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Driscoll C, Milford JB, Henze DK, Bell MD. Atmospheric reduced nitrogen: Sources, transformations, effects, and management. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2024; 74:362-415. [PMID: 38819428 DOI: 10.1080/10962247.2024.2342765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/02/2024] [Indexed: 06/01/2024]
Abstract
Human activities have increased atmospheric emissions and deposition of oxidized and reduced forms of nitrogen, but emission control programs have largely focused on oxidized nitrogen. As a result, in many regions of the world emissions of oxidized nitrogen are decreasing while emissions of reduced nitrogen are increasing. Emissions of reduced nitrogen largely originate from livestock waste and fertilizer application, with contributions from transportation sources in urban areas. Observations suggest a discrepancy between trends in emissions and deposition of reduced nitrogen in the U.S., likely due to an underestimate in emissions. In the atmosphere, ammonia reacts with oxides of sulfur and nitrogen to form fine particulate matter that impairs health and visibility and affects climate forcings. Recent reductions in emissions of sulfur and nitrogen oxides have limited partitioning with ammonia, decreasing long-range transport. Continuing research is needed to improve understanding of how shifting emissions alter formation of secondary particulates and patterns of transport and deposition of reactive nitrogen. Satellite remote sensing has potential for monitoring atmospheric concentrations and emissions of ammonia, but there remains a need to maintain and strengthen ground-based measurements and continue development of chemical transport models. Elevated nitrogen deposition has decreased plant and soil microbial biodiversity and altered the biogeochemical function of terrestrial, freshwater, and coastal ecosystems. Further study is needed on differential effects of oxidized versus reduced nitrogen and pathways and timescales of ecosystem recovery from elevated nitrogen deposition. Decreases in deposition of reduced nitrogen could alleviate exceedances of critical loads for terrestrial and freshwater indicators in many U.S. areas. The U.S. Environmental Protection Agency should consider using critical loads as a basis for setting standards to protect public welfare and ecosystems. The U.S. and other countries might look to European experience for approaches to control emissions of reduced nitrogen from agricultural and transportation sectors.Implications: In this Critical Review we synthesize research on effects, air emissions, environmental transformations, and management of reduced forms of nitrogen. Emissions of reduced nitrogen affect human health, the structure and function of ecosystems, and climatic forcings. While emissions of oxidized forms of nitrogen are regulated in the U.S., controls on reduced forms are largely absent. Decreases in emissions of sulfur and nitrogen oxides coupled with increases in ammonia are shifting the gas-particle partitioning of ammonia and decreasing long-range atmospheric transport of reduced nitrogen. Effort is needed to understand, monitor, and manage emissions of reduced nitrogen in a changing environment.
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Affiliation(s)
- Charles Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY, USA
| | - Jana B Milford
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA
| | - Daven K Henze
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA
| | - Michael D Bell
- Ecologist, National Park Service - Air Resources Division, Boulder, CO, USA
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2
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Chen X, Lu H, Ren Z, Zhang Y, Liu R, Zhang Y, Han X. Reproductive height determines the loss of clonal grasses with nitrogen enrichment in a temperate grassland. PLANT DIVERSITY 2024; 46:256-264. [PMID: 38807914 PMCID: PMC11128833 DOI: 10.1016/j.pld.2023.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/19/2023] [Accepted: 04/25/2023] [Indexed: 05/30/2024]
Abstract
Tall clonal grasses commonly display competitive advantages with nitrogen (N) enrichment. However, it is currently unknown whether the height is derived from the vegetative or reproductive module. Moreover, it is unclear whether the height of the vegetative or reproductive system regulates the probability of extinction and colonization, and determines species diversity. In this study, the impacts on clonal grasses were studied in a field experiment employing two frequencies (twice a year vs. monthly) crossing with nine N addition rates in a temperate grassland, China. We found that the N addition decreased species frequency and increased extinction probability, but did not change the species colonization probability. A low frequency of N addition decreased species frequency and colonization probability, but increased extinction probability. Moreover, we found that species reproductive height was the best index to predict the extinction probability of clonal grasses in N-enriched conditions. The low frequency of N addition may overestimate the negative effect from N deposition on clonal grass diversity, suggesting that a higher frequency of N addition is more suitable in assessing the ecological effects of N deposition. Overall, this study illustrates that reproductive height was associated with the clonal species extinction probability under N-enriched environment.
