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Lin J, Compton JE, Sabo RD, Herlihy AT, Hill RA, Weber MH, Brooks JR, Paulsen SG, Stoddard JL. The changing nitrogen landscape of United States streams: Declining deposition and increasing organic nitrogen. PNAS NEXUS 2024; 3:pgad362. [PMID: 38213613 PMCID: PMC10783649 DOI: 10.1093/pnasnexus/pgad362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 10/14/2023] [Accepted: 10/26/2023] [Indexed: 01/13/2024]
Abstract
Air quality regulations have led to decreased nitrogen (N) and sulfur deposition across the conterminous United States (CONUS) during the last several decades, particularly in the eastern parts. But it is unclear if declining deposition has altered stream N at large scales. We compared watershed N inputs with N chemistry from over 2,000 CONUS streams where deposition was the largest N input to the watershed. Weighted change analysis showed that deposition declined across most watersheds, especially in the Eastern CONUS. Nationally, declining N deposition was not associated with significant large-scale declines in stream nitrate concentration. Instead, significant increases in stream dissolved organic carbon (DOC) and total organic N (TON) were widespread across regions. Possible mechanisms behind these increases include declines in acidity and/or ionic strength drivers, changes in carbon availability, and/or climate variables. Our results also reveal a declining trend of DOC/TON ratio over the entire study period, primarily influenced by the trend in the Eastern region, suggesting the rate of increase in stream TON exceeded the rate of increase in DOC concentration during this period. Our results illustrate the complexity of nutrient cycling that links long-term atmospheric deposition to water quality. More research is needed to understand how increased dissolved organic N could affect aquatic ecosystems and downstream riverine nutrient export.
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Affiliation(s)
- Jiajia Lin
- Pacific Ecological Systems Division, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR 97333, USA
- Oak Ridge Institute for Science and Education, Corvallis, OR 97333, USA
- Oregon Department of Environmental Quality, Water Quality Division, Portland, OR 97232, USA
| | - Jana E Compton
- Pacific Ecological Systems Division, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR 97333, USA
| | - Robert D Sabo
- Center for Public Health and Environmental Assessment, Health and Environmental Effects Division, Office of Research and Development, US Environmental Protection Agency, Washington, DC 20004, USA
| | - Alan T Herlihy
- Pacific Ecological Systems Division, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR 97333, USA
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Ryan A Hill
- Pacific Ecological Systems Division, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR 97333, USA
| | - Marc H Weber
- Pacific Ecological Systems Division, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR 97333, USA
| | - J Renée Brooks
- Pacific Ecological Systems Division, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR 97333, USA
| | - Steve G Paulsen
- Pacific Ecological Systems Division, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR 97333, USA
| | - John L Stoddard
- Pacific Ecological Systems Division, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR 97333, USA
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2
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Nehring L, Kranabetter JM, Harper GJ, Hawkins BJ. Tree-ring δ15N as an indicator of nitrogen dynamics in stands with N2-fixing Alnus rubra. TREE PHYSIOLOGY 2023; 43:2064-2075. [PMID: 37672228 DOI: 10.1093/treephys/tpad110] [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: 06/22/2023] [Revised: 08/14/2023] [Accepted: 09/03/2023] [Indexed: 09/07/2023]
Abstract
Tree-ring δ15N may depict site-specific, long-term patterns in nitrogen (N) dynamics under N2-fixing species, but field trials with N2-fixing tree species are lacking and the relationship of temporal patterns in tree-ring δ15N to soil N dynamics is controversial. We examined whether the tree-ring δ15N of N2-fixing red alder (Alnus rubra Bong.) would mirror N accretion rates and δ15N of soils and whether the influence of alder-fixed N could be observed in the wood of a neighboring conifer. We sampled a 27-year-old replacement series trial on south-eastern Vancouver Island, with red alder and coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) planted in five proportions (0/100, 11/89, 25/75, 50/50 and 100/0) at a uniform stem density. An escalation in forest floor N content was evident with an increasing proportion of red alder, equivalent to a difference of ~750 kg N ha-1 between 100% Douglas-fir versus 100% alder. The forest floor horizon also had high δ15N values in treatments with more red alder. Red alder had a consistent quadratic fit in tree-ring δ15N over time, with a net increase of $\sim$1.5‰, on average, from initial values, followed by a plateau or slight decline. Douglas-fir tree-ring δ15N, in contrast, was largely unchanged over time (in three of four plots) but was significantly higher in the 50/50 mix. The minor differences in current leaf litter N content and δ15N between alder and Douglas-fir, coupled with declining growth in red alder, suggests the plateau or declining trend in alder tree-ring δ15N could coincide with lower N2-fixation rates, potentially by loss in alder vigor at canopy closure, or down-regulation via nitrate availability.
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Affiliation(s)
- L Nehring
- Centre for Forest Biology, University of Victoria, PO Box 3020, STN CSC, 3800 Finnerty Road,Victoria, British Columbia V8P 5C2, Canada
| | - J M Kranabetter
- British Columbia Ministry of Forests, PO Box 9536, Stn Prov Govt, 4300 North Road, Victoria, British Columbia V8Z 5J3, Canada
| | - G J Harper
- British Columbia Ministry of Forests, 4th Floor - 545 Superior Street, Victoria, British Columbia V8V 1T7, Canada
| | - B J Hawkins
- Centre for Forest Biology, University of Victoria, PO Box 3020, STN CSC, 3800 Finnerty Road,Victoria, British Columbia V8P 5C2, Canada
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3
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Prohaska A, Seddon AWR, Rach O, Smith A, Sachse D, Willis KJ. Long-term ecological responses of a lowland dipterocarp forest to climate changes and nutrient availability. THE NEW PHYTOLOGIST 2023; 240:2513-2529. [PMID: 37604200 DOI: 10.1111/nph.19169] [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: 12/05/2022] [Accepted: 06/16/2023] [Indexed: 08/23/2023]
Abstract
Understanding the long-term impact of projected climate change on tropical rainforests is critical given their central role in the Earth's system. Palaeoecological records can provide a valuable perspective on this problem. Here, we examine the effects of past climatic changes on the dominant forest type of Southeast Asia - lowland dipterocarp forest. We use a range of proxies extracted from a 1400-yr-old lacustrine sedimentary sequence from north-eastern Philippines to determine long-term vegetation responses of lowland dipterocarp forest, including its dominant tree group dipterocarps, to changes in precipitation, fire and nutrient availability over time. Our results show a positive relationship between dipterocarp pollen accumulation rates (PARs) and leaf wax hydrogen isotope values, which suggests a negative effect of drier conditions on dipterocarp abundance. Furthermore, we find a positive relationship between dipterocarp PARs and the proxy for phosphorus availability, which suggests phosphorus controls the productivity of these keystone trees on longer time scales. Other pollen taxa show widely varying relationships with the abiotic factors, demonstrating a high diversity of plant functional responses. Our findings provide novel insights into lowland dipterocarp forest responses to changing climatic conditions in the past and highlight potential impacts of future climate change on this globally important ecosystem.
