Water and carbon fluxes of artificial shrub vegetation have been extensively documented at the stand scale in arid and semi-arid regions. However, the carbon source/sink pattern of artificial vegetation is still uncertain regarding varied species, meteorological and hydrological conditions. 

Researchers from the Northwest Institute of Eco-Environment and Resources (NIEER) of the Chinese Academy of Sciences (CAS) assessed water and carbon fluxes and their influencing factors of an artificial Haloxylon ammodendron shrubland in arid region, northwest China. 

The study was published in Journal of Environmental Management on June 16. 

The researchers found that the actual annual evapotranspiration (ET) in 2021 was 189.5 mm, of which 85% (150 mm) occurred during the growing season. The total gross primary production (GPP) and ecosystem respiration (Re) were 598.7 and 152.3g C m^-2 yr^-1, respectively, and the net ecosystem productivity (NEP) was 446.4 g C m^-2 yr^-1, which was much higher than that of other surrounding shrubs, indicating that the ecosystem is a strong carbon sink. 

Random Forest showed that the total contribution rate of environmental factors to GPP and ET was 71.56% and 80.07%, respectively. However, the effects of different environmental factors on GPP and ET were different. 

According to Structural Equation Model, soil hydrothermal factors (soil water content and soil temperature) determined the size and seasonal pattern of ET and respiration (Re), while aerodynamic factors (net radiation, atmospheric temperature and wind speed) determined GPP and NEP. 

Heterogeneous response of abiotic factors determines the decoupling of carbon and water fluxes in artificial desert shuttle forests. Haloxylon ammodendron, with its low water consumption and high carbon sequestration, is a suitable shrub for large-scale artificial vegetation restoration in arid areas, especially in sandy areas. 

"Our study helps to sustainably manage the artificial vegetation and provides guidance for dryland conservation and afforestation in the future," said Prof. YU Tengfei from NIEER, first author of the study. 

YU Tengfei