25 results on '"Hui, Dafeng"'
Search Results
2. Global Climate Change and Greenhouse Gases Emissions in Terrestrial Ecosystems
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Hui, Dafeng, Deng, Qi, Tian, Hanqin, Luo, Yiqi, Lackner, Maximilian, editor, Sajjadi, Baharak, editor, and Chen, Wei-Yin, editor
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- 2022
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3. Impacts of Climate Change and Agricultural Practices on Nitrogen Processes, Genes, and Soil Nitrous Oxide Emissions: A Quantitative Review of Meta-Analyses.
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Hui, Dafeng, Ray, Avedananda, Kasrija, Lovish, and Christian, Jaekedah
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NITROUS oxide ,AGRICULTURE ,NITRITE reductase ,CLIMATE change ,NITRATE reductase ,AMMONIA-oxidizing bacteria - Abstract
Microbial-driven processes, including nitrification and denitrification closely related to soil nitrous oxide (N
2 O) production, are orchestrated by a network of enzymes and genes such as amoA genes from ammonia-oxidizing bacteria (AOB) and archaea (AOA), narG (nitrate reductase), nirS and nirK (nitrite reductase), and nosZ (N2 O reductase). However, how climatic factors and agricultural practices could influence these genes and processes and, consequently, soil N2 O emissions remain unclear. In this comprehensive review, we quantitatively assessed the effects of these factors on nitrogen processes and soil N2 O emissions using mega-analysis (i.e., meta-meta-analysis). The results showed that global warming increased soil nitrification and denitrification rates, leading to an overall increase in soil N2 O emissions by 159.7%. Elevated CO2 stimulated both nirK and nirS with a substantial increase in soil N2 O emission by 40.6%. Nitrogen fertilization amplified NH4 + -N and NO3 − -N contents, promoting AOB, nirS, and nirK, and caused a 153.2% increase in soil N2 O emission. The application of biochar enhanced AOA, nirS, and nosZ, ultimately reducing soil N2 O emission by 15.8%. Exposure to microplastics mostly stimulated the denitrification process and increased soil N2 O emissions by 140.4%. These findings provide valuable insights into the mechanistic underpinnings of nitrogen processes and the microbial regulation of soil N2 O emissions. [ABSTRACT FROM AUTHOR]- Published
- 2024
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4. Net greenhouse gas balance in U.S. croplands: How can soils be part of the climate solution?
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You, Yongfa, Tian, Hanqin, Pan, Shufen, Shi, Hao, Lu, Chaoqun, Batchelor, William D., Cheng, Bo, Hui, Dafeng, Kicklighter, David, Liang, Xin‐Zhong, Li, Xiaoyong, Melillo, Jerry, Pan, Naiqing, Prior, Stephen A., and Reilly, John
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CLIMATE change ,AGRICULTURAL conservation ,FARMS ,GREENHOUSE gases ,CLIMATE change mitigation - Abstract
Agricultural soils play a dual role in regulating the Earth's climate by releasing or sequestering carbon dioxide (CO2) in soil organic carbon (SOC) and emitting non‐CO2 greenhouse gases (GHGs) such as nitrous oxide (N2O) and methane (CH4). To understand how agricultural soils can play a role in climate solutions requires a comprehensive assessment of net soil GHG balance (i.e., sum of SOC‐sequestered CO2 and non‐CO2 GHG emissions) and the underlying controls. Herein, we used a model‐data integration approach to understand and quantify how natural and anthropogenic factors have affected the magnitude and spatiotemporal variations of the net soil GHG balance in U.S. croplands during 1960–2018. Specifically, we used the dynamic land ecosystem model for regional simulations and used field observations of SOC sequestration rates and N2O and CH4 emissions to calibrate, validate, and corroborate model simulations. Results show that U.S. agricultural soils sequestered 13.2±1.16$$ 13.2\pm 1.16 $$ Tg CO2‐C year−1 in SOC (at a depth of 3.5 m) during 1960–2018 and emitted 0.39±0.02$$ 0.39\pm 0.02 $$ Tg N2O‐N year−1 and 0.21±0.01$$ 0.21\pm 0.01 $$ Tg CH4‐C year−1, respectively. Based on the GWP100 metric (global warming potential on a 100‐year time horizon), the estimated national net GHG emission rate from agricultural soils was 122.3±11.46$$ 122.3\pm 11.46 $$ Tg CO2‐eq year−1, with the largest contribution from N2O emissions. The sequestered SOC offset ~28% of the climate‐warming effects resulting from non‐CO2 GHG emissions, and this offsetting effect increased over time. Increased nitrogen fertilizer use was the dominant factor contributing to the increase in net GHG emissions during 1960–2018, explaining ~47% of total changes. In contrast, reduced cropland area, the adoption of agricultural conservation practices (e.g., reduced tillage), and rising atmospheric CO2 levels attenuated net GHG emissions from U.S. croplands. Improving management practices to mitigate N2O emissions represents the biggest opportunity for achieving net‐zero emissions in U.S. croplands. Our study highlights the importance of concurrently quantifying SOC‐sequestered CO2 and non‐CO2 GHG emissions for developing effective agricultural climate change mitigation measures. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Climate Change and Carbon Sequestration in Forest Ecosystems
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Hui, Dafeng, Deng, Qi, Tian, Hanqin, Luo, Yiqi, Chen, Wei-Yin, editor, Suzuki, Toshio, editor, and Lackner, Maximilian, editor
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- 2017
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6. Quantifying the short-term dynamics of soil organic carbon decomposition using a power function model
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Zhou, Weiping, He, Jinhong, Hui, Dafeng, and Shen, Weijun
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- 2017
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7. Overcompensation of ecosystem productivity following sustained extreme drought in a semiarid grassland.