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Affiliation(s)
- Ana Prohaska
- Department of Biology, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
- Department of Zoology, University of Cambridge, Downing St, Cambridge, CB2 3EJ, UK
| | - Alistair W R Seddon
- Department of Biology, University of Bergen, Bergen, NO-5020, Norway
- Bjerknes Centre for Climate Research, University of Bergen, Bergen, NO-5020, Norway
| | - Oliver Rach
- Section 4.6: Geomorphology, Organic Surface Geochemistry Lab, Centre for Geosciences, GFZ-German Research, Telegrafenberg, Potsdam, 14473, Germany
| | - Andrew Smith
- National Environmental Isotope Facility, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
| | - Dirk Sachse
- Section 4.6: Geomorphology, Organic Surface Geochemistry Lab, Centre for Geosciences, GFZ-German Research, Telegrafenberg, Potsdam, 14473, Germany
| | - Katherine J Willis
- Department of Biology, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
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4
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Bassett KR, Östlund L, Gundale MJ, Fridman J, Jämtgård S. Forest inventory tree core archive reveals changes in boreal wood traits over seven decades. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165795. [PMID: 37499833 DOI: 10.1016/j.scitotenv.2023.165795] [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: 06/01/2023] [Revised: 07/21/2023] [Accepted: 07/23/2023] [Indexed: 07/29/2023]
Abstract
Boreal forests play an important role in the global carbon (C) cycle, and there is great interest in understanding how they respond to environmental change, including nitrogen (N) and water limitation, which could impact future forest growth and C storage. Utilizing tree cores archived by the Swedish National Forest Inventory, we measured stemwood traits, including stable N and C isotope composition which provides valuable information related to N availability and water stress, respectively, as well as N and C content, and C/N ratio over 1950-2017 in two central Swedish counties covering an area of ca. 55,000 sq. km (n = 1038). We tested the hypothesis that wood traits are changing over time, and that temporal patterns would differ depending on alternative dendrochronological reconstruction methods, i.e. the commonly applied "single tree method" (STM) or a conceptually stronger "multiple tree method" (MTM). Averaged across all MTMs, our data showed that all five wood traits for Picea abies and Pinus sylvestris changed over time. Wood δ15N strongly declined, indicating progressive nitrogen limitation. The decline in δ13C tracked the known atmospheric δ13CO2 signal, suggesting no change in water stress occurred. Additionally, wood N significantly increased, while C and C/N ratios declined over time. Furthermore, wood trait patterns sometimes differed between dendrochronological methods. The most notable difference was for δ15N, where the slope was much shallower for the STM compared to MTMs for both species, indicating that mobility of contemporary N is problematic when using the STM, resulting in substantially less sensitivity to detect historical signals. Our study indicates strong temporal changes in boreal wood traits and also indicates that the field of dendroecology should adopt new methods and archiving practices for studying highly mobile element cycles, such as nitrogen, which are critical for understanding environmental change in high latitude ecosystems.
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Affiliation(s)
- Kelley R Bassett
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE901-83 Umeå, Sweden.
| | - Lars Östlund
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE901-83 Umeå, Sweden
| | - Michael J Gundale
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE901-83 Umeå, Sweden
| | - Jonas Fridman
- Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE901-83 Umeå, Sweden
| | - Sandra Jämtgård
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE901-83 Umeå, Sweden
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5
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Choi WJ, Park HJ, Baek N, In Yang H, Kwak JH, Lee SI, Park SW, Shin ES, Lim SS. Patterns of δ 15N in forest soils and tree foliage and rings between climate zones in relation to atmospheric nitrogen deposition: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165866. [PMID: 37516182 DOI: 10.1016/j.scitotenv.2023.165866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
The stable nitrogen (N) isotope ratio (δ15N) of forest samples (soils, tree foliage, and tree rings) has been used as a powerful indicator to explore the responses of forest N cycling to atmospheric N deposition. This review investigated the patterns of δ15N in forest samples between climate zones in relation to N deposition. Forest samples exhibited distinctive δ15N patterns between climate zones due to differences in site conditions (i.e., N availability and retention capacity) and the atmospheric N deposition characteristics (i.e., N deposition rate, N species, and δ15N of deposited N). For example, the δ15N of soil and foliage was higher for tropical forests than for other forests by >1.2 ‰ and 4 ‰, respectively due to the site conditions favoring N losses coupled with relatively low N deposition for tropical forests. This was further supported by the unchanged or increased δ15N of tree rings in tropical forests, which contrasts with other climate zones that exhibited a decreased wood δ15N since the 1920s. Subtropical forests under a high deposition of reduced N (NHy) had a lower δ15N by 2-5 ‰ in the organic layer compared with the other forests, reflecting high retention of 15N-depleted NHy deposition. At severely polluted sites in East Asia, the decreased δ15N in wood also reflected the consistent deposition of 15N-depleted NHy. Though our data analysis represents only a subset of global forest sites where atmospheric N deposition is of interest, the results suggest that the direction and magnitude of the changes in the δ15N of forest samples are related to both atmospheric N and site conditions particularly for tropical vs. subtropical forests. Site-specific information on the atmospheric N deposition characteristics would allow more accurate assessment of the variations in the δ15N of forest samples in relation to N deposition.
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Affiliation(s)
- Woo-Jung Choi
- Department of Rural & Biosystems Engineering (Brain Korea 21), Chonnam National University, Gwangju 61186, Republic of Korea; AgriBio Institute of Climate Change Management, Chonnam National University, Gwangju 61186, Republic of Korea.
| | - Hyun-Jin Park
- Crop Production & Physiology Division, National Institute of Crop Science, Rural Development Administration, Wanju, Jeollabukdo 55365, Republic of Korea
| | - Nuri Baek
- Department of Rural & Biosystems Engineering (Brain Korea 21), Chonnam National University, Gwangju 61186, Republic of Korea
| | - Hye In Yang
- Max Planck Institute for Biogeochemistry, Jena 07745, Germany
| | - Jin-Hyeob Kwak
- Department of Rural Construction Engineering, Jeonbuk National University, Jeonju, Jeollabukdo 57896, Republic of Korea
| | - Sun-Il Lee
- Climate Change Assessment Division, National Institute of Agricultural Science, Rural Development Administration, Wanju, Jeollabukdo 55365, Republic of Korea
| | - Seo-Woo Park
- Department of Rural & Biosystems Engineering (Brain Korea 21), Chonnam National University, Gwangju 61186, Republic of Korea
| | - Eun-Seo Shin
- Department of Rural & Biosystems Engineering (Brain Korea 21), Chonnam National University, Gwangju 61186, Republic of Korea
| | - Sang-Sun Lim
- Bio R&D Center, CJ Cheiljedang, Suwon, Gyeonggi-do 16495, Republic of Korea
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6
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Savard MM, Marion J, Bégin C, Laganière J. On the significance of long-term trends in tree-ring N isotopes - The interplay of soil conditions and regional NOx emissions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159580. [PMID: 36280071 DOI: 10.1016/j.scitotenv.2022.159580] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/14/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
As anthropogenic nitrogen (N) emissions have been rising for decades, it is critical to develop natural archives that help understand how natural processes were modified in the past. Tree-ring δ15N values may represent such an indicator but its validity as faithful record of N cycling changes is still debated. Here we produce long-tree-ring δ15N series for five white spruce stands from two boreal regions submitted to moderate industrial N inputs. The obtained δ15N series show sharp differences among stands, even from the same region, despite the fact that they show similar increases in intrinsic water use efficiency (iWUE), a proxy for foliar strategies derived from δ13C values. The statistical modeling of these series and the basal area increment (BAI) of the trees allow to suggest that the mechanisms controlling the isotopic fractionation of N assimilated by tree rings are decoupled from the foliar strategies under the anthropogenic N emissions. The iWUE trends mainly reflect rise of pCO2 and changes in air quality. The long-term δ15N trends echo different biogeochemical processes responding to N deposition due to distinct original soil pH at the various sites. We contend that tree-ring δ15N series can record changes in the forest N cycle, but their rigorous interpretation requires laborious work, particularly an understanding of the biogeochemistry in the soil immediately around the investigated trees. "Seek simplicity and distrust it", Alfred North Whitehead.
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Affiliation(s)
- Martine M Savard
- Commission géologique du Canada (Ressources naturelles Canada), 490 de la Couronne, Québec, QC G1K 9A9, Canada.
| | - Joëlle Marion
- Commission géologique du Canada (Ressources naturelles Canada), 490 de la Couronne, Québec, QC G1K 9A9, Canada
| | - Christian Bégin
- Commission géologique du Canada (Ressources naturelles Canada), 490 de la Couronne, Québec, QC G1K 9A9, Canada
| | - Jérôme Laganière
- Centre de Foresterie des Laurentides, Service canadien des Forêts (Ressources naturelles Canada), 1055 rue du P.E.P.S., Stn. Sainte-Foy, P.O. Box 10380, Québec, QC G1V 4C7, Canada
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7
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Dong N, Wright IJ, Chen JM, Luo X, Wang H, Keenan TF, Smith NG, Prentice IC. Rising CO 2 and warming reduce global canopy demand for nitrogen. THE NEW PHYTOLOGIST 2022; 235:1692-1700. [PMID: 35297050 PMCID: PMC9545159 DOI: 10.1111/nph.18076] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 02/25/2022] [Indexed: 05/27/2023]
Abstract
Nitrogen (N) limitation has been considered as a constraint on terrestrial carbon uptake in response to rising CO2 and climate change. By extension, it has been suggested that declining carboxylation capacity (Vcmax ) and leaf N content in enhanced-CO2 experiments and satellite records signify increasing N limitation of primary production. We predicted Vcmax using the coordination hypothesis and estimated changes in leaf-level photosynthetic N for 1982-2016 assuming proportionality with leaf-level Vcmax at 25°C. The whole-canopy photosynthetic N was derived using satellite-based leaf area index (LAI) data and an empirical extinction coefficient for Vcmax , and converted to annual N demand using estimated leaf turnover times. The predicted spatial pattern of Vcmax shares key features with an independent reconstruction from remotely sensed leaf chlorophyll content. Predicted leaf photosynthetic N declined by 0.27% yr-1 , while observed leaf (total) N declined by 0.2-0.25% yr-1 . Predicted global canopy N (and N demand) declined from 1996 onwards, despite increasing LAI. Leaf-level responses to rising CO2 , and to a lesser extent temperature, may have reduced the canopy requirement for N by more than rising LAI has increased it. This finding provides an alternative explanation for declining leaf N that does not depend on increasing N limitation.
