Abstract: Dissolved organic carbon (DOC) in plant litter is one of the main sources of soil DOC, and the DOC leaching process of plant litter plays an important role in the ecosystem C cycle. Alpine timberline ecotone responses sensitively to climate change in the terrestrial ecosystem. Differences in decomposition microenvironment caused by different vegetation zones may affect DOC leaching from litter at alpine timberline ectone, which further have important impacts on C cycle in alpine ecosystem. In this study, field litterbag technology was taken to investigate the potential effects of three decomposition habitats on the DOC leaching from decomposing litter of 12 plant species at an alpine timberline ectone of Miyaluo, western Sichuan, China between October 2012 and May 2013. The results showed that: 1) the initial concentrations of DOC in litter of the 12 plant species ranged from 22.78 to 178.8 g·kg^-1, and showed a significant difference among species; 2) after a snow-covered season (182 d), litter DOC leaching loss rate was in the range of 18.92% and 62.33%, which responded differently to decomposition habitats; 3) decomposition habitats had significant effects on the litter DOC leaching loss, and the litter DOC leaching loss rate in the coniferous forest habitat was higher than that in the timberline and the alpine meadow; 4) snow cover was the most important factor controlling litter DOC leaching during winter at the alpine timberline ecotone. Our results suggested that the differences in snow distribution contributed to the spatial variability of leaching of DOC from decomposing litter, and the thicker snow cover favored more leaching of DOC from decomposing litter during the snow cover period at the alpine timberline ectone.

Key words: paper bag, grape berries, volatile constituent