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Affiliation(s)
- Xu Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
| | - Haining Lu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
| | - Zhengru Ren
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
| | - Yuqiu Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
| | - Ruoxuan Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
| | - Yunhai Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
| | - Xingguo Han
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
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3
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Shen H, Dong S, DiTommaso A, Westbrook AS, Li S, Zheng H, Zhi Y, Zuo H, Wang Q, Liu J. Physiological factors contribute to increased competitiveness of grass relative to sedge, forb and legume species under different N application levels. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167466. [PMID: 37788779 DOI: 10.1016/j.scitotenv.2023.167466] [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: 06/20/2023] [Revised: 09/20/2023] [Accepted: 09/28/2023] [Indexed: 10/05/2023]
Abstract
In alpine grasslands, increased N deposition is increasing the dominance of grasses relative to other functional types according to our previous study Shen et al. (2022). However, the mechanisms that drive this compositional change are not fully understood. We measured the effects of 4-6 years' N addition to simulate N deposition at rates of 0 (CK), 8 (N1), 24 (N2), 40 (N3), 56 (N4), and 72 (N5) kg N ha-1 year-1 on dominant representatives of four functional types, Leymus secalinus (grass), Carex capillifolia (sedge), Potentilla multifidi (non-leguminous forb), and Medicago ruthenica (legume), in the alpine grassland on the Qinghai-Tibetan Plateau (QTP). In-situ experiment showed that N addition increased aboveground biomass in L. secalinus but had negative or neutral effects on aboveground biomass in the other species. Consistent with this finding, N addition increased net photosynthesis, chlorophyll content, and rubisco activity in L. secalinus with less positive effects on the other species. Nitrogen addition increased leaf N content in L. secalinus and C. capillifolia and reduced leaf non-structural carbohydrate content in all four species. In L. secalinus, the highest N addition rate (N5) reduced MDA content, a marker of oxidative stress, by enhancing antioxidant enzyme activity. Overall, our findings suggested that physiological factors can contribute to increased competitiveness of grass relative to sedge, forb and legume species under high N application levels. The rapid growth of this grass species reduces resource availability to non-grass species, increasing its dominance in the alpine meadow.
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Affiliation(s)
- Hao Shen
- School of Grassland Science, Beijing Forestry University, Beijing, 100083, China
| | - Shikui Dong
- School of Grassland Science, Beijing Forestry University, Beijing, 100083, China; School of Environment, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Beijing Normal University, Beijing, 100875, China; Department of Natural Resources, Cornell University, Ithaca, NY 14853, United States.
| | - Antonio DiTommaso
- Soil and Crop Sciences, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, United States
| | - Anna S Westbrook
- Soil and Crop Sciences, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, United States
| | - Shuai Li
- College of Resource and Environment, Shanxi Agricultural University, Taigu 030801, China
| | - Hanzhong Zheng
- Department of Environmental Science, Radboud University, 6526 AJ Nijmegen, The Netherlands
| | - Yangliu Zhi
- School of Environment, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Beijing Normal University, Beijing, 100875, China
| | - Hui Zuo
- School of Grassland Science, Beijing Forestry University, Beijing, 100083, China
| | - Qiyun Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Junxiang Liu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
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4
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Eskelinen A, Jessen MT, Bahamonde HA, Bakker JD, Borer ET, Caldeira MC, Harpole WS, Jia M, Lannes LS, Nogueira C, Olde Venterink H, Peri PL, Porath-Krause AJ, Seabloom EW, Schroeder K, Tognetti PM, Yasui SLE, Virtanen R, Sullivan LL. Herbivory and nutrients shape grassland soil seed banks. Nat Commun 2023; 14:3949. [PMID: 37402739 DOI: 10.1038/s41467-023-39677-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 06/23/2023] [Indexed: 07/06/2023] Open
Abstract
Anthropogenic nutrient enrichment and shifts in herbivory can lead to dramatic changes in the composition and diversity of aboveground plant communities. In turn, this can alter seed banks in the soil, which are cryptic reservoirs of plant diversity. Here, we use data from seven Nutrient Network grassland sites on four continents, encompassing a range of climatic and environmental conditions, to test the joint effects of fertilization and aboveground mammalian herbivory on seed banks and on the similarity between aboveground plant communities and seed banks. We find that fertilization decreases plant species richness and diversity in seed banks, and homogenizes composition between aboveground and seed bank communities. Fertilization increases seed bank abundance especially in the presence of herbivores, while this effect is smaller in the absence of herbivores. Our findings highlight that nutrient enrichment can weaken a diversity maintaining mechanism in grasslands, and that herbivory needs to be considered when assessing nutrient enrichment effects on seed bank abundance.
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Affiliation(s)
- Anu Eskelinen
- Ecology and Genetics Unit, University of Oulu, P.O. Box 3000, Oulu, Finland.
- Department of Physiological Diversity, Helmholtz Centre for Environmental Research - UFZ, Puschstraße 4, 04103, Leipzig, Germany.
- German Centre for Integrative Biodiversity Research (iDiv), Puschstraße 4, 04103, Leipzig, Germany.