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Ru, Jingyi, Wan, Shiqiang, Hui, Dafeng, and Song, Jian
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DROUGHTS ,GRASSLANDS ,ECOSYSTEM dynamics ,ECOSYSTEMS ,ECOLOGICAL disturbances ,BIOMASS ,CLIMATE change - Abstract
Drought events are projected to be more extreme and frequent in the future and have profound influences on the structure and functions of terrestrial ecosystems. Thus, better understanding the mechanisms of recovery is critical for predicting the future dynamics of terrestrial ecosystems. We performed a 7‐year field precipitation experiment to examine recovery of a grassland ecosystem from different magnitudes of sustained drought, from slight to extreme. The ecosystem was exposed to precipitation treatments in the first 3 years (2010–2012) and recovered during the last 4 years (2013–2016) without precipitation treatments. Overall, large reductions of aboveground net primary productivity (ANPP, −43.3%) and perennial forb biomass (−83.1%) were observed in the third year (2012) of extreme drought only. Nevertheless, ANPP fully recovered within 1 year after the drought treatments were terminated, and the rapid recovery was mainly due to increased soil total nitrogen and root biomass allocation after drought. Surprisingly, large increases of ANPP under the extreme drought treatment occurred during the recovery periods from 2013 to 2015 (+74.1, +88.5, and +119.8 g m−2 year−1) compared to the control. The overcompensation offset the extreme drought‐induced reduction of ANPP in the treatment years and was primarily ascribed to the enhanced biomass of perennial grasses (PG). Higher resistance to drought and fast resource acquisition strategy might drive the rapid recovery and expansion of PG. Our findings revealed the rapid recovery of grasslands and the critical role of community overcompensation in maintaining grassland ecosystem function and stability under future climate change scenarios. [ABSTRACT FROM AUTHOR]
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- 2023
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8. Ecosystem carbon exchange in response to locust outbreaks in a temperate steppe
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Song, Jian, Wu, Dandan, Shao, Pengshuai, Hui, Dafeng, and Wan, Shiqiang
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- 2015
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9. Century-Scale Responses of Ecosystem Carbon Storage and Flux to Multiple Environmental Changes in the Southern United States
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Tian, Hanqin, Chen, Guangsheng, Zhang, Chi, Liu, Mingliang, Sun, Ge, Chappelka, Arthur, Ren, Wei, Xu, Xiaofeng, Lu, Chaoqun, Pan, Shufen, Chen, Hua, Hui, Dafeng, McNulty, Steven, Lockaby, Graeme, and Vance, Eric
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- 2012
10. Primary Productivity and Water Balance of Grassland Vegetation on Three Soils in a Continuous CO2 Gradient: Initial Results from the Lysimeter CO2 Gradient Experiment
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Fay, Philip A., Kelley, Alexia M., Procter, Andrew C., Hui, Dafeng, Jin, Virginia L., Jackson, Robert B., Johnson, Hyrum B., and Polley, H. Wayne
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- 2009
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11. Increased interannual precipitation variability enhances the carbon sink in a semi‐arid grassland.
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Ru, Jingyi, Wan, Shiqiang, Hui, Dafeng, Song, Jian, and Wang, Jing
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PRECIPITATION variability ,CARBON cycle ,GRASSLANDS ,CLIMATE feedbacks ,ROOT growth ,CLIMATE change - Abstract
The amplifying interannual precipitation variability has been observed globally and is projected to intensify under climate change scenarios. However, its impacts on terrestrial vegetation and carbon (C) sink have not been well investigated.As part of a field manipulative experiment with three precipitation variabilities (20%, 40% and 60%) in a semi‐arid grassland, this study was conducted to examine the responses of ecosystem C cycling to increased precipitation variability.Across the 3 experimental years from 2010 to 2012, amplified precipitation variability enhances gross primary productivity (GPP) and ecosystem respiration (ER), as both GPP and ER were more sensitive to above‐ than below‐average precipitation. In addition, the larger responses of GPP than ER to precipitation variability resulted in an enhancement of net ecosystem productivity (NEP), such that NEP increased with the increasing precipitation variability. More species with higher sensitivity to increased precipitation under wet conditions and the insensitivity of root growth to decreased precipitation could largely be responsible for the above observations, which suggest that the semi‐arid grassland was more sensitive to wet treatment yet strongly resistant to drought.Our results provide empirical evidence that intensified precipitation variability could stimulate grassland C sink. The findings revealed in this study could facilitate the mechanistic understanding and imply the potential positive feedback of climate variability‐terrestrial C sink. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]
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- 2022
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12. Elevated CO2 does not stimulate carbon sink in a semi‐arid grassland.
