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Lian X, Peñuelas J, Ryu Y, Piao S, Keenan TF, Fang J, Yu K, Chen A, Zhang Y, Gentine P. Diminishing carryover benefits of earlier spring vegetation growth. Nat Ecol Evol 2024; 8:218-228. [PMID: 38172284 DOI: 10.1038/s41559-023-02272-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 11/13/2023] [Indexed: 01/05/2024]
Abstract
Spring vegetation growth can benefit summer growth by increasing foliage area and carbon sequestration potential, or impair it by consuming additional resources needed for sustaining subsequent growth. However, the prevalent driving mechanism and its temporal changes remain unknown. Using satellite observations and long-term atmospheric CO2 records, here we show a weakening trend of the linkage between spring and summer vegetation growth/productivity in the Northern Hemisphere during 1982-2021. This weakening is driven by warmer and more extreme hot weather that becomes unfavourable for peak-season growth, shifting peak plant functioning away from earlier periods. This is further exacerbated by seasonally growing ecosystem water stress due to reduced water supply and enhanced water demand. Our finding suggests that beneficial carryover effects of spring growth on summer growth are diminishing or even reversing, acting as an early warning sign of the ongoing shift of climatic effects from stimulating to suppressing plant photosynthesis during the early to peak seasons.
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Affiliation(s)
- Xu Lian
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, USA.
| | - Josep Peñuelas
- CREAF, Barcelona, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Barcelona, Spain
| | - Youngryel Ryu
- Department of Landscape Architecture and Rural Systems Engineering, Seoul National University, Seoul, South Korea
| | - Shilong Piao
- Institute of Carbon Neutrality, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Trevor F Keenan
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Environmental Science Policy and Management, UC Berkeley, Berkeley, CA, USA
| | - Jianing Fang
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, USA
| | - Kailiang Yu
- Department of Ecology & Evolutionary Biology, High Meadows Environmental Institute, Princeton University, Princeton, NJ, USA
| | - Anping Chen
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA
| | - Yao Zhang
- Institute of Carbon Neutrality, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Pierre Gentine
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, USA
- Center for Learning the Earth with Artificial intelligence and Physics (LEAP), Columbia University, New York, NY, USA
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2
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Zhang X, Cao Q, Chen H, Quan Q, Li C, Dong J, Chang M, Yan S, Liu J. Effect of Vegetation Carryover and Climate Variability on the Seasonal Growth of Vegetation in the Upper and Middle Reaches of the Yellow River Basin. REMOTE SENSING 2022; 14:5011. [DOI: 10.3390/rs14195011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Vegetation dynamics are often affected by climate variability, but the past state of vegetation has a non-negligible impact on current vegetation growth. However, seasonal differences in the effects of these drivers on vegetation growth remain unclear, particularly in ecologically fragile areas. We used the normalized difference vegetation index (NDVI), gross primary productivity (GPP), and leaf area index (LAI) to describe the vegetation dynamic in the upper and middle reaches of the Yellow River basin (YRB). Three active vegetation growing seasons (early, peak, and late) were defined based on phenological metrics. In light of three vegetation indicators and the climatic data, we identified the correlation between the inter-annual variation of vegetation growth in the three sub-seasons. Then, we quantified the contributions of climate variability and the vegetation growth carryover (VGC) effect on seasonal vegetation greening between 2000–2019. Results showed that both the vegetation coverage and productivity in the study area increased over a 20-year period. The VGC effect dominated vegetation growth during the three active growing seasons, and the effect increased from early to late growing season. Vegetation in drought regions was found to generally have a stronger vegetation carryover ability, implying that negative disturbances might have severer effects on vegetation in these areas. The concurrent seasonal precipitation was another positive driving factor of vegetation greening. However, sunshine duration, including its immediate and lagged impacts, had a negative effect on vegetation growth. In addition, the VGC effect can sustain into the second year. The VGC effect showed that initial ecological restoration and sustainable conservation would promote vegetation growth and increase vegetation productivity. This study provides a comprehensive perspective on understanding the climate–vegetation interactions on a seasonal scale, which helps to accurately predict future vegetation dynamics over time in ecologically fragile areas.