| | - Maria-Theresa Jessen
- Department of Physiological Diversity, Helmholtz Centre for Environmental Research - UFZ, Puschstraße 4, 04103, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv), Puschstraße 4, 04103, Leipzig, Germany
- Department of Community Ecology, Helmholtz Centre for Environmental Research - UFZ, Halle, Theodor-Lieser-Str. 4, 06120, Halle, Germany
| | - Hector A Bahamonde
- Faculty of Agricultural and Forestry Sciences, National University of La Plata, Av. 60 y 119, La Plata, 1900, Buenos Aires, Argentina
| | - Jonathan D Bakker
- School of Environmental and Forest Sciences, University of Washington, Box 354115, Seattle, WA, 98195-4115, USA
| | - Elizabeth T Borer
- University of Minnesota, Department of Ecology, Evolution and Behavior, 140 Gortner Laboratory, 1479 Gortner Ave, St Paul, MN, 55108, USA
| | - Maria C Caldeira
- Forest Research Centre, Associate Laboratory TERRA, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017, Lisbon, Portugal
| | - W Stanley Harpole
- Department of Physiological Diversity, Helmholtz Centre for Environmental Research - UFZ, Puschstraße 4, 04103, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv), Puschstraße 4, 04103, Leipzig, Germany
- Martin Luther University Halle-Wittenberg, am Kirchtor 1, 06108, Halle (Saale), Germany
| | - Meiyu Jia
- School of Environmental and Forest Sciences, University of Washington, Box 354115, Seattle, WA, 98195-4115, USA
- School of Water Resources & Environmental Engineering, East China University of Technology, Nanchang, 330013, China
- College of Life Sciences, Beijing Normal University, No. 19 Xinjiekou Wai Street, Beijing City, 100875, China
| | - Luciola S Lannes
- Department of Biology and Animal Sciences, São Paulo State University-UNESP, Ilha Solteira, 01049-010, Brazil
| | - Carla Nogueira
- Forest Research Centre, Associate Laboratory TERRA, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017, Lisbon, Portugal
| | - Harry Olde Venterink
- Department of Biology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | - Pablo L Peri
- National Institute of Agricultural Research (INTA), Southern Patagonia National University (UNPA), CONICET, Río Gallegos, (CP 9400), Santa Cruz, Argentina
| | - Anita J Porath-Krause
- University of Minnesota, Department of Ecology, Evolution and Behavior, 140 Gortner Laboratory, 1479 Gortner Ave, St Paul, MN, 55108, USA
| | - Eric W Seabloom
- University of Minnesota, Department of Ecology, Evolution and Behavior, 140 Gortner Laboratory, 1479 Gortner Ave, St Paul, MN, 55108, USA
| | - Katie Schroeder
- University of Minnesota, Department of Ecology, Evolution and Behavior, 140 Gortner Laboratory, 1479 Gortner Ave, St Paul, MN, 55108, USA
- Odum School of Ecology, University of Georgia, Athens, GA, 30603, USA
| | - Pedro M Tognetti
- IFEVA, University of Buenos Aires, CONICET, Facultad de Agronomía, Av. San Martin, 4453 C1417DSE, Buenos Aires, Argentina
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Simone-Louise E Yasui
- Queensland University of Technology, School of Biological and Environmental Sciences, Brisbane, QLD 4072, Australia
| | - Risto Virtanen
- Ecology and Genetics Unit, University of Oulu, P.O. Box 3000, Oulu, Finland
| | - Lauren L Sullivan
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
- W. K. Kellogg Biological Station, Michigan State University, Hickory Corners, MI, 49060, USA
- Ecology, Evolution and Behavior Program, Michigan State University, East Lansing, MI, 48824, USA
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5
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Xu Z, Liu H, Meng Y, Yin J, Ren H, Li MH, Yang S, Tang S, Jiang Y, Jiang L. Nitrogen addition and mowing alter drought resistance and recovery of grassland communities. SCIENCE CHINA. LIFE SCIENCES 2023:10.1007/s11427-022-2217-9. [PMID: 36964460 DOI: 10.1007/s11427-022-2217-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 10/11/2022] [Indexed: 03/26/2023]
Abstract
Nitrogen enrichment and land use are known to influence various ecosystems, but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood. Here we investigated the effects of increased nitrogen input and mowing on the resistance and recovery of temperate semiarid grassland experiencing a three-year drought. Nitrogen addition increased grassland biomass recovery but decreased structural recovery after drought, whereas annual mowing increased grassland biomass recovery and structural recovery but reduced structural resistance to drought. The treatment effects on community biomass/structural resistance and recovery were largely modulated by the stability of the dominant species and asynchronous dynamics among species, and the community biomass resistance and recovery were also greatly driven by the stability of grasses. Community biomass resistance/recovery in response to drought was positively associated with its corresponding structural stability. Our study provides important experimental evidence that both nitrogen addition and mowing could substantially change grassland stability in both functional and structural aspects. Our findings emphasize the need to study changes across levels of ecological organization for a more complete understanding of ecosystem responses to disturbances under widespread environmental changes.
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Affiliation(s)
- Zhuwen Xu
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China.
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, 30332, USA.
- Autonomous Region Collaborative Innovation Center for Integrated Management of Water Resources and Water Environment in the Inner Mongolia Reaches of the Yellow River, Hohhot, 010018, China.
| | - Heyong Liu
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
- School of Life Sciences, Hebei University, Baoding, 071002, China
| | - Yani Meng
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Jinfei Yin
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Haiyan Ren
- Key Laboratory of Grassland Resources, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Mai-He Li
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
- School of Life Sciences, Hebei University, Baoding, 071002, China
| | - Shan Yang
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Shiming Tang
- Key Laboratory for Model Innovation in Forage Production Efficiency, Ministry of Agriculture and Rural Affairs, Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, 010010, China
| | - Yong Jiang
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
- School of Life Sciences, Hebei University, Baoding, 071002, China.
| | - Lin Jiang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, 30332, USA.
