scholarly journals INFLUENCE OF SEASONAL DROUGHT ON ECOSYSTEM WATER USE EFFICIENCY IN A SUBTROPICAL EVERGREEN CONIFEROUS PLANTATION

2016 ◽  
Vol 14 (3) ◽  
pp. 33-50
Author(s):  
N. MI
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Seasonal Drought ◽  
Coniferous Plantation ◽  
Ecosystem Water Use Efficiency ◽  
Use Efficiency

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 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.

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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