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Yu Y, Peñuelas J, Sardans J, Pei JY, Li G, Liu GL, Ye JS. Water addition but not reduction alters plant biomass-diversity relationship. GLOBAL CHANGE BIOLOGY 2024; 30:e17430. [PMID: 39031432 DOI: 10.1111/gcb.17430] [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: 04/11/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/22/2024]
Abstract
The relationship between plant aboveground biomass and diversity typically follows a unimodal pattern, showing a positive correlation in resource-poor habitats and a negative correlation in resource-rich environments. Precipitation is a crucial resource for both plant biomass and diversity in terrestrial ecosystems. However, the impact of precipitation changes on the relationship between plant biomass and diversity remains unclear. We conduct a water addition field experiment in a semiarid grassland and identify a unimodal relationship between plant biomass and species richness under ambient conditions. Water addition delays the declining phase of this unimodal curve and shift it upward compared to ambient conditions. Our meta-analysis of water addition experiments conducted across major biomes worldwide (grassland, shrubland, desert, and forest) supports this finding, while water reduction does not alter the biomass-diversity relationship. Water addition increases biomass in all climate but only increases species richness in arid and semiarid climate. Similarly, water reduction decreases biomass in all climate but only reduces species richness in arid and semiarid climate. Species richness in dry subhumid and humid climate does not change significantly. Furthermore, our field experiment shows that water addition increases plant diversity while decreasing soil inorganic nitrogen levels. The increase in one resource, such as water, leads to the scarcity of another, such as nutrient, thus postponing the declining phase of the plant biomass-diversity relationship typically observed in resource-rich habitats. Our research contributes to predicting the plant biomass-diversity relationship under changing precipitation conditions and highlights the complex interplay between water availability, nutrient level, and plant diversity.
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Affiliation(s)
- Yan Yu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Josep Peñuelas
- CSIC, Global Ecology Unit, CREAF-CSIC-UAB, Barcelona, Catalonia, Spain
- CREAF, Barcelona, Catalonia, Spain
| | - Jordi Sardans
- CSIC, Global Ecology Unit, CREAF-CSIC-UAB, Barcelona, Catalonia, Spain
- CREAF, Barcelona, Catalonia, Spain
| | - Jiu-Ying Pei
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Ge Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Guo-Lin Liu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Jian-Sheng Ye
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
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Zhang Y, Gao H, Cai Z, Zhang J, Müller C. Global patterns of soil available N production by mineralization-immobilization turnover in the tropical forest ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168194. [PMID: 37918753 DOI: 10.1016/j.scitotenv.2023.168194] [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: 08/03/2023] [Revised: 10/09/2023] [Accepted: 10/27/2023] [Indexed: 11/04/2023]
Abstract
Available N (Navail) is important to nurish plant-microbial system and sequestrate carbon (C) in terrestrial ecosystems. For forest ecosystem, Navail is usually calculated as the sum of N2 fixation (NN2-fixed), N deposition (Ndeposition) and soil available N production (Navail-soil), in which Navail-soil determined the Navail production and its temporal changes. While, there is still a lack of Navail-soil estimation at the global and regional level due to the temporal and spatial variability of influencing factors, such as climate and soil physicochemical properties. By assembling a dataset of gross rates of soil N mineralization (GRmin), immobilization of ammonium (NH4+) (GRac) and nitrate (NO3-) (GRnc), as well as their corresponding geographic information, climate and main soil physicochemical properties, the Navail-soil produced from organic N (Norg) mineralization and inorganic N (Ninorg) immobilization turnover (MIT) was calculated via building a random forest (RF) model in global tropical forests. The results revealed a good fit between the observed and predicted GRmin (R2 = 0.76), GRac (R2 = 0.77) and GRnc (R2 = 0.67). We further estimated that the total mineralized N, immobilized NH4+ and NO3- was 23.97 (10.48-37.46), 17.98 (5.81-30.15) and 4.86 (1.46-8.26) Pg N year-1, respectively, leading to the total Navail-soil of 1.13 (-0.95-3.21) Pg N year-1. Referring to the reported average density of NN2-fixed and Ndeposition, the total NN2-fixed and Ndeposition was 0.03-0.05 and 0.01 Pg N year-1, respectively, by producting density and square meter of global tropic forest. Then the total Navail of global tropic forest ecosystem was 1.18 (-0.91-3.27) Pg N year-1 (Navail-soil + NN2-fixed + Ndeposition). According to the tight stoichiometric relationship between C and N in the production of gross primary productivity (GPP) and soil respiration (Rs), C:N ratio of 31.8-41.9 and 22.7-48.2 was calculated, respectively, which all fall into the C:N ratio range of plants and litter (13.9-75.9) in tropical forest ecosystem. These results confirmed the prediction of Navail-soil production from MIT was in line with theoretic estimates by applying RF machine learning. To our knowledge, this is the first estimation of Navail-soil and the results provide the theoretical basis to evaluate soil C sequestration potential in tropical (e.g. southern America, southeast Asia and Africa) forest ecosystem.