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6
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Rogora M, Steingruber S, Marchetto A, Mosello R, Giacomotti P, Orru' A, Tartari GA, Tiberti R. Response of atmospheric deposition and surface water chemistry to the COVID-19 lockdown in an alpine area. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:62312-62329. [PMID: 35397723 PMCID: PMC8994528 DOI: 10.1007/s11356-022-20080-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 03/31/2022] [Indexed: 06/14/2023]
Abstract
The effects of the COVID-19 lockdown on deposition and surface water chemistry were investigated in an area south of the Alps. Long-term data provided by the monitoring networks revealed that the deposition of sulfur and nitrogen compounds in this area has stabilized since around 2010; in 2020, however, both concentrations and deposition were significantly below the average values of the previous decade for SO4 and NO3. Less evident changes were observed for NH4 and base cation. The estimated decrease of deposition in 2020 with respect to the previous decade was on average - 54% and - 46% for SO4 and NO3, respectively. The lower deposition of SO4 and NO3 recorded in 2020 was caused by the sharp decrease of SO2 and particularly of NOx air concentrations mainly due to the mobility restrictions consequent to the COVID-19 lockdown. The limited effects on NH4 deposition can be explained by the fact that NH3 emission was not affected by the lockdown, being mainly related to agricultural activities. A widespread response to the decreased deposition of S and N compounds was observed in a group of pristine freshwater sites, with NO3 concentrations in 2020 clearly below the long-term average. The rapid chemical recovery observed at freshwater sites in response to the sharp decrease of deposition put in evidence the high resilience potential of freshwater ecosystems in pristine regions and demonstrated the great potential of emission reduction policy in producing further substantial ameliorations of the water quality at sensitive sites.
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Affiliation(s)
- Michela Rogora
- National Research Council of Italy, Water Research Institute (CNR-IRSA) , Largo Tonolli 50, 28922, Verbania Pallanza (VB), Italy.
| | - Sandra Steingruber
- Ufficio dell'Aria, del Clima e e delle Energie Rinnovabili, Dipartimento del Territorio del Cantone Ticino, CH-6501, Bellinzona, Switzerland
| | - Aldo Marchetto
- National Research Council of Italy, Water Research Institute (CNR-IRSA) , Largo Tonolli 50, 28922, Verbania Pallanza (VB), Italy
| | - Rosario Mosello
- National Research Council of Italy, Water Research Institute (CNR-IRSA) , Largo Tonolli 50, 28922, Verbania Pallanza (VB), Italy
| | - Paola Giacomotti
- National Research Council of Italy, Water Research Institute (CNR-IRSA) , Largo Tonolli 50, 28922, Verbania Pallanza (VB), Italy
| | - Arianna Orru'
- National Research Council of Italy, Water Research Institute (CNR-IRSA) , Largo Tonolli 50, 28922, Verbania Pallanza (VB), Italy
| | - Gabriele A Tartari
- National Research Council of Italy, Water Research Institute (CNR-IRSA) , Largo Tonolli 50, 28922, Verbania Pallanza (VB), Italy
| | - Rocco Tiberti
- National Research Council of Italy, Water Research Institute (CNR-IRSA) , Largo Tonolli 50, 28922, Verbania Pallanza (VB), Italy
- Department of Earth and Environmental Sciences DSTA, University of Pavia, Via Ferrata 9, 27100, Pavia, Italy
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7
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Collins CG, Elmendorf SC, Smith JG, Shoemaker L, Szojka M, Swift M, Suding KN. Global change re-structures alpine plant communities through interacting abiotic and biotic effects. Ecol Lett 2022; 25:1813-1826. [PMID: 35763598 DOI: 10.1111/ele.14060] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/31/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022]
Abstract
Global change is altering patterns of community assembly, with net outcomes dependent on species' responses to the abiotic environment, both directly and mediated through biotic interactions. Here, we assess alpine plant community responses in a 15-year factorial nitrogen addition, warming and snow manipulation experiment. We used a dynamic competition model to estimate the density-dependent and -independent processes underlying changes in species-group abundances over time. Density-dependent shifts in competitive interactions drove long-term changes in abundance of species-groups under global change while counteracting environmental drivers limited the growth response of the dominant species through density-independent mechanisms. Furthermore, competitive interactions shifted with the environment, primarily with nitrogen and drove non-linear abundance responses across environmental gradients. Our results highlight that global change can either reshuffle species hierarchies or further favour already-dominant species; predicting which outcome will occur requires incorporating both density-dependent and -independent mechanisms and how they interact across multiple global change factors.
