J Plant Ecol ›› 2018, Vol. 11 ›› Issue (6): 877-886 .DOI: 10.1093/jpe/rtx054

• Research Articles • Previous Articles     Next Articles

Spatiotemporal variations of CO2 fluxes in a Cynodon-dominated riparian zone of the Three Gorges Reservoir (TGR), China

Wenli Zhang1,2,*, Jiquan Chen3, Ju Liu1, Fangqing Chen1,2, Quanfa Zhang4, Zutao Ouyang3, Changliang Shao3, Yi Fan3 and#br# Wennian Xu2,*   

  1. 1 College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, Hubei 443002, China
    2 Hubei International Scientific and Technological Cooperation Center of Ecological Conservation and Management in Three Gorges Area, China Three Gorges University, Yichang, 443002, China
    3 Center for Global Change and Earth Observations /Geography, Environment and Spatial Sciences, Michigan State University, East Lansing, MI 48823, USA
    4 Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan 430074, China
    *Correspondence address. Wenli Zhang and Wennian Xu, College of Biological and Pharmaceutical Sciences, China Three Gorges University, No.8 Daxue Road, Yichang, Hubei 443002, China. Tel: +86 07176395580; E-mail: wendyibcas@163.com, 814194318@qq.com
  • Received:2016-08-22 Revised:2017-09-16 Accepted:2017-09-28 Online:2017-10-03 Published:2018-12-21



Riparian ecosystems play an important role in overall ecosystem function, including the global carbon cycle of terrestrial ecosystems, at both landscape and global scales. Yet few studies have reported in situ measurements of CO2 in riparian areas where flooding is a unique disturbance to carbon cycling.


At multiple locations across riparian zones (RZ) with different water submergences in Xiangxi Bay (XXB), we studied seasonal variations of COexchange between this Cynodon-dominated community and the atmosphere for 2 years by using static chambers.

Important Findings

We found that the seasonal changes in CO2 fluxes were apparent and dependent on the biophysical environment. In the beginning of spring, low gross primary productivity (GPP) in lightly flooded zones (LFZ) resulted in a positive net ecosystem exchange (NEE), indicating a net CO2 source. With the increase in temperature, more species and vegetation abundance appeared, and the increased GPP turned the LFZ from a net CO2 source into a sink. This transition seemed predominantly controlled by the physiological growth of vegetation. The mean NEEs, REs and the light-use efficiency (α) of the vegetation at HFZ and MFZ were significantly higher than those at LFZ and UFZ. Yet the coefficients of variation (CV) of NEE and RE at MFZ and HFZ were lower than those at LFZ and UFZ. Submergence promoted the emission and uptake of COto the atmosphere. Elongated submergence reduced the number of species and lowered the spatial variability of the RZ, further lowering the variation of the CO2 exchange.

Key words: CO2 exchange, riparian, submergence, spatial variability, Q10, TGD