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Affiliation(s)
- Ning Dong
- Department of Life SciencesGeorgina Mace Centre for the Living PlanetImperial College LondonSilwood Park CampusAscotSL5 7PYUK
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | - Ian J. Wright
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - Jing M. Chen
- Department of Geography and PlanningUniversity of Toronto100 George StreetTorontoONMS5 3G3Canada
| | - Xiangzhong Luo
- Department of GeographyNational University of Singapore1 Arts LinkSingapore117570Singapore
| | - Han Wang
- Department of Earth System ScienceMinistry of Education Key Laboratory for Earth System ModellingInstitute for Global Change StudiesTsinghua UniversityBeijing100084China
| | - Trevor F. Keenan
- Department of Environmental Science, Policy and ManagementUC BerkeleyBerkeleyCAUSA
- Climate and Ecosystem Sciences DivisionLawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Nicholas G. Smith
- Department of Biological SciencesTexas Tech UniversityLubbockTX79409USA
| | - Iain Colin Prentice
- Department of Life SciencesGeorgina Mace Centre for the Living PlanetImperial College LondonSilwood Park CampusAscotSL5 7PYUK
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
- Department of Earth System ScienceMinistry of Education Key Laboratory for Earth System ModellingInstitute for Global Change StudiesTsinghua UniversityBeijing100084China
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8
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Oulehle F, Tahovská K, Ač A, Kolář T, Rybníček M, Čermák P, Štěpánek P, Trnka M, Urban O, Hruška J. Changes in forest nitrogen cycling across deposition gradient revealed by δ 15N in tree rings. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 304:119104. [PMID: 35301033 DOI: 10.1016/j.envpol.2022.119104] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/24/2022] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
Tree rings provide valuable insight into past environmental changes. This study aimed to evaluate perturbations in tree ring width (TRW) and δ15N alongside soil acidity and nutrient availability gradients caused by the contrasting legacy of air pollution (nitrogen [N] and sulphur [S] deposition) and tree species (European beech, Silver fir and Norway spruce). We found consistent declines of tree ring δ15N, which were temporarily unrelated to the changes in the TRW. The rate of δ15N change in tree rings was related to the contemporary foliar carbon (C) to phosphorus (P) ratio. This observation suggested that the long-term accumulation of 15N depleted N in tree rings, likely mediated by retained N from deposition, was restricted primarily to stands with currently higher P availability. The shifts observed in tree-ring δ15N and TRW suggest that acidic air pollution rather than changes in stand productivity determined alteration of N and C cycles. Stable N isotopes in tree rings provided helpful information on the trajectory of the N cycle over the last century with direct consequences for a better understanding of future interactions among N, P and C cycles in terrestrial ecosystems.
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Affiliation(s)
- Filip Oulehle
- Czech Geological Survey, Klárov 3, 118 21, Prague, Czech Republic; Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic.
| | - Karolina Tahovská
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Alexandr Ač
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic
| | - Tomáš Kolář
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic; Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00, Brno, Czech Republic
| | - Michal Rybníček
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic; Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00, Brno, Czech Republic
| | - Petr Čermák
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00, Brno, Czech Republic
| | - Petr Štěpánek
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic
| | - Miroslav Trnka
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic
| | - Otmar Urban
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic
| | - Jakub Hruška
- Czech Geological Survey, Klárov 3, 118 21, Prague, Czech Republic; Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic
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9
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Zhang Q, Bostic JT, Sabo RD. Regional patterns and drivers of total nitrogen trends in the Chesapeake Bay watershed: Insights from machine learning approaches and management implications. WATER RESEARCH 2022; 218:118443. [PMID: 35461100 PMCID: PMC9743807 DOI: 10.1016/j.watres.2022.118443] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 03/11/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
Anthropogenic nutrient inputs have led to nutrient enrichment in many waterbodies worldwide, including Chesapeake Bay (USA). River water quality integrates the spatial and temporal changes of watersheds and forms the foundation for disentangling the effects of anthropogenic inputs. We demonstrate with the Chesapeake Bay Non-Tidal Monitoring Network that machine learning approaches - i.e., hierarchical clustering and random forest (RF) classification - can be combined to better understand the regional patterns and drivers of total nitrogen (TN) trends in large monitoring networks, resulting in information useful for watershed management. Cluster analysis revealed regional patterns of short-term TN trends (2007-2018) and categorized the stations into three distinct trend clusters, namely, V-shape (n = 23), monotonic decline (n = 35), and monotonic increase (n = 26). RF models identified regional drivers of TN trend clusters by quantifying the effects of watershed characteristics (land use, geology, physiography) and major N sources on the trend clusters. Results provide encouraging evidence that improved agricultural nutrient management has resulted in declines in agricultural nonpoint sources, which in turn contributed to water-quality improvement in our period of analysis. Moreover, water-quality improvements are more likely in watersheds underlain by carbonate rocks, reflecting the relatively quick groundwater transport of this terrain. By contrast, water-quality improvements are less likely in Coastal Plain watersheds, reflecting the effect of legacy N in groundwater. Notably, results show degrading trends in forested watersheds, suggesting new and/or remobilized sources that may compromise management efforts. Finally, the developed RF models were used to predict TN trend clusters for the entire Chesapeake Bay watershed at the fine scale of river segments (n = 979), providing fine spatial information that can facilitate targeted watershed management, including unmonitored areas. More broadly, this combined use of clustering and classification approaches can be applied to other regional monitoring networks to address similar water-quality questions.
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Affiliation(s)
- Qian Zhang
- University of Maryland Center for Environmental Science, Chesapeake Bay Program Office, Annapolis, MD 21403, USA.
| | - Joel T Bostic
- University of Maryland Center for Environmental Science, Appalachian Laboratory, Frostburg, MD 21532, USA
| | - Robert D Sabo
- U.S. Environmental Protection Agency, Washington D.C. 20004, USA
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10
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Mason RE, Craine JM, Lany NK, Jonard M, Ollinger SV, Groffman PM, Fulweiler RW, Angerer J, Read QD, Reich PB, Templer PH, Elmore AJ. Evidence, causes, and consequences of declining nitrogen availability in terrestrial ecosystems. Science 2022; 376:eabh3767. [PMID: 35420945 DOI: 10.1126/science.abh3767] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The productivity of ecosystems and their capacity to support life depends on access to reactive nitrogen (N). Over the past century, humans have more than doubled the global supply of reactive N through industrial and agricultural activities. However, long-term records demonstrate that N availability is declining in many regions of the world. Reactive N inputs are not evenly distributed, and global changes-including elevated atmospheric carbon dioxide (CO2) levels and rising temperatures-are affecting ecosystem N supply relative to demand. Declining N availability is constraining primary productivity, contributing to lower leaf N concentrations, and reducing the quality of herbivore diets in many ecosystems. We outline the current state of knowledge about declining N availability and propose actions aimed at characterizing and responding to this emerging challenge.
