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Luo B, Luo D, Dai A, Xiao C, Simmonds I, Hanna E, Overland J, Shi J, Chen X, Yao Y, Duan W, Liu Y, Zhang Q, Xu X, Diao Y, Jiang Z, Gong T. Rapid summer Russian Arctic sea-ice loss enhances the risk of recent Eastern Siberian wildfires. Nat Commun 2024; 15:5399. [PMID: 38926364 DOI: 10.1038/s41467-024-49677-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
In recent decades boreal wildfires have occurred frequently over eastern Siberia, leading to increased emissions of carbon dioxide and pollutants. However, it is unclear what factors have contributed to recent increases in these wildfires. Here, using the data we show that background eastern Siberian Arctic warming (BAW) related to summer Russian Arctic sea-ice decline accounts for ~79% of the increase in summer vapor pressure deficit (VPD) that controls wildfires over eastern Siberia over 2004-2021 with the remaining ~21% related to internal atmospheric variability associated with changes in Siberian blocking events. We further demonstrate that Siberian blocking events are occurring at higher latitudes, are more persistent and have larger zonal scales and slower decay due to smaller meridional potential vorticity gradients caused by stronger BAW under lower sea-ice. These changes lead to more persistent, widespread and intense high-latitude warming and VPD, thus contributing to recent increases in eastern Siberian high-latitude wildfires.
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Affiliation(s)
- Binhe Luo
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, 100875, China
| | - Dehai Luo
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing, 100029, China.
- University of Chinese Academy of Sciences, Beijing, 101408, China.
| | - Aiguo Dai
- Department of Atmospheric and Environmental Sciences, State University of New York, Albany, NY, USA
| | - Cunde Xiao
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, 100875, China.
| | - Ian Simmonds
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Edward Hanna
- Department of Geography, School of Life and Environmental Sciences, University of Lincoln, Lincoln, UK
| | - James Overland
- NOAA/Pacific Marine Environmental Laboratory, Seattle, WA, USA
| | - Jiaqi Shi
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing, 100029, China
- University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Xiaodan Chen
- Department of atmospheric and oceanic sciences, Fudan University, Shanghai, 200438, China
| | - Yao Yao
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing, 100029, China
- University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Wansuo Duan
- State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Yimin Liu
- State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Qiang Zhang
- Department of Earth system Science, Tsinghua University, Beijing, 100084, China
| | - Xiyan Xu
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing, 100029, China
- University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Yina Diao
- College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, 266101, China
| | - Zhina Jiang
- Institute of Global Change and Polar Meteorology, Chinese Academy of Meteorological Sciences, Beijing, 100081, China
| | - Tingting Gong
- Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266400, China
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2
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Zhu X, Jia G, Xu X. Accelerated rise in wildfire carbon emissions from Arctic continuous permafrost. Sci Bull (Beijing) 2024:S2095-9273(24)00356-6. [PMID: 38910108 DOI: 10.1016/j.scib.2024.05.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 06/25/2024]
Abstract
Wildfires over permafrost put perennially frozen carbon at risk. However, wildfire emissions from biomass burning over the diverse range of permafrost regions and their share in global wildfire emissions have not been revealed. The results showed a dramatic increase in wildfire carbon emissions from permafrost regions over the period 1997-2021. The share of permafrost in global wildfire CO2 emissions increased from 2.42% in 1997 to 20.86% in 2021. Accelerating wildfire emissions from continuous permafrost region is the single largest contributor to increased emissions in northern permafrost regions. Fire-induced emissions from 2019 to 2021 alone accounted for approximately 40% of the 25-year total CO2 emissions from continuous permafrost regions. The rise in wildfire emissions from continuous permafrost regions is explained by desiccation within a 5-10 cm soil depth, where wildfires combust belowground fuel. These findings highlight the acceleration of fire-induced carbon emissions from continuous permafrost regions, which disturb the organic carbon stock and accelerate the positive feedback between permafrost degradation and climate warming, thus stimulating permafrost towards a climatic tipping point.
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Affiliation(s)
- Xingru Zhu
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gensuo Jia
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiyan Xu
- Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
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3
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Jones BM, Kanevskiy MZ, Shur Y, Gaglioti BV, Jorgenson MT, Ward Jones MK, Veremeeva A, Miller EA, Jandt R. Post-fire stabilization of thaw-affected permafrost terrain in northern Alaska. Sci Rep 2024; 14:8499. [PMID: 38605076 PMCID: PMC11009396 DOI: 10.1038/s41598-024-58998-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
In 2007, the Anaktuvuk River fire burned more than 1000 km2 of arctic tundra in northern Alaska, ~ 50% of which occurred in an area with ice-rich syngenetic permafrost (Yedoma). By 2014, widespread degradation of ice wedges was apparent in the Yedoma region. In a 50 km2 area, thaw subsidence was detected across 15% of the land area in repeat airborne LiDAR data acquired in 2009 and 2014. Updating observations with a 2021 airborne LiDAR dataset show that additional thaw subsidence was detected in < 1% of the study area, indicating stabilization of the thaw-affected permafrost terrain. Ground temperature measurements between 2010 and 2015 indicated that the number of near-surface soil thawing-degree-days at the burn site were 3 × greater than at an unburned control site, but by 2022 the number was reduced to 1.3 × greater. Mean annual ground temperature of the near-surface permafrost increased by 0.33 °C/yr in the burn site up to 7-years post-fire, but then cooled by 0.15 °C/yr in the subsequent eight years, while temperatures at the control site remained relatively stable. Permafrost cores collected from ice-wedge troughs (n = 41) and polygon centers (n = 8) revealed the presence of a thaw unconformity, that in most cases was overlain by a recovered permafrost layer that averaged 14.2 cm and 18.3 cm, respectively. Taken together, our observations highlight that the initial degradation of ice-rich permafrost following the Anaktuvuk River tundra fire has been followed by a period of thaw cessation, permafrost aggradation, and terrain stabilization.
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Affiliation(s)
- Benjamin M Jones
- Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
| | - Mikhail Z Kanevskiy
- Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Yuri Shur
- College of Engineering and Mines, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Benjamin V Gaglioti
- Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | | | - Melissa K Ward Jones
- Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Alexandra Veremeeva
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
| | - Eric A Miller
- Bureau of Land Management Alaska Fire Service, Fort Wainwright, AK, 99703, USA
| | - Randi Jandt
- Alaska Fire Science Consortium, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
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4
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Qu Y, Miralles DG, Veraverbeke S, Vereecken H, Montzka C. Wildfire precursors show complementary predictability in different timescales. Nat Commun 2023; 14:6829. [PMID: 37884516 PMCID: PMC10603132 DOI: 10.1038/s41467-023-42597-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 10/17/2023] [Indexed: 10/28/2023] Open
Abstract
In most of the world, conditions conducive to wildfires are becoming more prevalent. Net carbon emissions from wildfires contribute to a positive climate feedback that needs to be monitored, quantified, and predicted. Here we use a causal inference approach to evaluate the influence of top-down weather and bottom-up fuel precursors on wildfires. The top-down dominance on wildfires is more widespread than bottom-up dominance, accounting for 73.3% and 26.7% of regions, respectively. The top-down precursors dominate in the tropical rainforests, mid-latitudes, and eastern Siberian boreal forests. The bottom-up precursors dominate in North American and European boreal forests, and African and Australian savannahs. Our study identifies areas where wildfires are governed by fuel conditions and hence where fuel management practices may be more effective. Moreover, our study also highlights that top-down and bottom-up precursors show complementary wildfire predictability across timescales. Seasonal or interannual predictions are feasible in regions where bottom-up precursors dominate.
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Affiliation(s)
- Yuquan Qu
- Institute of Bio- and Geosciences: Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany.
| | | | - Sander Veraverbeke
- Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Harry Vereecken
- Institute of Bio- and Geosciences: Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Carsten Montzka
- Institute of Bio- and Geosciences: Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany
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Liu Q, Peng C, Schneider R, Cyr D, Liu Z, Zhou X, Du M, Li P, Jiang Z, McDowell NG, Kneeshaw D. Vegetation browning: global drivers, impacts, and feedbacks. TRENDS IN PLANT SCIENCE 2023; 28:1014-1032. [PMID: 37087358 DOI: 10.1016/j.tplants.2023.03.024] [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: 05/22/2022] [Revised: 03/22/2023] [Accepted: 03/30/2023] [Indexed: 05/03/2023]
Abstract
As global climate conditions continue to change, disturbance regimes and environmental drivers will continue to shift, impacting global vegetation dynamics. Following a period of vegetation greening, there has been a progressive increase in remotely sensed vegetation browning globally. Given the many societal benefits that forests provide, it is critical that we understand vegetation dynamic alterations. Here, we review associative drivers, impacts, and feedbacks, revealing the complexity of browning. Concomitant increases in browning include the weakening of ecosystem services and functions and alterations to vegetation structure and species composition, as well as the development of potential positive climate change feedbacks. Also discussed are the current challenges in browning detection and understanding associated impacts and feedbacks. Finally, we outline recommended strategies.
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Affiliation(s)
- Qiuyu Liu
- Institute of Environment Sciences, Department of Biology Sciences, University of Quebec at Montreal, Case Postale 8888, Succ. Centre-Ville, Montreal, H3C 3P8, Canada; School of Public Policy and Administration, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Changhui Peng
- Institute of Environment Sciences, Department of Biology Sciences, University of Quebec at Montreal, Case Postale 8888, Succ. Centre-Ville, Montreal, H3C 3P8, Canada; College of Geographic Science, Hunan Normal University, Changsha, 410081, China.
| | - Robert Schneider
- University of Quebec at Rimouski (UQAR), Rimouski, Quebec, G5L 3A1, Canada
| | - Dominic Cyr
- Science and Technology Branch, Environment and Climate Change Canada, 351 St-Joseph Blvd, Gatineau, Quebec, Canada
| | - Zelin Liu
- College of Geographic Science, Hunan Normal University, Changsha, 410081, China
| | - Xiaolu Zhou
- College of Geographic Science, Hunan Normal University, Changsha, 410081, China
| | - Mingxi Du
- School of Public Policy and Administration, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Peng Li
- College of Geographic Science, Hunan Normal University, Changsha, 410081, China
| | - Zihan Jiang
- Institute of Environment Sciences, Department of Biology Sciences, University of Quebec at Montreal, Case Postale 8888, Succ. Centre-Ville, Montreal, H3C 3P8, Canada; CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Lab, PO Box 999, Richland, WA 99352, USA; School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
| | - Daniel Kneeshaw
- Institute of Environment Sciences, Department of Biology Sciences, University of Quebec at Montreal, Case Postale 8888, Succ. Centre-Ville, Montreal, H3C 3P8, Canada; Centre for Forest Research, University of Quebec at Montreal, Case Postale 8888, Succ. Centre-Ville, Montreal, H3C 3P8, Canada
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6
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Descals A, Gaveau DLA, Verger A, Sheil D, Naito D, Peñuelas J. Unprecedented fire activity above the Arctic Circle linked to rising temperatures. Science 2022; 378:532-537. [DOI: 10.1126/science.abn9768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Arctic fires can release large amounts of carbon from permafrost peatlands. Satellite observations reveal that fires burned ~4.7 million hectares in 2019 and 2020, accounting for 44% of the total burned area in the Siberian Arctic for the entire 1982–2020 period. The summer of 2020 was the warmest in four decades, with fires burning an unprecedentedly large area of carbon-rich soils. We show that factors of fire associated with temperature have increased in recent decades and identified a near-exponential relationship between these factors and annual burned area. Large fires in the Arctic are likely to recur with climatic warming before mid-century, because the temperature trend is reaching a threshold in which small increases in temperature are associated with exponential increases in the area burned.
