the effect of geographical sources and biochemical traits of peatland plants on litter decomposition.Methods Along a latitudinal gradient,we collected plant materials from three peatlands,Dajiuhu,Hani and Mangui,to carry out a one-year decomposition experiment with litter bags in Hani Peatland,Changbai Mountains.Important findings When species identity was not considered,we found that overall initial nitrogen (N) content decreased while initial lignin content,carbon nitrogen ratio (C/N) and lignin/N increased with latitude in the litters from 3 peatlands.Litter decomposition differed with plant functional groups.After one year of decomposition,dry mass loss of both birch and sedge (ca.50%) was higher than that of peat mosses (ca.10%).No significant difference was observed in litter dry mass loss among different geographical sources.However,dry mass loss of Sphagnum magellanicum from the middle latitudinal peatland (19%) was higher than that from the high latitudinal site (9%).The factors affecting litter decomposition differed among plant functional groups.Initial total phenolics/N was the important factor to determine the difference in litter dry mass loss among the 3 genera.The initial N content and C/N,and Klason lignin content and total phenolics/N were positively related to litter decomposition of Carex and Sphagnum,respectively.If the decrease in latitude is used to indicate climate warming,to some extent,our study suggests that current climate warming,by changing the plant composition and biochemical traits,may alter litter decomposition and even carbon accumulation in high latitudinal peatlands.