1
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Campbell JL, Driscoll CT, Jones JA, Boose ER, Dugan HA, Groffman PM, Jackson CR, Jones JB, Juday GP, Lottig NR, Penaluna BE, Ruess RW, Suding K, Thompson JR, Zimmerman JK. Forest and Freshwater Ecosystem Responses to Climate Change and Variability at US LTER Sites. Bioscience 2022. [DOI: 10.1093/biosci/biab124] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Forest and freshwater ecosystems are tightly linked and together provide important ecosystem services, but climate change is affecting their species composition, structure, and function. Research at nine US Long Term Ecological Research sites reveals complex interactions and cascading effects of climate change, some of which feed back into the climate system. Air temperature has increased at all sites, and those in the Northeast have become wetter, whereas sites in the Northwest and Alaska have become slightly drier. These changes have altered streamflow and affected ecosystem processes, including primary production, carbon storage, water and nutrient cycling, and community dynamics. At some sites, the direct effects of climate change are the dominant driver altering ecosystems, whereas at other sites indirect effects or disturbances and stressors unrelated to climate change are more important. Long-term studies are critical for understanding the impacts of climate change on forest and freshwater ecosystems.
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Affiliation(s)
| | | | - Julia A Jones
- Oregon State University , Corvallis, Oregon, United States
| | - Emery R Boose
- Harvard University , Petersham, Massachusetts, United States
| | - Hilary A Dugan
- University of Wisconsin , Madison, Wisconsin, United States
| | - Peter M Groffman
- City University of New York, and with the Cary Institute of Ecosystem Studies , Millbrook, New York, United States
| | | | - Jeremy B Jones
- University of Alaska Fairbanks , Fairbanks, Alaska, United States
| | - Glenn P Juday
- University of Alaska Fairbanks , Fairbanks, Alaska, United States
| | - Noah R Lottig
- University of Wisconsin's Trout Lake Station , Boulder Junction, Wisconsin, United States
| | | | - Roger W Ruess
- University of Alaska Fairbanks , Fairbanks, Alaska, United States
| | | | | | - Jess K Zimmerman
- University of Puerto Rico-Rio Piedras , San Juan, Puerto Rico, United States
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2
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Dow C, Kim AY, D'Orangeville L, Gonzalez-Akre EB, Helcoski R, Herrmann V, Harley GL, Maxwell JT, McGregor IR, McShea WJ, McMahon SM, Pederson N, Tepley AJ, Anderson-Teixeira KJ. Warm springs alter timing but not total growth of temperate deciduous trees. Nature 2022; 608:552-557. [PMID: 35948636 DOI: 10.1038/s41586-022-05092-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 07/08/2022] [Indexed: 11/09/2022]
Abstract
As the climate changes, warmer spring temperatures are causing earlier leaf-out1-3 and commencement of CO2 uptake1,3 in temperate deciduous forests, resulting in a tendency towards increased growing season length3 and annual CO2 uptake1,3-7. However, less is known about how spring temperatures affect tree stem growth8,9, which sequesters carbon in wood that has a long residence time in the ecosystem10,11. Here we show that warmer spring temperatures shifted stem diameter growth of deciduous trees earlier but had no consistent effect on peak growing season length, maximum growth rates, or annual growth, using dendrometer band measurements from 440 trees across two forests. The latter finding was confirmed on the centennial scale by 207 tree-ring chronologies from 108 forests across eastern North America, where annual ring width was far more sensitive to temperatures during the peak growing season than in the spring. These findings imply that any extra CO2 uptake in years with warmer spring temperatures4,5 does not significantly contribute to increased sequestration in long-lived woody stem biomass. Rather, contradicting projections from global carbon cycle models1,12, our empirical results imply that warming spring temperatures are unlikely to increase woody productivity enough to strengthen the long-term CO2 sink of temperate deciduous forests.