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Affiliation(s)
- Adrià Descals
- CREAF, Centre de Recerca Ecològica i Aplicacions Forestals, Cerdanyola del Vallès, 08193 Barcelona, Catalonia, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain
| | | | - Aleixandre Verger
- CREAF, Centre de Recerca Ecològica i Aplicacions Forestals, Cerdanyola del Vallès, 08193 Barcelona, Catalonia, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain
- CIDE, CSIC-UV-GV, 46113 València, Spain
| | - Douglas Sheil
- Forest Ecology and Forest Management Group, Wageningen University and Research, Wageningen, Netherlands
- Center for International Forestry Research (CIFOR), Bogor 16000, Indonesia
| | - Daisuke Naito
- Center for International Forestry Research (CIFOR), Bogor 16000, Indonesia
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Josep Peñuelas
- CREAF, Centre de Recerca Ecològica i Aplicacions Forestals, Cerdanyola del Vallès, 08193 Barcelona, Catalonia, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain
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7
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Post E, Mack MC. Arctic wildfires at a warming threshold. Science 2022; 378:470-471. [DOI: 10.1126/science.ade9583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Bigger wildfires in the Siberian Arctic signal release of more carbon to the atmosphere
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Affiliation(s)
- Eric Post
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, Davis, CA, USA
| | - Michelle C. Mack
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
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8
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Scholten RC, Coumou D, Luo F, Veraverbeke S. Early snowmelt and polar jet dynamics co-influence recent extreme Siberian fire seasons. Science 2022; 378:1005-1009. [DOI: 10.1126/science.abn4419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The summers of 2019, 2020 and 2021 experienced unprecedented fire activity in northeastern Siberia, driven by record-high spring and summer temperatures. Many of these fires burned in permafrost peatlands within the Arctic Circle. Here, we show that early snowmelt together with an anomalous Arctic front jet over northeastern Siberia promoted unusually warm and dry surface conditions, followed by anomalously high lightning and fire activity. Since 1966, spring snowmelt has started 1.7 days earlier each decade. Moreover, Arctic front jet occurrences in summer have more than tripled in frequency over the last 40 years. These interconnected climatological drivers promote extreme fire activity in eastern Siberia, including a northward shift of fires, which may accelerate the degradation of carbon-rich permafrost peatlands.
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Affiliation(s)
| | - Dim Coumou
- Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands
| | - Fei Luo
- Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands
| | - Sander Veraverbeke
- Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
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9
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Dastoor A, Wilson SJ, Travnikov O, Ryjkov A, Angot H, Christensen JH, Steenhuisen F, Muntean M. Arctic atmospheric mercury: Sources and changes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 839:156213. [PMID: 35623517 DOI: 10.1016/j.scitotenv.2022.156213] [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: 03/01/2022] [Revised: 05/17/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Global anthropogenic and legacy mercury (Hg) emissions are the main sources of Arctic Hg contamination, primarily transported there via the atmosphere. This review summarizes the state of knowledge of the global anthropogenic sources of Hg emissions, and examines recent changes and source attribution of Hg transport and deposition to the Arctic using models. Estimated global anthropogenic Hg emissions to the atmosphere for 2015 were ~2220 Mg, ~20% higher than 2010. Global anthropogenic, legacy and geogenic Hg emissions were, respectively, responsible for 32%, 64% (wildfires: 6-10%) and 4% of the annual Arctic Hg deposition. Relative contributions to Arctic deposition of anthropogenic origin was dominated by sources in East Asia (32%), Commonwealth of Independent States (12%), and Africa (12%). Model results exhibit significant spatiotemporal variations in Arctic anthropogenic Hg deposition fluxes, driven by regional differences in Hg air transport routes, surface and precipitation uptake rates, and inter-seasonal differences in atmospheric circulation and deposition pathways. Model simulations reveal that changes in meteorology are having a profound impact on contemporary atmospheric Hg in the Arctic. Reversal of North Atlantic Oscillation phase from strongly negative in 2010 to positive in 2015, associated with lower temperature and more sea ice in the Canadian Arctic, Greenland and surrounding ocean, resulted in enhanced production of bromine species and Hg(0) oxidation and lower evasion of Hg(0) from ocean waters in 2015. This led to increased Hg(II) (and its deposition) and reduced Hg(0) air concentrations in these regions in line with High Arctic observations. However, combined changes in meteorology and anthropogenic emissions led to overall elevated modeled Arctic air Hg(0) levels in 2015 compared to 2010 contrary to observed declines at most monitoring sites, likely due to uncertainties in anthropogenic emission speciation, wildfire emissions and model representations of air-surface Hg fluxes.
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Affiliation(s)
- Ashu Dastoor
- Air Quality Research Division, Environment and Climate Change Canada, 2121 Trans-Canada Highway, Dorval, Québec H9P 1J3, Canada.
| | - Simon J Wilson
- Arctic Monitoring and Assessment Programme (AMAP). The Fram Centre, Box 6606 Stakkevollan, 9296 Tromsø, Norway.
| | - Oleg Travnikov
- Meteorological Synthesizing Centre-East, EMEP, 2nd Roshchinsky proezd, 8/5, 115419 Moscow, Russia
| | - Andrei Ryjkov
- Air Quality Research Division, Environment and Climate Change Canada, 2121 Trans-Canada Highway, Dorval, Québec H9P 1J3, Canada
| | - Hélène Angot
- Extreme Environments Research Laboratory, École Polytechnique Fédérale de Lausanne (EPFL) Valais Wallis, Sion, Switzerland
| | - Jesper H Christensen
- Department of Environmental Science, iClimate, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Frits Steenhuisen
- Arctic Centre, University of Groningen, Aweg 30, 9718CW Groningen, the Netherlands
| | - Marilena Muntean
- European Commission, Joint Research Centre (JRC), Via E. Fermi 2749 (T.P. 123), I-21027 Ispra, VA, Italy
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10
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Hudson AR, Peters DPC, Blair JM, Childers DL, Doran PT, Geil K, Gooseff M, Gross KL, Haddad NM, Pastore MA, Rudgers JA, Sala O, Seabloom EW, Shaver G. Cross-Site Comparisons of Dryland Ecosystem Response to Climate Change in the US Long-Term Ecological Research Network. Bioscience 2022; 72:889-907. [PMID: 36034512 PMCID: PMC9405733 DOI: 10.1093/biosci/biab134] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Long-term observations and experiments in diverse drylands reveal how ecosystems and services are responding to climate change. To develop generalities about climate change impacts at dryland sites, we compared broadscale patterns in climate and synthesized primary production responses among the eight terrestrial, nonforested sites of the United States Long-Term Ecological Research (US LTER) Network located in temperate (Southwest and Midwest) and polar (Arctic and Antarctic) regions. All sites experienced warming in recent decades, whereas drought varied regionally with multidecadal phases. Multiple years of wet or dry conditions had larger effects than single years on primary production. Droughts, floods, and wildfires altered resource availability and restructured plant communities, with greater impacts on primary production than warming alone. During severe regional droughts, air pollution from wildfire and dust events peaked. Studies at US LTER drylands over more than 40 years demonstrate reciprocal links and feedbacks among dryland ecosystems, climate-driven disturbance events, and climate change.
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Affiliation(s)
- Amy R Hudson
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
| | - Debra P C Peters
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
- US Department of Agriculture Agricultural Research Service's Jornada Experimental Range, Las Cruces , New Mexico, United States
- New Mexico State University , Las Cruces, New Mexico, United States
| | - John M Blair
- Kansas State University, Manhattan , Kansas, United States
| | | | - Peter T Doran
- Louisiana State University , Baton Rouge, Louisiana, United States
| | - Kerrie Geil
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
| | | | - Katherine L Gross
- W. K. Kellogg Biological Station, Vermont , United States
- Department of Plant Biology, Vermont , United States
| | - Nick M Haddad
- W. K. Kellogg Biological Station, Vermont , United States
- Department of Plant Biology, Vermont , United States
| | | | | | - Osvaldo Sala
- Arizona State University , Tempe, Arizona, United States
- Global Drylands Center and the School of Life Sciences, Arizona State University , Tempe, Arizona, United States
| | - Eric W Seabloom
- University of Minnesota , St. Paul, Minnesota, United States
| | - Gaius Shaver
- Marine Biological Laboratory, Woods Hole , Massachusetts, United States
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11
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Microbiogeochemical Traits to Identify Nitrogen Hotspots in Permafrost Regions. NITROGEN 2022. [DOI: 10.3390/nitrogen3030031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Permafrost-affected tundra soils are large carbon (C) and nitrogen (N) reservoirs. However, N is largely bound in soil organic matter (SOM), and ecosystems generally have low N availability. Therefore, microbial induced N-cycling processes and N losses were considered negligible. Recent studies show that microbial N processing rates, inorganic N availability, and lateral N losses from thawing permafrost increase when vegetation cover is disturbed, resulting in reduced N uptake or increased N input from thawing permafrost. In this review, we describe currently known N hotspots, particularly bare patches in permafrost peatland or permafrost soils affected by thermokarst, and their microbiogeochemical characteristics, and present evidence for previously unrecorded N hotspots in the tundra. We summarize the current understanding of microbial N cycling processes that promote the release of the potent greenhouse gas (GHG) nitrous oxide (N2O) and the translocation of inorganic N from terrestrial into aquatic ecosystems. We suggest that certain soil characteristics and microbial traits can be used as indicators of N availability and N losses. Identifying N hotspots in permafrost soils is key to assessing the potential for N release from permafrost-affected soils under global warming, as well as the impact of increased N availability on emissions of carbon-containing GHGs.
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12
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Hermesdorf L, Elberling B, D'Imperio L, Xu W, Lambæk A, Ambus PL. Effects of fire on CO 2 , CH 4 , and N 2 O exchange in a well-drained Arctic heath ecosystem. GLOBAL CHANGE BIOLOGY 2022; 28:4882-4899. [PMID: 35543023 PMCID: PMC9544550 DOI: 10.1111/gcb.16222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 06/14/2023]
Abstract
Wildfire frequency and expanse in the Arctic have increased in recent years and are projected to increase further with changes in climatic conditions due to warmer and drier summers. Yet, there is a lack of knowledge about the impacts such events may have on the net greenhouse gas (GHG) balances in Arctic ecosystems. We investigated in situ effects of an experimental fire in 2017 on carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2 O) surface fluxes in the most abundant tundra ecosystem in West Greenland in ambient and warmer conditions. Measurements from the growing seasons 2017 to 2019 showed that burnt areas became significant net CO2 sources for the entire study period, driven by increased ecosystem respiration (ER) immediately after the fire and decreased gross ecosystem production (GEP). Warming by open-top chambers significantly increased both ER and GEP in control, but not in burnt plots. In contrast to CO2 , measurements suggest that the overall sink capacity of atmospheric CH4 , as well as net N2 O emissions, were not affected by fire in the short term, but only immediately after the fire. The minor effects on CH4 and N2 O, which was surprising given the significantly higher nitrate availability observed in burnt plots. However, the minor effects are aligned with the lack of significant effects of fire on soil moisture and soil temperature. Net uptake and emissions of all three GHG from burnt soils were less temperature-sensitive than in the undisturbed control plots. Overall, this study highlights that wildfires in a typical tundra ecosystem in Greenland may not lead to markedly increased net GHG emissions other than CO2 . Additional investigations are needed to assess the consequences of more severe fires.
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Affiliation(s)
- Lena Hermesdorf
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| | - Bo Elberling
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| | - Ludovica D'Imperio
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
- University of Copenhagen, IGN, Section for Forest, Nature and BiomassFrederiksberg CDenmark
| | - Wenyi Xu
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| | - Anders Lambæk
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| | - Per L. Ambus
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
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13
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Abstract
Arctic shrub expansion alters carbon budgets, albedo, and warming rates in high latitudes but remains challenging to predict due to unclear underlying controls. Observational studies and models typically use relationships between observed shrub presence and current environmental suitability (bioclimate and topography) to predict shrub expansion, while omitting shrub demographic processes and non-stationary response to changing climate. Here, we use high-resolution satellite imagery across Alaska and western Canada to show that observed shrub expansion has not been controlled by environmental suitability during 1984-2014, but can only be explained by considering seed dispersal and fire. These findings provide the impetus for better observations of recruitment and for incorporating currently underrepresented processes of seed dispersal and fire in land models to project shrub expansion and climate feedbacks. Integrating these dynamic processes with projected fire extent and climate, we estimate shrubs will expand into 25% of the non-shrub tundra by 2100, in contrast to 39% predicted based on increasing environmental suitability alone. Thus, using environmental suitability alone likely overestimates and misrepresents shrub expansion pattern and its associated carbon sink.
