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Liu L, Zheng J, Guan J, Li C, Ma L, Liu Y, Han W. Strong positive direct impact of soil moisture on the growth of central asian grasslands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 954:176663. [PMID: 39362565 DOI: 10.1016/j.scitotenv.2024.176663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 09/23/2024] [Accepted: 09/30/2024] [Indexed: 10/05/2024]
Abstract
As the issue of global climate change becomes increasingly prominent, the grassland ecosystems in Central Asia are facing severe challenges posed by the impacts of climate change. However, the dominant factors, impact pathways, and cumulative and time-lagged effects of climate factors on various grassland indices remain to be explored. This study selected data from 1988 to 2019, including Fractional Vegetation Cover (FVC), Leaf Area Index (LAI), Net Primary Productivity (NPP), and Vegetation Optical Depth (VOD), to characterize grassland coverage, greenness, biomass accumulation, and water content features. Utilizing multiple linear regression, path analysis, and correlation analysis, this study investigated the dominant effects, direct impacts, indirect influences, and cumulative and time-lagged effects of climate factors on various grassland indices from spatial and climatic zone perspectives. The research findings indicate that over time, the grassland FVC and NPP exhibited increasing trends, while the LAI and VOD showed decreasing trends. Grassland indices are primarily influenced by precipitation and soil moisture (SM). The direct impact of SM on grassland indices was higher than precipitation. Vapour pressure deficit (VPD) has a direct negative impact on grassland indices. Grassland indices are subject to positive indirect effects from precipitation via SM and negative indirect effects from VPD via SM. Precipitation and SM mainly exhibited no cumulative and time-lagged effects on the impact of grassland VOD. VPD primarily demonstrated cumulative and time-lagged effects on grassland indices. The research findings offer valuable insights for conserving grassland ecosystems in Central Asia, as well as for shaping socioeconomic strategies and formulating climate policies.
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Affiliation(s)
- Liang Liu
- College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China
| | - Jianghua Zheng
- College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China; Xinjiang Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, China.
| | - Jingyun Guan
- College of Tourism, Xinjiang University of Finance & Economics, Urumqi 830012, China
| | - Congren Li
- College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China
| | - Lisha Ma
- College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China
| | - Yujia Liu
- College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China
| | - Wanqiang Han
- College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China
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Zhang Q, Chen Y, Li Z, Sun C, Xiang Y, Liu Z. Spatio-Temporal Development of Vegetation Carbon Sinks and Sources in the Arid Region of Northwest China. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3608. [PMID: 36834302 PMCID: PMC9966209 DOI: 10.3390/ijerph20043608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Drylands, which account for 41% of Earth's land surface and are home to more than two billion people, play an important role in the global carbon balance. This study analyzes the spatio-temporal patterns of vegetation carbon sinks and sources in the arid region of northwest China (NWC), using the net ecosystem production (NEP) through the Carnegie-Ames-Stanford approach (CASA). It quantitatively evaluates regional ecological security over a 20-year period (2000-2020) via a remote sensing ecological index (RSEI) and other ecological indexes, such as the Normalized Difference Vegetation Index (NDVI), fraction of vegetation cover (FVC), net primary productivity (NPP), and land use. The results show that the annual average carbon capacity of vegetation in NWC changed from carbon sources to carbon sinks, and the vegetation NEP increased at a rate of 1.98 gC m-2 yr-1 from 2000 to 2020. Spatially, the annual NEP in northern Xinjiang (NXJ), southern Xinjiang (SXJ) and Hexi Corridor (HX) increased at even faster rates of 2.11, 2.22, and 1.98 gC m-2 yr-1, respectively. Obvious geographically heterogeneous distributions and changes occurred in vegetation carbon sinks and carbon sources. Some 65.78% of the vegetation areas in NWC were carbon sources during 2000-2020, which were concentrated in the plains, and SXJ, the majority carbon sink areas are located in the mountains. The vegetation NEP in the plains exhibited a positive trend (1.21 gC m-2 yr-1) during 2000-2020, but this speed has slowed since 2010. The vegetation NEP in the mountain exhibited only intermittent changes (2.55 gC m-2 yr-1) during 2000-2020; it exhibited a negative trend during 2000-2010, but this trend has reversed strongly since 2010. The entire ecological security of NWC was enhanced during the study period. Specifically, the RSEI increased from 0.34 to 0.49, the NDVI increased by 0.03 (17.65%), the FVC expanded by 19.56%, and the NPP increased by 27.44%. Recent positive trends in NDVI, FVC and NPP have enhanced the capacity of vegetation carbon sinks, and improved the eco-environment of NWC. The scientific outcomes of this study are of great importance for maintaining ecological stability and sustainable economic development along China's Silk Road Economic Belt.
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Affiliation(s)
- Qifei Zhang
- School of Geographical Sciences, Shanxi Normal University, Taiyuan 030031, China
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Research Center of Ecology and Environment in the Middle Reaches of the Yellow River, Shanxi Normal University, Taiyuan 030031, China
| | - Yaning Chen
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Zhi Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Congjian Sun
- School of Geographical Sciences, Shanxi Normal University, Taiyuan 030031, China
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Research Center of Ecology and Environment in the Middle Reaches of the Yellow River, Shanxi Normal University, Taiyuan 030031, China
| | - Yanyun Xiang
- School of Public Administration, Shanxi University of Finance and Economics, Taiyuan 030006, China
| | - Zhihui Liu
- School of Geographical Sciences, Shanxi Normal University, Taiyuan 030031, China
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