Litter decomposition is a key process controlling carbon (C) sequestration in Sphagnum dominated peatlands. Peatland drainage lowers the water table, increases vascular plant richness, and alters species evenness. We hypothesized that abiotic and biotic changes following peatland drainage would greatly accelerate litter decomposition. This hypothesis was tested by a litter decomposition experiment in an undrained and a drained area of a peatland which was partially drained 30 years ago. Litter bags filled with shoots of the peat moss Sphagnum magellanicum and leaves of the dwarf shrub Potentilla fruticosa as single species and species mixtures with three evenness treatments were placed at the surface of the peatland. After 6 months (from August onwards) of decomposition, the single species litter of Potentilla fruticosa, with low initial C/N ratio, decomposed much faster than S. magellanicum litter, with high initial C/N ratio in both undrained and drained areas. Overall, mixed litter produced antagonistic effects (observed values less than expected) on decomposition and C/N ratio. Litter mixtures dominated by S. magellanicum showed lower mass loss than other mixtures. Contrary to our expectation, the undrained area showed higher decomposition than the drained area. Our study suggests that drainage-induced alteration in plant diversity slows down litter decomposition in a short term. However, in drained peatlands, lower C/N ratio of mixed litter may enhance decomposition and reduce C sequestration over time.

凋落物分解是控制以泥炭藓为主的泥炭地中碳 (C) 封存的关键过程。泥炭地排水降低了地下水位，增加了维管植物的丰富度，并改变了物种的均匀度。我们假设泥炭地排水后的非生物和生物变化会大大加速凋落物分解。该假设通过在 30 年前部分排水的泥炭地的不排水和排水区域中的凋落物分解实验进行了检验。装满泥炭藓Sphagnum magellanicum枝条和矮灌木Potentilla fruticosa叶子的垃圾袋作为单一物种和具有三种均匀度处理的物种混合物被放置在泥炭地表面。分解的6个月（从八月起）后，的单个物种垫料委陵˚F ruticosa，具有低的初始C / N比，分解速度远远超过S. magellanicum垫料，具有较高的初始C / N比在两者不排水和排出区. 总体而言，混合凋落物对分解和 C/N 比产生了拮抗作用（观察值小于预期）。以S. magellanicum为主的垫料混合物表现出比其他混合物更低的质量损失。与我们的预期相反，不排水区域比排水区域显示出更高的分解。我们的研究表明，排水引起的植物多样性改变会在短期内减缓凋落物分解。然而，在排水泥炭地中，混合凋落物的较低 C/N 比可能会随着时间的推移增强分解并减少 C 封存。