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Song, Jian, Wan, Shiqiang, Piao, Shilong, Hui, Dafeng, Hovenden, Mark J., Ciais, Philippe, Liu, Yongwen, Liu, Yinzhan, Zhong, Mingxing, Zheng, Mengmei, Ma, Gaigai, Zhou, Zhenxing, Ru, Jingyi, and Knops, Johannes
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CARBON cycle ,CARBON dioxide ,CARBON in soils ,CLIMATE change ,EVAPOTRANSPIRATION - Abstract
Elevated CO2 is widely accepted to enhance terrestrial carbon sink, especially in arid and semi‐arid regions. However, great uncertainties exist for the CO2 fertilisation effects, particularly when its interactions with other global change factors are considered. A four‐factor (CO2, temperature, precipitation and nitrogen) experiment revealed that elevated CO2 did not affect either gross ecosystem productivity or ecosystem respiration, and consequently resulted in no changes of net ecosystem productivity in a semi‐arid grassland despite whether temperature, precipitation and nitrogen were elevated or not. The observations could be primarily attributable to the offset of ecosystem carbon uptake by enhanced soil carbon release under CO2 enrichment. Our findings indicate that arid and semi‐arid ecosystems may not be sensitive to CO2 enrichment as previously expected and highlight the urgent need to incorporate this mechanism into most IPCC carbon‐cycle models for convincing projection of terrestrial carbon sink and its feedback to climate change. [ABSTRACT FROM AUTHOR]
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- 2019
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13. Shifts of growing‐season precipitation peaks decrease soil respiration in a semiarid grassland.
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Ru, Jingyi, Zhou, Yaqiong, Hui, Dafeng, Zheng, Mengmei, and Wan, Shiqiang
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VEGETATION & climate ,GROWING season ,SOIL respiration ,CARBON cycle ,SOIL microbial ecology - Abstract
Abstract: Changing precipitation regimes could have profound influences on carbon (C) cycle in the biosphere. However, how soil C release from terrestrial ecosystems responds to changing seasonal distribution of precipitation remains unclear. A field experiment was conducted for 4 years (2013–2016) to examine the effects of altered precipitation distributions in the growing season on soil respiration in a temperate steppe in the Mongolian Plateau. Over the 4 years, both advanced and delayed precipitation peaks suppressed soil respiration, and the reductions mainly occurred in August. The decreased soil respiration could be primarily attributable to water stress and subsequently limited plant growth (community cover and belowground net primary productivity) and soil microbial activities in the middle growing season, suggesting that precipitation amount in the middle growing season is more important than that in the early, late, or whole growing seasons in regulating soil C release in grasslands. The observations of the additive effects of advanced and delayed precipitation peaks indicate semiarid grasslands will release less C through soil respiratory processes under the projected seasonal redistribution of precipitation in the future. Our findings highlight the potential role of intra‐annual redistribution of precipitation in regulating ecosystem C cycling in arid and semiarid regions. [ABSTRACT FROM AUTHOR]
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- 2018
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14. Responses of seedling performance to altered seasonal precipitation in a secondary tropical forest, southern China.
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Wang, Jun, Sun, Zhongyu, Hui, Dafeng, Yang, Long, Wang, Faming, Liu, Nan, and Ren, Hai
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SEEDLINGS ,METEOROLOGICAL precipitation ,FORESTS & forestry ,FOREST regeneration ,CLIMATE change - Abstract
Given the intensified global climate change, understanding the responses of seedlings in tropical forests to changing precipitation patterns is critical for predicting plant community regeneration. In a field study, we investigated the potential effects of changes in seasonal precipitation on seedling establishment and growth of Cinnamomum burmanni , a dominant tree species in a secondary tropical forest, southern China. The field precipitation treatments included ambient rainfall (CT), increased precipitation (IP) in the wet season, and extended dry (ED) season without change in annual rainfall. For the IP treatment, 25% of the mean annual precipitation was added in the wet season using pumps and sprinklers. For the ED treatment, 60% of incoming throughfall was removed in March and April to extend dry season for two months using transparent roofs, and re-added back in October and November with the total annual rainfall amount not changed. The results showed that the IP treatment increased seedling height growth in June and August when extra water was applied. By the end of experiment, stem biomass was significantly greater in IP plots than in ED plots. Precipitation treatments also affected biomass allocation. Seedlings in ED plots had a lower root/shoot ratio and root mass to total mass ratio. Compared to the control, the IP treatment significantly increased leaf and stem nitrogen concentrations of the seedlings. Nitrogen and phosphorus contents in stems and roots were much higher in IP plots than in ED plots, which might be explained by the increased NO 3 − -N and available phosphorus concentrations in soil. Our findings indicate that extended dry season without change in annual rainfall or increased precipitation in the wet season induced by climate change, is likely to affect soil nutrients, seedling biomass accumulation and partitioning, and nutrient uptake, and thereby impact regeneration dynamics and future community structure in tropical forests. [ABSTRACT FROM AUTHOR]
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- 2018
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15. Long-term antagonistic effect of increased precipitation and nitrogen addition on soil respiration in a semiarid steppe.
