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Zhang S, Liu T, Duan L, Hao L, Tong X, Jia T, Li X, Lun S. Characterization and drivers of water and carbon fluxes dynamics in dune ecosystems of the Horqin Sandy Land. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170517. [PMID: 38296087 DOI: 10.1016/j.scitotenv.2024.170517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/05/2024] [Accepted: 01/26/2024] [Indexed: 02/09/2024]
Abstract
Sandy regions constitute pivotal components of terrestrial ecosystems, exerting significant influences on global ecological equilibrium and security. This study meticulously explored water and carbon fluxes dynamics within a dune ecosystem in the Horqin Sandy Land throughout the growing seasons from 2013 to 2022 by employing an advanced eddy covariance system. The dynamic characteristics of these fluxes and their underlying driving forces were extensively analyzed, with a particular focus on the impact of precipitation. The main results are as follows: (1) During the growing seasons of 2015 and 2016, the dune ecosystem acted as a modest carbon source, while in 2013, 2014, and 2017- 2022, it transformed into a net carbon sink. Notably, the annual mean values of water use efficiency (WUE) and evapotranspiration (ET) were 5.16 gC·kg-1H2O and 255.4 mm, respectively. (2) The intensity, frequency, and temporal distribution of precipitation were found to significantly influence the carbon and water fluxes dynamics. Isolated minor precipitation events did not trigger substantial fluctuations, but substantial and prolonged precipitation events spanning multiple days or consecutive minor precipitation events resulted in notable assimilation delays. (3) Air temperature, soil temperature, and fractional vegetation cover (FVC) were found to be key factors influencing the carbon and water fluxes. Specifically, FVC exhibited a negative logarithmic correlation with net ecosystem CO2 exchange (NEE) and a power function relationship with WUE. (4) The interaction between carbon and water fluxes is exhibited by exponential increases in ecosystem respiration (Reco) and gross primary productivity (GPP) with WUE, while NEE displayed an exponential decrease in relation to WUE. These findings are of high significance in predicting the potential ramifications of climate change on the intricate carbon and water cycles, and enhance our understanding of ecosystem dynamics in sandy environments.
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Affiliation(s)
- Simin Zhang
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Tingxi Liu
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Autonomous Region Key Laboratory of Water Resources Protection and Utilization, Hohhot 010018, China; Inner Mongolia section of the Yellow River Basin Water Resources and Water Environment Comprehensive Management Autonomous Region Collaborative Innovation Center, Hohhot 010018, China.
| | - Limin Duan
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Autonomous Region Key Laboratory of Water Resources Protection and Utilization, Hohhot 010018, China; Inner Mongolia section of the Yellow River Basin Water Resources and Water Environment Comprehensive Management Autonomous Region Collaborative Innovation Center, Hohhot 010018, China
| | - Lina Hao
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Autonomous Region Key Laboratory of Water Resources Protection and Utilization, Hohhot 010018, China; Inner Mongolia section of the Yellow River Basin Water Resources and Water Environment Comprehensive Management Autonomous Region Collaborative Innovation Center, Hohhot 010018, China.
| | - Xin Tong
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Autonomous Region Key Laboratory of Water Resources Protection and Utilization, Hohhot 010018, China; Inner Mongolia section of the Yellow River Basin Water Resources and Water Environment Comprehensive Management Autonomous Region Collaborative Innovation Center, Hohhot 010018, China
| | - Tianyu Jia
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Xia Li
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Shuo Lun
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
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Du Z, Zhang X, Liu S, An H. Nitrogen and water addition alters species diversity and interspecific relationship in a desert grassland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168386. [PMID: 37963527 DOI: 10.1016/j.scitotenv.2023.168386] [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: 07/31/2023] [Revised: 11/04/2023] [Accepted: 11/05/2023] [Indexed: 11/16/2023]
Abstract
Water and nitrogen (N) often affect plant species diversity and interspecific relationship among plant populations in global terrestrial ecosystems. However, the effects of water and N addition on plant diversity and interspecific relationship remain poorly understood. In the study, we designed a three-year field experiment in a desert grassland to assess the effect of increased water (natural +50 %) and N addition (10 g·N·m-2·a-1) on plant diversity and interspecific relationship. Our results showed that the alpha diversity was significantly changed under increased water (W), N addition (N), and water plus N addition (WN). The species richness was decreased significantly on year scales (10 %-27 %), whereas the Pielou index first increased and then decreased over three years and was significantly affected by the interaction between increased water and N addition. The total and pairwise beta diversity were significantly increased by N addition, the community was mainly caused by the turnover component after N addition, especially in 2019 and 2020 (16.6 % and 9 %, respectively). There were significant negative associations among overall populations and dominant populations under N addition, especially Stipa bungeana and Gypsophila davurica, Gypsophila davurica and Oxytropis acemose, Artemisia dalai-lamae, and Haplophyllum dauricum. Our findings suggested that plant community structure and composition changes may be due to competition for resources among dominant populations and the turnover component under increased water and N addition, which should be considered in ecosystem management.