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Affiliation(s)
- Rachel E Mason
- National Socio-Environmental Synthesis Center, Annapolis, MD, USA
| | | | - Nina K Lany
- Northern Research Station, USDA Forest Service, Durham, NH, USA
| | - Mathieu Jonard
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Scott V Ollinger
- Earth Systems Research Center, University of New Hampshire, Durham, NH, USA
| | - Peter M Groffman
- Advanced Science Research Center, The Graduate Center, City University of New York, New York, NY, USA.,Cary Institute of Ecosystem Studies, Millbrook, NY, USA
| | - Robinson W Fulweiler
- Department of Earth and Environment, Boston University, Boston, MA, USA.,Department of Biology, Boston University, Boston, MA, USA
| | - Jay Angerer
- Fort Keogh Livestock and Range Research Laboratory, USDA Agricultural Research Service, Miles City, MT, USA
| | - Quentin D Read
- National Socio-Environmental Synthesis Center, Annapolis, MD, USA
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA.,Institute for Global Change Biology and School for Environment and Sustainability, University of Michigan, Ann Arbor, MI, USA.,Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | | | - Andrew J Elmore
- National Socio-Environmental Synthesis Center, Annapolis, MD, USA.,Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, MD, USA
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11
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Martin AC, Macias-Fauria M, Bonsall MB, Forbes BC, Zetterberg P, Jeffers ES. Common mechanisms explain nitrogen-dependent growth of Arctic shrubs over three decades despite heterogeneous trends and declines in soil nitrogen availability. THE NEW PHYTOLOGIST 2022; 233:670-686. [PMID: 34087005 DOI: 10.1111/nph.17529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
Heterogeneity has been observed in the responses of Arctic shrubs to climate variability over recent decades, which may reflect landscape-scale variability in belowground resources. At a northern fringe of tall shrub expansion (Yuribei, Yamal Peninsula, Russia), we sought to determine the mechanisms relating nitrogen (N) limitation to shrub growth over decadal time. We analysed the ratio of 15 N to 14 N isotopes in wood rings of 10 Salix lanata individuals (399 measurements) to reconstruct annual point-based bioavailable N between 1980 and 2013. We applied a model-fitting/model-selection approach with a suite of competing ecological models to assess the most-likely mechanisms that explain each shrub's individual time-series. Shrub δ15 N time-series indicated declining (seven shrubs), increasing (two shrubs) and no trend (one shrub) in N availability. The most appropriate model for all shrubs included N-dependent growth of linear rather than saturating form. Inclusion of plant-soil feedbacks better explained ring width and δ15 N for eight of 10 individuals. Although N trajectories were individualistic, common mechanisms of varying strength confirmed the N-dependency of shrub growth. The linear mechanism may reflect intense scavenging of scarce N; the importance of plant-soil feedbacks suggests that shrubs subvert the microbial bottleneck by actively controlling their environment.
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Affiliation(s)
- Andrew C Martin
- Oxford Long-Term Ecology Laboratory, Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK
- Biogeosciences Lab, School of Geography and the Environment, University of Oxford, Oxford, OX1 3QY, UK
| | - Marc Macias-Fauria
- Biogeosciences Lab, School of Geography and the Environment, University of Oxford, Oxford, OX1 3QY, UK
| | - Michael B Bonsall
- Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK
| | - Bruce C Forbes
- Arctic Centre, University of Lapland, Pohjoisranta 4, Rovaniemi, 96100, Finland
| | - Pentti Zetterberg
- Department of Forest Sciences, University of Eastern Finland, Joensuu, 80101, Finland
| | - Elizabeth S Jeffers
- Oxford Long-Term Ecology Laboratory, Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK
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12
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Fuentealba M, Latorre C, Frugone-Álvarez M, Sarricolea P, Godoy-Aguirre C, Armesto J, Villacís LA, Laura Carrevedo M, Meseguer-Ruiz O, Valero-Garcés B. Crossing a critical threshold: Accelerated and widespread land use changes drive recent carbon and nitrogen dynamics in Vichuquén Lake (35°S) in central Chile. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 791:148209. [PMID: 34126491 DOI: 10.1016/j.scitotenv.2021.148209] [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: 01/29/2021] [Revised: 05/10/2021] [Accepted: 05/30/2021] [Indexed: 06/12/2023]
Abstract
Global afforestation/deforestation processes (e.g., Amazon deforestation and Europe afforestation) create new anthropogenic controls on carbon cycling and nutrient supply that have not been fully assessed. Here, we use a watershed-lake dynamics approach to investigate how human-induced land cover changes have altered nutrient transference during the last 700 years in a mediterranean coastal area (Vichuquén Lake). We compare our multiproxy reconstruction with historical documentation and use satellite images to reconstruct land use/cover changes for the last 45 years. Historical landscape changes, including those during the indigenous settlements, Spanish conquest, and the Chilean Republic up to mid-20th century did not significantly alter sediment and nutrient fluxes to the lake. In contrast, the largest changes in the lake-watershed system occurred in the mid-20th century and particularly after the 1980s-90s and were characterized by a large increase in total nitrogen and organic carbon fluxes as well as negative shifts in sediment δ15N and δ13C values. This shift was coeval with the largest land cover transformation in the Vichuquén watershed, as native forests nearly disappeared while anthropogenic tree plantations expanded up to 60% of the surface area.
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Affiliation(s)
- Magdalena Fuentealba
- Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile; Institute of Ecology and Biodiversity (IEB), Santiago, Chile.
| | - Claudio Latorre
- Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile; Institute of Ecology and Biodiversity (IEB), Santiago, Chile.
| | - Matías Frugone-Álvarez
- Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile; Institute of Ecology and Biodiversity (IEB), Santiago, Chile
| | - Pablo Sarricolea
- Departamento de Geografía, Universidad de Chile, Marcoleta 250, Santiago, Chile
| | - Carolina Godoy-Aguirre
- Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile; Institute of Ecology and Biodiversity (IEB), Santiago, Chile
| | - Juan Armesto
- Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile; Institute of Ecology and Biodiversity (IEB), Santiago, Chile; Cary Institute of Ecosystem Studies, Millbrook, NY 12545, USA
| | - Leonardo A Villacís
- Departamento de Ciencias Ecológicas, Universidad de Chile, Las Palmeras 3425, Ñuñoa, Santiago, Chile; Núcleo Milenio Paleoclima and Center for Climate and Resilience Research (CR2), Chile
| | | | - Oliver Meseguer-Ruiz
- Departamento de Ciencias Históricas y Geográficas, Universidad de Tarapacá, Sede Iquique, Chile
| | - Blas Valero-Garcés
- Instituto Pirenaico de Ecología (IPE-CSIC), Avenida Montañana, 1005, Zaragoza 50059, Spain
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13
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Adams MA, Buckley TN, Binkley D, Neumann M, Turnbull TL. CO 2, nitrogen deposition and a discontinuous climate response drive water use efficiency in global forests. Nat Commun 2021; 12:5194. [PMID: 34465788 PMCID: PMC8408268 DOI: 10.1038/s41467-021-25365-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/28/2021] [Indexed: 02/07/2023] Open
Abstract
Reduced stomatal conductance is a common plant response to rising atmospheric CO2 and increases water use efficiency (W). At the leaf-scale, W depends on water and nitrogen availability in addition to atmospheric CO2. In hydroclimate models W is a key driver of rainfall, droughts, and streamflow extremes. We used global climate data to derive Aridity Indices (AI) for forests over the period 1965-2015 and synthesised those with data for nitrogen deposition and W derived from stable isotopes in tree rings. AI and atmospheric CO2 account for most of the variance in W of trees across the globe, while cumulative nitrogen deposition has a significant effect only in regions without strong legacies of atmospheric pollution. The relation of aridity and W displays a clear discontinuity. W and AI are strongly related below a threshold value of AI ≈ 1 but are not related where AI > 1. Tree ring data emphasise that effective demarcation of water-limited from non-water-limited behaviour of stomata is critical to improving hydrological models that operate at regional to global scales.