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Han, Hongyan, Du, Yue, Hui, Dafeng, Jiang, Lin, Zhong, Mingxing, and Wan, Shiqiang
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SOIL respiration ,ARID regions ,STEPPES ,CLIMATE change ,METEOROLOGICAL precipitation ,ECOSYSTEM services - Abstract
Changes in water and nitrogen (N) availability due to climate change and atmospheric N deposition could have significant effects on soil respiration, a major pathway of carbon (C) loss from terrestrial ecosystems. A manipulative experiment simulating increased precipitation and atmospheric N deposition has been conducted for 9 years (2005-2013) in a semiarid grassland in Mongolian Plateau, China. Increased precipitation and N addition interactively affect soil respiration through the 9 years. The interactions demonstrated that N addition weakened the precipitation-induced stimulation of soil respiration, whereas increased precipitation exacerbated the negative impacts of N addition. The main effects of increased precipitation and N addition treatment on soil respiration were 15.8% stimulated and 14.2% suppressed, respectively. Moreover, a declining pattern and 2-year oscillation were observed for soil respiration response to N addition under increased precipitation. The dependence of soil respiration upon gross primary productivity and soil moisture, but not soil temperature, suggests that resources C substrate supply and water availability are more important than temperature in regulating interannual variations of soil C release in semiarid grassland ecosystems. The findings indicate that atmospheric N deposition may have the potential to mitigate soil C loss induced by increased precipitation, and highlight that long-term and multi-factor global change studies are critical for predicting the general patterns of terrestrial C cycling in response to global change in the future. [ABSTRACT FROM AUTHOR]
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- 2017
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16. Responses of terrestrial ecosystem phosphorus cycling to nitrogen addition: A meta-analysis.
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Deng, Qi, Hui, Dafeng, Dennis, Sam, Reddy, K. Chandra, and Xu, Xiaofeng
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PLANT biomass , *CLIMATE change , *ANTHROPOGENIC effects on nature , *PREDICTION models , *META-analysis - Abstract
Aim Anthropogenic additions of nitrogen (N) are expected to drive terrestrial ecosystems toward greater phosphorus (P) limitation. However, a comprehensive understanding of how an ecosystem's P cycle responds to external N inputs remains elusive, making model predictions of the anthropogenic P limitation and its impacts largely uncertain. Location Global. Time period 1986-2015. Major taxa studied Terrestrial ecosystems. Methods We conducted a meta-analysis including 288 independent study sites from 192 articles to evaluate global patterns and controls of 10 variables associated with ecosystem P cycling under N addition. Results Overall, N addition increased biomass in plants (+34%) and litter (+15%) as well as plant P content (+17%), while decreasing P concentrations in plants and litter (−8% and −11%, respectively). N addition did not change soil labile P or microbial P, but enhanced phosphatase activity (+24%). The effects of N addition on the litter P pool and soil total P remained unclear due to significant publication biases. The response of P cycling to N addition in tropical forests was different from that in other ecosystem types. N addition did not change plant biomass or phosphatase activity in tropical forests but significantly reduced plant P and soil labile P concentrations. The shift in plant P concentration under N addition was negatively correlated with the N application rate or total N load. N-induced change in soil labile P was strongly regulated by soil pH value at the control sites, with a significant decrease of 14% only in acidic soils (pH < 5.5). Main conclusions Our results suggest that as anthropogenic N enhancement continues in the future it could induce P limitation in terrestrial ecosystems while accelerating P cycling, particularly in tropical forests. A quantitative framework generated on the basis of this meta-analysis is useful for our understanding of ecosystem P cycling with N addition, and for incorporating the anthropogenic P limitation into ecosystem models used to analyse effects of future climate change. [ABSTRACT FROM AUTHOR]
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- 2017
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17. Down-regulation of tissue N:P ratios in terrestrial plants by elevated CO2.
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Deng, Qi, Hui, Dafeng, Luo, Yiqi, Elser, James, Wang, Ying-Ping, Loladze, Irakli, Zhang, Quanfa, and Dennis, Sam
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PLANT fibers , *EUKARYOTES , *ENDOPHYTES , *CLIMATE change , *ECOSYSTEMS - Abstract
Increasing atmospheric CO2 concentrations generally alter element stoichiometry in plants. However, a comprehensive evaluation of the elevated CO2 impact on plant nitrogen : phosphorus (N:P) ratios and the underlying mechanism has not been conducted. We synthesized the results from 112 previously published studies using meta-analysis to evaluate the effects of elevated CO2 on the N:P ratio of terrestrial plants and to explore the underlying mechanism based on plant growth and soil P dynamics. Our results show that terrestrial plants grown under elevated CO2 had lower N:P ratios in both above-and below-ground biomass across different ecosystem types. The response ratio for plant N:P was negatively correlated with the response ratio for plant growth in croplands and grasslands, and showed a stronger relationship for P than for N. In addition, the CO2-induced down-regulation of plant N:P was accompanied by 19.3% and 4.2% increases in soil phosphatase activity and labile P, respectively, and a 10.1% decrease in total soil P. Our results show that down-regulation of plant N:P under elevated CO2 corresponds with accelerated soil P cycling. These findings should be useful for better understanding of terrestrial plant stoichiometry in response to elevated CO2 and of the underlying mechanisms affecting nutrient dynamics under climate change. [ABSTRACT FROM AUTHOR]
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- 2015
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18. Down-regulation of tissue N:P ratios in terrestrial plants by elevated CO2.
