Responses of Water Use Efficiency to Drought in Southwest China

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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Remote Sensing of Water Use Efficiency and Terrestrial Drought Recovery across the Contiguous United States

Remote Sensing ◽

10.3390/rs11060731 ◽

2019 ◽

Vol 11 (6) ◽

pp. 731 ◽

Cited By ~ 16

Author(s):

Behzad Ahmadi ◽

Ali Ahmadalipour ◽

Glenn Tootle ◽

Hamid Moradkhani

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Land Surface ◽

Terrestrial Ecosystems ◽

Agricultural Drought ◽

Carbon Gain ◽

Drought Severity ◽

Drought Recovery ◽

Ecosystem Water Use Efficiency ◽

Use Efficiency

Ecosystem water-use efficiency (WUE) is defined as the ratio of carbon gain (i.e., gross primary productivity; GPP) to water consumption (i.e., evapotranspiration; ET). WUE is markedly influential on carbon and water cycles, both of which are fundamental for ecosystem state, climate and the environment. Drought can affect WUE, subsequently disturbing the composition and functionality of terrestrial ecosystems. In this study, the impacts of drought on WUE and its components (i.e., GPP and ET) are assessed across the Contiguous US (CONUS) at fine spatial and temporal resolutions. Soil moisture simulations from land surface modeling are utilized to detect and characterize agricultural drought episodes and remotely sensed GPP and ET are retrieved from the moderate resolution imaging spectroradiometer (MODIS). GPP, as the biome vitality indicator against drought stress, is employed to investigate drought recovery and the ecosystems’ required time to revert to pre-drought condition. Results show that drought recovery duration indicates a positive correlation with drought severity and duration, meaning that a protracted drought recovery is more likely to happen following severe droughts with prolonged duration. WUE is found to almost always increase in response to severe (or worse) drought episodes. Additionally, ET anomalies are negatively correlated with drought severity and ET is expected to decrease during severe (or worse) drought episodes. Lastly, the changes of WUE are decomposed in relation to its components and the cross-relation among the variables is revealed and a consistent changing pattern is detected.

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Effects and implications of ecological restoration projects on ecosystem water use efficiency in the karst region of Southwest China

Ecological Engineering ◽

10.1016/j.ecoleng.2021.106356 ◽

2021 ◽

Vol 170 ◽

pp. 106356

Author(s):

Zhi Ding ◽

Ying Liu ◽

Lunche Wang ◽

Yanan Chen ◽

Pujia Yu ◽

...

Keyword(s):

Water Use Efficiency ◽

Ecological Restoration ◽

Water Use ◽

Southwest China ◽

Karst Region ◽

Ecosystem Water Use Efficiency ◽

Use Efficiency

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Comment on "Spatial and temporal variations in plant Water Use Efficiency inferred from tree-ring, eddy covariance and atmospheric observations" by Margriet Groenendijk et al.

10.5194/esd-2016-4-rc2 ◽

2016 ◽

Author(s):

Anonymous

Keyword(s):

Water Use Efficiency ◽

Eddy Covariance ◽

Water Use ◽

Tree Ring ◽

Temporal Variations ◽

Spatial And Temporal Variations ◽

Plant Water ◽

Plant Water Use ◽

Atmospheric Observations ◽

Use Efficiency

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

Sensors ◽

10.3390/s20030581 ◽

2020 ◽

Vol 20 (3) ◽

pp. 581 ◽

Cited By ~ 3

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.

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