Analysis of the spatiotemporal dynamics of grassland carbon sinks in Xinjiang via the improved CASA model
Accurate assessment of grassland carbon sinks provides scientific data for quantifying the global carbon balance. Currently, methods for precisely calculating NPP (net primary productivity) and NEP (net ecosystem productivity) in arid grasslands are limited, and the changes in NEP and their driving...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-01-01
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| Series: | Ecological Indicators |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1470160X2401519X |
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| author | Xuewei Liu Renping Zhang Jing Guo Haoen Xu Yuhao Miao Feifei Niu Zhengjie Gao Xiaming Yang Fengqin Xiong Jianli Zhang |
| author_facet | Xuewei Liu Renping Zhang Jing Guo Haoen Xu Yuhao Miao Feifei Niu Zhengjie Gao Xiaming Yang Fengqin Xiong Jianli Zhang |
| author_sort | Xuewei Liu |
| collection | DOAJ |
| description | Accurate assessment of grassland carbon sinks provides scientific data for quantifying the global carbon balance. Currently, methods for precisely calculating NPP (net primary productivity) and NEP (net ecosystem productivity) in arid grasslands are limited, and the changes in NEP and their driving mechanisms remain unclear. This study optimized LUEmax (maximum light use efficiency) and Wε (water stress coefficient) in the CASA (Carnegie–Ames–Stanford Approach) model and developed eight improved CASA model configurations. NEP was calculated as the difference between the NPP estimated by the optimal CASA model and soil heterotrophic respiration (Rh). The changes in grassland NPP and NEP from 2000 to 2022 and the effects of different factors on grassland NEP were explored. The analysis revealed that (1) the R2 value of the optimal CASA model was 0.70, and the RMSE was 22.30 gC·m−2. (2) The 23-year average NEP in Xinjiang grassland was 113.00 gC·m−2·a−1, with 82.20 % carbon sink areas and 17.80 % carbon source areas. (3) NEPs of meadows, steppes, and desert grasslands in the Xinjiang region tended to increase during spring, summer, and autumn. (4) During the 23-year period, 15.77 % of the Xinjiang grassland area transitioned from carbon sources to carbon sinks. (5) Relative humidity and soil pH strongly influenced the NEP of Xinjiang grassland. This study provides a more accurate model for calculating NPP and estimating the variation in carbon source and carbon sink areas in arid grasslands, providing theoretical guidance for the development of grassland management policies. |
| format | Article |
| id | doaj-art-2bb7706a43c34e14ac1b61fec342cb44 |
| institution | Kabale University |
| issn | 1470-160X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Ecological Indicators |
| spelling | doaj-art-2bb7706a43c34e14ac1b61fec342cb442025-01-31T05:10:44ZengElsevierEcological Indicators1470-160X2025-01-01170113062Analysis of the spatiotemporal dynamics of grassland carbon sinks in Xinjiang via the improved CASA modelXuewei Liu0Renping Zhang1Jing Guo2Haoen Xu3Yuhao Miao4Feifei Niu5Zhengjie Gao6Xiaming Yang7Fengqin Xiong8Jianli Zhang9College of Ecology and Environment, Xinjiang University, Urumqi 830046, China; Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, ChinaCollege of Ecology and Environment, Xinjiang University, Urumqi 830046, China; Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, China; Corresponding author at: College of Ecology and Environment, Xinjiang University, Urumqi 830046, China.Xinjiang Academy of Forestry Sciences, Urumqi 830000, ChinaState Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaCollege of Ecology and Environment, Xinjiang University, Urumqi 830046, China; Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, ChinaCollege of Ecology and Environment, Xinjiang University, Urumqi 830046, China; Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, ChinaCollege of Ecology and Environment, Xinjiang University, Urumqi 830046, China; Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, ChinaCollege of Ecology and Environment, Xinjiang University, Urumqi 830046, China; Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, ChinaCollege of Ecology and Environment, Xinjiang University, Urumqi 830046, China; Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, ChinaXinjiang Uygur Autonomous Region Grassland General Station, Urumqi, 830000, ChinaAccurate assessment of grassland carbon sinks provides scientific data for quantifying the global carbon balance. Currently, methods for precisely calculating NPP (net primary productivity) and NEP (net ecosystem productivity) in arid grasslands are limited, and the changes in NEP and their driving mechanisms remain unclear. This study optimized LUEmax (maximum light use efficiency) and Wε (water stress coefficient) in the CASA (Carnegie–Ames–Stanford Approach) model and developed eight improved CASA model configurations. NEP was calculated as the difference between the NPP estimated by the optimal CASA model and soil heterotrophic respiration (Rh). The changes in grassland NPP and NEP from 2000 to 2022 and the effects of different factors on grassland NEP were explored. The analysis revealed that (1) the R2 value of the optimal CASA model was 0.70, and the RMSE was 22.30 gC·m−2. (2) The 23-year average NEP in Xinjiang grassland was 113.00 gC·m−2·a−1, with 82.20 % carbon sink areas and 17.80 % carbon source areas. (3) NEPs of meadows, steppes, and desert grasslands in the Xinjiang region tended to increase during spring, summer, and autumn. (4) During the 23-year period, 15.77 % of the Xinjiang grassland area transitioned from carbon sources to carbon sinks. (5) Relative humidity and soil pH strongly influenced the NEP of Xinjiang grassland. This study provides a more accurate model for calculating NPP and estimating the variation in carbon source and carbon sink areas in arid grasslands, providing theoretical guidance for the development of grassland management policies.http://www.sciencedirect.com/science/article/pii/S1470160X2401519XArid and semiarid regionsNet primary productivityNet ecosystem productivityDriving factors |
| spellingShingle | Xuewei Liu Renping Zhang Jing Guo Haoen Xu Yuhao Miao Feifei Niu Zhengjie Gao Xiaming Yang Fengqin Xiong Jianli Zhang Analysis of the spatiotemporal dynamics of grassland carbon sinks in Xinjiang via the improved CASA model Ecological Indicators Arid and semiarid regions Net primary productivity Net ecosystem productivity Driving factors |
| title | Analysis of the spatiotemporal dynamics of grassland carbon sinks in Xinjiang via the improved CASA model |
| title_full | Analysis of the spatiotemporal dynamics of grassland carbon sinks in Xinjiang via the improved CASA model |
| title_fullStr | Analysis of the spatiotemporal dynamics of grassland carbon sinks in Xinjiang via the improved CASA model |
| title_full_unstemmed | Analysis of the spatiotemporal dynamics of grassland carbon sinks in Xinjiang via the improved CASA model |
| title_short | Analysis of the spatiotemporal dynamics of grassland carbon sinks in Xinjiang via the improved CASA model |
| title_sort | analysis of the spatiotemporal dynamics of grassland carbon sinks in xinjiang via the improved casa model |
| topic | Arid and semiarid regions Net primary productivity Net ecosystem productivity Driving factors |
| url | http://www.sciencedirect.com/science/article/pii/S1470160X2401519X |
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