Shrub encroachment decreases soil inorganic carbon stocks in Mongolian grasslands

作  者:Liu SS, Zhou LH, Li H, Zhao X, Yang YH, Zhu YK, Hu HF, Chen LY, Zhang PJ, Shen HH*, Fang JY*
影响因子:5.687
刊物名称:Journal of Ecology
出版年份:2020
卷:108  期:2  页码:678-686

论文摘要:

1. Widespread shrub encroachment in global drylands may increase plant biomass and change soil organic carbon stocks of grassland ecosystems. However, the response of soil inorganic carbon (SIC), which is a major component of dryland carbon pools, to this vegetation shift remains unknown.

2. We conducted a systematic field survey in 75 pairs of shrubencroached grassland (SEG) and control plots at 25 sites in the grasslands of the Inner Mongolia Plateau to evaluate how shrub encroachment affects SIC density (SICD) in these ecosystems.

3. We found that shrub encroachment significantly reduced SICD in the upper 100 cm (3.85 vs. 4.74 kg C m-2, p < .05), especially in the subsurface soil (20– 50 cm layer). The magnitude of SICD changes was related to the change in soil pH, shrub patch size and initial SICD, reflecting that the reduction in SICD might be attributed to the shrub encroachmentrelated soil acidification. Our results also revealed that the lost SIC was mainly released into the atmosphere rather than redistributed into deeper soil layers.

4. Synthesis. We provide the first evidence for the soil acidificationinduced SIC loss caused by shrub encroachment. Our findings highlight the nonnegligible role of SIC dynamics in the C budget of SEG ecosystems and the need to consider these dynamics in terrestrial C cycle research.

全文链接:https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2745.13298