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14
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Steketee JK, Rocha AV, Gough L, Griffin KL, Klupar I, An R, Williamson N, Rowe RJ. Small herbivores with big impacts: Tundra voles (Microtus oeconomus) alter post-fire ecosystem dynamics. Ecology 2022; 103:e3689. [PMID: 35324006 DOI: 10.1002/ecy.3689] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 10/14/2021] [Accepted: 10/28/2021] [Indexed: 11/11/2022]
Abstract
Fire is an important ecological disturbance that can reset ecosystems and initiate changes in plant community composition, ecosystem biogeochemistry, and primary productivity. Since herbivores rely on primary producers for food, changes in vegetation may alter plant-herbivore interactions with important - but often unexplored - feedbacks to ecosystems. Here we examined the impact of post-fire changes in plant community composition and structure on habitat suitability and rodent herbivore activity in response to a large, severe, and unprecedented fire in northern Alaskan tundra. In moist acidic tundra where the fire occurred, tundra voles (Microtus oeconomus) are the dominant herbivore and rely on the tussock forming sedge Eriophorum vaginatum for both food and nesting material. Seven to twelve years after the fire, tundra voles were 10 times more abundant at the burned site compared to nearby unburned tundra. Fire increased habitat suitability for voles by increasing plant productivity and biomass, food quality, and cover through both taller vegetation and increased microtopography. As a result of elevated vole abundance, Eriophorum mortality caused by vole herbivory was two orders of magnitude higher than natural mortality and approached the magnitude of the mortality rate resulting directly from the fire. These findings suggest that post-fire increases in herbivore pressure on Eriophorum could, in turn, disrupt graminoid recovery and enhance shrub encroachment. Tundra state transitions from graminoid to shrub dominated are also evident following other disturbances and fertilization experiments, suggesting that as Arctic temperatures rise, greater available nutrients and increased frequencies of large-scale disturbances may also alter plant-animal interactions with cascading impacts on plant communities and ecosystem function.
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Affiliation(s)
- Jess K Steketee
- Natural Resources and the Environment, University of New Hampshire, 114 James Hall, 56 College Road, Durham, NH, USA
| | - Adrian V Rocha
- Department of Biological Sciences and the Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Laura Gough
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Kevin L Griffin
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA.,Department of Earth and Environmental Sciences, Columbia University, Palisades, NY, USA.,Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - Ian Klupar
- Department of Biological Sciences and the Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Ruby An
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ
| | - Nicole Williamson
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Rebecca J Rowe
- Natural Resources and the Environment, University of New Hampshire, 114 James Hall, 56 College Road, Durham, NH, USA
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15
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Juselius T, Ravolainen V, Zhang H, Piilo S, Müller M, Gallego-Sala A, Väliranta M. Newly initiated carbon stock, organic soil accumulation patterns and main driving factors in the High Arctic Svalbard, Norway. Sci Rep 2022; 12:4679. [PMID: 35304558 PMCID: PMC8933566 DOI: 10.1038/s41598-022-08652-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 02/28/2022] [Indexed: 11/25/2022] Open
Abstract
High latitude organic soils form a significant carbon storage and deposition of these soils is largely driven by climate. Svalbard, Norway, has experienced millennial-scale climate variations and in general organic soil processes have benefitted from warm and humid climate phases while cool late Holocene has been unfavourable. In addition to direct effect of cool climate, the advancing glaciers have restricted the vegetation growth, thus soil accumulation. Since the early 1900's climate has been warming at unprecedented rate, assumingly promoting organic soil establishment. Here we present results of multiple organic soil profiles collected from Svalbard. The profiles have robust chronologies accompanied by soil property analyses, carbon stock estimations and testate amoeba data as a proxy for soil moisture. Our results reveal relatively recent initiation of organic soils across the Isfjorden area. The initiation processes could be linked to glacier retreat, and improvement of growing conditions and soil stabilization. Carbon stock analyses suggested that our sites are hot spots for organic matter accumulation. Testate amoebae data suggested drying of soil surfaces, but the reason remained unresolved. If continued, such a process may lead to carbon release. Our data suggest that detailed palaeoecological data from the Arctic is needed to depict the on-going processes and to estimate future trajectories.
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Affiliation(s)
- T. Juselius
- grid.7737.40000 0004 0410 2071Environmental Change Research Unit (ECRU), Ecosystems, Environment Research Programme, Faculty of Biological and Environmental Sciences, and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, Viikinkaari 1, P.O. Box 65, 00014 Helsinki, Finland
| | - V. Ravolainen
- grid.418676.a0000 0001 2194 7912Fram Centre, Norwegian Polar Institute (NPI), 9296 Tromsø, Norway
| | - H. Zhang
- grid.7737.40000 0004 0410 2071Environmental Change Research Unit (ECRU), Ecosystems, Environment Research Programme, Faculty of Biological and Environmental Sciences, and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, Viikinkaari 1, P.O. Box 65, 00014 Helsinki, Finland ,grid.9227.e0000000119573309Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - S. Piilo
- grid.7737.40000 0004 0410 2071Environmental Change Research Unit (ECRU), Ecosystems, Environment Research Programme, Faculty of Biological and Environmental Sciences, and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, Viikinkaari 1, P.O. Box 65, 00014 Helsinki, Finland
| | - M. Müller
- grid.7737.40000 0004 0410 2071Department of Geosciences and Geography, Faculty of Science, University of Helsinki, Yliopistonkatu 3, P.O. Box 4, 00014 Helsinki, Finland
| | - A. Gallego-Sala
- grid.8391.30000 0004 1936 8024Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - M. Väliranta
- grid.7737.40000 0004 0410 2071Environmental Change Research Unit (ECRU), Ecosystems, Environment Research Programme, Faculty of Biological and Environmental Sciences, and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, Viikinkaari 1, P.O. Box 65, 00014 Helsinki, Finland
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16
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Fires on Ice: Emerging Permafrost Peatlands Fire Regimes in Russia’s Subarctic Taiga. LAND 2022. [DOI: 10.3390/land11030322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Wildfires in permafrost areas, including smoldering fires (e.g., “zombie fires”), have increasingly become a concern in the Arctic and subarctic. Their detection is difficult and requires ground truthing. Local and Indigenous knowledge are becoming useful sources of information that could guide future research and wildfire management. This paper focuses on permafrost peatland fires in the Siberian subarctic taiga linked to local communities and their infrastructure. It presents the results of field studies in Evenki and old-settler communities of Tokma and Khanda in the Irkutsk region of Russia in conjunction with concurrent remote sensing data analysis. The study areas located in the discontinuous permafrost zone allow examination of the dynamics of wildfires in permafrost peatlands and adjacent forested areas. Interviews revealed an unusual prevalence and witness-observed characteristics of smoldering peatland fires over permafrost, such as longer than expected fire risk periods, impacts on community infrastructure, changes in migration of wild animals, and an increasing number of smoldering wildfires including overwintering “zombie fires” in the last five years. The analysis of concurrent satellite remote sensing data confirmed observations from communities, but demonstrated a limited capacity of satellite imagery to accurately capture changing wildfire activity in permafrost peatlands, which may have significant implications for global climate.
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17
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Xu W, Elberling B, Ambus PL. Fire increases soil nitrogen retention and alters nitrogen uptake patterns among dominant shrub species in an Arctic dry heath tundra. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150990. [PMID: 34656575 DOI: 10.1016/j.scitotenv.2021.150990] [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: 08/11/2021] [Revised: 10/11/2021] [Accepted: 10/11/2021] [Indexed: 06/13/2023]
Abstract
Climate change increases the frequency and severity of fire in the Arctic tundra regions. We assessed effects of fire in combination with summer warming on soil biogeochemical N- and P cycles with a focus on mineral N over two years following an experimental fire in a dry heath tundra, West Greenland. We applied stable isotopes (15NH4+-N and 15NO3--N) to trace the post-fire mineral N pools. The partitioning of 15N in the bulk soils, soil dissolved organic N (TDN), microbes and plants (roots and leaves) was established. The fire tended to increase microbial P pools by four-fold at both one and two years after the fire. Two years after the fire, the bulk soil 15N recovery has decreased to 10.4% in unburned plots while relatively high recovery was maintained (30%) in burned plots, suggesting an increase in soil N retention after the fire. The contribution of microbial 15N recovery to bulk soil 15N recovery increased from 11.2% at 21 days to 31.5% two years after the fire, suggesting that higher post-fire N retention was due largely to the increased incorporation of N into microbial biomass. Fire also increased 15N recovery in bulk roots after one and two years, but only under summer warming. This suggests that higher retention of post-fire N can strongly increase the potential for N uptake of recovering plants under a future warmer climate. There was significantly lower 15N enrichment of Betula nana leaves while higher 15N enrichment of Vaccinium uliginosum leaves (after three years) in burned than control plots. This shows that fire can alter the N uptake differently among dominant shrub species in this tundra ecosystem, and implies that wildfires may change plant species composition in the longer term.
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Affiliation(s)
- Wenyi Xu
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark.
| | - Bo Elberling
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark
| | - Per Lennart Ambus
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark
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18
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Chen Y, Kelly R, Genet H, Lara MJ, Chipman ML, McGuire AD, Hu FS. Resilience and sensitivity of ecosystem carbon stocks to fire-regime change in Alaskan tundra. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151482. [PMID: 34742811 DOI: 10.1016/j.scitotenv.2021.151482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
Fire disturbance has increased in some tundra ecosystems due to anthropogenic climate change, with important ramifications for terrestrial carbon cycling. Assessment of the potential impact of fire-regime change on tundra carbon stocks requires long-term perspectives because tundra fires have been rare historically. Here we integrated the process-based Dynamic Organic Soil version of the Terrestrial Ecosystem Model with paleo-fire records to evaluate the responses of tundra carbon stocks to changes in fire return interval (FRI). Paleorecords reveal that mean FRIs of tundra ecosystems in Alaska ranged from centennial to millennial timescales (200-6000 years) during the late Quaternary, but projected FRIs by 2100 decrease to a few hundred years to several decades (70-660 years). Our simulations indicate threshold effects of changing FRIs on tundra carbon stocks. Shortening FRI from 5000 to 1000 years results in minimal carbon release (<5%) from Alaskan tundra ecosystems. Rapid carbon stock loss occurs when FRI declines below 800 years trigger sustained mobilization of ancient carbon stocks from permafrost soils. However, substantial spatial heterogeneity in the resilience/sensitivity of tundra carbon stocks to FRI change exists, largely attributable to vegetation types. We identified the carbon stocks in shrub tundra as the most vulnerable to decreasing FRI because shrub tundra stores a large share of carbon in combustible biomass and organic soils. Moreover, our results suggest that ecosystems characterized by large carbon stocks and relatively long FRIs (e.g. Brooks Foothills) may transition towards hotspots of permafrost carbon emission as a response to crossing FRI thresholds in the coming decades. These findings combined imply that fire disturbance may play an increasingly important role in future carbon balance of tundra ecosystems, but the net outcome may be strongly modulated by vegetation composition.
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Affiliation(s)
- Yaping Chen
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Ryan Kelly
- UNC Health Care System, 1025 Think Place, Morrisville, NC, USA
| | - Hélène Genet
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, USA
| | - Mark Jason Lara
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Geography, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Melissa Lynn Chipman
- Department of Earth and Environmental Sciences, Syracuse University, Syracuse, NY, USA
| | - A David McGuire
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK, USA
| | - Feng Sheng Hu
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Geology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Biology, Washington University in Saint Louis, Saint Louis, MO, USA; Department of Earth and Planetary Sciences, Washington University in Saint Louis, Saint Louis, MO, USA.
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19
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OUP accepted manuscript. Bioscience 2022. [DOI: 10.1093/biosci/biac034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Rein G, Huang X. Smouldering wildfires in peatlands, forests and the arctic: Challenges and perspectives. CURRENT OPINION IN ENVIRONMENTAL SCIENCE & HEALTH 2021; 24:None. [PMID: 34950823 PMCID: PMC8660648 DOI: 10.1016/j.coesh.2021.100296] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Wildfires can be divided into two types, flaming or smouldering, depending on the dominant combustion processes. Both types are present in most wildfires, and despite being fundamentally different in chemical and physical terms, one transitions to the other. Traditionally, science has focused on flames, while smouldering is often misinterpreted. But smouldering wildfires are emerging as a global concern because they cause extensive air pollution, emit very large amounts of carbon, are difficult to detect and suppress, and could accelerate climate change. Central to the topic are smouldering peat fires that lead to the largest fires on Earth. Smouldering also dominates the residual burning after flames have died out and firebrand ignition. Finally, smouldering is an important part of Arctic wildfires, which are increasing in frequency. Here, we present a scientific overview of smouldering wildfires, the associated environmental and health issues, including climate change, and the challenges in prevention and mitigation.
