scholarly journals Drought Affected Ecosystem Water Use Efficiency of a Natural Oak Forest in Central China

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 839
Author(s):  
Xiaodong Niu ◽  
Shirong Liu
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Central China ◽  
Surface Conductance ◽  
Oak Forest ◽  
Summer Drought ◽  
Water Regulation ◽  
Seasonal Drought ◽  
Ecosystem Water Use Efficiency ◽  
Use Efficiency

Global climate models project more frequent drought events in Central China. However, the effect of seasonal drought on ecosystem water use efficiency (WUE) and water regulation strategy in Central China’s natural forests is poorly understood. This study investigated variations in WUE associated with drought in a natural oak (Quercus aliena) forest in Central China from 2017 to 2020 at several timescales based on continuous CO2 and water vapor flux measurements. Results showed that the 4-year mean gross ecosystem production (GEP), evapotranspiration (ET) and WUE of the natural oak forest was 1613.2 ± 116 g Cm−2, 637.8 ± 163.3 mm and 2.6 ± 0.68 g Ckg−1 H2O, with a coefficient of variation (CV) of 7.2%, 25.6% and 26.4%, respectively. The inter-annual variation in WUE was large, primarily due to the variation in ET caused by seasonal drought. Drought increased WUE distinctly in summer and decreased it slightly in autumn. During summer drought, surface conductance (gs) usually decreased with an increase in VPD, but the ratios of stomatal sensitivity (m) and reference conductance (gsref) were 0.21 and 0.3 molm−2s−1ln(kPa)−1 in the summer of 2019 and 2020. Strong drought can also affect ecosystem WUE and water regulation strategy in the next year. Decrease in precipitation in spring increased annual WUE. These results suggested that drought in different seasons had different effects on ecosystem WUE. Overall, our findings suggest that the natural oak forest did not reduce GEP by increasing WUE (i.e., reducing ET) under spring and summer drought, which could be due to its typical anisohydric characteristics, although it can also reduce stomatal opening during long-term drought.

scholarly journals Response of Ecosystem Water Use Efficiency to Drought over China during 1982–2015: Spatiotemporal Variability and Resilience

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 598 ◽  
Author(s):  
Limai Guo ◽  
Fubao Sun ◽  
Wenbin Liu ◽  
Yongguang Zhang ◽  
Hong Wang ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Inner Mongolia ◽  
Northeast China ◽  
Southern China ◽  
Central China ◽  
Spatiotemporal Variability ◽  
Chinese Government ◽  
Ecosystem Water Use Efficiency ◽  
Use Efficiency

Ecosystem water use efficiency (WUE describes carbon-water flux coupling in terrestrial ecosystems. Understanding response and resilience of WUE to drought are essential for sustainable water resource and ecosystem management under increasing drought risks over China due to climate warming. Here we analyzed the response of ecosystem WUE to drought (spatiotemporal variability and resilience) over China during 1982–2015 based on an evapotranspiration (ET) dataset based on the model tree ensemble (MTE) algorithm using flux-tower ET measurements and satellite-retrieved GPP data. The results showed that the multiyear average WUE was 1.55 g C kg−1 H2O over China. WUE increased in 77.1% of Chinese territory during the past 34 years. During drought periods, the ecosystem WUE increased mainly in the northeast of Inner Mongolia, Northeast China and some regions in southern China with abundant forests but decreased in northwestern and central China. An apparent lagging effect of drought on ecosystem WUE was observed in the east of Inner Mongolia and Northeast China, the west and east regions of North China and the central part of Tibetan Plateau. Some ecosystems (e.g., deciduous needle-leaf forests, deciduous broadleaf forests, evergreen broadleaf forests and evergreen needle-leaf forests) in Central China, Northeast and Southwest China exhibited relatively greater resilience to drought than others by improving their WUE. Our findings would provide useful information for Chinese government to adopt a reasonable approach for maintaining the structure and functions of ecosystems under drought disturbance in future.

scholarly journals Water Use Efficiency and Stress Tolerance of the Potential Energy Crop Miscanthus lutarioriparius Grown on the Loess Plateau of China

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 544
Author(s):  
Xuhong Zhao ◽  
Lifang Kang ◽  
Qian Wang ◽  
Cong Lin ◽  
Wei Liu ◽  
...  
Keyword(s):  
Potential Energy ◽  
Water Use Efficiency ◽  
Water Use ◽  
Loess Plateau ◽  
Survival Rates ◽  
Energy Crops ◽  
Central China ◽  
Energy Crop ◽  
Miscanthus Lutarioriparius ◽  
Use Efficiency

As a potential energy crop with high biomass yield, Miscanthus lutarioriparius (M. lutarioriparius), endemic to the Long River Range in central China, needs to be investigated for its acclimation to stressful climatic and soil conditions often found on the marginal land. In this study, traits related to acclimation and yield, including survival rates, plant height (PH), stem diameter (SD), tiller number (TN), water use efficiency (WUE), and photosynthetic rates (A), were examined for 41 M. lutarioriparius populations that transplanted to the arid and cold Loess Plateau of China. The results showed that the average survival rate of M. lutarioriparius populations was only 4.16% over the first winter but the overwinter rate increased to 35.03% after the second winter, suggesting that plants having survived the first winter could have acclaimed to the low temperature. The strikingly high survival rates over the second winter were found to be 95.83% and 80.85%, respectively, for HG18 and HG39 populations. These populations might be especially valuable for the selection of energy crops for such an area. Those individuals surviving for the two consecutive winters showed significantly higher WUE than those measured after the first winter. The high WUE and low stomatal conductance (gs) observed in survived individuals could have been responsible for their acclimation to this new and harsh environment. A total of 61 individuals with productive growth traits and strong resistance to cold and drought were identified for further energy crop development. This study showed that the variation of M. lutarioriparius held great potential for developing energy crops following continuous field selection.

scholarly journals Seasonal drought may alter N availability but not water use efficiency of dominant trees in a subtropical forest

2018 ◽  
Vol 16 ◽  
pp. e00475 ◽  
Author(s):  
Songbo Tang ◽  
Yimin Xu ◽  
Yongbiao Lin ◽  
Enqing Hou ◽  
Weijun Shen ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Subtropical Forest ◽  
N Availability ◽  
Seasonal Drought ◽  
Use Efficiency

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.

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