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Affiliation(s)
- Zhongyu Du
- School of Ecology and Environment, Ningxia University; Breeding Base for State Key Lab. of Land Degradation and Ecological Restoration in Northwestern China; Key Lab. of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Yinchuan 750021, China; Research Institute of subtropical forestry, Chinese academy of forestry, Hangzhou 311400, China
| | - Xinwen Zhang
- School of Ecology and Environment, Ningxia University; Breeding Base for State Key Lab. of Land Degradation and Ecological Restoration in Northwestern China; Key Lab. of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Yinchuan 750021, China
| | - Shuxuan Liu
- School of Ecology and Environment, Ningxia University; Breeding Base for State Key Lab. of Land Degradation and Ecological Restoration in Northwestern China; Key Lab. of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Yinchuan 750021, China
| | - Hui An
- School of Ecology and Environment, Ningxia University; Breeding Base for State Key Lab. of Land Degradation and Ecological Restoration in Northwestern China; Key Lab. of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Yinchuan 750021, China.
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Zhang L, Shen M, Yang Z, Wang Y, Chen J. Spatial variations in the difference in elevational shifts between greenness and temperature isolines across the Tibetan Plateau grasslands under warming. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167715. [PMID: 37820790 DOI: 10.1016/j.scitotenv.2023.167715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/26/2023] [Accepted: 10/08/2023] [Indexed: 10/13/2023]
Abstract
Climate warming has induced widespread isotherm shifts toward higher elevations on the Tibetan Plateau, but elevational shifts of vegetation greenness (indicated by Normalized Difference Vegetation Index, NDVI) do not necessarily keep pace with the isotherm shifts. Thus, there should be spatial variations in the difference between the velocities of vertical movement of greenness isolines (VNDVI) and isotherms (VT) across the Tibetan Plateau grasslands. Using satellite-observed NDVI and gridded climate data during 2000-2017, we found uphill shifts of the isotherms in 81.8 % of the surveyed areas, mainly in the eastern, central, southwestern, and northeastern parts, whereas upward shifts of the greenness isolines were observed only in 49.7 % of these areas, mainly in the southeastern, west-central, and southwestern edge of Tibetan Plateau grasslands. In the areas where both the greenness isolines and isotherms shifted uphill, VDNVI was faster than VT in the west-central and northeastern parts, and VNDVI was smaller than VT in the western, south-central, central, and southeastern regions; the difference between VNDVI and VT was positively related with elevational gradient of NDVI (NDVIEG) in the areas where NDVIEG was negative and the temporal trend of NDVI was positive, and was negatively related with NDVIEG and temporal trends of NDVI and temperature in the areas where NDVIEG was positive and temporal trend of NDVI was negative. Our results revealed spatial heterogeneity in the difference in the elevational shifts between the isotherm and vegetation greenness isoline across the Tibetan Plateau grasslands, which is related with both diverse adaptation to local environment (NDVIEG) and complex responses of vegetation greenness to warming in terms of both direction and magnitude. These findings have important implications for the prediction of vegetation production and carbon cycle and the adaptive management of alpine grasslands under climate change.
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Affiliation(s)
- Lei Zhang
- Institute of Tibetan Plateau Research, University of the Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Miaogen Shen
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, 100875, China.
| | - Zhiyong Yang
- Institute of Tibetan Plateau Research, University of the Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China.
| | - Yafeng Wang
- Institute of Tibetan Plateau Research, University of the Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Jin Chen
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, 100875, China
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