scholarly journals Assessing the spatiotemporal dynamics of ecosystem water use efficiency across China and the response to natural and human activities

2021 ◽  
Vol 126 ◽  
pp. 107680
Author(s):  
Guangchao Li ◽  
Wei Chen ◽  
Ruren Li ◽  
Xuepeng Zhang ◽  
Jialiang Liu
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Human Activities ◽  
Spatiotemporal Dynamics ◽  
Ecosystem Water Use Efficiency ◽  
Use Efficiency

scholarly journals Effects of Climate Factors and Human Activities on the Ecosystem Water Use Efficiency throughout Northern China

2019 ◽  
Vol 11 (23) ◽  
pp. 2766 ◽  
Author(s):  
Xiaozheng Du ◽  
Xiang Zhao ◽  
Tao Zhou ◽  
Bo Jiang ◽  
Peipei Xu ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Human Activities ◽  
Large Scale ◽  
Terrestrial Ecosystems ◽  
Northern China ◽  
Climate Factors ◽  
Ecosystem Water Use Efficiency ◽  
Use Efficiency ◽  
The Impact

Global climate changes have increased the imbalance of water resources, especially in northern China, which comprises typical arid and semiarid regions. Large-scale afforestation has been implemented over the past three decades in northern China. The ecosystem water use efficiency (WUE) connects the carbon cycle and water cycle of the terrestrial ecosystems and is defined as the ratio of the gross primary productivity (GPP) to the evapotranspiration. However, there are still an insufficient number of studies on the impact of the afforestation on the WUE. In this study, we applied the random forest (RF) model to explore the impacts of climate and nonclimate factors on the WUE in northern China. The results showed that in areas with high precipitation, the forests had the highest WUE, while in the arid areas, the croplands had the highest WUE. Of the total area, 44.34% showed a significant increase, and 5.89% showed a significant decrease in the WUE from 1982–2015 in northern China. The main driving factors for the changes in the WUE were climate factors, including the precipitation, temperature and solar radiation, which contributed to approximately 84% of the WUE trends, while human activities, such as afforestation, contributed to approximately 16% of the WUE trends. Overall, although the climate had a larger impact on the WUE dynamics than the human activities, our results suggested that the impacts of the afforestation programs on forest carbon and water cycles should be considered in the context of climate change.

scholarly journals Assessing the Response of Ecosystem Water Use Efficiency to Drought During and after Drought Events across Central Asia

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 581 ◽  
Author(s):  
Jie Zou ◽  
Jianli Ding ◽  
Martin Welp ◽  
Shuai Huang ◽  
Bohua Liu
Keyword(s):  
Water Use Efficiency ◽  
Central Asia ◽  
Water Use ◽  
Severe Drought ◽  
Vegetation Types ◽  
Drought Period ◽  
Legacy Effect ◽  
Ecosystem Water Use Efficiency ◽  
Use Efficiency ◽  
The Mean

The frequency and intensity of drought are expected to increase worldwide in the future. However, it is still unclear how ecosystems respond to drought. Ecosystem water use efficiency (WUE) is an essential ecological index used to measure the global carbon–water cycles, and is defined as the carbon absorbed per unit of water lost by the ecosystem. In this study, we applied gross primary productivity (GPP), evapotranspiration (ET), land surface temperature (LST), and normalized difference vegetation index (NDVI) data to calculate the WUE and drought index (temperature vegetation dryness index (TVDI)), all of which were retrieved from moderate resolution imaging spectroradiometer (MODIS) data. We compared the mean WUE across different vegetation types, drought classifications, and countries. The temporal and spatial changes in WUE and drought were analyzed. The correlation between drought and WUE was calculated and compared across different vegetation types, and the differences in WUE between drought and post-drought periods were compared. The results showed that (1) ecosystems with a low (high) productivity had a high (low) WUE, and the mean ecosystem WUE of Central Asia showed vast differences across various drought levels, countries, and vegetation types. (2) The WUE in Central Asia exhibited an increasing trend from 2000 to 2014, and Central Asia experienced both drought (from 2000 to 2010) and post-drought (from 2011 to 2014) periods. (3) The WUE showed a negative correlation with drought during the drought period, and an obvious drought legacy effect was found, in which severe drought affected the ecosystem WUE over the following two years, while a positive correlation between WUE and drought was found in the post-drought period. (4) A significant increase in ecosystem WUE was found after drought, which revealed that arid ecosystems exhibit high resilience to drought stress. Our results can provide a specific reference for understanding how ecosystems will respond to climate change.

Environmental and canopy stomatal control on ecosystem water use efficiency in a riparian poplar plantation

2020 ◽  
Vol 287 ◽  
pp. 107953 ◽  
Author(s):  
Hang Xu ◽  
Zhiqiang Zhang ◽  
Jingfeng Xiao ◽  
Jiquan Chen ◽  
Mengxun Zhu ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Poplar Plantation ◽  
Stomatal Control ◽  
Ecosystem Water Use Efficiency ◽  
Use Efficiency
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