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Deng, Qi, Hui, Dafeng, Luo, Yiqi, Elser, James, Wang, Ying-Ping, Loladze, Irakli, Zhang, Quanfa, and Dennis, Sam
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PLANT fibers ,EUKARYOTES ,ENDOPHYTES ,CLIMATE change ,ECOSYSTEMS - Abstract
Increasing atmospheric CO
2 concentrations generally alter element stoichiometry in plants. However, a comprehensive evaluation of the elevated CO2 impact on plant nitrogen : phosphorus (N:P) ratios and the underlying mechanism has not been conducted. We synthesized the results from 112 previously published studies using meta-analysis to evaluate the effects of elevated CO2 on the N:P ratio of terrestrial plants and to explore the underlying mechanism based on plant growth and soil P dynamics. Our results show that terrestrial plants grown under elevated CO2 had lower N:P ratios in both above-and below-ground biomass across different ecosystem types. The response ratio for plant N:P was negatively correlated with the response ratio for plant growth in croplands and grasslands, and showed a stronger relationship for P than for N. In addition, the CO2 -induced down-regulation of plant N:P was accompanied by 19.3% and 4.2% increases in soil phosphatase activity and labile P, respectively, and a 10.1% decrease in total soil P. Our results show that down-regulation of plant N:P under elevated CO2 corresponds with accelerated soil P cycling. These findings should be useful for better understanding of terrestrial plant stoichiometry in response to elevated CO2 and of the underlying mechanisms affecting nutrient dynamics under climate change. [ABSTRACT FROM AUTHOR]- Published
- 2015
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19. Influences of biotic and abiotic factors on the relationship between tree productivity and biomass in China.
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Hui, Dafeng, Wang, Jun, Le, Xuan, Shen, Weijun, and Ren, Hai
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CARBON cycle ,BIOMASS ,PLANT adaptation ,CLIMATE change ,FOREST management ,TREE age ,FOREST productivity - Abstract
Abstract: The relationship between tree productivity and biomass not only reflects plant adaptation and the interaction of plants and the environment, but also has significant implications in global carbon cycling, climate change, and forest management. However, how biotic factors (e.g. tree age, diameter at breast height [DBH], height) and abiotic factors (e.g. elevation, latitude, and longitude) influence the relationship between tree productivity and biomass has not been well investigated. We analyzed a large database on tree productivity and biomass in China to derive the relationships between these two variables. The entire database was split into different groups by tree age, DBH, height, latitude, longitude and elevation. The relationship between productivity and biomass was developed using both a linear regression model and an allometric equation (i.e. power function) for each group. Differences in model parameters among groupings based on biotic or abiotic factors indicate the effect of each factor on the relationship between productivity and biomass. The slope of the linear regression model decreased with tree age, DBH, height, and elevation, but increased with tree density and longitude. The scaling exponent of the power function varied with tree age, height, and density following a quadratic pattern, but decreased linearly with elevation. Our results indicated that there is a significant relationship between tree productivity and biomass in China, but the relationship varies with some biotic and abiotic factors. To better predict tree productivity from biomass, tree age and size need to be considered. [Copyright &y& Elsevier]
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- 2012
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20. Growth controls over flowering phenology response to climate change in three temperate steppes along a precipitation gradient.
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Zhou, Zhenxing, Li, Ying, Song, Jian, Ru, Jingyi, Lei, Lingjie, Zhong, Mingxing, Zheng, Mengmei, Zhang, Ang, Hui, Dafeng, and Wan, Shiqiang
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PLANT phenology , *FLOWERING of plants , *STEPPES , *CLIMATE change , *METEOROLOGICAL precipitation , *GROWING season , *PLANT growth - Abstract
• Night warming had contrasting impacts on flowering date in 3 temperate steppes. • Divergent precipitation impacts on flowering date were found in 3 temperate steppes. • The findings highlight the vital role of plant growth in modulating flowering date. Our understanding of how simultaneous climate warming and changing precipitation influence plant phenology in grasslands is still limited. As part of a field transplant experiment, this study was conducted to explore the flowering phenology of the dominant species in three temperate steppes (i.e. a desert, typical, and meadow steppe) along a precipitation gradient in response to simulated night warming and precipitation manipulation (i.e. decreased, ambient, and increased precipitation). Of all monitored species and across three growing seasons (2015–2017), night warming advanced flowering date in the desert and typical steppes, but delayed it in the meadow steppe. Decreased precipitation postponed flowering date but increased precipitation advanced it in all the three steppes. Plant growth largely determined the changes in flowering date under night warming and changing precipitation across and in each of the three steppes. The dominant role of plant growth in modulating reproductive phenology provides mechanistic understanding in interpreting phenological response and facilitate the projections of response of temperate grasslands under future climate change scenarios. [ABSTRACT FROM AUTHOR]
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- 2019
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21. Changing rainfall frequency rather than drought rapidly alters annual soil respiration in a tropical forest.