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Affiliation(s)
- Cameron Dow
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA.,Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, USA
| | - Albert Y Kim
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA.,Statistical & Data Sciences, Smith College, Northampton, MA, USA
| | - Loïc D'Orangeville
- Harvard Forest, Petersham, MA, USA.,Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Erika B Gonzalez-Akre
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA
| | - Ryan Helcoski
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA
| | - Valentine Herrmann
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA
| | - Grant L Harley
- Department of Earth and Spatial Sciences, University of Idaho, Moscow, ID, USA
| | - Justin T Maxwell
- Department of Geography, Indiana University, Bloomington, IN, USA
| | - Ian R McGregor
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA.,Center for Geospatial Analytics, North Carolina State University, Raleigh, NC, USA
| | - William J McShea
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA
| | - Sean M McMahon
- Smithsonian Environmental Research Center, Edgewater, MD, USA.,Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Panama, Republic of Panama
| | | | - Alan J Tepley
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA.,Canadian Forest Service, Northern Forestry Centre, Edmonton, Alberta, Canada.,Department of Forestry and Wildland Resources, Cal Poly Humboldt University, Arcata, CA, USA
| | - Kristina J Anderson-Teixeira
- Conservation Ecology Center, Smithsonian's National Zoo & Conservation Biology Institute, Front Royal, VA, USA. .,Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Panama, Republic of Panama.
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3
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Kukarskih VV, Devi NM, Bubnov MO, Agafonov LI. Recreation and Radial Growth of Pine Forests of the Natural Monument “Lake Turgoyak”, Southern Urals. RUSS J ECOL+ 2022. [DOI: 10.1134/s1067413622030079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Jia G, Chen L, Yu X, Liu Z. Soil water stress overrides the benefit of water-use efficiency from rising CO 2 and temperature in a cold semi-arid poplar plantation. PLANT, CELL & ENVIRONMENT 2022; 45:1172-1186. [PMID: 35037279 DOI: 10.1111/pce.14260] [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: 05/02/2021] [Revised: 09/15/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The counteractive effect of atmospheric CO2 (ca ) enrichment and drought stress on tree growth results in great uncertainty in the growth patterns of forest plantations in cold semi-arid regions. We analysed tree ring chronologies and carbon isotopes in Populus simonii plantations in cold semi-arid areas in northern China over the past four decades. We hypothesized that the hydraulic stress from drought would override the stimulating effect of increasing ca and temperature (T) on stem growth (basal area increment [BAI]). We found the stimulating effect of rising ca and T on the growth, indicated by continuous increase of intrinsic water-use efficiency in all stands and a positive correlation between T and BAI. However, these effects failed to alleviate the negative impacts of drought on tree growth. Concurrent acceleration of BAI reversed during the intensive drought episodes. Water stress resulted from inaccessibility of roots to deep soil water rather than from lack of precipitation, suggested by the decoupling of BAI from precipitation and vapour pressure deficit. Local soil water limitation might also cause greater stomatal regulation in declining trees, indicated by lower intercellular CO2 concentration. Thus, site-specific soil moisture conditions growth sensitivity to global warming resulting in site-specific decline episodes in drought-prone areas.
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Affiliation(s)
- Guodong Jia
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Lixin Chen
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Xinxiao Yu
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Ziqiang Liu
- School of Forestry, Nanjing Forestry University, Nanjing, China
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5
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Benson MC, Miniat CF, Oishi AC, Denham SO, Domec JC, Johnson DM, Missik JE, Phillips RP, Wood JD, Novick KA. The xylem of anisohydric Quercus alba L. is more vulnerable to embolism than isohydric codominants. PLANT, CELL & ENVIRONMENT 2022; 45:329-346. [PMID: 34902165 DOI: 10.1111/pce.14244] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
The coordination of plant leaf water potential (ΨL ) regulation and xylem vulnerability to embolism is fundamental for understanding the tradeoffs between carbon uptake and risk of hydraulic damage. There is a general consensus that trees with vulnerable xylem more conservatively regulate ΨL than plants with resistant xylem. We evaluated if this paradigm applied to three important eastern US temperate tree species, Quercus alba L., Acer saccharum Marsh. and Liriodendron tulipifera L., by synthesizing 1600 ΨL observations, 122 xylem embolism curves and xylem anatomical measurements across 10 forests spanning pronounced hydroclimatological gradients and ages. We found that, unexpectedly, the species with the most vulnerable xylem (Q. alba) regulated ΨL less strictly than the other species. This relationship was found across all sites, such that coordination among traits was largely unaffected by climate and stand age. Quercus species are perceived to be among the most drought tolerant temperate US forest species; however, our results suggest their relatively loose ΨL regulation in response to hydrologic stress occurs with a substantial hydraulic cost that may expose them to novel risks in a more drought-prone future.