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Affiliation(s)
- Courtney G Collins
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA.,Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sarah C Elmendorf
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
| | - Jane G Smith
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
| | - Lauren Shoemaker
- Department of Botany, University of Wyoming, Laramie, Wyoming, USA
| | - Megan Szojka
- Department of Botany, University of Wyoming, Laramie, Wyoming, USA
| | - Margaret Swift
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
| | - Katharine N Suding
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
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8
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Werner CM, Tuomi M, Eskelinen A. Trait-based responses to cessation of nutrient enrichment in a tundra plant community. Oecologia 2021; 197:675-684. [PMID: 34716491 PMCID: PMC8585805 DOI: 10.1007/s00442-021-05064-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 10/17/2021] [Indexed: 11/25/2022]
Abstract
Plant communities worldwide show varied responses to nutrient enrichment-including shifts in species identity, decreased diversity, and changes in functional trait composition-but the factors determining community recovery after the cessation of nutrient addition remain uncertain. We manipulated nutrient levels in a tundra community for 6 years of nutrient addition followed by 8 years of recovery. We examined how community recovery was mediated by traits related to plant resource-use strategy and plant ability to modify their environment. Overall, we observed persistent effects of fertilization on plant communities. We found that plants with fast-growing traits, including higher specific leaf area, taller stature and lower foliar C:N, were more likely to show a persistent increase in fertilized plots than control plots, maintaining significantly higher cover in fertilized plots 8 years after cessation of fertilization. Additionally, although graminoids responded most strongly to the initial fertilization treatment, forb species were more vulnerable to fertilization effects in the long-term, showing persistent decline and no recovery in 8 years. Finally, these persistent fertilization effects were accompanied by modified environmental conditions, including persistent increases in litter depth and soil phosphorous and lower soil C:N. Our results demonstrate the potential for lasting effects of nutrient enrichment in nutrient-limited systems and identify species traits related to rapid growth and nutrient-use efficiency as the main predictors of the persistence of nutrient enrichment effects. These findings highlight the usefulness of trait-based approach for understanding the persistent feedbacks of nutrient enrichment, plant dynamics, and niche construction via litter and nutrient build-up.
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Affiliation(s)
- Chhaya M Werner
- Department of Physiological Diversity, Helmholtz Center for Environmental Research (UFZ), 04318, Leipzig, Germany.
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103, Leipzig, Germany.
- Department of Ecology and Genetics, University of Oulu, 90014, Oulu, Finland.
| | - Maria Tuomi
- Department of Arctic and Marine Biology, UiT, The Arctic University of Norway, 9019, Tromso, Norway
| | - Anu Eskelinen
- Department of Physiological Diversity, Helmholtz Center for Environmental Research (UFZ), 04318, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103, Leipzig, Germany
- Department of Ecology and Genetics, University of Oulu, 90014, Oulu, Finland
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9
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Brigham LM, Bueno de Mesquita CP, Smith JG, Sartwell SA, Schmidt SK, Suding KN. Do plant-soil interactions influence how the microbial community responds to environmental change? Ecology 2021; 103:e03554. [PMID: 34622953 DOI: 10.1002/ecy.3554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 05/03/2021] [Accepted: 07/15/2021] [Indexed: 01/04/2023]
Abstract
Global change alters ecosystems and their functioning, and biotic interactions can either buffer or amplify such changes. We utilized a long-term nitrogen (N) addition and species removal experiment in the Front Range of Colorado, USA to determine whether a codominant forb and a codominant grass, with different effects on nutrient cycling and plant community structure, would buffer or amplify the effects of simulated N deposition on soil bacterial and fungal communities. While the plant community was strongly shaped by both the presence of dominant species and N addition, we did not find a mediating effect of the plant community on soil microbial response to N. In contrast to our hypothesis, we found a decoupling of the plant and microbial communities such that the soil microbial community shifted under N independently of directional shifts in the plant community. These findings suggest there are not strong cascading effects of N deposition across the plant-soil interface in our system.
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Affiliation(s)
- Laurel M Brigham
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA.,Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80301, USA
| | - Clifton P Bueno de Mesquita
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA.,Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80301, USA
| | - Jane G Smith
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80301, USA
| | - Samuel A Sartwell
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80301, USA
| | - Steven K Schmidt
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA
| | - Katharine N Suding
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA.,Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, 80301, USA
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10
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Eskelinen A, Elwood E, Harrison S, Beyen E, Gremer JR. Vulnerability of grassland seed banks to resource-enhancing global changes. Ecology 2021; 102:e03512. [PMID: 34358331 DOI: 10.1002/ecy.3512] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/20/2021] [Accepted: 05/27/2021] [Indexed: 12/18/2022]
Abstract
Soil seed banks represent reservoirs of diversity in the soil that may increase resilience of communities to global changes. Two global change factors that can dramatically alter the composition and diversity of aboveground communities are nutrient enrichment and increased rainfall. In a full-factorial nutrient and rainfall addition experiment in an annual Californian grassland, we asked whether shifts in aboveground composition and diversity were reflected in belowground seed banks. Nutrient and rainfall additions increased exotic and decreased native abundances, while rainfall addition increased exotic richness, both in aboveground communities and seed banks. Under nutrient addition, forbs and short-statured plants were replaced by grasses and tall-statured species, both above and below ground, and whole-community responses to the treatments were similar. Structural equation models indicated that especially nutrient addition effects on seed banks were largely indirect via aboveground communities. However, rainfall addition also had a direct negative effect on native species richness and abundance of species with high specific leaf area (SLA) in seed banks, showing that seed banks are sensitive to the direct effects of temporary increases in rainfall. Our findings highlight the vulnerability of seed banks in annual, resource-poor grasslands to shifts in compositional and trait changes in aboveground communities and show how invasion of exotics and depletion of natives are critical for these above-belowground compositional shifts. Our findings suggest that seed banks have limited potential to buffer resource-poor annual grasslands from the community changes caused by resource enrichment.