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3
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The Spatiotemporal Response of Vegetation Changes to Precipitation and Soil Moisture in Drylands in the North Temperate Mid-Latitudes. REMOTE SENSING 2022. [DOI: 10.3390/rs14153511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vegetation growth in drylands is highly constrained by water availability. How dryland vegetation responds to changes in precipitation and soil moisture in the context of a warming climate is not well understood. In this study, warm drylands in the temperate zone between 30 and 50° N, including North America (NA), the Mediterranean region (MD), Central Asia (CA), and East Asia (EA), were selected as the study area. After verifying the trends and anomalies of three kinds of leaf area index (LAI) datasets (GLASS LAI, GLEAM LAI, and GLOBAMAP LAI) in the study area, we mainly used the climate (GPCC precipitation and ERA5 temperature), GLEAM soil moisture, and GLASS LAI datasets from 1981 to 2018 to analyze the response of vegetation growth to changes in precipitation and soil moisture. The results of the three mutually validated LAI datasets show an overall greening of dryland vegetation with the same increasing trend of 0.002 per year in LAI over the past 38 years. LAI and precipitation exhibited a strong correlation in the eastern part of the NA drylands and the northeastern part of the EA drylands. LAI and soil moisture exhibited a strong correlation in the eastern part of the NA drylands, the eastern part of the MD drylands, the southern part of the CA drylands, and the northeastern part of the EA drylands. The results of this study will contribute to the understanding of vegetation dynamics and their response to changing water conditions in the Northern Hemisphere midlatitude drylands.
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4
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Lian X, Jeong S, Park CE, Xu H, Li LZX, Wang T, Gentine P, Peñuelas J, Piao S. Biophysical impacts of northern vegetation changes on seasonal warming patterns. Nat Commun 2022; 13:3925. [PMID: 35798743 PMCID: PMC9262912 DOI: 10.1038/s41467-022-31671-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 06/20/2022] [Indexed: 11/09/2022] Open
Abstract
The seasonal greening of Northern Hemisphere (NH) ecosystems, due to extended growing periods and enhanced photosynthetic activity, could modify near-surface warming by perturbing land-atmosphere energy exchanges, yet this biophysical control on warming seasonality is underexplored. By performing experiments with a coupled land-atmosphere model, here we show that summer greening effectively dampens NH warming by −0.15 ± 0.03 °C for 1982–2014 due to enhanced evapotranspiration. However, greening generates weak temperature changes in spring (+0.02 ± 0.06 °C) and autumn (−0.05 ± 0.05 °C), because the evaporative cooling is counterbalanced by radiative warming from albedo and water vapor feedbacks. The dwindling evaporative cooling towards cool seasons is also supported by state-of-the-art Earth system models. Moreover, greening-triggered energy imbalance is propagated forward by atmospheric circulation to subsequent seasons and causes sizable time-lagged climate effects. Overall, greening makes winter warmer and summer cooler, attenuating the seasonal amplitude of NH temperature. These findings demonstrate complex tradeoffs and linkages of vegetation-climate feedbacks among seasons. The seasonal greening of Northern Hemisphere ecosystems due to extended growing periods and enhanced photosynthetic activity is, via experiments, shown to modify near-surface warming by perturbing land-atmosphere energy exchanges.