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Affiliation(s)
- Michael C Benson
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Chelcy F Miniat
- USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, North Carolina, USA
| | - Andrew C Oishi
- USDA Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory, Otto, North Carolina, USA
| | - Sander O Denham
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro, INRA UMR 1391 ISPA, Gradignan, France
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - Justine E Missik
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Richard P Phillips
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Jeffrey D Wood
- University of Missouri, School of Natural Resources, Columbia, Missouri, USA
| | - Kimberly A Novick
- O'Neill School of Public and Environmental Affairs, Indiana University Bloomington, Bloomington, Indiana, USA
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6
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Rastetter EB, Ohman MD, Elliott KJ, Rehage JS, Rivera‐Monroy VH, Boucek RE, Castañeda‐Moya E, Danielson TM, Gough L, Groffman PM, Jackson CR, Miniat CF, Shaver GR. Time lags: insights from the U.S. Long Term Ecological Research Network. Ecosphere 2021. [DOI: 10.1002/ecs2.3431] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Edward B. Rastetter
- The Ecosystems Center Marine Biological Laboratory Woods Hole Massachusetts02543USA
| | - Mark D. Ohman
- Scripps Institution of Oceanography University of California, San Diego La Jolla California92093USA
| | - Katherine J. Elliott
- Center for Forest Watershed Research Coweeta Hydrologic LaboratoryUSDA Forest ServiceSouthern Research Station Otto North Carolina28763USA
| | - J. S. Rehage
- Institute of Environment Florida International University Miami Florida33199USA
| | - Victor H. Rivera‐Monroy
- Department of Oceanography and Coastal Sciences College of the Coast and Environment Louisiana State University Baton Rouge Louisiana70803USA
| | - R. E. Boucek
- Institute of Environment Florida International University Miami Florida33199USA
| | - Edward Castañeda‐Moya
- Southeast Environmental Research Center Florida International University Miami Florida33199USA
| | - Tess M. Danielson
- Department of Oceanography and Coastal Sciences College of the Coast and Environment Louisiana State University Baton Rouge Louisiana70803USA
| | - Laura Gough
- Department of Biological Sciences Towson University Towson Maryland21252USA
| | - Peter M. Groffman
- City University of New York Advanced Science Research Center at the Graduate Center New York New York10031USA
- Cary Institute of Ecosystem Studies 2801 Sharon Turnpike Millbrook New York12545USA
| | - C. Rhett Jackson
- Warnell School of Forestry and Environmental Science University of Georgia Athens Georgia30602‐2152USA
| | - Chelcy Ford Miniat
- Center for Forest Watershed Research Coweeta Hydrologic LaboratoryUSDA Forest ServiceSouthern Research Station Otto North Carolina28763USA
| | - Gaius R. Shaver
- The Ecosystems Center Marine Biological Laboratory Woods Hole Massachusetts02543USA
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7
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Impacts of strengthened warming by urban heat island on carbon sequestration of urban ecosystems in a subtropical city of China. Urban Ecosyst 2021. [DOI: 10.1007/s11252-021-01104-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Briegel F, Lee SC, Black TA, Jassal RS, Christen A. Factors controlling long-term carbon dioxide exchange between a Douglas-fir stand and the atmosphere identified using an artificial neural network approach. Ecol Modell 2020. [DOI: 10.1016/j.ecolmodel.2020.109266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Beamesderfer ER, Arain MA, Khomik M, Brodeur JJ. The Impact of Seasonal and Annual Climate Variations on the Carbon Uptake Capacity of a Deciduous Forest Within the Great Lakes Region of Canada. JOURNAL OF GEOPHYSICAL RESEARCH. BIOGEOSCIENCES 2020; 125:e2019JG005389. [PMID: 33042720 PMCID: PMC7540005 DOI: 10.1029/2019jg005389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/30/2020] [Accepted: 09/03/2020] [Indexed: 06/11/2023]
Abstract
In eastern North America, many deciduous forest ecosystems grow at the northernmost extent of their geographical ranges, where climate change could aid or impede their growth. This region experiences frequent extreme weather conditions, allowing us to study the response of these forests to environmental conditions, reflective of future climates. Here we determined the impact of seasonal and annual climate variations and extreme weather events on the carbon (C) uptake capacity of an oak-dominated forest in southern Ontario, Canada, from 2012 to 2016. We found that changes in meteorology during late May to mid-July were key in determining the C sink strength of the forest, impacting the seasonal and annual variability of net ecosystem productivity (NEP). Overall, higher temperatures and dry conditions reduced ecosystem respiration (RE) much more than gross ecosystem productivity (GEP), leading to higher NEP. Variability in NEP was primarily driven by changes in RE, rather than GEP. The mean annual GEP, RE, and NEP values at our site during the study were 1,343 ± 85, 1,171 ± 139, and 206 ± 92 g C m-2 yr-1, respectively. The forest was a C sink even in years that experienced heat and water stresses. Mean annual NEP at our site was within the range of NEP (69-459 g C m-2 yr-1) observed in similar North American forests from 2012 to 2016. The growth and C sequestration capabilities of our oak-dominated forest were not adversely impacted by changes in environmental conditions and extreme weather events experienced over the study period.