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Affiliation(s)
- Yi Zhang
- School of Geography, Nanjing Normal University, Nanjing 210023, China
| | - Hong Gao
- Faculty of Geomatics, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - Zucong Cai
- School of Geography, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China
| | - Jinbo Zhang
- School of Geography, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China; Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Germany.
| | - Christoph Müller
- Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Germany; Institute of Plant Ecology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany; School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin, Ireland
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Liu Y, Men M, Peng Z, Chen HYH, Yang Y, Peng Y. Spatially explicit estimate of nitrogen effects on soil respiration across the globe. GLOBAL CHANGE BIOLOGY 2023; 29:3591-3600. [PMID: 37052888 DOI: 10.1111/gcb.16716] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 04/03/2023] [Indexed: 06/06/2023]
Abstract
Soil respiration (Rs), as the second largest flux of carbon dioxide (CO2 ) between terrestrial ecosystems and the atmosphere, is vulnerable to global nitrogen (N) enrichment. However, the global distribution of the N effects on Rs remains uncertain. Here, we compiled a new database containing 1282 observations of Rs and its heterotrophic component (Rh) in field N manipulative experiments from 317 published papers. Using this up-to-date database, we first performed a formal meta-analysis to explore the responses of Rs and Rh to N addition, and then presented a global spatially explicit quantification of the N effects using a Random Forest model. Our results showed that experimental N addition significantly increased Rs but had a minimal impact on Rh, not supporting the prevailing view that N enrichment inhibits soil microbial respiration. For the major biomes, the magnitude of N input was the main determinant of the spatial variation in Rs response, while the most important predictors for Rh response were biome specific. Based on the key predictors, global mapping visually demonstrated a positive N effect in the regions with higher anthropogenic N inputs (i.e., atmospheric N deposition and agricultural fertilization). Overall, our analysis not only provides novel insight into the N effects on soil CO2 fluxes, but also presents a spatially explicit assessment of the N effects at the global scale, which are pivotal for understanding ecosystem carbon dynamics in future scenarios with more frequent anthropogenic activities.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Resources and Environmental Sciences, Key Laboratory of Farmland Eco-Environment of Hebei, Hebei Agricultural University, Baoding, China
| | - Mingxin Men
- College of Resources and Environmental Sciences, Key Laboratory of Farmland Eco-Environment of Hebei, Hebei Agricultural University, Baoding, China
| | - Zhengping Peng
- College of Resources and Environmental Sciences, Key Laboratory of Farmland Eco-Environment of Hebei, Hebei Agricultural University, Baoding, China
| | - Han Y H Chen
- Faculty of Natural Resources Management, Lakehead University, Thunder Bay, Ontario, Canada
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
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Bai T, Wang P, Qiu Y, Zhang Y, Hu S. Nitrogen availability mediates soil carbon cycling response to climate warming: A meta-analysis. GLOBAL CHANGE BIOLOGY 2023; 29:2608-2626. [PMID: 36744998 DOI: 10.1111/gcb.16627] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 01/10/2023] [Indexed: 05/31/2023]
Abstract