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Affiliation(s)
- Xu Lian
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China.,Department of Earth and Environmental Engineering, Columbia University, New York, NY, USA
| | - Sujong Jeong
- Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul, Republic of Korea. .,Environmental Planning Institute, Seoul National University, Seoul, Republic of Korea.
| | - Chang-Eui Park
- Center for Sustainable Environment Research, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Hao Xu
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Laurent Z X Li
- Laboratoire de Météorologie Dynamique, CNRS, Sorbonne Université, Ecole Normale Supérieure, Ecole Polytechnique, Paris, France
| | - Tao Wang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Pierre Gentine
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, USA.,Earth Institute, Columbia University, New York, NY, USA
| | - Josep Peñuelas
- CREAF, Cerdanyola del Valles, Barcelona, Catalonia, Spain.,CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, Catalonia, Spain
| | - Shilong Piao
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China. .,State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China.
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5
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Yuan Y, Bao A, Jiapaer G, Jiang L, De Maeyer P. Phenology-based seasonal terrestrial vegetation growth response to climate variability with consideration of cumulative effect and biological carryover. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 817:152805. [PMID: 34982988 DOI: 10.1016/j.scitotenv.2021.152805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/06/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Vegetation growth is influenced not only by climate variability but also by its past states. However, the differences in the degree of the climate variability and past states affecting vegetation growth over seasons are still poorly understood, particularly given the cumulative climate effects. Relying on the Normalized Difference Vegetation Index (NDVI) data from 1982 to 2014, the vegetation growing season was decomposed into three periods (sub-seasons) - green-up (GSgp), maturity (GSmp), and senescence (GSsp) - following a phenology-based definition. A distributed lag model was then utilized to analyze the time-lag effect of vegetation growth response to climatic factors including precipitation, temperature, and solar radiation during each sub-season. On this basis, the relative importance of climatic factors and vegetation growth carryover (VGC) effect on vegetation growth was quantified at the phenology-based seasonal scale. Results showed that the longest peak lag of precipitation, temperature, and solar radiation occurred in the GSmp, GSsp, and GSgp, with 1.27 (1.13 SD), 0.89 (1.02 SD), and 0.80 (1.04 SD) months, respectively. The influence of climate variability was strongest in the GSgp, and diminished over the season, while the opposite for the VGC effect. The relative influence of each climatic factor also varied between sub-seasons. Vegetation in more than 58% of areas was more affected by temperature in the GSgp, and the proportion decreased to 34.00% and 31.78% in the GSmp and GSsp, respectively. Precipitation and solar radiation acted as the dominant climatic factors in only 28.80% and 20.88% of vegetation areas in the GSgp, but they increased to 35.21%, 32.61% in the GSmp, and 38.20%, 30.02% in the GSsp, respectively. The increased regions influenced by precipitation were mainly in dry areas especially for the boreal and cool temperate climate zones, while increased regions influenced by solar radiation were primarily located in moist areas of mid-high latitudes of the Northern Hemisphere. By introducing the cumulative climate effect, our findings highlight seasonal patterns of vegetation growth affected by climate variability and the VGC effect. The results provide a more comprehensive perspective on climate-vegetation interactions, which may help us to accurately forecast future vegetation growth under accelerating global warming.
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Affiliation(s)
- Ye Yuan
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China; Department of Geography, Ghent University, Ghent 9000, Belgium
| | - Anming Bao
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; China-Pakistan Joint Research Center on Earth Sciences, CAS-HEC, Islamabad 45320, Pakistan; Sino-Belgian Laboratory for Geo-Information, Urumqi 83011, China.