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Affiliation(s)
- Guillermo Rein
- Department of Mechanical Engineering, Imperial College London, UK
| | - Xinyan Huang
- Research Centre for Fire Safety Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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21
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Lin S, Liu Y, Huang X. Climate-induced Arctic-boreal peatland fire and carbon loss in the 21st century. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 796:148924. [PMID: 34265612 DOI: 10.1016/j.scitotenv.2021.148924] [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: 03/15/2021] [Revised: 07/05/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
Boreal peatlands are increasingly vulnerable to wildfires as climate change continues accelerating. Fires consume substantial quantities of organic soils and rapidly transfer large stocks of terrestrial carbon to the atmosphere. Herein, we quantify the minimum environmental temperature from -45 °C to 45 °C that allows the moist peat to smolder, as the fire threshold of peatlands. We then apply a typical vertical soil temperature profile to estimate the future depth of burn and carbon emissions from boreal peatland fires under the impact of global warming. If the boreal region continues warming at a rate of 0.44 °C/decade, we estimate the carbon loss from the boreal peat fires on a warmer soil layer may increase from 143 Mt. in 2015 to 544 Mt. in 2100 and reach a total of 28 Gt in the 21st century. If the global human efforts successfully reduce the boreal warming rate to 0.3 °C/decade, the peat fire carbon loss would drop by 21% to 22 Gt in the 21st century. This work helps understand the vulnerability of boreal peatland to more frequent and severer wildfires driven by global warming and estimate climate-induced carbon emissions from boreal peatland fires in the 21st century.
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Affiliation(s)
- Shaorun Lin
- Research Centre for Fire Safety Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, Guangdong, China
| | - Yanhui Liu
- Research Centre for Fire Safety Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Xinyan Huang
- Research Centre for Fire Safety Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
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22
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Xu W, Lambæk A, Holm SS, Furbo-Halken A, Elberling B, Ambus PL. Effects of experimental fire in combination with climate warming on greenhouse gas fluxes in Arctic tundra soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 795:148847. [PMID: 34246149 DOI: 10.1016/j.scitotenv.2021.148847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
The frequency and severity of fire is increasing in Arctic tundra regions with climate change. Here we investigated effects of experimental low-intensity fire and shrub cutting, in combination with warming, on soil biogeochemical cycles and post-fire greenhouse gas (GHG) emissions in a dry heath tundra, West Greenland. We performed in vitro incubation experiments based on soil samples collected for up to two years after the fire. We observed tendency for increased soil nitrate (14-fold) and significant increases in soil ammonium and phosphate (four-fold and five-fold, respectively) two years after the fire, but no effects of shrub cutting on these compounds. Thus, changes appear to be largely due to fire effects rather than indirect effects by vegetation destruction. Two years after fire, nitrous oxide (N2O) and carbon dioxide (CO2) production was significantly increased (three-fold and 32% higher, respectively), in burned than unburned soils, while methane (CH4) uptake remained unchanged. This stimulated N2O and CO2 production by the fire, however, was only apparent under conditions when soil was at maximum water holding capacity, suggesting that fire effects can be masked under dry conditions in this tundra ecosystem. There were positive effects by modest 2.5 °C warming on CO2 production in control but not in burned soils, suggesting that fire may decrease the temperature response in soil respiration. Methane uptake was neither altered by the modest warming in shrub-cut nor in burned soils after two years, suggesting that the removal of vegetation may play a key role in controlling future temperature response of CH4 oxidation. Altogether, our results show that post-fire tundra soils have the potential to enhance soil GHG emissions (e.g. N2O and CO2) especially during episodes with wet soil conditions. On the other hand, the lack of warming responses in post-fire soil respiration may weaken this positive feedback to climate change.
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Affiliation(s)
- Wenyi Xu
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark.
| | - Anders Lambæk
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark
| | - Signe Skjold Holm
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark
| | - Annesofie Furbo-Halken
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark
| | - Bo Elberling
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark
| | - Per Lennart Ambus
- Center for Permafrost, Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark
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23
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Kharuk VI, Ponomarev EI, Ivanova GA, Dvinskaya ML, Coogan SCP, Flannigan MD. Wildfires in the Siberian taiga. AMBIO 2021; 50:1953-1974. [PMID: 33512668 PMCID: PMC8497666 DOI: 10.1007/s13280-020-01490-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/12/2020] [Accepted: 12/16/2020] [Indexed: 05/09/2023]
Abstract
The majority of area burned by wildfire are located in Siberia. Mainly low-intensity surface fires occur in larch forests, whereas in evergreen forests both surface and crown fires are observed. Warming has led to an increase in the frequency and area of wildfires that have reached the Arctic Ocean shore. However, wildfires are the most important factor in taiga dynamics; larch and Scots pine have evolved under conditions of periodic forest fires, thereby gaining a competitive advantage over non-fire adapted species; in the permafrost zone, periodic fires are a prerequisite for the dominance of larch. Wildfires support ecosystem health, biodiversity, and conservation; periodic wildfires decrease the danger of catastrophic wildfires. With an amplified rate of increase in fires, it is necessary to focus fire suppression on areas of high social, natural, and economic value, while allowing a greater number of wildfires to burn in the vast Siberian forest landscapes.
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Affiliation(s)
- Viacheslav I. Kharuk
- Sukachev Institute of Forests, Federal Research Center, Russian Academy of Science, Siberian Branch, Academgorodok 50/28, Krasnoyarsk, Russia 660036
- Siberian Federal University, Svobodny str.79, Krasnoyarsk, Russia 660041
| | - Evgenii I. Ponomarev
- Sukachev Institute of Forests, Federal Research Center, Russian Academy of Science, Siberian Branch, Academgorodok 50/28, Krasnoyarsk, Russia 660036
- Siberian Federal University, Svobodny str.79, Krasnoyarsk, Russia 660041
| | - Galina A. Ivanova
- Sukachev Institute of Forests, Federal Research Center, Russian Academy of Science, Siberian Branch, Academgorodok 50/28, Krasnoyarsk, Russia 660036
| | - Maria L. Dvinskaya
- Sukachev Institute of Forests, Federal Research Center, Russian Academy of Science, Siberian Branch, Academgorodok 50/28, Krasnoyarsk, Russia 660036
| | - Sean C. P. Coogan
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2H1 Canada
| | - Mike D. Flannigan
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2H1 Canada
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24
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Walker XJ, Howard BK, Jean M, Johnstone JF, Roland C, Rogers BM, Schuur EAG, Solvik KK, Mack MC. Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone. PLoS One 2021; 16:e0258558. [PMID: 34710129 PMCID: PMC8553150 DOI: 10.1371/journal.pone.0258558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/29/2021] [Indexed: 11/18/2022] Open
Abstract
Wildfire frequency and extent is increasing throughout the boreal forest-tundra ecotone as climate warms. Understanding the impacts of wildfire throughout this ecotone is required to make predictions of the rate and magnitude of changes in boreal-tundra landcover, its future flammability, and associated feedbacks to the global carbon (C) cycle and climate. We studied 48 sites spanning a gradient from tundra to low-density spruce stands that were burned in an extensive 2013 wildfire on the north slope of the Alaska Range in Denali National Park and Preserve, central Alaska. We assessed wildfire severity and C emissions, and determined the impacts of severity on understory vegetation composition, conifer tree recruitment, and active layer thickness (ALT). We also assessed conifer seed rain and used a seeding experiment to determine factors controlling post-fire tree regeneration. We found that an average of 2.18 ± 1.13 Kg C m-2 was emitted from this fire, almost 95% of which came from burning of the organic soil. On average, burn depth of the organic soil was 10.6 ± 4.5 cm and both burn depth and total C combusted increased with pre-fire conifer density. Sites with higher pre-fire conifer density were also located at warmer and drier landscape positions and associated with increased ALT post-fire, greater changes in pre- and post-fire understory vegetation communities, and higher post-fire boreal tree recruitment. Our seed rain observations and seeding experiment indicate that the recruitment potential of conifer trees is limited by seed availability in this forest-tundra ecotone. We conclude that the expected climate-induced forest infilling (i.e. increased density) at the forest-tundra ecotone could increase fire severity, but this infilling is unlikely to occur without increases in the availability of viable seed.
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Affiliation(s)
- Xanthe J. Walker
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Brain K. Howard
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Mélanie Jean
- Département de biologie, Université de Moncton, Moncton, New Brunswick, Canada
| | - Jill F. Johnstone
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States of America
| | - Carl Roland
- National Park Service, Central Alaska Network, Fairbanks, AK, United States of America
| | - Brendan M. Rogers
- Woodwell Climate Research Center, Falmouth, Massachusetts, United States of America
| | - Edward A. G. Schuur
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Kylen K. Solvik
- Woodwell Climate Research Center, Falmouth, Massachusetts, United States of America
| | - Michelle C. Mack
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States of America
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25
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Michaelides RJ, Bryant MB, Siegfried MR, Borsa AA. Quantifying Surface-Height Change Over a Periglacial Environment With ICESat-2 Laser Altimetry. EARTH AND SPACE SCIENCE (HOBOKEN, N.J.) 2021; 8:e2020EA001538. [PMID: 34595326 PMCID: PMC8459227 DOI: 10.1029/2020ea001538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/09/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
We use Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) laser altimetry crossovers and repeat tracks collected over the North Slope of Alaska to estimate ground surface-height change due to the seasonal freezing and thawing of the active layer. We compare these measurements to a time series of surface deformation from Sentinel-1 interferometric synthetic aperture radar (InSAR) and demonstrate agreement between these independent observations of surface deformation at broad spatial scales. We observe a relationship between ICESat-2-derived surface subsidence/uplift and changes in normalized accumulated degree days, which is consistent with the thermodynamically driven seasonal freezing and thawing of the active layer. Integrating ICESat-2 crossover estimates of surface-height change yields an annual time series of surface-height change that is sensitive to changes in snow cover during spring and thawing of the active layer throughout spring and summer. Furthermore, this time series exhibits temporal correlation with independent reanalysis datasets of temperature and snow cover, as well as an InSAR-derived time series. ICESat-2-derived surface-height change estimates can be significantly affected by short length-scale topographic gradients and changes in snow cover and snow depth. We discuss optimal strategies of post-processing ICESat-2 data for permafrost applications, as well as the future potential of joint ICESat-2 and InSAR investigations of permafrost surface-dynamics.
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Affiliation(s)
| | - M. B. Bryant
- Institute of Geophysics and Planetary PhysicsScripps Institution of OceanographyUniversity of California San DiegoLa JollaCAUSA
| | | | - A. A. Borsa
- Institute of Geophysics and Planetary PhysicsScripps Institution of OceanographyUniversity of California San DiegoLa JollaCAUSA
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26
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Klupar I, Rocha AV, Rastetter EB. Alleviation of nutrient co-limitation induces regime shifts in post-fire community composition and productivity in Arctic tundra. GLOBAL CHANGE BIOLOGY 2021; 27:3324-3335. [PMID: 33960082 DOI: 10.1111/gcb.15646] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 03/21/2021] [Indexed: 06/12/2023]
Abstract
Recent unprecedented fires in the Arctic during the past two decades have indicated a pressing need to understand the long-term ecological impacts of fire in this biome. Anecdotal evidence suggests that tundra fires can induce regime shifts that change tussock tundra to more shrub-dominated ecosystems. However, the ecological mechanisms regulating these shifts are poorly understood, but are hypothesized to involve changes to nutrient availability in this nutrient limited system. Here we conducted a 4-year two-factorial (control: C, nitrogen along: N+ , phosphorus alone: P+ , nitrogen and phosphorus combined: NP+ ) fertilization experiment in both unburned and burned tundra to test this hypothesis after a decade of post-fire recovery. A decade after fire, the burned site exhibited an increase in soil nitrogen and phosphorus availability and a transition toward taller, more productive, and more deciduous vegetation. This shift in vegetation structure, composition, and function was induced at the unburned site through the addition of both NP+ and the alleviation of their co-limitation. Both burned and unburned tundra responded similarly to fertilizer treatments by increasing leaf area index, greenness, and canopy height in NP+ treatments, and exhibited no significant response in individual N+ or P+ treatments. These results point to a greater need to understand coupled carbon, nitrogen, and phosphorus cycles in this system, and suggest that post-fire regime shifts are regulated by the alleviation of nitrogen and phosphorus co-limitation in Arctic tundra.