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Affiliation(s)
- Mark A. Adams
- grid.1027.40000 0004 0409 2862Department of Chemistry and Biotechnology, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, VIC Australia ,grid.1013.30000 0004 1936 834XSchool of Life and Environmental Sciences, University of Sydney, Sydney, NSW Australia
| | - Thomas N. Buckley
- grid.27860.3b0000 0004 1936 9684Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California, Davis, CA USA
| | - Dan Binkley
- grid.261120.60000 0004 1936 8040School of Forestry, Northern Arizona University, Flagstaff, AZ USA
| | - Mathias Neumann
- grid.5173.00000 0001 2298 5320Institute of Silviculture, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Tarryn L. Turnbull
- grid.1027.40000 0004 0409 2862Department of Chemistry and Biotechnology, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, VIC Australia ,grid.1013.30000 0004 1936 834XSchool of Life and Environmental Sciences, University of Sydney, Sydney, NSW Australia
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14
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Hobbie E, Rinne-Garmston (Rinne) K, Penttilä R, Vadeboncoeur M, Chen J, Mäkipää R. Carbon and nitrogen acquisition strategies by wood decay fungi influence their isotopic signatures in Picea abies forests. FUNGAL ECOL 2021. [DOI: 10.1016/j.funeco.2021.101069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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15
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Belmecheri S, Maxwell RS, Taylor AH, Davis KJ, Guerrieri R, Moore DJP, Rayback SA. Precipitation alters the CO 2 effect on water-use efficiency of temperate forests. GLOBAL CHANGE BIOLOGY 2021; 27:1560-1571. [PMID: 33464665 DOI: 10.1111/gcb.15491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 05/08/2023]
Abstract
Increasing water-use efficiency (WUE), the ratio of carbon gain to water loss, is a key mechanism that enhances carbon uptake by terrestrial vegetation under rising atmospheric CO2 (ca ). Existing theory and empirical evidence suggest a proportional WUE increase in response to rising ca as plants maintain a relatively constant ratio between the leaf intercellular (ci ) and ambient (ca ) partial CO2 pressure (ci /ca ). This has been hypothesized as the main driver of the strengthening of the terrestrial carbon sink over the recent decades. However, proportionality may not characterize CO2 effects on WUE on longer time-scales and the role of climate in modulating these effects is uncertain. Here, we evaluate long-term WUE responses to ca and climate from 1901 to 2012 CE by reconstructing intrinsic WUE (iWUE, the ratio of photosynthesis to stomatal conductance) using carbon isotopes in tree rings across temperate forests in the northeastern USA. We show that iWUE increased steadily from 1901 to 1975 CE but remained constant thereafter despite continuously rising ca . This finding is consistent with a passive physiological response to ca and coincides with a shift to significantly wetter conditions across the region. Tree physiology was driven by summer moisture at multi-decadal time-scales and did not maintain a constant ci /ca in response to rising ca indicating that a point was reached where rising CO2 had a diminishing effect on tree iWUE. Our results challenge the mechanism, magnitude, and persistence of CO2 's effect on iWUE with significant implications for projections of terrestrial productivity under a changing climate.
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Affiliation(s)
- Soumaya Belmecheri
- Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ, USA
| | | | - Alan H Taylor
- Department of Geography and Earth and Environmental Systems Institute, The Pennsylvania State University, University Park, PA, USA
| | - Kenneth J Davis
- Department of Meteorology and Atmospheric Science and Earth and Environmental Systems Institute, The Pennsylvania State University, University Park, PA, USA
| | - Rossella Guerrieri
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, Bologna, Italy
| | - David J P Moore
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA
| | - Shelly A Rayback
- Department of Geography, University of Vermont, Burlington, VT, USA
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16
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Wang S, Zhang Y, Ju W, Chen JM, Ciais P, Cescatti A, Sardans J, Janssens IA, Wu M, Berry JA, Campbell E, Fernández-Martínez M, Alkama R, Sitch S, Friedlingstein P, Smith WK, Yuan W, He W, Lombardozzi D, Kautz M, Zhu D, Lienert S, Kato E, Poulter B, Sanders TGM, Krüger I, Wang R, Zeng N, Tian H, Vuichard N, Jain AK, Wiltshire A, Haverd V, Goll DS, Peñuelas J. Recent global decline of CO
2
fertilization effects on vegetation photosynthesis. Science 2020; 370:1295-1300. [DOI: 10.1126/science.abb7772] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 10/23/2020] [Indexed: 01/12/2023]
Affiliation(s)
- Songhan Wang
- International Institute for Earth System Science, Nanjing University, Nanjing, Jiangsu 210023, China
- Jiangsu Provincial Key Laboratory of Geographic Information Technology, Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources, School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Yongguang Zhang
- International Institute for Earth System Science, Nanjing University, Nanjing, Jiangsu 210023, China
- Jiangsu Provincial Key Laboratory of Geographic Information Technology, Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources, School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu 210023, China
- Huangshan Park Ecosystem Observation and Research Station, Ministry of Education, Huangshan, China
| | - Weimin Ju
- International Institute for Earth System Science, Nanjing University, Nanjing, Jiangsu 210023, China
- Jiangsu Provincial Key Laboratory of Geographic Information Technology, Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources, School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Jing M. Chen
- International Institute for Earth System Science, Nanjing University, Nanjing, Jiangsu 210023, China
- Department of Geography and Planning, University of Toronto, Toronto, Ontario, Canada
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l’Environnement, CEA CNRS UVSQ, Gif-sur-Yvette, France
| | | | - Jordi Sardans
- CSIC, Global ecology Unit CREAF-CSIC-UAB, Bellaterra 08193, Catalonia, Spain
- CREAF, Cerdanyola del Vallès 08193, Catalonia, Spain
| | - Ivan A. Janssens
- Department of Biology, Centre of Excellence PLECO (Plant and Vegetation Ecology), University of Antwerp, Wilrijk, Belgium
| | - Mousong Wu
- International Institute for Earth System Science, Nanjing University, Nanjing, Jiangsu 210023, China
- Jiangsu Provincial Key Laboratory of Geographic Information Technology, Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources, School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Joseph A. Berry
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Elliott Campbell
- Sierra Nevada Research Institute, University of California, Merced, CA 95343, USA
| | - Marcos Fernández-Martínez
- Department of Biology, Centre of Excellence PLECO (Plant and Vegetation Ecology), University of Antwerp, Wilrijk, Belgium
| | - Ramdane Alkama
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Stephen Sitch
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Pierre Friedlingstein
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - William K. Smith
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA
| | - Wenping Yuan
- School of Atmospheric Sciences, Center for Monsoon and Environment Research, Sun Yat-Sen University, Guangzhou, China
| | - Wei He
- International Institute for Earth System Science, Nanjing University, Nanjing, Jiangsu 210023, China
- Jiangsu Provincial Key Laboratory of Geographic Information Technology, Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources, School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Danica Lombardozzi
- Terrestrial Sciences Section, National Center for Atmospheric Research, Boulder, CO, USA
| | - Markus Kautz
- Forest Research Institute Baden-Württemberg, Freiburg, Germany
| | - Dan Zhu
- Laboratoire des Sciences du Climat et de l’Environnement, CEA CNRS UVSQ, Gif-sur-Yvette, France
| | - Sebastian Lienert
- Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | | | | | - Tanja G. M. Sanders
- Thünen Institute of Forest Ecosystems, Alfred-Möller-Str. 1, 16225 Eberswalde, Germany
| | - Inken Krüger
- Thünen Institute of Forest Ecosystems, Alfred-Möller-Str. 1, 16225 Eberswalde, Germany
| | - Rong Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China
| | - Ning Zeng
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD 20742, USA
- LASG, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing 100029, China
| | - Hanqin Tian
- International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, USA
| | - Nicolas Vuichard
- Laboratoire des Sciences du Climat et de l’Environnement, CEA CNRS UVSQ, Gif-sur-Yvette, France
| | - Atul K. Jain
- Department of Atmospheric Sciences, University of Illinois, 105 South Gregory Street, Urbana, IL 61801-3070, USA
| | - Andy Wiltshire
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Vanessa Haverd
- CSIRO Oceans and Atmosphere, Canberra, ACT 2601, Australia
| | - Daniel S. Goll
- Laboratoire des Sciences du Climat et de l’Environnement, CEA CNRS UVSQ, Gif-sur-Yvette, France
- Institute of Geography, University of Augsburg, Augsburg, Germany
| | - Josep Peñuelas
- CSIC, Global ecology Unit CREAF-CSIC-UAB, Bellaterra 08193, Catalonia, Spain
- CREAF, Cerdanyola del Vallès 08193, Catalonia, Spain
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17
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Brookshire ENJ, Stoy PC, Currey B, Finney B. The greening of the Northern Great Plains and its biogeochemical precursors. GLOBAL CHANGE BIOLOGY 2020; 26:5404-5413. [PMID: 32289875 DOI: 10.1111/gcb.15115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/02/2020] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
Vegetation greenness has increased across much of the global land surface over recent decades. This trend is projected to continue-particularly in northern latitudes-but future greening may be constrained by nutrient availability needed for plant carbon (C) assimilation in response to CO2 enrichment (eCO2 ). eCO2 impacts foliar chemistry and function, yet the relative strengths of these effects versus climate in driving patterns of vegetative greening remain uncertain. Here we combine satellite measurements of greening with a 135 year record of plant C and nitrogen (N) concentrations and stable isotope ratios (δ13 C and δ15 N) in the Northern Great Plains (NGP) of North America to examine N constraints on greening. We document significant greening over the past two decades with the highest proportional increases in net greening occurring in the dries and warmest areas. In contrast to the climate dependency of greening, we find spatially uniform increases in leaf-level intercellular CO2 and intrinsic water use efficiency that track rising atmospheric CO2 . Despite large spatial variation in greening, we find sustained and climate-independent declines in foliar N over the last century. Parallel declines in foliar δ15 N and increases in C:N ratios point to diminished N availability as the likely cause. The simultaneous increase in greening and decline in foliar N across our study area points to increased N use efficiency (NUE) over the last two decades. However, our results suggest that plant NUE responses are likely insufficient to sustain observed greening trends in NGP grasslands in the future.