| | - Guli Jiapaer
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Liangliang Jiang
- School of Geography and Tourism, Chongqing Normal University, Chongqing 401331, China
| | - Philippe De Maeyer
- Department of Geography, Ghent University, Ghent 9000, Belgium; Sino-Belgian Laboratory for Geo-Information, Ghent 9000, Belgium
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6
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Zhao A, Yu Q, Wang D, Zhang A. Spatiotemporal dynamics of ecosystem water use efficiency over the Chinese Loess Plateau base on long-time satellite data. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:2298-2310. [PMID: 34365605 DOI: 10.1007/s11356-021-15801-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Ecosystem water use efficiency (eWUE), defined as the ratio between carbon gains and water loss from the system, has been recognized as an important characteristic of carbon and water balances. The long-lasting "Grain for Green" Program (GFGP) initiated in 1999 in China's Loess Plateau (CLP) is a large-scale ecological program in the world, which aims to improve the CLP's ecosystem resilience by enhancing vegetation cover and productivity. Understanding how the GFGP can affect eWUE is imperative to ensuring sustainable water resources and to promoting sustainable management strategies. In this study, we evaluated the spatiotemporal variability of growing-season eWUE and examined its response to both climate change and vegetation coverage from 1982 to 2017. Our results indicate that growing-season eWUE, gross primary productivity (GPP), and evapotranspiration (ET) in CLP area increased significantly from 1982 to 2017. Specifically, eWUE, GPP, and ET increased more rapidly after China established the program. The most significant growth area of eWUE was found in main areas conducting GFGP project, including the Loess hilly and gully area (LHGA). Spatially, eWUE, GPP, and ET in the growing season increased from northwest to southeast, and higher eWUE was found in areas with high vegetation cover. The spatial and temporal variability of eWUE was related to vegetation cover (expressed as leaf area index, LAI) and climatic variability. Significant positive correlations were observed between growing-season LAI, temperature, and eWUE, because the LAI and temperature have a greater effect on photosynthesis than ET. Our results suggested that the GFGP was the main driving force that causes the spatial-temporal variability of eWUE in CLP.
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Affiliation(s)
- Anzhou Zhao
- College of Mining and Geomatics, Hebei University of Engineering, Handan, 056038, China.
- State Key Laboratory of Resources and Environmental Information System, Chinese Academy of Science, Beijing, 100101, China.
| | - Qiuyan Yu
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM, 88003, USA
| | - Dongli Wang
- College of Mining and Geomatics, Hebei University of Engineering, Handan, 056038, China
| | - Anbing Zhang
- College of Mining and Geomatics, Hebei University of Engineering, Handan, 056038, China
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7
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Li K, Huang G, Zhang X, Lu C, Wang S. Temporal-Spatial changes of monthly vegetation growth and their driving forces in the ancient Yellow river irrigation system, China. JOURNAL OF CONTAMINANT HYDROLOGY 2021; 243:103911. [PMID: 34763242 DOI: 10.1016/j.jconhyd.2021.103911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 08/29/2021] [Accepted: 10/17/2021] [Indexed: 06/13/2023]
Abstract
Irrigation systems play vital roles not only in food production but also in supporting ecosystems. Understanding how the ecosystem has evolved in response to human activities is crucial for sustainable food production, especially for arid and semi-arid regions. In this study, we examined the trends of vegetation growth on a monthly basis in the ancient Yellow River irrigation system in Ningxia, China. We used the leaf area index (LAI) to characterize the vegetation growth from 2007 to 2019. The LAI trends were associated with a series of driving forces, explaining the spatial and temporal change of vegetation growth. With the provision of the Wilks feature importance method, 2-month averaged air temperature and irrigation were identified as the two most important variables for monthly LAI simulation. Future climate projections based on the Regional Climate Model system (RegCM) suggested dryer and longer summers under the RCP 8.5 scenario. These changes will increase the crop water demand during the growing months. In the future, water conflict might be further intensified in May, in which the present irrigation water has already led to a decreased crop growth. Our findings demonstrated that the Mann Kendall monthly trend analysis could provide more helpful information for monitoring the vegetation growth than the trend analysis on a yearly and seasonal basis.