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Affiliation(s)
- Ian Klupar
- Department of Biological Sciences and the Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Adrian V Rocha
- Department of Biological Sciences and the Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Edward B Rastetter
- Marine Biological Laboratory, The Ecosystems Center, Woods Hole, MA, USA
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27
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Abbott BW, Rocha AV, Shogren A, Zarnetske JP, Iannucci F, Bowden WB, Bratsman SP, Patch L, Watts R, Fulweber R, Frei RJ, Huebner AM, Ludwig SM, Carling GT, O'Donnell JA. Tundra wildfire triggers sustained lateral nutrient loss in Alaskan Arctic. GLOBAL CHANGE BIOLOGY 2021; 27:1408-1430. [PMID: 33394532 DOI: 10.1111/gcb.15507] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/13/2020] [Indexed: 06/12/2023]
Abstract
Climate change is creating widespread ecosystem disturbance across the permafrost zone, including a rapid increase in the extent and severity of tundra wildfire. The expansion of this previously rare disturbance has unknown consequences for lateral nutrient flux from terrestrial to aquatic environments. Lateral loss of nutrients could reduce carbon uptake and slow recovery of already nutrient-limited tundra ecosystems. To investigate the effects of tundra wildfire on lateral nutrient export, we analyzed water chemistry in and around the 10-year-old Anaktuvuk River fire scar in northern Alaska. We collected water samples from 21 burned and 21 unburned watersheds during snowmelt, at peak growing season, and after plant senescence in 2017 and 2018. After a decade of ecosystem recovery, aboveground biomass had recovered in burned watersheds, but overall carbon and nitrogen remained ~20% lower, and the active layer remained ~10% deeper. Despite lower organic matter stocks, dissolved organic nutrients were substantially elevated in burned watersheds, with higher flow-weighted concentrations of organic carbon (25% higher), organic nitrogen (59% higher), organic phosphorus (65% higher), and organic sulfur (47% higher). Geochemical proxies indicated greater interaction with mineral soils in watersheds with surface subsidence, but optical analysis and isotopes suggested that recent plant growth, not mineral soil, was the main source of organic nutrients in burned watersheds. Burned and unburned watersheds had similar δ15 N-NO3 - , indicating that exported nitrogen was of preburn origin (i.e., not recently fixed). Lateral nitrogen flux from burned watersheds was 2- to 10-fold higher than rates of background nitrogen fixation and atmospheric deposition estimated in this area. These findings indicate that wildfire in Arctic tundra can destabilize nitrogen, phosphorus, and sulfur previously stored in permafrost via plant uptake and leaching. This plant-mediated nutrient loss could exacerbate terrestrial nutrient limitation after disturbance or serve as an important nutrient release mechanism during succession.
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Affiliation(s)
- Benjamin W Abbott
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Adrian V Rocha
- Department of Biological Sciences & the Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Arial Shogren
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA
| | - Jay P Zarnetske
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA
| | - Frances Iannucci
- Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - William B Bowden
- Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA
| | - Samuel P Bratsman
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Leika Patch
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Rachel Watts
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Randy Fulweber
- Toolik GIS, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Rebecca J Frei
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - Amanda M Huebner
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, USA
| | - Sarah M Ludwig
- Department of Earth and Environmental Science, Columbia University, NY, NY, USA
| | - Gregory T Carling
- Department of Geological Sciences, Brigham Young University, Provo, UT, USA
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Heim RJ, Bucharova A, Brodt L, Kamp J, Rieker D, Soromotin AV, Yurtaev A, Hölzel N. Post-fire vegetation succession in the Siberian subarctic tundra over 45 years. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 760:143425. [PMID: 33172629 DOI: 10.1016/j.scitotenv.2020.143425] [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: 07/28/2020] [Revised: 10/28/2020] [Accepted: 10/28/2020] [Indexed: 06/11/2023]
Abstract
Wildfires are relatively rare in subarctic tundra ecosystems, but they can strongly change ecosystem properties. Short-term fire effects on subarctic tundra vegetation are well documented, but long-term vegetation recovery has been studied less. The frequency of tundra fires will increase with climate warming. Understanding the long-term effects of fire is necessary to predict future ecosystem changes. We used a space-for-time approach to assess vegetation recovery after fire over more than four decades. We studied soil and vegetation patterns on three large fire scars (>44, 28 and 12 years old) in dry, lichen-dominated forest tundra in Western Siberia. On 60 plots, we determined soil temperature and permafrost thaw depth, sampled vegetation and measured plant functional traits. We assessed trends in Normalized Difference Vegetation Index (NDVI) to support the field-based results on vegetation recovery. Soil temperature, permafrost thaw depth and total vegetation cover had recovered to pre-fire levels after >44 years, as well as total vegetation cover. In contrast, after >44 years, functional groups had not recovered to the pre-fire state. Burnt areas had lower lichen and higher bryophyte and shrub cover. The dominating shrub species, Betula nana, exhibited a higher vitality (higher specific leaf area and plant height) on burnt compared with control plots, suggesting a fire legacy effect in shrub growth. Our results confirm patterns of shrub encroachment after fire that were detected before in other parts of the Arctic and Subarctic. In the so far poorly studied Western Siberian forest tundra we demonstrate for the first time, long-term fire-legacies on the functional composition of relatively dry shrub- and lichen-dominated vegetation.
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Affiliation(s)
- Ramona J Heim
- Institute of Landscape Ecology, University of Münster, Heisenbergstraße 2, 48149 Münster, Germany.
| | - Anna Bucharova
- Institute of Landscape Ecology, University of Münster, Heisenbergstraße 2, 48149 Münster, Germany
| | - Leya Brodt
- Research Institute of Ecology and Natural Resources Management, Tyumen State University, 6 Volodarskogo Street, Tyumen, Russia
| | - Johannes Kamp
- Institute of Landscape Ecology, University of Münster, Heisenbergstraße 2, 48149 Münster, Germany; Department of Conservation Biology, University of Göttingen, Bürgerstr. 50, 37073 Göttingen, Germany
| | - Daniel Rieker
- Institute of Landscape Ecology, University of Münster, Heisenbergstraße 2, 48149 Münster, Germany; Institute of Ecology, Diversity and Evolution, Goethe University Frankfurt/Main, 60438 Frankfurt am Main, Germany
| | - Andrey V Soromotin
- Research Institute of Ecology and Natural Resources Management, Tyumen State University, 6 Volodarskogo Street, Tyumen, Russia
| | - Andrey Yurtaev
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, 6 Volodarskogo Street, Tyumen, Russia
| | - Norbert Hölzel
- Institute of Landscape Ecology, University of Münster, Heisenbergstraße 2, 48149 Münster, Germany
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29
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Chen Y, Hu FS, Lara MJ. Divergent shrub-cover responses driven by climate, wildfire, and permafrost interactions in Arctic tundra ecosystems. GLOBAL CHANGE BIOLOGY 2021; 27:652-663. [PMID: 33216446 DOI: 10.1111/gcb.15451] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/26/2020] [Accepted: 11/14/2020] [Indexed: 05/22/2023]
Abstract
The expansion of shrubs across the Arctic tundra may fundamentally modify land-atmosphere interactions. However, it remains unclear how shrub expansion pattern is linked with key environmental drivers, such as climate change and fire disturbance. Here we used 40+ years of high-resolution (~1.0 m) aerial and satellite imagery to estimate shrub-cover change in 114 study sites across four burned and unburned upland (ice-poor) and lowland (ice-rich) tundra ecosystems in northern Alaska. Validated with data from four additional upland and lowland tundra fires, our results reveal that summer precipitation was the most important climatic driver (r = 0.67, p < 0.001), responsible for 30.8% of shrub expansion in the upland tundra between 1971 and 2016. Shrub expansion in the uplands was largely enhanced by wildfire (p < 0.001) and it exhibited positive correlation with fire severity (r = 0.83, p < 0.001). Three decades after fire disturbance, the upland shrub cover increased by 1077.2 ± 83.6 m2 ha-1 , ~7 times the amount identified in adjacent unburned upland tundra (155.1 ± 55.4 m2 ha-1 ). In contrast, shrub cover markedly decreased in lowland tundra after fire disturbance, which triggered thermokarst-associated water impounding and resulted in 52.4% loss of shrub cover over three decades. No correlation was found between lowland shrub cover with fire severity (r = 0.01). Mean summer air temperature (MSAT) was the principal factor driving lowland shrub-cover dynamics between 1951 and 2007. Warmer MSAT facilitated shrub expansion in unburned lowlands (r = 0.78, p < 0.001), but accelerated shrub-cover losses in burned lowlands (r = -0.82, p < 0.001). These results highlight divergent pathways of shrub-cover responses to fire disturbance and climate change, depending on near-surface permafrost and drainage conditions. Our study offers new insights into the land-atmosphere interactions as climate warming and burning intensify in high latitudes.
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Affiliation(s)
- Yaping Chen
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Feng Sheng Hu
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Geology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Biology, Washington University in Saint Louis, Saint Louis, MO, USA
- Department of Earth and Planetary Sciences, Washington University in Saint Louis, Saint Louis, MO, USA
| | - Mark J Lara
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Geography, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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30
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Berner LT, Massey R, Jantz P, Forbes BC, Macias-Fauria M, Myers-Smith I, Kumpula T, Gauthier G, Andreu-Hayles L, Gaglioti BV, Burns P, Zetterberg P, D'Arrigo R, Goetz SJ. Summer warming explains widespread but not uniform greening in the Arctic tundra biome. Nat Commun 2020; 11:4621. [PMID: 32963240 PMCID: PMC7509805 DOI: 10.1038/s41467-020-18479-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 08/25/2020] [Indexed: 11/16/2022] Open
Abstract
Arctic warming can influence tundra ecosystem function with consequences for climate feedbacks, wildlife and human communities. Yet ecological change across the Arctic tundra biome remains poorly quantified due to field measurement limitations and reliance on coarse-resolution satellite data. Here, we assess decadal changes in Arctic tundra greenness using time series from the 30 m resolution Landsat satellites. From 1985 to 2016 tundra greenness increased (greening) at ~37.3% of sampling sites and decreased (browning) at ~4.7% of sampling sites. Greening occurred most often at warm sampling sites with increased summer air temperature, soil temperature, and soil moisture, while browning occurred most often at cold sampling sites that cooled and dried. Tundra greenness was positively correlated with graminoid, shrub, and ecosystem productivity measured at field sites. Our results support the hypothesis that summer warming stimulated plant productivity across much, but not all, of the Arctic tundra biome during recent decades.
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Affiliation(s)
- Logan T Berner
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA.
| | - Richard Massey
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Patrick Jantz
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Bruce C Forbes
- Arctic Centre, University of Lapland, 96101, Rovaniemi, Finland
| | - Marc Macias-Fauria
- School of Geography and the Environment, University of Oxford, Oxford, OX1 3QF, UK
| | - Isla Myers-Smith
- School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Timo Kumpula
- Department of Geographical and Historical Studies, University of Eastern Finland, 80101, Joensuu, Finland
| | - Gilles Gauthier
- Department of Biology and Centre d'études nordiques, Université Laval, Quebec City, QC, G1V0A6, Canada
| | - Laia Andreu-Hayles
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA
| | - Benjamin V Gaglioti
- Water and Environment Research Center, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Patrick Burns
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Pentti Zetterberg
- Department of Forest Sciences, University of Eastern Finland, 80101, Joensuu, Finland
| | - Rosanne D'Arrigo
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA
| | - Scott J Goetz
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA
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Abstract
AbstractArctic and subarctic ecosystems are changing rapidly in species composition and functioning as they warm twice as fast as the global average. It has been suggested that tree-less boreal landscapes may shift abruptly to tree-dominated states as climate warms. Yet, we insufficiently understand the conditions and mechanisms underlying tree establishment in the subarctic and arctic regions to anticipate how climate change may further affect ecosystem structure and functioning. We conducted a field experiment to assess the role of permafrost presence, micro-topography and shrub canopy on tree establishment in almost tree-less subarctic peatlands of northern Finland. We introduced seeds and seedlings of four tree-line species and monitored seedling survival and environmental conditions for six growing seasons. Our results show that once seedlings have emerged, the absence of permafrost can enhance early tree seedling survival, but shrub cover is the most important driver of subsequent tree seedling survival in subarctic peatlands. Tree seedling survival was twice as high under an intact shrub canopy than in open conditions after shrub canopy removal. Under unclipped control conditions, seedling survival was positively associated with dense shrub canopies for half of the tree species studied. These strong positive interactions between shrubs and trees may facilitate the transition from today’s treeless subarctic landscapes towards tree-dominated states. Our results suggest that climate warming may accelerate this vegetation shift as permafrost is lost, and shrubs further expand across the subarctic.