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Affiliation(s)
- Eric R. Beamesderfer
- School of Earth, Environment and Society and McMaster Centre for Climate ChangeMcMaster UniversityHamiltonOntarioCanada
| | - M. Altaf Arain
- School of Earth, Environment and Society and McMaster Centre for Climate ChangeMcMaster UniversityHamiltonOntarioCanada
| | - Myroslava Khomik
- School of Earth, Environment and Society and McMaster Centre for Climate ChangeMcMaster UniversityHamiltonOntarioCanada
- Geography and Environmental ManagementUniversity of WaterlooWaterlooOntarioCanada
| | - Jason J. Brodeur
- School of Earth, Environment and Society and McMaster Centre for Climate ChangeMcMaster UniversityHamiltonOntarioCanada
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10
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Zhang Q, Barnes M, Benson M, Burakowski E, Oishi AC, Ouimette A, Sanders-DeMott R, Stoy PC, Wenzel M, Xiong L, Yi K, Novick KA. Reforestation and surface cooling in temperate zones: Mechanisms and implications. GLOBAL CHANGE BIOLOGY 2020; 26:3384-3401. [PMID: 32145125 DOI: 10.1111/gcb.15069] [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: 10/01/2019] [Accepted: 02/15/2020] [Indexed: 06/10/2023]
Abstract
Land-use/cover change (LUCC) is an important driver of environmental change, occurring at the same time as, and often interacting with, global climate change. Reforestation and deforestation have been critical aspects of LUCC over the past two centuries and are widely studied for their potential to perturb the global carbon cycle. More recently, there has been keen interest in understanding the extent to which reforestation affects terrestrial energy cycling and thus surface temperature directly by altering surface physical properties (e.g., albedo and emissivity) and land-atmosphere energy exchange. The impacts of reforestation on land surface temperature and their mechanisms are relatively well understood in tropical and boreal climates, but the effects of reforestation on warming and/or cooling in temperate zones are less certain. This study is designed to elucidate the biophysical mechanisms that link land cover and surface temperature in temperate ecosystems. To achieve this goal, we used data from six paired eddy-covariance towers over co-located forests and grasslands in the temperate eastern United States, where radiation components, latent and sensible heat fluxes, and meteorological conditions were measured. The results show that, at the annual time scale, the surface of the forests is 1-2°C cooler than grasslands, indicating a substantial cooling effect of reforestation. The enhanced latent and sensible heat fluxes of forests have an average cooling effect of -2.5°C, which offsets the net warming effect (+1.5°C) of albedo warming (+2.3°C) and emissivity cooling effect (-0.8°C) associated with surface properties. Additional daytime cooling over forests is driven by local feedbacks to incoming radiation. We further show that the forest cooling effect is most pronounced when land surface temperature is higher, often exceeding -5°C. Our results contribute important observational evidence that reforestation in the temperate zone offers opportunities for local climate mitigation and adaptation.