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Affiliation(s)
- E N Jack Brookshire
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
| | - Paul C Stoy
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
- Department of Biological Systems Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Bryce Currey
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
| | - Bruce Finney
- Departments of Biological Sciences and Geosciences, Idaho State University, Pocatello, ID, USA
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18
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Craine JM. Looking back in time to reconstruct nitrogen availability trajectories. GLOBAL CHANGE BIOLOGY 2020; 26:5353-5355. [PMID: 32530557 DOI: 10.1111/gcb.15222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
This is a commentary on Brookshire et al. 26, 5404-5413 For the Northern Great Plains, Brookshire, Stoy, Currey, and Finney (Global Change Biology, 2020) analyze satellite-based reconstructions of greenness and foliar nutrition and isotopic composition from herbarium samples. Their results of greater productivity coupled with reduced N availability are part of an inflection in our understanding of the global N cycle as much of the terrestrial biosphere appears to be experiencing reduced N availability.
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19
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Bauters M, Meeus S, Barthel M, Stoffelen P, De Deurwaerder HPT, Meunier F, Drake TW, Ponette Q, Ebuy J, Vermeir P, Beeckman H, Wyffels F, Bodé S, Verbeeck H, Vandelook F, Boeckx P. Century-long apparent decrease in intrinsic water-use efficiency with no evidence of progressive nutrient limitation in African tropical forests. GLOBAL CHANGE BIOLOGY 2020; 26:4449-4461. [PMID: 32364642 DOI: 10.1111/gcb.15145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Forests exhibit leaf- and ecosystem-level responses to environmental changes. Specifically, rising carbon dioxide (CO2 ) levels over the past century are expected to have increased the intrinsic water-use efficiency (iWUE) of tropical trees while the ecosystem is gradually pushed into progressive nutrient limitation. Due to the long-term character of these changes, however, observational datasets to validate both paradigms are limited in space and time. In this study, we used a unique herbarium record to go back nearly a century and show that despite the rise in CO2 concentrations, iWUE has decreased in central African tropical trees in the Congo Basin. Although we find evidence that points to leaf-level adaptation to increasing CO2 -that is, increasing photosynthesis-related nutrients and decreasing maximum stomatal conductance, a decrease in leaf δ13 C clearly indicates a decreasing iWUE over time. Additionally, the stoichiometric carbon to nitrogen and nitrogen to phosphorus ratios in the leaves show no sign of progressive nutrient limitation as they have remained constant since 1938, which suggests that nutrients have not increasingly limited productivity in this biome. Altogether, the data suggest that other environmental factors, such as increasing temperature, might have negatively affected net photosynthesis and consequently downregulated the iWUE. Results from this study reveal that the second largest tropical forest on Earth has responded differently to recent environmental changes than expected, highlighting the need for further on-ground monitoring in the Congo Basin.
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Affiliation(s)
- Marijn Bauters
- Isotope Bioscience Laboratory - ISOFYS, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
- Computational and Applied Vegetation Ecology - CAVElab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | | | - Matti Barthel
- Sustainable Agroecosystems, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | | | - Hannes P T De Deurwaerder
- Computational and Applied Vegetation Ecology - CAVElab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Félicien Meunier
- Computational and Applied Vegetation Ecology - CAVElab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Travis W Drake
- Sustainable Agroecosystems, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Quentin Ponette
- UCL-ELI, Earth and Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Jerôme Ebuy
- UCL-ELI, Earth and Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- Université de Kisangani (UNIKIS/FGRNR), Kisangani, République Démocratique du Congo
| | - Pieter Vermeir
- Laboratory for Chemical Analyses - LCA, Department of Green Chemistry and Technology, Ghent University, Ghent, Belgium
| | | | - Francis Wyffels
- AIRO, Electronics and Information Systems Department, Ghent University-Imec, Ghent, Belgium
| | - Samuel Bodé
- Isotope Bioscience Laboratory - ISOFYS, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Hans Verbeeck
- Computational and Applied Vegetation Ecology - CAVElab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | | | - Pascal Boeckx
- Isotope Bioscience Laboratory - ISOFYS, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
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20
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Guerrieri R, Vanguelova E, Pitman R, Benham S, Perks M, Morison JIL, Mencuccini M. Climate and atmospheric deposition effects on forest water-use efficiency and nitrogen availability across Britain. Sci Rep 2020; 10:12418. [PMID: 32709879 PMCID: PMC7381603 DOI: 10.1038/s41598-020-67562-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 06/08/2020] [Indexed: 11/09/2022] Open
Abstract
Rising atmospheric CO2 (ca) has been shown to increase forest carbon uptake. Yet, whether the ca-fertilization effect on forests is modulated by changes in sulphur (Sdep) and nitrogen (Ndep) deposition and how Ndep affects ecosystem N availability remains unclear. We explored spatial and temporal (over 30-years) changes in tree-ring δ13C-derived intrinsic water-use efficiency (iWUE), δ18O and δ15N for four species in twelve forests across climate and atmospheric deposition gradients in Britain. The increase in iWUE was not uniform across sites and species-specific underlying physiological mechanisms reflected the interactions between climate and atmospheric drivers (oak and Scots pine), but also an age effect (Sitka spruce). Most species showed no significant trends for tree-ring δ15N, suggesting no changes in N availability. Increase in iWUE was mostly associated with increase in temperature and decrease in moisture conditions across the South-North gradient and over 30-years. However, when excluding Sitka spruce (to account for age or stand development effects), variations in iWUE were significantly associated with changes in ca and Sdep. Our data suggest that overall climate had the prevailing effect on changes in iWUE across the investigated sites. Whereas, detection of Ndep, Sdep and ca signals was partially confounded by structural changes during stand development.
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Affiliation(s)
- Rossella Guerrieri
- Centre for Ecological Research and Forestry Applications, CREAF, c/o Universidad Autonoma de Barcelona, Edificio C, 08290, Cerdanyola, Barcelona, Spain.
- Department of Agricultural and Food Sciences, University of Bologna, 40127, Bologna, Italy.
| | - Elena Vanguelova
- Forest Research, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK
| | - Rona Pitman
- Forest Research, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK
| | - Sue Benham
- Forest Research, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK
| | - Michael Perks
- Forest Research, Northern Research Station, Roslin, EH25 9SY, Midlothian, Scotland, UK
| | | | - Maurizio Mencuccini
- Centre for Ecological Research and Forestry Applications, CREAF, c/o Universidad Autonoma de Barcelona, Edificio C, 08290, Cerdanyola, Barcelona, Spain
- ICREA, Barcelona, Spain
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21
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Kou D, Yang G, Li F, Feng X, Zhang D, Mao C, Zhang Q, Peng Y, Ji C, Zhu Q, Fang Y, Liu X, Xu-Ri, Li S, Deng J, Zheng X, Fang J, Yang Y. Progressive nitrogen limitation across the Tibetan alpine permafrost region. Nat Commun 2020; 11:3331. [PMID: 32620773 PMCID: PMC7335038 DOI: 10.1038/s41467-020-17169-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 06/15/2020] [Indexed: 11/13/2022] Open
Abstract
The ecosystem carbon (C) balance in permafrost regions, which has a global significance in understanding the terrestrial C-climate feedback, is significantly regulated by nitrogen (N) dynamics. However, our knowledge on temporal changes in vegetation N limitation (i.e., the supply of N relative to plant N demand) in permafrost ecosystems is still limited. Based on the combination of isotopic observations derived from a re-sampling campaign along a ~3000 km transect and simulations obtained from a process-based biogeochemical model, here we detect changes in ecosystem N cycle across the Tibetan alpine permafrost region over the past decade. We find that vegetation N limitation becomes stronger despite the increased available N production. The enhanced N limitation on vegetation growth is driven by the joint effects of elevated plant N demand and gaseous N loss. These findings suggest that N would constrain the future trajectory of ecosystem C cycle in this alpine permafrost region.