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32
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Bishop K, Shanley JB, Riscassi A, de Wit HA, Eklöf K, Meng B, Mitchell C, Osterwalder S, Schuster PF, Webster J, Zhu W. Recent advances in understanding and measurement of mercury in the environment: Terrestrial Hg cycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 721:137647. [PMID: 32197286 DOI: 10.1016/j.scitotenv.2020.137647] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/23/2020] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
This review documents recent advances in terrestrial mercury cycling. Terrestrial mercury (Hg) research has matured in some areas, and is developing rapidly in others. We summarize the state of the science circa 2010 as a starting point, and then present the advances during the last decade in three areas: land use, sulfate deposition, and climate change. The advances are presented in the framework of three Hg "gateways" to the terrestrial environment: inputs from the atmosphere, uptake in food, and runoff with surface water. Among the most notable advances: These and other advances reported here are of value in evaluating the effectiveness of the Minamata Convention on reducing environmental Hg exposure to humans and wildlife.
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Affiliation(s)
- Kevin Bishop
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden.
| | | | - Ami Riscassi
- Department of Environmental Sciences, University of Virginia, P.O. Box 400123, Charlottesville, VA 22904-4123, USA.
| | - Heleen A de Wit
- Norwegian Institute for Water Research, Gaustadalléen 21, NO-0349, Norway.
| | - Karin Eklöf
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden.
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
| | - Carl Mitchell
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada.
| | - Stefan Osterwalder
- Institut des Géosciences de l'Environnement, Université Grenoble Alpes, CNRS, IRD, Grenoble 18 INP, 38000 Grenoble, France.
| | - Paul F Schuster
- U.S. Geological Survey, 3215 Marine Street, Suite E-127, Boulder, CO 80303-1066, USA.
| | - Jackson Webster
- Department of Civil Engineering, California State University, 400 W. 1st Street, 21 95929-0930 Chico, CA, USA.
| | - Wei Zhu
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden.
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33
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Hoecker TJ, Higuera PE, Kelly R, Hu FS. Arctic and boreal paleofire records reveal drivers of fire activity and departures from Holocene variability. Ecology 2020; 101:e03096. [PMID: 32386341 DOI: 10.1002/ecy.3096] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 01/09/2020] [Accepted: 03/30/2020] [Indexed: 11/06/2022]
Abstract
Boreal forest and tundra biomes are key components of the Earth system because the mobilization of large carbon stocks and changes in energy balance could act as positive feedbacks to ongoing climate change. In Alaska, wildfire is a primary driver of ecosystem structure and function, and a key mechanism coupling high-latitude ecosystems to global climate. Paleoecological records reveal sensitivity of fire regimes to climatic and vegetation change over centennial-millennial time scales, highlighting increased burning concurrent with warming or elevated landscape flammability. To quantify spatiotemporal patterns in fire-regime variability, we synthesized 27 published sediment-charcoal records from four Alaskan ecoregions, and compared patterns to paleoclimate and paleovegetation records. Biomass burning and fire frequency increased significantly in boreal forest ecoregions with the expansion of black spruce, ca. 6,000-4,000 years before present (yr BP). Biomass burning also increased during warm periods, particularly in the Yukon Flats ecoregion from ca. 1,000 to 500 yr BP. Increases in biomass burning concurrent with constant fire return intervals suggest increases in average fire severity (i.e., more biomass burning per fire) during warm periods. Results also indicate increases in biomass burning over the last century across much of Alaska that exceed Holocene maxima, providing important context for ongoing change. Our analysis documents the sensitivity of fire activity to broad-scale environmental change, including climate warming and biome-scale shifts in vegetation. The lack of widespread, prolonged fire synchrony suggests regional heterogeneity limited simultaneous fire-regime change across our study areas during the Holocene. This finding implies broad-scale resilience of the boreal forest to extensive fire activity, but does not preclude novel responses to 21st-century changes. If projected increases in fire activity over the 21st century are realized, they would be unprecedented in the context of the last 8,000 yr or more.
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Affiliation(s)
- Tyler J Hoecker
- Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, 59812, USA
| | - Philip E Higuera
- Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, 59812, USA
| | - Ryan Kelly
- UNC Health Care System, 1025 Think Place, Morrisville, North Carolina, 27560, USA
| | - Feng Sheng Hu
- Department of Plant Biology, University of Illinois, Urbana, Illinois, 61801, USA.,Department of Geology, University of Illinois, Urbana, Illinois, 61801, USA
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34
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Ravolainen V, Soininen EM, Jónsdóttir IS, Eischeid I, Forchhammer M, van der Wal R, Pedersen ÅØ. High Arctic ecosystem states: Conceptual models of vegetation change to guide long-term monitoring and research. AMBIO 2020; 49:666-677. [PMID: 31955396 PMCID: PMC6989444 DOI: 10.1007/s13280-019-01310-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 12/03/2019] [Accepted: 12/13/2019] [Indexed: 05/26/2023]
Abstract
Vegetation change has consequences for terrestrial ecosystem structure and functioning and may involve climate feedbacks. Hence, when monitoring ecosystem states and changes thereof, the vegetation is often a primary monitoring target. Here, we summarize current understanding of vegetation change in the High Arctic-the World's most rapidly warming region-in the context of ecosystem monitoring. To foster development of deployable monitoring strategies, we categorize different kinds of drivers (disturbances or stresses) of vegetation change either as pulse (i.e. drivers that occur as sudden and short events, though their effects may be long lasting) or press (i.e. drivers where change in conditions remains in place for a prolonged period, or slowly increases in pressure). To account for the great heterogeneity in vegetation responses to climate change and other drivers, we stress the need for increased use of ecosystem-specific conceptual models to guide monitoring and ecological studies in the Arctic. We discuss a conceptual model with three hypothesized alternative vegetation states characterized by mosses, herbaceous plants, and bare ground patches, respectively. We use moss-graminoid tundra of Svalbard as a case study to discuss the documented and potential impacts of different drivers on the possible transitions between those states. Our current understanding points to likely additive effects of herbivores and a warming climate, driving this ecosystem from a moss-dominated state with cool soils, shallow active layer and slow nutrient cycling to an ecosystem with warmer soil, deeper permafrost thaw, and faster nutrient cycling. Herbaceous-dominated vegetation and (patchy) bare ground would present two states in response to those drivers. Conceptual models are an operational tool to focus monitoring efforts towards management needs and identify the most pressing scientific questions. We promote greater use of conceptual models in conjunction with a state-and-transition framework in monitoring to ensure fit for purpose approaches. Defined expectations of the focal systems' responses to different drivers also facilitate linking local and regional monitoring efforts to international initiatives, such as the Circumpolar Biodiversity Monitoring Program.
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Affiliation(s)
- Virve Ravolainen
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway.
- Norwegian Polar Institute, Fram Centre, 9062, Tromsø, Norway.
| | | | - Ingibjörg Svala Jónsdóttir
- University of Iceland, 101, Reykjavik, Iceland
- The University Centre in Svalbard, 9171, Longyearbyen, Norway
| | - Isabell Eischeid
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway
- UiT, The Arctic University of Norway, 9037, Tromsø, Norway
| | - Mads Forchhammer
- The University Centre in Svalbard, 9171, Longyearbyen, Norway
- The Centre for Macroecology, Evolution and Climate (CMEC) and Greenland Perspective (GP), Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - René van der Wal
- Department of Ecology, Swedish University of Agricultural Sciences (SLU), Ulls väg 16, 75651, Uppsala, Sweden
- University of Aberdeen, AB24 3UU, Aberdeen, Scotland
| | - Åshild Ø Pedersen
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway
- Norwegian Polar Institute, Fram Centre, 9062, Tromsø, Norway
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Alvarez J, Yumashev D, Whiteman G. A framework for assessing the economic impacts of Arctic change. AMBIO 2020; 49:407-418. [PMID: 31236784 PMCID: PMC6965338 DOI: 10.1007/s13280-019-01211-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 05/20/2019] [Accepted: 06/03/2019] [Indexed: 05/29/2023]
Abstract
The scientific literature on physical changes in the Arctic region driven by climate change is extensive. In addition, the emerging understanding of physical feedbacks and teleconnections between the Arctic and the rest of the world suggests that the warming in the Arctic region is likely to cause impacts that extend well beyond the region itself. However, there is only limited research on how Arctic change may affect economies and individual industry sectors around the world. We argue that there is a pressing need for more research on this topic and present a conceptual framework to guide future research for assessing the regional and global economic impacts of Arctic change, including both possible benefits and costs. We stress on the importance of a transdisciplinary approach, which includes an integration of the natural sciences, economics and social sciences, as well as engagement with a wide range of stakeholders to better understand and manage the implications of Arctic change.
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Affiliation(s)
- Jimena Alvarez
- Pentland Centre for Sustainability in Business, Lancaster University, Lancaster, LA1 4YX UK
- Salguero 3055, 1425, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Dmitry Yumashev
- Pentland Centre for Sustainability in Business, Lancaster University, Lancaster, LA1 4YX UK
| | - Gail Whiteman
- Pentland Centre for Sustainability in Business, Lancaster University, Lancaster, LA1 4YX UK
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Kim JS, Kug JS, Jeong SJ, Park H, Schaepman-Strub G. Extensive fires in southeastern Siberian permafrost linked to preceding Arctic Oscillation. SCIENCE ADVANCES 2020; 6:eaax3308. [PMID: 31934623 PMCID: PMC6949040 DOI: 10.1126/sciadv.aax3308] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 11/07/2019] [Indexed: 06/10/2023]
Abstract
Carbon release through boreal fires could considerably accelerate Arctic warming; however, boreal fire occurrence mechanisms and dynamics remain largely unknown. Here, we analyze fire activity and relevant large-scale atmospheric conditions over southeastern Siberia, which has the largest burned area fraction in the circumboreal and high-level carbon emissions due to high-density peatlands. It is found that the annual burned area increased when a positive Arctic Oscillation (AO) takes place in early months of the year, despite peak fire season occurring 1 to 2 months later. A local high-pressure system linked to the AO drives a high-temperature anomaly in late winter, causing premature snowmelt. This causes earlier ground surface exposure and drier ground in spring due to enhanced evaporation, promoting fire spreading. Recently, southeastern Siberia has experienced warming and snow retreat; therefore, southeastern Siberia requires appropriate fire management strategies to prevent massive carbon release and accelerated global warming.
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Affiliation(s)
- Jin-Soo Kim
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
- National Centre for Earth Observation, University of Edinburgh, Edinburgh, UK
| | - Jong-Seong Kug
- Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea
| | - Su-Jong Jeong
- Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul, South Korea
- Institute for Sustainable Development (ISD), Seoul National University, Seoul, South Korea
| | - Hotaek Park
- Institute of Arctic Climate and Environmental Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Gabriela Schaepman-Strub
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
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Using Long-Term SAR Backscatter Data to Monitor Post-Fire Vegetation Recovery in Tundra Environment. REMOTE SENSING 2019. [DOI: 10.3390/rs11192230] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Wildfires could have a strong impact on tundra environment by combusting surface vegetation and soil organic matter. For surface vegetation, many years are required to recover to pre-fire level. In this paper, by using C-band (VV/HV polarization) and L-band (HH polarization) synthetic aperture radar (SAR) images acquired before and after fire from 2002 to 2016, we investigated vegetation change affected by the Anaktuvuk River Fire in Arctic tundra environment. Compared to the unburned areas, C- and L-band SAR backscatter coefficients increased by up to 5.5 and 4.4 dB in the severely burned areas after the fire. Then past 5 years following the fire, the C-band SAR backscatter differences decreased to pre-fire level between the burned and unburned areas, suggesting that vegetation coverage in burned sites had recovered to the unburned level. This duration is longer than the 3-year recovery suggested by optical-based Normalized Difference Vegetation Index (NDVI) observations. While for the L-band SAR backscatter after 10-year recovery, about 2 dB higher was still found in the severely burned area, compared to the unburned area. The increased roughness of the surface is probably the reason for such sustained differences. Our analysis implies that long records of space-borne SAR backscatter can monitor post-fire vegetation recovery in Arctic tundra environment and complement optical observations.
