Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 4888 Shengbei Rd, Changchun 130102, China; The Three Gorges Institute of Ecological Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, 266 Fangzheng Rd, Chongqing 400714, China.
Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 4888 Shengbei Rd, Changchun 130102, China.
Sci Total Environ. 2018 Jun 1;626:678-683. doi: 10.1016/j.scitotenv.2018.01.162. Epub 2018 Feb 19.
In boreal peatlands, litter decomposition plays an important role in modulating ecosystem carbon (C) cycling and nutrient turnover. However, how climate warming and plant functional group interact to affect litter decomposition is still unclear in these ecosystems. Here, we collected fresh litters of six plant functional groups (nitrogen (N)-fixing species, deciduous tree, deciduous shrub, evergreen shrub, graminoid, and Sphagnum moss) from a boreal peatland located in northeast China. A laboratory incubation experiment was used to determine the effect of temperature (10 °C vs. 20 °C) on microbial respiration and mass loss during decomposition. Among the six functional groups, the litters of N-fixing species and deciduous shrub, followed by deciduous tree, generally had the greatest mass losses and microbial respiration rates, whereas the Sphagnum moss decomposed with the slowest rate at both incubation temperatures. Increasing incubation temperature from 10 °C to 20 °C, microbial respiration rate and mass loss increased slightly for Sphagnum moss litters (25% and 19%, respectively), but increased dramatically for vascular plant litters (84-135% and 49-85%, respectively). For litters from vascular plants, both decomposition rate and temperature sensitivity showed a tight linear correlation with the initial C:N and C:phosphorus ratios. Considering that climate warming will cause increased dominance of woody plant species coupled with decreased cover by Sphagnum mosses, this study provides clear evidence that climate warming and the associated changes to vegetation community composition can synergistically accelerate plant litter decomposition in boreal peatlands.
在北方泥炭地中，凋落物分解在调节生态系统碳（C）循环和养分周转方面起着重要作用。然而，在这些生态系统中，气候变暖与植物功能群如何相互作用来影响凋落物分解仍不清楚。在这里，我们从位于中国东北的北方泥炭地收集了六种植物功能群（固氮物种、落叶乔木、落叶灌木、常绿灌木、草本植物和泥炭藓）的新鲜凋落物。使用实验室培养实验来确定温度（10°C 与 20°C）对微生物呼吸和分解过程中质量损失的影响。在这六个功能群中，固氮物种和落叶灌木的凋落物，其次是落叶乔木，通常具有最大的质量损失和微生物呼吸速率，而在两种培养温度下，泥炭藓的分解速度最慢。将培养温度从 10°C 升高到 20°C 时，泥炭藓凋落物的微生物呼吸速率和质量损失分别略有增加（分别为 25%和 19%），但维管束植物凋落物的增加幅度很大（分别为 84-135%和 49-85%）。对于维管束植物的凋落物，分解速率和温度敏感性与初始 C:N 和 C:磷比均呈紧密的线性相关。考虑到气候变暖将导致木本植物物种的优势增加，同时泥炭藓的覆盖减少，本研究提供了明确的证据，表明气候变暖以及相关的植被群落组成变化可以协同加速北方泥炭地的植物凋落物分解。