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Affiliation(s)
- Quan Zhang
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, China
- O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, IN, USA
| | - Mallory Barnes
- O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, IN, USA
| | - Michael Benson
- O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, IN, USA
| | - Elizabeth Burakowski
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
| | - A Christopher Oishi
- Coweeta Hydrologic Laboratory, Southern Research Station, USDA Forest Service, Otto, NC, USA
| | - Andrew Ouimette
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
| | - Rebecca Sanders-DeMott
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
| | - Paul C Stoy
- Department of Biological Systems Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
| | - Matt Wenzel
- National Ecological Observatory Network, Battelle, Jamestown, ND, USA
| | - Lihua Xiong
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, China
| | - Koong Yi
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
| | - Kimberly A Novick
- O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, IN, USA
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11
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Patterns of Carbon Sequestration in a Young Forest Ecosystem after Clear-Cutting. FORESTS 2020. [DOI: 10.3390/f11020126] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A large area of Estonian hemiboreal forest is recovering from clear-cut harvesting and changing carbon (C) balance of the stands. However, there is a lack of information about C- source/sink relationships during recovery of such stands. The eddy covariance technique was used to estimate C-status through net ecosystem exchange (NEE) of CO2 in two stands of different development stages located in southeast Estonia in 2014. Measured summertime (June–September) mean CO2 concentration was 337.75 ppm with mean NEE −1.72 µmol m−2 s−1. June NEE was −4.60 µmol m−2 s−1; July, August, and September NEE was −1.17, −0.77, and −0.25 µmol m−2 s−1, respectively. The two stands had similar patterns of CO2 exchange; measurement period temperature drove NEE. Our results show that after clear-cutting a 6-year-old forest ecosystem was a light C-sink and 8-year-old young stand demonstrated a stronger C-sink status during the measurement period.
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12
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Landuyt D, De Lombaerde E, Perring MP, Hertzog LR, Ampoorter E, Maes SL, De Frenne P, Ma S, Proesmans W, Blondeel H, Sercu BK, Wang B, Wasof S, Verheyen K. The functional role of temperate forest understorey vegetation in a changing world. GLOBAL CHANGE BIOLOGY 2019; 25:3625-3641. [PMID: 31301199 DOI: 10.1111/gcb.14756] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 06/17/2019] [Indexed: 06/10/2023]
Abstract
Temperate forests cover 16% of the global forest area. Within these forests, the understorey is an important biodiversity reservoir that can influence ecosystem processes and functions in multiple ways. However, we still lack a thorough understanding of the relative importance of the understorey for temperate forest functioning. As a result, understoreys are often ignored during assessments of forest functioning and changes thereof under global change. We here compiled studies that quantify the relative importance of the understorey for temperate forest functioning, focussing on litter production, nutrient cycling, evapotranspiration, tree regeneration, pollination and pathogen dynamics. We describe the mechanisms driving understorey functioning and develop a conceptual framework synthesizing possible effects of multiple global change drivers on understorey-mediated forest ecosystem functioning. Our review illustrates that the understorey's contribution to temperate forest functioning is significant but varies depending on the ecosystem function and the environmental context, and more importantly, the characteristics of the overstorey. To predict changes in understorey functioning and its relative importance for temperate forest functioning under global change, we argue that a simultaneous investigation of both overstorey and understorey functional responses to global change will be crucial. Our review shows that such studies are still very scarce, only available for a limited set of ecosystem functions and limited to quantification, providing little data to forecast functional responses to global change.
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Affiliation(s)
- Dries Landuyt
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Emiel De Lombaerde
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Michael P Perring
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
- Ecosystem Restoration and Intervention Ecology Research Group, The University of Western Australia, Crawley, WA, Australia
| | - Lionel R Hertzog
- Terrestrial Ecology Research Unit, Department of Biology, Ghent University, Gent, Belgium
| | - Evy Ampoorter
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Sybryn L Maes
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Pieter De Frenne
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Shiyu Ma
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Willem Proesmans
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Haben Blondeel
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Bram K Sercu
- Terrestrial Ecology Research Unit, Department of Biology, Ghent University, Gent, Belgium
| | - Bin Wang
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Safaa Wasof
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
| | - Kris Verheyen
- Forest & Nature Lab, Department of Environment, Ghent University, Melle-Gontrode, Belgium
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13
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Minucci JM, Miniat CF, Wurzburger N. Drought sensitivity of an N 2 -fixing tree may slow temperate deciduous forest recovery from disturbance. Ecology 2019; 100:e02862. [PMID: 31386760 DOI: 10.1002/ecy.2862] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 06/14/2019] [Accepted: 07/11/2019] [Indexed: 11/05/2022]
Abstract
Increased drought intensity and frequency due to climate change may reduce the abundance and activity of nitrogen (N2 )-fixing plants, which supply new N to terrestrial ecosystems. As a result, drought may indirectly reduce ecosystem productivity through its effect on the N cycle. Here, we manipulated growing season net rainfall across a series of plots in an early successional mesic deciduous forest to understand how drought affects the aboveground productivity of the N2 -fixing tree Robinia pseudoacacia and three co-occurring nonfixing tree species. We found that lower soil moisture was associated with reduced productivity of R. pseudoacacia but not of nonfixing trees. As a result, the relative biomass and density of R. pseudoacacia declined in drier soils over time. Greater aboveground biomass of R. pseudoacacia was also associated with greater total soil N, extractable inorganic N, N mineralization rates, and productivity of nonfixing trees. These soil N effects may reflect current N2 fixation by R. pseudoacacia saplings, or the legacy effect of former trees in the same location. Our results suggest that R. pseudoacacia promotes the growth of nonfixing trees in early succession through its effect on the N cycle. However, the sensitivity of R. pseudoacacia to dry soils may reduce N2 fixation under scenarios of increasing drought intensity and frequency, demonstrating a mechanism by which drought may indirectly diminish potential forest productivity and recovery rate from disturbance.