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Mekonnen ZA, Riley WJ, Randerson JT, Grant RF, Rogers BM. Expansion of high-latitude deciduous forests driven by interactions between climate warming and fire. NATURE PLANTS 2019; 5:952-958. [PMID: 31451797 DOI: 10.1038/s41477-019-0495-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 07/16/2019] [Indexed: 05/12/2023]
Abstract
High-latitude regions have experienced rapid warming in recent decades, and this trend is projected to continue over the twenty-first century1. Fire is also projected to increase with warming2,3. We show here, consistent with changes during the Holocene4, that changes in twenty-first century climate and fire are likely to alter the composition of Alaskan boreal forests. We hypothesize that competition for nutrients after fire in early succession and for light in late succession in a warmer climate will cause shifts in plant functional type. Consistent with observations, our ecosystem model predicts evergreen conifers to be the current dominant tree type in Alaska. However, under future climate and fire, our analysis suggests the relative dominance of deciduous broadleaf trees nearly doubles, accounting for 58% of the Alaska ecosystem's net primary productivity by 2100, with commensurate declines in contributions from evergreen conifer trees and herbaceous plants. Post-fire deciduous broadleaf tree growth under a future climate is sustained from enhanced microbial nitrogen mineralization caused by warmer soils and deeper active layers, resulting in taller trees that compete more effectively for light. The expansion of deciduous broadleaf forests will affect the carbon cycle, surface energy fluxes and ecosystem function, thereby modifying important feedbacks with the climate system.
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Affiliation(s)
- Zelalem A Mekonnen
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - William J Riley
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James T Randerson
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - Robert F Grant
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
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Increasing wildfires threaten historic carbon sink of boreal forest soils. Nature 2019; 572:520-523. [DOI: 10.1038/s41586-019-1474-y] [Citation(s) in RCA: 187] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 07/03/2019] [Indexed: 11/08/2022]
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Patterns of Arctic Tundra Greenness Based on Spatially Downscaled Solar-Induced Fluorescence. REMOTE SENSING 2019. [DOI: 10.3390/rs11121460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A general greening trend in the Arctic tundra biome has been indicated by satellite remote sensing data over recent decades. However, since 2011, there have been signs of browning trends in many parts of the region. Previous research on tundra greenness across the Arctic region has relied on the satellite-derived normalized difference vegetation index (NDVI). In this research, we initially used spatially downscaled solar-induced fluorescence (SIF) data to analyze the spatiotemporal variation of Arctic tundra greenness (2007–2013). The results derived from the SIF data were also compared with those from two NDVIs (the Global Inventory Modeling and Mapping Studies NDVI3g and MOD13Q1 NDVI), and the eddy-covariance (EC) observed gross primary production (GPP). It was found that most parts of the Arctic tundra below 75° N were browning (–0.0098 mW/m2/sr/nm/year, where sr is steradian and nm is nanometer) using SIF, whereas spatially and temporally heterogeneous trends (greening or browning) were obtained based on the two NDVI products. This research has further demonstrated that SIF data can provide an alternative direct proxy for Arctic tundra greenness.
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Carcaillet C, Blarquez O. Glacial refugia in the south-western Alps? THE NEW PHYTOLOGIST 2019; 222:663-667. [PMID: 30734310 DOI: 10.1111/nph.15673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/31/2018] [Indexed: 06/09/2023]
Affiliation(s)
- Christopher Carcaillet
- Laboratory for Ecology of Natural and Anthropised Hydrosystems (UMR 5023 CNRS ENTPE), Université Claude Bernard-Lyon, Villeurbanne, F-69622, France
- Paris Sciences & Lettres University (PSL), École Pratique des Hautes Études (EPHE), 4-14 rue Ferrus, F-75014, Paris, France
| | - Olivier Blarquez
- Département de Géographie, Université de Montréal, C.P. 6128 Succ. Centre Ville, Montréal, QC, H3C 3J7, Canada
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Treharne R, Bjerke JW, Tømmervik H, Stendardi L, Phoenix GK. Arctic browning: Impacts of extreme climatic events on heathland ecosystem CO 2 fluxes. GLOBAL CHANGE BIOLOGY 2019; 25:489-503. [PMID: 30474169 PMCID: PMC7379734 DOI: 10.1111/gcb.14500] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/05/2018] [Accepted: 10/15/2018] [Indexed: 05/22/2023]
Abstract
Extreme climatic events are among the drivers of recent declines in plant biomass and productivity observed across Arctic ecosystems, known as "Arctic browning." These events can cause landscape-scale vegetation damage and so are likely to have major impacts on ecosystem CO2 balance. However, there is little understanding of the impacts on CO2 fluxes, especially across the growing season. Furthermore, while widespread shoot mortality is commonly observed with browning events, recent observations show that shoot stress responses are also common, and manifest as high levels of persistent anthocyanin pigmentation. Whether or how this response impacts ecosystem CO2 fluxes is not known. To address these research needs, a growing season assessment of browning impacts following frost drought and extreme winter warming (both extreme climatic events) on the key ecosystem CO2 fluxes Net Ecosystem Exchange (NEE), Gross Primary Productivity (GPP), ecosystem respiration (Reco ) and soil respiration (Rsoil ) was carried out in widespread sub-Arctic dwarf shrub heathland, incorporating both mortality and stress responses. Browning (mortality and stress responses combined) caused considerable site-level reductions in GPP and NEE (of up to 44%), with greatest impacts occurring at early and late season. Furthermore, impacts on CO2 fluxes associated with stress often equalled or exceeded those resulting from vegetation mortality. This demonstrates that extreme events can have major impacts on ecosystem CO2 balance, considerably reducing the carbon sink capacity of the ecosystem, even where vegetation is not killed. Structural Equation Modelling and additional measurements, including decomposition rates and leaf respiration, provided further insight into mechanisms underlying impacts of mortality and stress on CO2 fluxes. The scale of reductions in ecosystem CO2 uptake highlights the need for a process-based understanding of Arctic browning in order to predict how vegetation and CO2 balance will respond to continuing climate change.
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Affiliation(s)
- Rachael Treharne
- Department of Animal and Plant SciencesThe University of SheffieldSheffieldUK
| | - Jarle W. Bjerke
- Norwegian Institute for Nature ResearchHigh North Research Centre for Climate and the EnvironmentTromsøNorway
| | - Hans Tømmervik
- Norwegian Institute for Nature ResearchHigh North Research Centre for Climate and the EnvironmentTromsøNorway
| | | | - Gareth K. Phoenix
- Department of Animal and Plant SciencesThe University of SheffieldSheffieldUK
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Song X, Wang G, Hu Z, Ran F, Chen X. Boreal forest soil CO 2 and CH 4 fluxes following fire and their responses to experimental warming and drying. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 644:862-872. [PMID: 30743884 DOI: 10.1016/j.scitotenv.2018.07.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 07/01/2018] [Accepted: 07/01/2018] [Indexed: 06/09/2023]
Abstract
Boreal forests store large amounts of organic carbon and are susceptible to climate changes, particularly rising temperature, changed soil water and increased fire frequency. The young post-fire ecosystems might occupy larger proportions of the boreal forests region with the expected increases in fire frequency in the future and change the carbon (C) balance of this region. However, it is unclear how soil C fluxes in the post-fire boreal forest response to the climate changes. Therefore, a two-year field experiment was conducted in a boreal forest to investigate the effects of fire on the soil C (CO2 and CH4) fluxes and the responses of these fluxes to simulated warmer and drier climate conditions. The results showed that the boreal forest recovered form wildfire 7-8 years had higher soil CO2 flux than the mature forest. Furthermore, the treatments of warming, drying and the combination of warming and drying increased growing season cumulative soil CO2 flux in the post-fire forest by 15.8%, 20.4% and 34.2%, respectively. However, the boreal forest soil changed from a weak CH4 source to a weak CH4 sink after fire disturbance. Although CH4 absorption increased by warming and drying treatments, the interaction of warming and drying led to a decrease in soil CH4 uptake. The results indicated that the post-fire soil showed CO2 and CH4 fluxes with a greater global warming potential than before burning and that the global warming potential of the soil gas fluxes further increased by warming and drying. The predictive power of models of C cycle-climate feedbacks could be increased by incorporating the distinct ecosystem following fire with permafrost degradation and climate change across the boreal zone.
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Affiliation(s)
- Xiaoyan Song
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Genxu Wang
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China.
| | - Zhaoyong Hu
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China
| | - Fei Ran
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China
| | - Xiaopeng Chen
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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Koltz AM, Burkle LA, Pressler Y, Dell JE, Vidal MC, Richards LA, Murphy SM. Global change and the importance of fire for the ecology and evolution of insects. CURRENT OPINION IN INSECT SCIENCE 2018; 29:110-116. [PMID: 30551816 DOI: 10.1016/j.cois.2018.07.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 06/09/2023]
Abstract
Climate change is drastically altering global fire regimes, which may affect the structure and function of insect communities. Insect responses to fire are strongly tied to fire history, plant responses, and changes in species interactions. Many insects already possess adaptive traits to survive fire or benefit from post-fire resources, which may result in community composition shifting toward habitat and dietary generalists as well as species with high dispersal abilities. However, predicting community-level resilience of insects is inherently challenging due to the high degree of spatiotemporal and historical heterogeneity of fires, diversity of insect life histories, and potential interactions with other global change drivers. Future work should incorporate experimental approaches that specifically consider spatiotemporal variability and regional fire history in order to integrate eco-evolutionary processes in understanding insect responses to fire.
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Affiliation(s)
- Amanda M Koltz
- Department of Biology, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA.
| | - Laura A Burkle
- Department of Ecology, Montana State University, 310 Lewis Hall, Bozeman, MT 59717, USA
| | - Yamina Pressler
- Natural Resource Ecology Laboratory, Colorado State University, 1499 Campus Delivery, Fort Collins, CO 80523, USA
| | - Jane E Dell
- Department of Biology, University of Nevada, 1664 N. Virginia St., Reno, NV 89557, USA
| | - Mayra C Vidal
- Department of Biological Sciences, University of Denver, 2050 E Iliff Ave, Boettcher West, Denver, CO 80210, USA
| | - Lora A Richards
- Department of Biology, University of Nevada, 1664 N. Virginia St., Reno, NV 89557, USA
| | - Shannon M Murphy
- Department of Biological Sciences, University of Denver, 2050 E Iliff Ave, Boettcher West, Denver, CO 80210, USA.
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McGuire AD, Genet H, Lyu Z, Pastick N, Stackpoole S, Birdsey R, D'Amore D, He Y, Rupp TS, Striegl R, Wylie BK, Zhou X, Zhuang Q, Zhu Z. Assessing historical and projected carbon balance of Alaska: A synthesis of results and policy/management implications. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1396-1412. [PMID: 29923353 DOI: 10.1002/eap.1768] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/25/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
We summarize the results of a recent interagency assessment of land carbon dynamics in Alaska, in which carbon dynamics were estimated for all major terrestrial and aquatic ecosystems for the historical period (1950-2009) and a projection period (2010-2099). Between 1950 and 2009, upland and wetland (i.e., terrestrial) ecosystems of the state gained 0.4 Tg C/yr (0.1% of net primary production, NPP), resulting in a cumulative greenhouse gas radiative forcing of 1.68 × 10-3 W/m2 . The change in carbon storage is spatially variable with the region of the Northwest Boreal Landscape Conservation Cooperative (LCC) losing carbon because of fire disturbance. The combined carbon transport via various pathways through inland aquatic ecosystems of Alaska was estimated to be 41.3 Tg C/yr (17% of terrestrial NPP). During the projection period (2010-2099), carbon storage of terrestrial ecosystems of Alaska was projected to increase (22.5-70.0 Tg C/yr), primarily because of NPP increases of 10-30% associated with responses to rising atmospheric CO2 , increased nitrogen cycling, and longer growing seasons. Although carbon emissions to the atmosphere from wildfire and wetland CH4 were projected to increase for all of the climate projections, the increases in NPP more than compensated for those losses at the statewide level. Carbon dynamics of terrestrial ecosystems continue to warm the climate for four of the six future projections and cool the climate for only one of the projections. The attribution analyses we conducted indicated that the response of NPP in terrestrial ecosystems to rising atmospheric CO2 (~5% per 100 ppmv CO2 ) saturates as CO2 increases (between approximately +150 and +450 ppmv among projections). This response, along with the expectation that permafrost thaw would be much greater and release large quantities of permafrost carbon after 2100, suggests that projected carbon gains in terrestrial ecosystems of Alaska may not be sustained. From a national perspective, inclusion of all of Alaska in greenhouse gas inventory reports would ensure better accounting of the overall greenhouse gas balance of the nation and provide a foundation for considering mitigation activities in areas that are accessible enough to support substantive deployment.