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Deng, Qi, Zhang, Deqiang, Chu, Guowei, Han, Xi, Zhang, Quanfa, and Hui, Dafeng
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TROPICAL forests , *CARBON cycle , *SOIL productivity , *CARBON compounds , *RAINFALL frequencies ,ENVIRONMENTAL aspects - Abstract
Tropical forests play an important role in global carbon (C) cycling due to high primary productivity and rapid litter and soil organic C decomposition. However, it is still unclear how changing rainfall will influence soil CO 2 losses (i.e. via soil respiration) in tropical forests. Here, using a rainfall and litter manipulation experiment in a tropical forest, we show that enhanced litter-leached dissolved organic carbon (DOC) production with increased rainfall frequency drives substantial CO 2 loss via soil respiration. A 50% increase in rainfall frequency (no change in total rainfall amount) enhanced inputs of DOC by 28%, total dissolved nitrogen (TDN) by 17%, and total dissolved phosphorus (TDP) by 34% through leaching from litter layer to soil surface likely due to faster litter decomposition rate, and stimulated soil respiration by ∼17% (about 1.16 t C ha −1 yr −1 ). Soil respiration responded to altered rainfall frequency with limited when litter layer was removed. Accordingly, soil microbial biomass C (MBC) and fine root biomass were increased by 23% and 20%, respectively only in the plots with litter layer. A 50% reduction in total rainfall (no change in rainfall frequency) did not change litter-leached DOC and nutrients fluxes, soil MBC, fine root biomass, or annual mean soil respiration rates. The new finding – that enhanced leached-DOC production with increased rainfall frequency drives profound increases in soil respiration in tropical forests – suggests that future climate changes may have significant impacts on soil C dynamics and global C budget, and argues for the importance of incorporating this underappreciated feedback into prognostic models used to predict future C-climate interactions. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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22. Climate warming enhances precipitation sensitivity of flowering phenology in temperate steppes on the Mongolian Plateau.
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Zhou, Zhenxing, Yue, Xiaojing, Li, Heng, Zhang, Jiajia, Liang, Junqin, Yuan, Xueting, Ru, Jingyi, Song, Jian, Li, Ying, Zheng, Mengmei, Hui, Dafeng, and Wan, Shiqiang
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PLANT phenology , *GRASSLAND soils , *STEPPES , *NORMALIZED difference vegetation index , *PHENOLOGY - Abstract
• Symmetric flowering sensitivity to precipitation shift was found in temperate steppes. • Climate warming stimulated precipitation sensitivity (S p) in the desert steppe only. • Warming enhanced dependences of s p on abiotic and biotic factors during flowering stage. The phenological sensitivity of terrestrial plants to precipitation change (precipitation sensitivity, S p) and whether S p is affected by climatic warming remain largely unknown. A four-year (2015–2018) field experiment with warming and increased/decreased precipitation was conducted to investigate the impacts of climate change on S p in three dominant temperate grasslands (i.e., desert, typical, and meadow steppes) on the Mongolian Plateau of Northern China. Results showed that S p of flowering phenology to reduced and increased precipitation was symmetric in each of the three steppes. Experimental warming stimulated S p by 0.30 day/(10 mm· °C) over the three steppes, however, by 1.20 day/(10 mm· °C) in the desert steppe, which could be primarily attributed to enhanced dependences of S p on soil moisture and normalized difference vegetation index (NDVI) during the flowering stage. These findings suggest that warming has the greater potential to stimulate S p of phenological events in arid rather than semiarid and mesic grasslands and that S p is jointly controlled by soil water availability and community development indicated by NDVI in different flowering stages in temperate grasslands. Considering the above two factors in phenology models will promote robust prediction of grassland reproductive phenology in temperate regions under concurrent climate warming and changing precipitation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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23. Climatic and edaphic controls over the elevational pattern of microbial necromass in subtropical forests.