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Affiliation(s)
- Kailong Li
- Faculty of Engineering, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Guohe Huang
- Faculty of Engineering, University of Regina, Regina, Saskatchewan S4S 0A2, Canada.
| | - Xiaoyue Zhang
- Faculty of Engineering, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Chen Lu
- Faculty of Engineering, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Shuo Wang
- Department of Land Surveying and Geo-Informatics, Hong Kong Polytechnic University, Hong Kong, China
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8
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Li Y, Piao S, Chen A, Ciais P, Li LZX. Local and teleconnected temperature effects of afforestation and vegetation greening in China. Natl Sci Rev 2020; 7:897-912. [PMID: 34692111 PMCID: PMC8289082 DOI: 10.1093/nsr/nwz132] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 07/10/2019] [Accepted: 08/05/2019] [Indexed: 01/13/2023] Open
Abstract
Afforestation in China provides carbon sequestration and prevents soil erosion, but its remote impacts on climate in other regions via the coupling of forest energy fluxes with atmospheric circulation are largely unknown. Here, we prescribe inventory-based forest cover change and satellite-observed leaf area index from 1982 to 2011 in a coupled land-atmosphere model to simulate their biophysical climate effects. Both local and global surface air temperatures show a seasonal contrast in response to past vegetation cover expansion over China: a phenomenon we primarily attribute to a variation of seasonality of vegetation greening. A large cooling in spring results in concurrent decreases in geopotential height over China and zonal wind over Mongolia, causing a dipole structure in the upper troposphere over the Arctic. This accounts for ∼58% of simulated spring warming over the Russian Arctic and ∼61% of simulated spring cooling over the Canadian Artic. Our results imply that spring vegetation dynamics in China may affect climate in northern high latitudes.
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Affiliation(s)
- Yue Li
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Shilong Piao
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.,Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China.,Center for Excellence in Tibetan Earth Science, Chinese Academy of Sciences, Beijing 100085, China
| | - Anping Chen
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement/Institut Pierre Simon Laplace, Commissariat à l'Énergie Atomique et aux Énergies Alternatives-CNRS-Université de Versailles Saint-Quentin, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - Laurent Z X Li
- Laboratoire de Météorologie Dynamique, Centre National de la Recherche Scientifique, Sorbonne Université, Ecole Normale Supérieure, Ecole Polytechnique, 75252 Paris, France
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9
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Liu M, Xu X, Jiang Y, Huang Q, Huo Z, Liu L, Huang G. Responses of crop growth and water productivity to climate change and agricultural water-saving in arid region. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 703:134621. [PMID: 31759711 DOI: 10.1016/j.scitotenv.2019.134621] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/16/2019] [Accepted: 09/21/2019] [Indexed: 06/10/2023]
Abstract
Climate change and associated elevated atmospheric CO2 concentration and rising temperature have become a great challenge to agricultural production especially in arid and semiarid regions, and a great concern to scientists worldwide. Thus, it is very important to assess the response of crop growth and water productivity to climate change projections, which in turn can help devise adaptive strategies to mitigate their impact. An agro-hydrological model with well consideration of CO2 effects on both the stomatal conductance and leaf area was established. The model was well calibrated and validated using the data collected from the middle oasis of Heihe River basin, northwest China, which was selected as a typical arid region. Simulations of soil water contents and crop growth matched well with observations. Then various scenarios were designed with considering three climate change alternatives (RCP 2.6, RCP 4.5 and RCP 8.5) and three agricultural water-saving alternatives in the context of irrigation water availability being constant. Responses of crop growth and water productivity were predicted for thirty years from 2018 to 2047. As compared to current situation, there would be a reduction of 3.4-8.6% in crop yield during the period of 2018-2027 and an increase of 1.5-18.7% in crop yield during the period of 2028-2047 for seed corn, and an increase of 7.4-26.7% in crop yield during the period of 2018-2047 for spring wheat, respectively. Moreover, results showed an increase in water productivity ranged from 14.3% to 44.5% for seed corn and from 34.7% to 52.0% for spring wheat, respectively. Furthermore, adaptive strategies to climate change were recommended for the seed corn and spring wheat, respectively. Our results are expected to provide implications for devising adaptive strategies to changing environments in other arid and irrigation-fed areas.