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Affiliation(s)
- A David McGuire
- U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Hélène Genet
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Zhou Lyu
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Neal Pastick
- Stinger Ghaffarian Technologies Inc., contractor to the U.S. Geological Survey, Sioux Falls, South Dakota, 57198, USA
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, 55108, USA
| | - Sarah Stackpoole
- Water Mission Area, Denver Federal Center, MS413, U.S. Geological Survey, Denver, Colorado, 80225, USA
| | - Richard Birdsey
- Woods Hole Research Center, Falmouth, Massachusetts, 02540, USA
| | - David D'Amore
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Juneau, Alaska, 99801, USA
| | - Yujie He
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - T Scott Rupp
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Robert Striegl
- National Research Program, U.S. Geological Survey, 3215 Marine Street, Boulder, Colorado, 80303, USA
| | - Bruce K Wylie
- The Earth Resources Observation Systems Center, U.S. Geological Survey, Sioux Falls, South Dakota, 57198, USA
| | - Xiaoping Zhou
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, Oregon, 97208, USA
| | - Qianlai Zhuang
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Zhiliang Zhu
- U.S. Geological Survey, Reston, Virginia, 12201, USA
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Walker XJ, Rogers BM, Baltzer JL, Cumming SG, Day NJ, Goetz SJ, Johnstone JF, Schuur EAG, Turetsky MR, Mack MC. Cross-scale controls on carbon emissions from boreal forest megafires. GLOBAL CHANGE BIOLOGY 2018; 24:4251-4265. [PMID: 29697169 DOI: 10.1111/gcb.14287] [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: 02/20/2018] [Revised: 04/08/2018] [Accepted: 04/09/2018] [Indexed: 06/08/2023]
Abstract
Climate warming and drying is associated with increased wildfire disturbance and the emergence of megafires in North American boreal forests. Changes to the fire regime are expected to strongly increase combustion emissions of carbon (C) which could alter regional C balance and positively feedback to climate warming. In order to accurately estimate C emissions and thereby better predict future climate feedbacks, there is a need to understand the major sources of heterogeneity that impact C emissions at different scales. Here, we examined 211 field plots in boreal forests dominated by black spruce (Picea mariana) or jack pine (Pinus banksiana) of the Northwest Territories (NWT), Canada after an unprecedentedly large area burned in 2014. We assessed both aboveground and soil organic layer (SOL) combustion, with the goal of determining the major drivers in total C emissions, as well as to develop a high spatial resolution model to scale emissions in a relatively understudied region of the boreal forest. On average, 3.35 kg C m-2 was combusted and almost 90% of this was from SOL combustion. Our results indicate that black spruce stands located at landscape positions with intermediate drainage contribute the most to C emissions. Indices associated with fire weather and date of burn did not impact emissions, which we attribute to the extreme fire weather over a short period of time. Using these results, we estimated a total of 94.3 Tg C emitted from 2.85 Mha of burned area across the entire 2014 NWT fire complex, which offsets almost 50% of mean annual net ecosystem production in terrestrial ecosystems of Canada. Our study also highlights the need for fine-scale estimates of burned area that represent small water bodies and regionally specific calibrations of combustion that account for spatial heterogeneity in order to accurately model emissions at the continental scale.
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Affiliation(s)
- Xanthe J Walker
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona
| | | | - Jennifer L Baltzer
- Biology Department, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Steven G Cumming
- Department of Wood and Forest Sciences, Laval University, Quebec City, Quebec, Canada
| | - Nicola J Day
- Biology Department, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Scott J Goetz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona
- Woods Hole Research Center, Falmouth, Massachusetts
- School of Informatics, Computing and Cyber Systems (SICCS), Northern Arizona University, Flagstaff, Arizona
| | - Jill F Johnstone
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Edward A G Schuur
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona
| | - Merritt R Turetsky
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Michelle C Mack
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona
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Gibson CM, Chasmer LE, Thompson DK, Quinton WL, Flannigan MD, Olefeldt D. Wildfire as a major driver of recent permafrost thaw in boreal peatlands. Nat Commun 2018; 9:3041. [PMID: 30072751 PMCID: PMC6072743 DOI: 10.1038/s41467-018-05457-1] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 07/03/2018] [Indexed: 11/08/2022] Open
Abstract
Permafrost vulnerability to climate change may be underestimated unless effects of wildfire are considered. Here we assess impacts of wildfire on soil thermal regime and rate of thermokarst bog expansion resulting from complete permafrost thaw in western Canadian permafrost peatlands. Effects of wildfire on permafrost peatlands last for 30 years and include a warmer and deeper active layer, and spatial expansion of continuously thawed soil layers (taliks). These impacts on the soil thermal regime are associated with a tripled rate of thermokarst bog expansion along permafrost edges. Our results suggest that wildfire is directly responsible for 2200 ± 1500 km2 (95% CI) of thermokarst bog development in the study region over the last 30 years, representing ~25% of all thermokarst bog expansion during this period. With increasing fire frequency under a warming climate, this study emphasizes the need to consider wildfires when projecting future circumpolar permafrost thaw.
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Affiliation(s)
- Carolyn M Gibson
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - Laura E Chasmer
- Department of Geography, University of Lethbridge, Lethbridge, AB, T1K 6T5, Canada
| | - Dan K Thompson
- Natural Resources Canada, Canadian Forest Service, Edmonton, AB, T6H 3S5, Canada
| | - William L Quinton
- Cold Regions Research Centre, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
| | - Mike D Flannigan
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - David Olefeldt
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2R3, Canada.
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Du L, Mikle N, Zou Z, Huang Y, Shi Z, Jiang L, McCarthy HR, Liang J, Luo Y. Global patterns of extreme drought-induced loss in land primary production: Identifying ecological extremes from rain-use efficiency. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 628-629:611-620. [PMID: 29454202 DOI: 10.1016/j.scitotenv.2018.02.114] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 02/09/2018] [Accepted: 02/10/2018] [Indexed: 06/08/2023]
Abstract
Quantifying the ecological patterns of loss of ecosystem function in extreme drought is important to understand the carbon exchange between the land and atmosphere. Rain-use efficiency [RUE; gross primary production (GPP)/precipitation] acts as a typical indicator of ecosystem function. In this study, a novel method based on maximum rain-use efficiency (RUEmax) was developed to detect losses of ecosystem function globally. Three global GPP datasets from the MODIS remote sensing data (MOD17), ground upscaling FLUXNET observations (MPI-BGC), and process-based model simulations (BESS), and a global gridded precipitation product (CRU) were used to develop annual global RUE datasets for 2001-2011. Large, well-known extreme drought events were detected, e.g. 2003 drought in Europe, 2002 and 2011 drought in the U.S., and 2010 drought in Russia. Our results show that extreme drought-induced loss of ecosystem function could impact 0.9% ± 0.1% of earth's vegetated land per year and was mainly distributed in semi-arid regions. The reduced carbon uptake caused by functional loss (0.14 ± 0.03 PgC/yr) could explain >70% of the interannual variation in GPP in drought-affected areas (p ≤ 0.001). Our results highlight the impact of ecosystem function loss in semi-arid regions with increasing precipitation variability and dry land expansion expected in the future.
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Affiliation(s)
- Ling Du
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Nathaniel Mikle
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA; US Geological Survey, Northern Rocky Mountain Science Center, West Glacier, MT 59936, USA
| | - Zhenhua Zou
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Yuanyuan Huang
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA; Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS-UVSQ, 91191 Gif sur Yvette, France
| | - Zheng Shi
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Lifen Jiang
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Heather R McCarthy
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Junyi Liang
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA; Environmental Sciences Division & Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Yiqi Luo
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA; Department of Earth System Science, Tsinghua University, Beijing 100084, China.
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Dutta H. Insights into the phenomenon of alien plant invasion and its synergistic interlinkage with three current ecological issues. JOURNAL OF ASIA-PACIFIC BIODIVERSITY 2018. [DOI: 10.1016/j.japb.2018.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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50
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Genet H, He Y, Lyu Z, McGuire AD, Zhuang Q, Clein J, D'Amore D, Bennett A, Breen A, Biles F, Euskirchen ES, Johnson K, Kurkowski T, Kushch Schroder S, Pastick N, Rupp TS, Wylie B, Zhang Y, Zhou X, Zhu Z. The role of driving factors in historical and projected carbon dynamics of upland ecosystems in Alaska. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:5-27. [PMID: 29044791 DOI: 10.1002/eap.1641] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/26/2017] [Accepted: 08/25/2017] [Indexed: 06/07/2023]
Abstract
It is important to understand how upland ecosystems of Alaska, which are estimated to occupy 84% of the state (i.e., 1,237,774 km2 ), are influencing and will influence state-wide carbon (C) dynamics in the face of ongoing climate change. We coupled fire disturbance and biogeochemical models to assess the relative effects of changing atmospheric carbon dioxide (CO2 ), climate, logging and fire regimes on the historical and future C balance of upland ecosystems for the four main Landscape Conservation Cooperatives (LCCs) of Alaska. At the end of the historical period (1950-2009) of our analysis, we estimate that upland ecosystems of Alaska store ~50 Pg C (with ~90% of the C in soils), and gained 3.26 Tg C/yr. Three of the LCCs had gains in total ecosystem C storage, while the Northwest Boreal LCC lost C (-6.01 Tg C/yr) because of increases in fire activity. Carbon exports from logging affected only the North Pacific LCC and represented less than 1% of the state's net primary production (NPP). The analysis for the future time period (2010-2099) consisted of six simulations driven by climate outputs from two climate models for three emission scenarios. Across the climate scenarios, total ecosystem C storage increased between 19.5 and 66.3 Tg C/yr, which represents 3.4% to 11.7% increase in Alaska upland's storage. We conducted additional simulations to attribute these responses to environmental changes. This analysis showed that atmospheric CO2 fertilization was the main driver of ecosystem C balance. By comparing future simulations with constant and with increasing atmospheric CO2 , we estimated that the sensitivity of NPP was 4.8% per 100 ppmv, but NPP becomes less sensitive to CO2 increase throughout the 21st century. Overall, our analyses suggest that the decreasing CO2 sensitivity of NPP and the increasing sensitivity of heterotrophic respiration to air temperature, in addition to the increase in C loss from wildfires weakens the C sink from upland ecosystems of Alaska and will ultimately lead to a source of CO2 to the atmosphere beyond 2100. Therefore, we conclude that the increasing regional C sink we estimate for the 21st century will most likely be transitional.
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Affiliation(s)
- Hélène Genet
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Yujie He
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Zhou Lyu
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - A David McGuire
- U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Qianlai Zhuang
- Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Joy Clein
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - David D'Amore
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Juneau, Alaska, 99801, USA
| | - Alec Bennett
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Amy Breen
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Frances Biles
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Juneau, Alaska, 99801, USA
| | - Eugénie S Euskirchen
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Kristofer Johnson
- U.S. Department of Agriculture, Forest Service, Northern Research Station, Newtown Square, Pennsylvania, 19073, USA
| | - Tom Kurkowski
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Svetlana Kushch Schroder
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, 98195, USA
| | - Neal Pastick
- Stinger Ghaffarian Technologies Inc., contractor to the U.S. Geological Survey, Sioux Falls, South Dakota, 57198, USA
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, 55108, USA
| | - T Scott Rupp
- Scenarios Network for Alaska and Arctic Planning, International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, 99775, USA
| | - Bruce Wylie
- U.S. Geological Survey, The Earth Resources Observation Systems Center, Sioux Falls, South Dakota, 57198, USA
| | | | - Xiaoping Zhou
- U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, Oregon, 97208, USA
| | - Zhiliang Zhu
- U.S. Geological Survey, Reston, Virginia, 12201, USA
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