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Affiliation(s)
- Anu Eskelinen
- Department of Physiological Diversity, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig, 04318, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstraße 4, Leipzig, 04103, Germany.,Department of Ecology and Genetics, University of Oulu, P.O. Box 8000, Oulu, FI-90014, Finland
| | - Elise Elwood
- Department of Evolution and Ecology, University of California, Davis, California, 95616, USA
| | - Susan Harrison
- Department of Environmental Science and Policy, University of California, Davis, California, 95616, USA
| | - Eva Beyen
- Department of Evolution and Ecology, University of California, Davis, California, 95616, USA
| | - Jennifer R Gremer
- Department of Evolution and Ecology, University of California, Davis, California, 95616, USA
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11
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Yang T, Lupwayi N, Marc SA, Siddique KH, Bainard LD. Anthropogenic drivers of soil microbial communities and impacts on soil biological functions in agroecosystems. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01521] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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12
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Ambient urban N deposition drives increased biomass and total plant N in two native prairie grass species in the U.S. Southern Great Plains. PLoS One 2021; 16:e0251089. [PMID: 33956866 PMCID: PMC8101712 DOI: 10.1371/journal.pone.0251089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 04/19/2021] [Indexed: 11/19/2022] Open
Abstract
Remnants of native tallgrass prairie experience elevated atmospheric nitrogen (N) deposition in urban areas, with potential effects on species traits that are important for N cycling and species composition. We quantified bulk (primarily wet) inorganic N (NH4+-N + NO3--N) deposition at six sites along an urban development gradient (6–64% urban) in the Dallas-Fort Worth metropolitan area from April 2014 to October 2015. In addition, we conducted a phytometer experiment with two common native prairie bunchgrass species––one well studied (Schizachyrium scoparium) and one little studied (Nasella leucotricha)––to investigate ambient N deposition effects on plant biomass and tissue quality. Bulk inorganic N deposition ranged from 6.1–9.9 kg ha-1 yr-1, peaked in spring, and did not vary consistently with proportion of urban land within 10 km of the sites. Total (wet + dry) inorganic N deposition estimated using bulk deposition measured in this study and modeled dry deposition was 12.9–18.2 kg ha-1 yr-1. Although the two plant species studied differ in photosynthetic pathway, biomass, and tissue N, they exhibited a maximum 2-3-fold and 2-4-fold increase in total biomass and total plant N, respectively, with 1.6-fold higher bulk N deposition. In addition, our findings indicate that while native prairie grasses may exhibit a positive biomass response to increased N deposition up to ~18 kg ha-1 yr-1, total inorganic N deposition is well above the estimated critical load for herbaceous plant species richness in the tallgrass prairie of the Great Plains ecoregion and thus may negatively affect these plant communities.
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13
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Ren Z, Zhang Y, Zhang Y. Nitrogen deposition magnifies the positive response of plant community production to precipitation: Ammonium to nitrate ratio matters. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 276:116659. [PMID: 33621734 DOI: 10.1016/j.envpol.2021.116659] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
The impacts of atmospheric nitrogen (N) deposition amount on plant communities have been extensively explored. However, the responses of plant communities to the ratio of reduced (NH4+-N) and oxidized (NO3--N) forms remain unclear in natural ecosystems. A field N enrichment experiment using different NH4+-N/NO3--N ratios was conducted in a natural semi-arid grassland in northern China from 2014 to 2019. Nitrogen addition tended to reduce plant species richness and significantly enhanced plant community aboveground net primary productivity (ANPP). Neither plant species richness nor plant ANPP at species and community levels was significantly affected by NH4+-N/NO3--N ratios. At the plant functional group level, ANPP of grasses was not significantly affected by the NH4+-N/NO3--N ratios examined, whereas ANPP of forbs was significantly increased at 1:1 NH4+-N/NO3--N. Regardless of N supplied using the different ratios of NH4+-N/NO3--N examined, plant community ANPP was positively associated with growing season precipitation. Unexpectedly, 1:1 NH4+-N/NO3--N (NH4NO3) significantly improved the positive response of plant community ANPP to precipitation (it had the biggest slope value). Our results suggest that precipitation was the main determinant of the influence of NH4+-N/NO3--N ratios on plant community ANPP. Therefore, the results of our study showed that without referring to NH4+-N/NO3--N ratios and precipitation, models using NH4NO3 enrichment may overestimate the positive effect of atmospheric N deposition on ecosystem ANPP in semi-arid ecozones.