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Affiliation(s)
- Minghuan Liu
- Chinese-Israeli International Center for Research and Training in Agriculture, China Agricultural University, Beijing 100083, PR China; Center for Agricultural Water Research, China Agricultural University, Beijing 100083, PR China.
| | - Xu Xu
- Chinese-Israeli International Center for Research and Training in Agriculture, China Agricultural University, Beijing 100083, PR China; Center for Agricultural Water Research, China Agricultural University, Beijing 100083, PR China.
| | - Yao Jiang
- Chinese-Israeli International Center for Research and Training in Agriculture, China Agricultural University, Beijing 100083, PR China; Center for Agricultural Water Research, China Agricultural University, Beijing 100083, PR China
| | - Quanzhong Huang
- Chinese-Israeli International Center for Research and Training in Agriculture, China Agricultural University, Beijing 100083, PR China; Center for Agricultural Water Research, China Agricultural University, Beijing 100083, PR China.
| | - Zailin Huo
- Center for Agricultural Water Research, China Agricultural University, Beijing 100083, PR China.
| | - Liu Liu
- Center for Agricultural Water Research, China Agricultural University, Beijing 100083, PR China.
| | - Guanhua Huang
- Chinese-Israeli International Center for Research and Training in Agriculture, China Agricultural University, Beijing 100083, PR China; Center for Agricultural Water Research, China Agricultural University, Beijing 100083, PR China.
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10
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Dettori S, Filigheddu MR, Deplano G, Molgora JE, Ruiu M, Sedda L. Employing a spatio-temporal contingency table for the analysis of cork oak cover change in the Sa Serra region of Sardinia. Sci Rep 2018; 8:16946. [PMID: 30446680 PMCID: PMC6240039 DOI: 10.1038/s41598-018-35319-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/29/2018] [Indexed: 11/09/2022] Open
Abstract
Land cover change analyses are common and, especially in the absence of explanatory variables, they are mainly carried out by employing qualitative methods such as transition matrices or raster operations. These methods do not provide any estimation of the statistical significance of the changes, or the uncertainty of the model and data, and are usually limited in supporting explicit biological/ecological interpretation of the processes determining the changes. Here we show how the original nearest-neighbour contingency table, proposed by Dixon to evaluate spatial segregation, has been extended to the temporal domain to map the intensity, statistical significance and uncertainty of land cover changes. This index was then employed to quantify the changes in cork oak forest cover between 1998 and 2016 in the Sa Serra region of Sardinia (Italy). The method showed that most statistically significant cork oak losses were concentrated in the centre of Sa Serra and characterised by high intensity. A spatial binomial-logit generalised linear model estimated the probability of changes occurring in the area but not the type of change. We show how the spatio-temporal Dixon’s index can be an attractive alternative to other land cover change analysis methods, since it provides a robust statistical framework and facilitates direct biological/ecological interpretation.
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Affiliation(s)
- Sandro Dettori
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100, Sassari, Italy
| | - Maria Rosaria Filigheddu
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100, Sassari, Italy
| | - Giovanni Deplano
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100, Sassari, Italy
| | - Juan Escamilla Molgora
- Lancaster Environmental Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom
| | - Maddalena Ruiu
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100, Sassari, Italy
| | - Luigi Sedda
- Centre for Health Informatics Computing and Statistics (CHICAS), Lancaster University, Lancaster, LA1 4YQ, United Kingdom.