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Affiliation(s)
- Jeffrey M Minucci
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, Georgia, 30602, USA
| | - Chelcy F Miniat
- Coweeta Hydrologic Lab, U.S. Department of Agriculture Forest Service, Southern Research Station, 3160 Coweeta Lab Road, Otto, North Carolina, 28763, USA
| | - Nina Wurzburger
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, Georgia, 30602, USA
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14
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Chen X, Xie M, Hays MD, Edgerton E, Schwede D, Walker JT. Characterization of organic nitrogen in aerosols at a forest site in the southern Appalachian Mountains. ATMOSPHERIC CHEMISTRY AND PHYSICS 2018; 18:6829-6846. [PMID: 32704249 PMCID: PMC7377252 DOI: 10.5194/acp-18-6829-2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This study investigates the composition of organic particulate matter in PM2.5 in a remote montane forest in the southeastern US, focusing on the role of organic nitrogen (N) in sulfur-containing secondary organic aerosol (nitrooxy-organosulfates) and aerosols associated with biomass burning (nitro-aromatics). Bulk water-soluble organic N (WSON) represented ~ 14% w/w of water-soluble total N (WSTN) in PM2.5 on average across seasonal measurement campaigns conducted in the spring, summer, and fall of 2015. The largest contributions of WSON to WSTN were observed in spring (~ 18% w/w) and the lowest in the fall (~ 10% w/w). On average, identified nitro-aromatic and nitrooxy-organosulfate compounds accounted for a small fraction of WSON, ranging from ~ 1% in spring to ~ 4% in fall, though were observed to contribute as much as 28% w/w of WSON in individual samples that were impacted by local biomass burning. The highest concentrations of oxidized organic N species occurred during summer (average of 0.65 ng N m-3) along with a greater relative abundance of higher-generation oxygenated terpenoic acids, indicating an association with more aged aerosol. The highest concentrations of nitro-aromatics (e.g., nitrocatechol and methyl-nitrocatechol), levoglucosan, and aged SOA tracers were observed during fall, associated with aged biomass burning plumes. Nighttime nitrate radical chemistry is the most likely formation pathway for nitrooxy-organosulfates observed at this low NO x site (generally < 1 ppb). Isoprene-derived organosulfate (MW216, 2-methyltetrol derived), which is formed from isoprene epoxydiols (IEPOX) under low NO x conditions, was the most abundant individual organosulfate. Concentration-weighted average WSON / WSOC ratios for nitro-aromatics + organosulfates + terpenoic acids were 1 order of magnitude lower than the overall aerosol WSON / WSOC ratio, indicating the presence of other uncharacterized higher-N-content species. Although nitrooxy-organosulfates and nitro-aromatics contributed a small fraction of WSON, our results provide new insight into the atmospheric formation processes and sources of these largely uncharacterized components of atmospheric organic N, which also helps to advance the atmospheric models to better understand the chemistry and deposition of reactive N.
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Affiliation(s)
- Xi Chen
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
| | - Mingjie Xie
- Oak Ridge Institute for Science and Education (ORISE), National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
| | - Michael D. Hays
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
| | - Eric Edgerton
- Atmospheric Research and Analysis, Inc., Cary, NC 27513, USA
| | - Donna Schwede
- National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
| | - John T. Walker
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
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