Chin J Plan Ecolo ›› 2016, Vol. 40 ›› Issue (9): 902-911.DOI: 10.17521/cjpe.2016.0029

• Research Articles • Previous Articles     Next Articles

Characteristics of methane emission fluxes in the Zoigê Plateau wetland on microtopography

Wen-Chang ZHOU1,2, Li-Juan CUI1,*(), Yi-Fei WANG1, Wei LI1, Xiao-Ming KANG1   

  1. 1Beijing Key Laboratory of Wetland Services and Restoration, Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China
    and
    2Hubei Academy of Forestry, Wuhan 430075, China
  • Received:2016-01-17 Accepted:2016-05-09 Online:2016-09-10 Published:2016-09-29
  • Contact: Li-Juan CUI

Abstract:

AimsThe Zoigê Plateau, as a very important wetland distribution region of China, was the major methane (CH4) emission center of the Qinghai-Xizang Plateau. The objective of this study is to study the effects of microtopographic changes on CH4 emission fluxes from five plots across three marshes in the littoral zone of the Zoigê Plateau wetland.
Methods CH4 emission fluxes were measured in five plots across three marshes in Zoigê Plateau wetland using the closed chamber method and Fast Greenhouse Gas Analyzer from May to October in 2014.
Important findings During the growing season, mean CH4 emission fluxes from the permanently flooded hollow (P-hollow) and hummock (P-hummock) in the Zoigê Plateau wetland were 68.48 and 40.32 mg·m-2·h-1, while mean CH4 emission fluxes from the seasonally flooded hollow (S-hollow) and hummock (S-hummock) were 2.38 and 0.63 mg·m-2·h-1. CH4 emission fluxes from non-flooded lawn was 3.68 mg·m-2·h-1. Mean CH4 emission fluxes from five plots across three sites was 23.10 mg·m-2·h-1, with a standard deviation of 30.28 mg·m-2·h-1 and the coefficient of variation was 131%. We also found that there was a significant and positive correlation between mean CH4 emission fluxes and mean water table depth in the five plots across three sites (R2 = 0.919, p < 0.01), indicating that water table depth was controlling the spatial variability of CH4 emission fluxes from the Zoigê Plateau wetland on microtopography. CH4 emission fluxes in the P-hollow, P-hummock, and S-hummock showed an obvious seasonal pattern, which was not observed in the lawn and S-hollow. However, CH4 emission peaks were observed in all the plots during summer and/or autumn, which could be closely related to the water table depth, soil temperature, and the magnitude of litter mass. In addition, we found that the CH4 emission flux in the P-hollow was much higher than the other four plots in the Zoigê Plateau wetland, suggesting that CH4 in the P-hollow could be often transported to the surface by ebullition and CH4 emission from the Zoigê Plateau wetland may be under estimated in the past.

Key words: CH4 emission flux, hummock, hollow, lawn, Zoigê Plateau wetland