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Affiliation(s)
- Dan Kou
- State 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, China
- Biogeochemistry Research Group, Department of Biological and Environmental Sciences, University of Eastern Finland, Kuopio, 70210, Finland
- Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Guibiao Yang
- State 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, China
| | - Fei Li
- State 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, China
| | - Xuehui Feng
- State 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, China
| | - Dianye 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, Beijing, 100049, China
| | - Chao Mao
- State 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, China
| | - Qiwen 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, Beijing, 100049, China
| | - Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Chengjun Ji
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, China
| | - Qiuan Zhu
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China
| | - Yunting Fang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Xueyan Liu
- School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Xu-Ri
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Siqi Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Jia Deng
- Earth Systems Research Centre, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH, 03824, USA
| | - Xunhua Zheng
- University of Chinese Academy of Sciences, Beijing, 100049, China
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Jingyun Fang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, China
| | - Yuanhe Yang
- State 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, China.
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22
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Penuelas J, Fernández-Martínez M, Vallicrosa H, Maspons J, Zuccarini P, Carnicer J, Sanders TGM, Krüger I, Obersteiner M, Janssens IA, Ciais P, Sardans J. Increasing atmospheric CO 2 concentrations correlate with declining nutritional status of European forests. Commun Biol 2020; 3:125. [PMID: 32170162 PMCID: PMC7070084 DOI: 10.1038/s42003-020-0839-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 02/20/2020] [Indexed: 11/10/2022] Open
Abstract
The drivers of global change, including increases in atmospheric CO2 concentrations, N and S deposition, and climate change, likely affect the nutritional status of forests. Here we show forest foliar concentrations of N, P, K, S and Mg decreased significantly in Europe by 5%, 11%, 8%, 6% and 7%, respectively during the last three decades. The decrease in nutritional status was especially large in Mediterranean and temperate forests. Increasing atmospheric CO2 concentration was well correlated with the decreases in N, P, K, Mg, S concentrations and the increase of N:P ratio. Regional analyses indicated that increases in some foliar nutrient concentrations such as N, S and Ca in northern Europe occurred associated with increasingly favourable conditions of mean annual precipitation and temperature. Crucial changes in forest health, structure, functioning and services, including negative feedbacks on C capture can be expected if these trends are not reversed.
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Affiliation(s)
- Josep Penuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, 08913, Bellaterra, Catalonia, Spain. .,CREAF, 08913, Cerdanyola del Vallès, Catalonia, Spain.
| | - Marcos Fernández-Martínez
- Research group PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, 2610, Wilrijk, Belgium
| | - Helena Vallicrosa
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, 08913, Bellaterra, Catalonia, Spain.,CREAF, 08913, Cerdanyola del Vallès, Catalonia, Spain
| | - Joan Maspons
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, 08913, Bellaterra, Catalonia, Spain.,CREAF, 08913, Cerdanyola del Vallès, Catalonia, Spain
| | - Paolo Zuccarini
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, 08913, Bellaterra, Catalonia, Spain.,CREAF, 08913, Cerdanyola del Vallès, Catalonia, Spain
| | - Jofre Carnicer
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, 08913, Bellaterra, Catalonia, Spain.,CREAF, 08913, Cerdanyola del Vallès, Catalonia, Spain
| | - Tanja G M Sanders
- Thünen Institute of Forest Ecosystems, Alfred-Möller-Straße 1, Haus 41/42, Eberswalde, 16225, Germany
| | - Inken Krüger
- Thünen Institute of Forest Ecosystems, Alfred-Möller-Straße 1, Haus 41/42, Eberswalde, 16225, Germany
| | - Michael Obersteiner
- International Institute for Applied Systems Analysis (IIASA), Ecosystems Services and Management, Schlossplatz 1, A-2361, Laxenburg, Austria
| | - Ivan A Janssens
- Research group PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, 2610, Wilrijk, Belgium
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, IPSL, 91191, Gif-sur-Yvette, France
| | - Jordi Sardans
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, 08913, Bellaterra, Catalonia, Spain.,CREAF, 08913, Cerdanyola del Vallès, Catalonia, Spain
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23
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Sabo RD, Elmore AJ, Nelson DM, Clark CM, Fisher T, Eshleman KN. Positive correlation between wood δ 15N and stream nitrate concentrations in two temperate deciduous forests. ENVIRONMENTAL RESEARCH COMMUNICATIONS 2020; 2:1-17. [PMID: 36313933 PMCID: PMC9610404 DOI: 10.1088/2515-7620/ab77f8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A limitation to understanding drivers of long-term trends in terrestrial nitrogen (N) availability in forests and its subsequent influence on stream nitrate export is a general lack of integrated analyses using long-term data on terrestrial and aquatic N cycling at comparable spatial scales. Here we analyze relationships between stream nitrate concentrations and wood δ 15N records (n = 96 trees) across five neighboring headwater catchments in the Blue Ridge physiographic province and within a single catchment in the Appalachian Plateau physiographic province in the eastern United States. Climatic, acidic deposition, and forest disturbance datasets were developed to elucidate the influence of these factors on terrestrial N availability through time. We hypothesized that spatial and temporal variation of terrestrial N availability, for which tree-ring δ 15N records serve as a proxy, affects the variation of stream nitrate concentration across space and time. Across space at the Blue Ridge study sites, stream nitrate concentration increased linearly with increasing catchment mean wood δ 15N. Over time, stream nitrate concentrations decreased with decreasing wood δ 15N in five of the six catchments. Wood δ 15N showed a significant negative relationship with disturbance and acidic deposition. Disturbance likely exacerbated N limitation by inducing nitrate leaching and ultimately enhancing vegetative uptake. As observed elsewhere, lower rates of acidic deposition and subsequent deacidification of soils may increase terrestrial N availability. Despite the ephemeral modifications of terrestrial N availability by these two drivers and climate, long-term declines in terrestrial N availability were robust and have likely driven much of the declines in stream nitrate concentration throughout the central Appalachians.
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Affiliation(s)
- Robert D Sabo
- Oak Ridge Institute for Science and Education, United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, US EPA (8623-P),1200 Pennsylvania Ave NW; Washington, DC 20460, United States of America
| | - Andrew J Elmore
- University of Maryland Center for Environmental Science, Appalachian Laboratory, 301 Braddock Road, Frostburg, MD 21532, United States of America
| | - David M Nelson
- University of Maryland Center for Environmental Science, Appalachian Laboratory, 301 Braddock Road, Frostburg, MD 21532, United States of America
| | - Christopher M Clark
- United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, US EPA (8623-P),1200 Pennsylvania Ave NW; Washington, DC 20460, United States of America
| | - Thomas Fisher
- University of Maryland Center for Environmental Science, Appalachian Laboratory, 301 Braddock Road, Frostburg, MD 21532, United States of America
| | - Keith N Eshleman
- University of Maryland Center for Environmental Science, Appalachian Laboratory, 301 Braddock Road, Frostburg, MD 21532, United States of America
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24
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Burnham MB, Adams MB, Peterjohn WT. Assessing tree ring δ 15N of four temperate deciduous species as an indicator of N availability using independent long-term records at the Fernow Experimental Forest, WV. Oecologia 2019; 191:971-981. [PMID: 31617000 DOI: 10.1007/s00442-019-04528-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/05/2019] [Indexed: 11/25/2022]
Abstract
Nitrogen deposition in the northeastern US changed N availability in the latter part of the twentieth century, with potential legacy effects. However, long-term N cycle measurements are scarce. N isotopes in tree rings have been used as an indicator of N availability through time, but there is little verification of whether species differ in the strength of this signal. Using long-term records at the Fernow Experimental Forest in West Virginia, we examined the relationship between soil conditions, including net nitrification rates, and wood δ15N in 2014, and tested the strength of correlation between tree ring δ15N of four species and stream water NO3- loss from 1971 to 2000. Higher soil NO3- was weakly associated with higher wood δ15N across species, and higher soil net nitrification rates were associated with higher δ15N for Quercus rubra only. The δ15N of Liriodendron tulipifera and Q. rubra, but neither Fagus grandifolia nor Prunus serotina, was correlated with stream water NO3-. L. tulipifera tree ring δ15N had a stronger association with stream water NO3- than Q. rubra. Overall, we found only limited evidence of a relationship between soil N cycling and tree ring δ15N, with a strong correlation between the wood δ15N and NO3- leaching loss through time for one of four species. Tree species differ in their ability to preserve legacies of N cycling in tree ring δ15N, and given the weak relationships between contemporary wood δ15N and soil N cycle measurements, caution is warranted when using wood δ15N to infer changes in the N cycle.