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Mou, Zhijian, Kuang, Luhui, He, Lingfeng, Zhang, Jing, Zhang, Xinyu, Hui, Dafeng, Li, Yue, Wu, Wenjia, Mei, Qiming, He, Xianjin, Kuang, Yuanwen, Wang, Jun, Wang, Yunqiang, Lambers, Hans, Sardans, Jordi, Peñuelas, Josep, and Liu, Zhanfeng
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SOIL moisture , *HIGH performance liquid chromatography , *NITROGEN in soils , *CLIMATE change , *SOIL respiration - Abstract
[Display omitted] • Altitude and season jointly affect microbial necromass and its contribution to SOC. • Microbial necromass shows linear or quadratic patterns with elevation. • Microbial necromass and its contribution to SOC are higher in the dry season. • Soil micro-climate and nutrient directly regulate microbial necromass accumulation. The sequestration of soil organic carbon (SOC) in terrestrial ecosystems is determined by the balance between plant- and microbial-derived carbon inputs and losses through soil respiration. However, a consensus on the elevational patterns of soil microbial necromass and its contribution to SOC is rare, and the information on how climatic and edaphic factors affect the accumulation of microbial necromass remains limited. In this study, soil samples were collected with a 50-m interval along an elevational gradient (200–950 m above sea level) to investigate the effects of climatic and edaphic variability associated with elevation and season on microbial necromass in subtropical forests. The concentration of soil amino sugar was measured by high-performance liquid chromatography (HPLC) to characterize soil microbial necromass. Partial least squares path modeling (PLS-PM) was used for testing climatic and edaphic controls over the elevational pattern of microbial necromass. The concentration of soil microbial necromass and its contribution to SOC were affected by elevation and season, with lower concentration and contribution in the wet season than in the dry season. Soil microbial necromass linearly increased or followed a quadratic pattern with elevation, and accounted for 18.9% of SOC on average with a greater contribution from fungal necromass (13.2%) than from bacterial necromass (5.7%). Soil temperature, soil nitrogen and moisture content directly influenced the accumulation of soil microbial necromass with varied effects on fungal and bacterial necromass. Warmer and nutrient-impoverished environments were linked with the depletion of fungal necromass, whereas higher soil moisture and nutrient availability were positively associated with the accumulation of bacterial necromass. Our findings demonstrate that less microbial necromass, especially fungal necromass will accumulate in SOC in response to future climate warming in subtropical forests. Such information is valuable for improving our understanding of the potential impacts of future climatic change on soil carbon cycling in subtropical regions. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
24. Memory effects of climate and vegetation affecting net ecosystem CO2 fluxes in global forests
- Author
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Simon Besnard, M. Altaf Arain, Alexander Knohl, Martin Herold, Martin Jung, Markus Reichstein, Xudong Zhang, Fabian Gans, Beverly E. Law, Andrew Black, Nuno Carvalhais, Benjamin Brede, Annalea Lohila, Riccardo Valentini, Jiquan Chen, Sebastian Wolf, Olivier Roupsard, Nina Buchmann, Lutz Merbold, Jan G. P. W. Clevers, Eugénie Paul-Limoges, L.P. Dutrieux, Yoshiko Kosugi, University of Zurich, Hui, Dafeng, Besnard, Simon, Max Planck Society, Wageningen University and Research Centre (WUR), Universidade Nova de Lisboa = NOVA University Lisbon (NOVA), McMaster University, Faculty of Land and Food Systems, University of British Columbia (UBC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), CGCEO/Geography, Michigan State University [East Lansing], Michigan State University System-Michigan State University System, Comision Nacional para el conocimiento y uso de la biodiversidad, Kyoto University [Kyoto], Faculty of Forest Sciences, University of Joensuu, College of Forestry, Oregon State University (OSU), Finnish Meteorological Institute (FMI), Mazingira Centre, International Livestock Research Institute, Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Tuscia University, Chinese Academy of Forestry, CENSE - Centro de Investigação em Ambiente e Sustentabilidade, DCEA - Departamento de Ciências e Engenharia do Ambiente, Kyoto University, and Università degli studi della Tuscia [Viterbo]
- Subjects
0106 biological sciences ,[SDV.SA]Life Sciences [q-bio]/Agricultural sciences ,Atmospheric Science ,Saison ,Vapor Pressure ,010504 meteorology & atmospheric sciences ,échange atmosphère biosphère ,Biodiversity ,Forests ,Atmospheric sciences ,01 natural sciences ,Cognition ,Learning and Memory ,Seasons ,Forest ecology ,Carbon dioxide ,Ecosystems ,Memory ,Solar radiation ,Vapor pressure ,Laboratory of Geo-information Science and Remote Sensing ,forêt ,K01 - Foresterie - Considérations générales ,Environmental monitoring ,SDG 13 - Climate Action ,910 Geography & travel ,SDG 15 - Life on Land ,Multidisciplinary ,Ecology ,Agricultural and Biological Sciences(all) ,U10 - Informatique, mathématiques et statistiques ,effet mémoire ,Physics ,Electromagnetic Radiation ,Classical Mechanics ,Biosphere ,Vegetation ,PE&RC ,Terrestrial Environments ,Agricultural sciences ,Chemistry ,séquestration du carbone ,10122 Institute of Geography ,Physical Sciences ,Medicine ,Solar Radiation ,réseau neuromimetique ,Research Article ,P33 - Chimie et physique du sol ,cycle du carbone ,Forest Ecology ,F40 - Écologie végétale ,P40 - Météorologie et climatologie ,Science ,Climate change ,1100 General Agricultural and Biological Sciences ,010603 evolutionary biology ,Carbon cycle ,Greenhouse Gases ,Radiation solaire ,1300 General Biochemistry, Genetics and Molecular Biology ,Pressure ,Environmental Chemistry ,Life Science ,Couverture végétale ,Ecosystem ,Laboratorium voor Geo-informatiekunde en Remote Sensing ,approche statistique ,General ,écosystème forestier ,0105 earth and related environmental sciences ,1000 Multidisciplinary ,Biochemistry, Genetics and Molecular Biology(all) ,flux de co2 ,Ecology and Environmental Sciences ,Climat ,Chemical Compounds ,Biology and Life Sciences ,Carbon Dioxide ,15. Life on land ,13. Climate action ,Atmospheric Chemistry ,Earth Sciences ,Cognitive Science ,Environmental science ,Sciences agricoles ,Neuroscience - Abstract
