Characteristics of water use efficiency in terrestrial ecosystems and its influence factors in Ningxia Province

Water use efficiency (WUE) measures the tradeoff between carbon uptake and water consumption in terrestrial ecosystems. It remains unclear how the responses of WUE to drought vary with drought severity. We assessed the spatio-temporal variations of ecosystem WUE and its responses to drought for terrestrial ecosystems in Southwest China over the period 2000–2017. The annual WUE values varied with vegetation type in the region: Forests (3.25 gC kg−1H2O) > shrublands (2.00 gC kg−1H2O) > croplands (1.76 gC kg−1H2O) > grasslands (1.04 gC kg−1H2O). During the period 2000–2017, frequent droughts occurred in Southwest China, and overall, drought had an enhancement effect on WUE. However, the effects of drought on WUE varied with vegetation type and drought severity. Croplands were the most sensitive to drought, and slight water deficiency led to the decline of cropland WUE. Over grasslands, mild drought increased its WUE while moderate and severe drought reduced its WUE. For forests and shrublands, mild and moderate drought increased their WUE, and only severe drought reduce their WUE, indicating that these ecosystems had stronger resistance to drought. Assessing the patterns and trends of ecosystem WUE and its responses to drought are essential for understanding plant water use strategy and informing ecosystem water management.

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Enhanced water use efficiency in global terrestrial ecosystems under increasing aerosol loadings

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2017.02.002 ◽

2017 ◽

Vol 237-238 ◽

pp. 39-49 ◽

Cited By ~ 14

Author(s):

Xiaoliang Lu ◽

Min Chen ◽

Yaling Liu ◽

Diego G. Miralles ◽

Faming Wang

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Terrestrial Ecosystems ◽

Use Efficiency

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Contrasting responses of water use efficiency to drought across global terrestrial ecosystems

Scientific Reports ◽

10.1038/srep23284 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 88

Author(s):

Yuting Yang ◽

Huade Guan ◽

Okke Batelaan ◽

Tim R. McVicar ◽

Di Long ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Terrestrial Ecosystems ◽

Use Efficiency

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Quantifying Soil Moisture Impacts on Water Use Efficiency in Terrestrial Ecosystems of China

Remote Sensing ◽

10.3390/rs13214257 ◽

2021 ◽

Vol 13 (21) ◽

pp. 4257

Author(s):

Xingming Hao ◽

Jingjing Zhang ◽

Xue Fan ◽

Haichao Hao ◽

Yuanhang Li

Keyword(s):

Soil Moisture ◽

Water Use Efficiency ◽

Water Use ◽

Land Surface ◽

Net Primary Production ◽

Terrestrial Ecosystems ◽

Sensitivity Coefficient ◽

Analytical Framework ◽

Average Value ◽

Use Efficiency

Soil moisture (SM) significantly affects the exchange of land surface energy and the stability of terrestrial ecosystems. Although some conclusions have been drawn about the effects of SM on the ecosystem water use efficiency (WUE), the influence mechanism and the quantitative assessment framework of SM on WUE are still unclear. This study provides an analysis framework for the feedback relationship between SM and WUE based on the dependence of the evaporation fraction on SM and output datasets from remote sensing and the Global Land Data Assimilation System. The results show that the range of WUE of terrestrial ecosystems of China was0.02–19.26 g C/kg H2O in the growing season with an average value of 1.05 g C/kg H2O. They also show a downward trend in43.99% of the total area. In the evapotranspiration (ET) pathway, SM negatively affected WUE, and the sensitivity coefficient ranged from −18.49 to −0.04. In the net primary production (NPP) pathway, the sensitivity coefficient ranged from −68.66 to 43.19. Under the dual effects of the ET and NPP pathways, the influence of SM on WUE was negative in 84.62% of the area. Variation in SM led to significant WUE variability. Generally, the percentage change in WUE (ΔWUE) ranged from 0% to 190.86%, with an average value of 28.02%. The maximum ΔWUE ranged from 0% to 758.78%, with an average value of 109.29%. The WUE of forest ecosystems showed strong resistance to SM variation, whereas that of non-forest vegetation was more sensitive to SM variation. This analytical framework provides a new perspective on the feedback relationship between WUE and SM in terrestrial ecosystems.

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Estimation of water use efficiency in the terrestrial ecosystems of the Yangtze River Delta region, China

Terrestrial Atmospheric and Oceanic Sciences ◽

10.3319/tao.2018.09.07.01 ◽

2019 ◽

Vol 30 (2) ◽

pp. df

Author(s):

Fan Wang ◽

Hong Jiang ◽

Min Cheng ◽

Linjing Zhang ◽

Jian Liu ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Yangtze River ◽

Terrestrial Ecosystems ◽

Yangtze River Delta ◽

The Yangtze River ◽

Delta Region ◽

Yangtze River Delta Region ◽

Use Efficiency ◽

The Yangtze River Delta

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AmazonFACE – Assessing the response of Amazon rainforest functioning to elevated atmospheric carbon dioxide concentrations

10.5194/egusphere-egu2020-18290 ◽

2020 ◽

Author(s):

Anja Rammig ◽

Katrin Fleischer ◽

Sabrina Garcia ◽

Nathielly Martins ◽

Juliane Menezes ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Carbon Sink ◽

Global Climate ◽

Terrestrial Ecosystems ◽

Amazon Rainforest ◽

Past Century ◽

Sink Strength ◽

Climate Conditions ◽

Use Efficiency

The rapid rise in atmospheric CO2 concentration over the past century is unprecedented. It has unambiguously influenced Earth&#8217;s climate system and terrestrial ecosystems. Elevated atmospheric CO2 concentrations (eCO2) have induced an increase in biomass and thus, a carbon sink in forests worldwide. It is assumed that eCO2 stimulates photosynthesis and plant productivity and enhances water-use efficiency &#8211; the so-called CO2-fertilization effect, which may provide an important buffering effect for plants during adverse climate conditions. For these reasons, current global climate simulations consistently predict that tropical forests will continue to sequester more carbon in aboveground biomass, partially compensating human emissions and decelerating climate change by acting as a carbon sink. In contrast to model simulations, several lines of evidence point towards a decreasing carbon sink strength of the Amazon rainforest. Reliable predictions of eCO2 effects in the Amazon rainforest are hindered by a lack of process-based information gained from ecosystem scale eCO2 experiments. Here we report on baseline measurements from the Amazon Free Air CO2 Enrichment (AmazonFACE) experiment and preliminary results from open-top chamber (OTC) experiments with eCO2. After three months of eCO2, we find that understory saplings increased carbon assimilation by 17% (under light saturated conditions) and water use efficiency by 39% in the OTC experiment. We present our main hypotheses for the FACE experiment, and discuss our expectations on the potential driving processes for limiting or stimulating the Amazon rainforest carbon sink under eCO2. We focus on possible effects of eCO2 on carbon uptake and allocation, nutrient cycling, water-use and plant-herbivore interactions, which need to be implemented in dynamic vegetation models to estimate future changes of the Amazon carbon sink.

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

Remote Sensing ◽

10.3390/rs11232766 ◽

2019 ◽

Vol 11 (23) ◽

pp. 2766 ◽

Cited By ~ 1

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.

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