Global climate warming may induce a positive feedback through increasing soil carbon (C) release to the atmosphere. Although warming can affect both C input to and output from soil, direct and convincing evidence illustrating that warming induces a net change in soil C is still lacking. We synthesized the results from field warming experiments at 165 sites across the globe and found that climate warming had no significant effect on soil C stock. On average, warming significantly increased root biomass and soil respiration, but warming effects on root biomass and soil respiration strongly depended on soil nitrogen (N) availability. Under high N availability (soil C:N ratio < 15), warming had no significant effect on root biomass, but promoted the coupling between effect sizes of root biomass and soil C stock. Under relative N limitation (soil C:N ratio > 15), warming significantly enhanced root biomass. However, the enhancement of root biomass did not induce a corresponding C accumulation in soil, possibly because warming promoted microbial CO2 release that offset the increased root C input. Also, reactive N input alleviated warming-induced C loss from soil, but elevated atmospheric CO2 or precipitation increase/reduction did not. Together, our findings indicate that the relative availability of soil C to N (i.e., soil C:N ratio) critically mediates warming effects on soil C dynamics, suggesting that its incorporation into C-climate models may improve the prediction of soil C cycling under future global warming scenarios.
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Affiliation(s)
- Tongshuo Bai
- Ecosystem Ecology Laboratory, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Peng Wang
- Ecosystem Ecology Laboratory, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yunpeng Qiu
- Ecosystem Ecology Laboratory, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yi Zhang
- Ecosystem Ecology Laboratory, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Shuijin Hu
- Ecosystem Ecology Laboratory, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
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Liu Y, Men M, Peng Z, Houx JH, Peng Y. Nitrogen availability determines ecosystem productivity in response to climate warming. Ecology 2022; 103:e3823. [PMID: 35857189 DOI: 10.1002/ecy.3823] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/08/2022] [Indexed: 11/11/2022]
Abstract
One of the major uncertainties for carbon-climate feedback predictions is an inadequate understanding of the mechanisms governing variations in ecosystem productivity response to warming. Temperature and water availability are regarded as the primary controls over the direction and magnitude of warming effects, but some unexplained results signal that our understanding is incomplete. Using two complementary meta-analyses, we present evidence that soil nitrogen (N) availability drives the warming effects on ecosystem productivity more strongly than thermal and hydrological factors over a broad geographical scale. First, by synthesizing temperature manipulation experiments, meta-regression model analysis showed that the warming effect on productivity is mainly driven by its effect on soil N availability. Sites with higher warming-induced increase in N availability were characterized by stronger productivity enhancement and vice versa, suggesting that N is a limiting factor across sites. Second, a synthesis of full-factorial warming×N addition experiments demonstrated that N addition significantly weakened the positive warming effect, because the additional N induced by warming may not further benefit plant growth when N limitation is relieved, providing experimental evidence that N regulates the warming effect. Further, we demonstrated that warming effects on soil N availability were modulated by changes in dissolved organic N and soil microbes. Overall, our findings enrich a new mechanistic understanding of the varying magnitudes of observed productivity response to warming, and the N scaling of warming effects may help constrain climate projections.
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Affiliation(s)
- Yang Liu
- College of Resources and Environmental Sciences/Key Laboratory of Farmland Eco-Environment of Hebei, Hebei Agricultural University, Baoding, China.,State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Mingxin Men
- College of Resources and Environmental Sciences/Key Laboratory of Farmland Eco-Environment of Hebei, Hebei Agricultural University, Baoding, China
| | - Zhengping Peng
- College of Resources and Environmental Sciences/Key Laboratory of Farmland Eco-Environment of Hebei, Hebei Agricultural University, Baoding, China
| | - James H Houx
- Agriculture Research and Technology, National Crop Insurance Services, Overland Park, KS, USA
| | - Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
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