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Affiliation(s)
- Zhengru Ren
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
| | - Yuqiu Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China
| | - Yunhai Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, China.
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14
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Zhang K, Ni Y, Liu X, Chu H. Microbes changed their carbon use strategy to regulate the priming effect in an 11-year nitrogen addition experiment in grassland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 727:138645. [PMID: 32330721 DOI: 10.1016/j.scitotenv.2020.138645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/04/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
Nitrogen availability is a key factor that regulates soil priming (the strong short-term changes in microbial decomposition of soil organic carbon after addition of fresh carbon resources); however, how soil priming changes under nitrogen addition is unclear. In this study, we collected soils from a grassland with 11-year history of nitrogen addition (0, 60, 120, and 240 kg N ha-1 yr-1 NH4NO3), and the soils were incubated for 6 weeks to estimate the direction and magnitude of soil priming and the underlying microbial carbon use strategy. We found glucose addition triggered a positive priming effect among all the treatments; however, the magnitude of the positive priming did not change under nitrogen addition. The stable soil organic carbon content under different nitrogen addition levels might support the no significant change in the magnitude of those positive priming. Using DNA stable-isotope probing (DNA-SIP), we found that bacterial and fungal taxa consuming the added glucose were different in different nitrogen addition levels. The relative abundance of the K-strategist Acidobacteria increased with increasing nitrogen addition levels, while the r-strategist Firmicutes decreased with increasing nitrogen addition levels. Our results indicated microbial taxa exhibited carbon use plasticity, with most taxa altering their use of glucose under nitrogen addition.
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Affiliation(s)
- Kaoping Zhang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingying Ni
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuejun Liu
- College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions of the Ministry of Education, China Agricultural University, Beijing 100193, China
| | - Haiyan Chu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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15
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Roos RE, Birkemoe T, Asplund J, Ľuptáčik P, Raschmanová N, Alatalo JM, Olsen SL, Klanderud K. Legacy effects of experimental environmental change on soil micro‐arthropod communities. Ecosphere 2020. [DOI: 10.1002/ecs2.3030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Ruben Erik Roos
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 Ås1432Norway
| | - Tone Birkemoe
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 Ås1432Norway
| | - Johan Asplund
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 Ås1432Norway
| | - Peter Ľuptáčik
- Institute of Biology and Ecology Faculty of Science Pavol Jozef Šafárik University Košice Slovakia
| | - Natália Raschmanová
- Institute of Biology and Ecology Faculty of Science Pavol Jozef Šafárik University Košice Slovakia
| | - Juha M. Alatalo
- Department of Biological and Environmental Sciences College of Arts and Sciences Qatar University P.O. Box 2713 Doha Qatar
- Environmental Science Center Qatar University P.O. Box 2713 Doha Qatar
| | - Siri Lie Olsen
- Norwegian Institute for Nature Research Gaustadalléen 21 Oslo0349Norway
| | - Kari Klanderud
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 Ås1432Norway
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16
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Cao J, Pang S, Wang Q, Williams MA, Jia X, Dun S, Yang J, Zhang Y, Wang J, Lü X, Hu Y, Li L, Li Y, Han X. Plant–bacteria–soil response to frequency of simulated nitrogen deposition has implications for global ecosystem change. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13484] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Jirong Cao
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Shuang Pang
- 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
| | - Qibing Wang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Mark A. Williams
- School of Plant and Environmental Science Virginia Tech Blacksburg VA USA
| | - Xiu Jia
- 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
| | - Shasha Dun
- 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
| | - Junjie Yang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Yunhai Zhang
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Jing Wang
- 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
| | - Xiaotao Lü
- State Key Laboratory of Forest and Soil Ecology Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
| | - Yecui Hu
- School of Land Science and Technology China University of Geosciences Beijing China
| | - Linghao Li
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
| | - Yuncong Li
- Tropical Research and Education Center, Soil and Water Science Department University of Florida Homestead FL USA
| | - Xingguo Han
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing China
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17
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Britton AJ, Gibbs S, Fisher JM, Helliwell RC. Impacts of nitrogen deposition on carbon and nitrogen cycling in alpine Racomitrium heath in the UK and prospects for recovery. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 254:112986. [PMID: 31394340 DOI: 10.1016/j.envpol.2019.112986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/24/2019] [Accepted: 07/30/2019] [Indexed: 06/10/2023]
Abstract
Deposition of reactive nitrogen (N) is a major threat to terrestrial ecosystems associated with impacts on ecosystem properties and functions including carbon (C) and nutrient stocks, soil water quality and nutrient retention. In the oceanic-alpine Racomitrium heath habitat, N deposition is associated with moss mat degradation and a shift from bryophyte to graminoid dominance. To investigate the effects of moss mat decline on C and N stocks and fluxes, we collected Racomitrium heath vegetation/soil cores from sites along a gradient of N deposition in the UK. Cores were maintained under controlled conditions and exposed to scenarios of current (8-40 kg N ha-1 y-1), reduced (8 kg N ha-1 y-1) and elevated (50 kg N ha-1 y-1) N deposition. Cores from high N deposition sites had smaller aboveground C and N stocks and, under current conditions, leached large amounts of inorganic N and had low soil water pH compared with low N deposition sites. With reduced N deposition there was evidence for rapid recovery of soil water quality in terms of reduced N leaching and small increases in pH. Under high N deposition, cores from low N deposition sites retained much of the applied N while those with a history of high N deposition leached large amounts of inorganic N. Carbon fluxes in soil water and net CO2 fluxes varied according to core source site but were not affected by the N deposition scenarios. We conclude that C and N stocks and cycling in Racomitrium heath are strongly affected by long-term exposure to N deposition but that soil water quality may improve rapidly, if N deposition rates are reduced. The legacy of N deposition impacts on moss mat cover and vegetation composition however, mean that the ecosystem remains sensitive to future pulses in N input.