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Affiliation(s)
- Mark B Burnham
- Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois Urbana-Champaign, 1200 IGB, 1206 West Gregory Drive, Urbana, IL, 61801, USA.
| | - Mary Beth Adams
- USDA Forest Service Northern Research Station, Morgantown, WV, USA
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25
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Craine JM, Elmore AJ, Wang L, Boeckx P, Delzon S, Fang Y, Gray A, Guerrieri R, Gundale MJ, Hietz P, Nelson DM, Peri PL, Templer PH, Werner C. Reply to: Data do not support large-scale oligotrophication of terrestrial ecosystems. Nat Ecol Evol 2019; 3:1287-1288. [DOI: 10.1038/s41559-019-0949-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 06/18/2019] [Indexed: 02/02/2023]
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26
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Marinos RE, Campbell JL, Driscoll CT, Likens GE, McDowell WH, Rosi EJ, Rustad LE, Bernhardt ES. Give and Take: A Watershed Acid Rain Mitigation Experiment Increases Baseflow Nitrogen Retention but Increases Stormflow Nitrogen Export. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:13155-13165. [PMID: 30379543 DOI: 10.1021/acs.est.8b03553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In many temperate forested watersheds, hydrologic nitrogen export has declined substantially in recent decades, and many of these watersheds show enduring effects from historic acid deposition. A watershed acid remediation experiment in New Hampshire reversed many of these legacy effects of acid deposition and also increased watershed nitrogen export, suggesting that these two phenomena may be coupled. Here we examine stream nitrate dynamics in this watershed acid remediation experiment for indicators of nitrogen saturation in the terrestrial and aquatic ecosystems. Post-treatment, the (positive) slope of the relationship between nitrate concentration and discharge increased by a median of 82% ( p = 0.004). This resulted in greater flushing of nitrate during storm events, a key indicator of early stage nitrogen saturation. Hysteretic behavior of the concentration-discharge relationship indicated that the mobilization of soil nitrate pools was responsible for this increased flushing. In contrast to this evidence for nitrogen saturation in the terrestrial ecosystem, we found that nitrogen uptake increased, post-treatment, in the aquatic ecosystem, substantially attenuating growing-season nitrate flux by up to 71.1% ( p = 0.025). These results suggest that, as forests slowly recover from acid precipitation, terrestrial, and aquatic ecosystem nitrogen balance may be substantially altered.
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Affiliation(s)
- Richard E Marinos
- Nicholas School of the Environment , Duke University , Durham North Carolina 27708 , United States
| | - John L Campbell
- USDA Forest Service, Northern Research Station , Durham , New Hampshire 03824 , United States
| | | | - Gene E Likens
- University of Connecticut , Storrs , Connecticut 06269 , United States
- Cary Institute of Ecosystem Studies , Millbrook , New York 12545 , United States
| | - William H McDowell
- University of New Hampshire , Durham , New Hampshire 03824 , United States
| | - Emma J Rosi
- Cary Institute of Ecosystem Studies , Millbrook , New York 12545 , United States
| | - Lindsey E Rustad
- USDA Forest Service, Northern Research Station , Durham , New Hampshire 03824 , United States
| | - Emily S Bernhardt
- Department of Biology , Duke University , Durham North Carolina 27708 , United States
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27
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Du E, de Vries W. Nitrogen-induced new net primary production and carbon sequestration in global forests. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 242:1476-1487. [PMID: 30142563 DOI: 10.1016/j.envpol.2018.08.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 05/11/2023]
Abstract
Nitrogen (N) deposition and biological N fixation (BNF) are main external N inputs into terrestrial ecosystems. However, few studies have simultaneously quantified the contribution of these two external N inputs to global NPP and consequent C sequestration. Based on literature analysis, we estimated new net primary production (NPP) due to external N inputs from BNF and N deposition and the consequent C sinks in global boreal, temperate and tropical forest biomes via a stoichiometric scaling approach. Nitrogen-induced new NPP is estimated to be 3.48 Pg C yr-1 in global established forests and contributes to a C sink of 1.83 Pg C yr-1. More specifically, the aboveground and belowground new NPP are estimated to be 2.36 and 1.12 Pg C yr-1, while the external N-induced C sinks in wood and soil are estimated to be 1.51 and 0.32 Pg C yr-1, respectively. BNF contributes to a major proportion of N-induced new NPP (3.07 Pg C yr-1) in global forest, and accounts for a C sink of 1.58 Pg C yr-1. Compared with BNF, N deposition only makes a minor contribution to new NPP (0.41 Pg C yr-1) and C sinks (0.25 Pg C yr-1) in global forests. At the biome scale, rates of N-induced new NPP and C sink show an increase from boreal forest towards tropical forest, as mainly driven by an increase of BNF. In contrast, N deposition leads to a larger C sink in temperate forest (0.11 Pg C yr-1) than boreal (0.06 Pg C yr-1) and tropical forest (0.08 Pg C yr-1). Our estimate of total C sink due to N-induced new NPP approximately matches an independent assessment of total C sink in global established forests, suggesting that external N inputs by BNF and atmospheric deposition are key drivers of C sinks in global forests.
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Affiliation(s)
- Enzai Du
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, 100875, China; School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing, 100875, China.
| | - Wim de Vries
- Environmental Systems Analysis Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, the Netherlands; Alterra, Wageningen University and Research Center, PO Box 47, 6700 AA, Wageningen, the Netherlands.
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28
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Isotopic evidence for oligotrophication of terrestrial ecosystems. Nat Ecol Evol 2018; 2:1735-1744. [DOI: 10.1038/s41559-018-0694-0] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/12/2018] [Indexed: 11/09/2022]
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29
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Seasonal drought may alter N availability but not water use efficiency of dominant trees in a subtropical forest. Glob Ecol Conserv 2018. [DOI: 10.1016/j.gecco.2018.e00475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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30
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Mathias JM, Thomas RB. Disentangling the effects of acidic air pollution, atmospheric CO 2 , and climate change on recent growth of red spruce trees in the Central Appalachian Mountains. GLOBAL CHANGE BIOLOGY 2018; 24:3938-3953. [PMID: 29781219 DOI: 10.1111/gcb.14273] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 05/24/2023]
Abstract
In the 45 years after legislation of the Clean Air Act, there has been tremendous progress in reducing acidic air pollutants in the eastern United States, yet limited evidence exists that cleaner air has improved forest health. Here, we investigate the influence of recent environmental changes on the growth and physiology of red spruce (Picea rubens Sarg.) trees, a key indicator species of forest health, spanning three locations along a 100 km transect in the Central Appalachian Mountains. We incorporated a multiproxy approach using 75-year tree ring chronologies of basal tree growth, carbon isotope discrimination (∆13 C, a proxy for leaf gas exchange), and δ15 N (a proxy for ecosystem N status) to examine tree and ecosystem level responses to environmental change. Results reveal the two most important factors driving increased tree growth since ca. 1989 are reductions in acidic sulfur pollution and increases in atmospheric CO2 , while reductions in pollutant emissions of NOx and warmer springs played smaller, but significant roles. Tree ring ∆13 C signatures increased significantly since 1989, concurrently with significant declines in tree ring δ15 N signatures. These isotope chronologies provide strong evidence that simultaneous changes in C and N cycling, including greater photosynthesis and stomatal conductance of trees and increases in ecosystem N retention, were related to recent increases in red spruce tree growth and are consequential to ecosystem recovery from acidic pollution. Intrinsic water use efficiency (iWUE) of the red spruce trees increased by ~51% across the 75-year chronology, and was driven by changes in atmospheric CO2 and acid pollution, but iWUE was not linked to recent increases in tree growth. This study documents the complex environmental interactions that have contributed to the recovery of red spruce forest ecosystems from pervasive acidic air pollution beginning in 1989, about 15 years after acidic pollutants started to decline in the United States.
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Affiliation(s)
- Justin M Mathias
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | - Richard B Thomas
- Department of Biology, West Virginia University, Morgantown, West Virginia
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31
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Gilliam FS, Walter CA, Adams MB, Peterjohn WT. Nitrogen (N) Dynamics in the Mineral Soil of a Central Appalachian Hardwood Forest During a Quarter Century of Whole-Watershed N Additions. Ecosystems 2018. [DOI: 10.1007/s10021-018-0234-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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