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11
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Wang L, Tian F, Wang Y, Wu Z, Schurgers G, Fensholt R. Acceleration of global vegetation greenup from combined effects of climate change and human land management. GLOBAL CHANGE BIOLOGY 2018; 24:5484-5499. [PMID: 29963745 DOI: 10.1111/gcb.14369] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/16/2018] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
Global warming and human land management have greatly influenced vegetation growth through both changes in spring phenology and photosynthetic primary production. This will presumably impact the velocity of vegetation greenup (Vgreenup, the daily rate of changes in vegetation productivity during greenup period), yet little is currently known about the spatio-temporal patterns of Vgreenup of global vegetation. Here, we define Vgreenup as the ratio of the amplitude of greenup (Agreenup) to the duration of greenup (Dgreenup) and derive global Vgreenup from 34-year satellite leaf area index (LAI) observations to study spatio-temporal dynamics of Vgreenup at the global, hemispheric, and ecosystem scales. We find that 19.9% of the pixels analyzed (n = 1,175,453) experienced significant trends toward higher greenup rates by an average of 0.018 m2 m-2 day-1 for 1982-2015 as compared to 8.6% of pixels with significant negative trends (p < 0.05). Global distribution and dynamics of Vgreenup show high spatial heterogeneity and ecosystem-specific patterns, which is primarily determined by the high spatial variation in Agreenup, while the temporal dynamics of Vgreenup are directly controlled by both changes in Dgreenup and Agreenup. Areas with the largest Vgreenup and largest positive trends are both observed in deciduous and mixed forests as compared to nonforest ecosystems showing both lower Vgreenup and trends. For nonforest ecosystems, human-managed ecosystems (e.g., rangelands and rainfed croplands) exhibited higher Vgreenup and positive trends than those of natural counterparts, suggesting strong imprints of human land management on terrestrial ecosystem functioning. Globally, warming has accelerated Vgreenup in temperature-constrained high latitude forest ecosystems and arctic regions, but decelerated Vgreenup in temperate and arid/semiarid areas. These results suggest that the combined effects of climate change and human land management have greatly accelerated global vegetation greenup, with important implications for changes in terrestrial ecosystem functioning and global carbon cycling.
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Affiliation(s)
- Lanhui Wang
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Feng Tian
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Yuhang Wang
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Zhendong Wu
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Guy Schurgers
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus Fensholt
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
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Satellite Leaf Area Index: Global Scale Analysis of the Tendencies Per Vegetation Type Over the Last 17 Years. REMOTE SENSING 2018. [DOI: 10.3390/rs10030424] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Keenan T, Riley W. Greening of the land surface in the world's cold regions consistent with recent warming. NATURE CLIMATE CHANGE 2018; 8:825-828. [PMID: 30319714 PMCID: PMC6180328 DOI: 10.1038/s41558-018-0258-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 07/19/2018] [Indexed: 05/19/2023]
Abstract
Global ecosystem function is highly dependent on climate and atmospheric composition, yet ecosystem responses to environmental changes remain uncertain. Cold, high-latitude ecosystems in particular have experienced rapid warming1, with poorly understood consequences2-4. Here, we use a satellite observed proxy for vegetation cover - the fraction of absorbed photosynthetically active radiation5 - to identify a decline in the temperature limitation of vegetation in global ecosystems between 1982 and 2012. We quantify the spatial functional response of maximum annual vegetation cover to temperature and show that the observed temporal decline in temperature limitation is consistent with expectations based on observed recent warming. An ensemble of Earth system models from the Coupled Model Intercomparison Project (CMIP5) mischaracterized the functional response to temperature, leading to a large overestimation of vegetation cover in cold regions. We identify a 16.4% decline in the area of vegetated land that is limited by temperature over the past three decades, and suggest an expected large decline in temperature limitation under future warming scenarios. This rapid observed and expected decline in temperature limitation highlights the need for an improved understanding of other limitations to vegetation growth in cold regions3,4,6, such as soil characteristics, species migration, recruitment, establishment, competition, and community dynamics.
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Affiliation(s)
- T.F. Keenan
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA
- Department of Environmental Science, Policy and Management, UC Berkeley, Berkeley, CA 94720, USA
- Correspondence: Correspondence and requests for materials should be directed to Trevor F. Keenan (),
| | - W.J. Riley
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA
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