Forests play a crucial role in the global carbon (C) cycle by storing and sequestering a substantial amount of C in the terrestrial biosphere. Due to temporal dynamics in climate and vegetation activity, there are significant regional variations in carbon dioxide (CO₂) fluxes between the biosphere and atmosphere in forests that are affecting the global C cycle. Current forest CO₂ flux dynamics are controlled by instantaneous climate, soil, and vegetation conditions, which carry legacy effects from disturbances and extreme climate events. Our level of understanding from the legacies of these processes on net CO₂ fluxes is still limited due to their complexities and their long-term effects. Here, we combined remote sensing, climate, and eddy-covariance flux data to study net ecosystem CO₂ exchange (NEE) at 185 forest sites globally. Instead of commonly used non-dynamic statistical methods, we employed a type of recurrent neural network (RNN), called Long Short-Term Memory network (LSTM) that captures information from the vegetation and climate’s temporal dynamics. The resulting data-driven model integrates interannual and seasonal variations of climate and vegetation by using Landsat and climate data at each site. The presented LSTM algorithm was able to effectively describe the overall seasonal variability (Nash-Sutcliffe efficiency, NSE = 0.66) and across-site (NSE = 0.42) variations in NEE, while it had less success in predicting specific seasonal and interannual anomalies (NSE = 0.07). This analysis demonstrated that an LSTM approach with embedded climate and vegetation memory effects outperformed a non-dynamic statistical model (i.e. Random Forest) for estimating NEE. Additionally, it is shown that the vegetation mean seasonal cycle embeds most of the information content to realistically explain the spatial and seasonal variations in NEE. These findings show the relevance of capturing memory effects from both climate and vegetation in quantifying spatio-temporal variations in forest NEE., 28 Feb 2019: The PLOS ONE Staff (2019) Correction: Memory effects of climate and vegetation affecting net ecosystem CO2 fluxes in global forests. PLOS ONE 14(2): e0213467. https://doi.org/10.1371/journal.pone.0213467.
- Published
- 2019
25. Decomposition of recalcitrant carbon under experimental warming in boreal forest
- Author
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Steven D. Allison, Kathleen K. Treseder, Adriana L. Romero-Olivares, and Hui, Dafeng
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,lcsh:Medicine ,Forests ,01 natural sciences ,Global Warming ,Lignin ,Biochemistry ,Trees ,chemistry.chemical_compound ,Mathematical and Statistical Techniques ,lcsh:Science ,Climatology ,Multidisciplinary ,Ecology ,Chemistry ,Organic Compounds ,Chemical Reactions ,04 agricultural and veterinary sciences ,Plant litter ,Plants ,Terrestrial Environments ,Enzymes ,Environmental chemistry ,Physical Sciences ,Statistics (Mathematics) ,Research Article ,General Science & Technology ,Climate Change ,chemistry.chemical_element ,Research and Analysis Methods ,Ecosystems ,Botany ,Hemicellulose ,Statistical Methods ,Cellulose ,0105 earth and related environmental sciences ,Decomposition ,Analysis of Variance ,lcsh:R ,Global warming ,Organic Chemistry ,Ecology and Environmental Sciences ,Chemical Compounds ,Organisms ,Biology and Life Sciences ,Proteins ,Soil carbon ,15. Life on land ,Carbon ,13. Climate action ,040103 agronomy & agriculture ,Litter ,Enzymology ,Earth Sciences ,0401 agriculture, forestry, and fisheries ,lcsh:Q ,Spruces ,Alaska ,Mathematics - Abstract
Over the long term, soil carbon (C) storage is partly determined by decomposition rate of carbon that is slow to decompose (i.e., recalcitrant C). According to thermodynamic theory, decomposition rates of recalcitrant C might differ from those of non-recalcitrant C in their sensitivities to global warming. We decomposed leaf litter in a warming experiment in Alaskan boreal forest, and measured mass loss of recalcitrant C (lignin) vs. non-recalcitrant C (cellulose, hemicellulose, and sugars) throughout 16 months. We found that these C fractions responded differently to warming. Specifically, after one year of decomposition, the ratio of recalcitrant C to non-recalcitrant C remaining in litter declined in the warmed plots compared to control. Consistent with this pattern, potential activities of enzymes targeting recalcitrant C increased with warming, relative to those targeting non-recalcitrant C. Even so, mass loss of individual C fractions showed that non-recalcitrant C is preferentially decomposed under control conditions whereas recalcitrant C losses remain unchanged between control and warmed plots. Moreover, overall mass loss was greater under control conditions. Our results imply that direct warming effects, as well as indirect warming effects (e.g. drying), may serve to maintain decomposition rates of recalcitrant C compared to non-recalcitrant C despite negative effects on overall decomposition.
- Published
- 2017
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