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Affiliation(s)
- Andrea J Britton
- The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK.
| | - Sheila Gibbs
- The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
| | - Julia M Fisher
- The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
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18
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Schichtel BA, Gebhart KA, Morris KH, Cheatham JR, Vimont J, Larson RS, Beachley G. Long-term trends of wet inorganic nitrogen deposition in Rocky Mountain National Park: Influence of missing data imputation methods and associated uncertainty. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 687:817-826. [PMID: 31412485 PMCID: PMC7525823 DOI: 10.1016/j.scitotenv.2019.06.104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/23/2019] [Accepted: 06/06/2019] [Indexed: 06/10/2023]
Abstract
Excess reactive nitrogen (Nr) deposition is occurring in Rocky Mountain National Park and impacting sensitive ecosystems. In 2006, the National Park Service, State of Colorado, and Environmental Protection Agency established the goal to reduce Nr deposition to below the ecosystem critical load by 2032. Progress is tracked using 5-year averages of annual wet inorganic nitrogen (IN) deposition measured at Loch Vale, Colorado, by the National Atmospheric Deposition Program (NADP). This remote high alpine site is challenging to operate, and large fractions of the annual precipitation, at times >40%, had invalid IN concentrations. Annual wet IN deposition is calculated using the NADP protocol, which replaces missing concentrations with the annual precipitation-weighted mean (PWM) concentration of valid samples. This protocol does not account for seasonal variations in IN concentrations and the inverse relationship between concentration and precipitation amounts. Invalid samples occurred more frequently in the winter and at high and low precipitation amounts, and the NADP protocol generally overestimated annual deposition rates, by as much as 20%. Here, a new method for imputing missing weekly IN concentrations that accounts for their seasonal and precipitation dependence is introduced. Using a bootstrapping analysis shows that the new method reduced the errors in the annual deposition rates by about 30% compared to the NADP protocol and the biases were near zero. The overall trend in the wet IN deposition rates was found to be flat from 1990 to 2017, but the nitrate contribution decreased about 33%, which was offset by a nearly equal increase in ammonium wet deposition. These trends are consistent with known changes in nitrate and ammonium precursor emissions. The long-term trends in the annual IN deposition rates were similar using both data imputation methods, but the 2013-2017 average was about 10% smaller using the new method.
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Affiliation(s)
- Bret A Schichtel
- National Park Service, Air Resources Division, Lakewood, CO 80228, United States of America.
| | - Kristi A Gebhart
- National Park Service, Air Resources Division, Lakewood, CO 80228, United States of America
| | - Kristi H Morris
- National Park Service, Air Resources Division, Lakewood, CO 80228, United States of America
| | - James R Cheatham
- National Park Service, Air Resources Division, Lakewood, CO 80228, United States of America
| | - John Vimont
- National Park Service, Air Resources Division, Lakewood, CO 80228, United States of America
| | - Robert S Larson
- Wisconsin State Laboratory of Hygiene, University of Wisconsin - Madison, 53706, United States of America
| | - Gregory Beachley
- U.S. Environmental Protection Agency, Office of Air Programs, Washington, DC 20460, United States of America
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19
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Affiliation(s)
- Carly J Stevens
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
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20
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Potter TS, Owens WM, Bowman WD. Do plant–microbe interactions and aluminum tolerance influence alpine sedge species’ responses to nitrogen deposition? Ecosphere 2019. [DOI: 10.1002/ecs2.2775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Teal S. Potter
- Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80309‐0334 USA
| | - William M. Owens
- Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80309‐0334 USA
| | - William D. Bowman
- Department of Ecology and Evolutionary Biology University of Colorado Boulder Colorado 80309‐0334 USA
- Institute of Arctic and Alpine Research University of Colorado Boulder Colorado 80309‐0450 USA
- Mountain Research Station University of Colorado Nederland Colorado 80466 USA
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21
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Weiss SB. Dead flowers. NATURE PLANTS 2019; 5:654-655. [PMID: 31263242 DOI: 10.1038/s41477-019-0424-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Stuart B Weiss
- Creekside Center for Earth Observation, Menlo Park, CA, USA.
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