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Xu Z, Qin L, Zhou G, SiQing B, Du W, Meng S, Yu J, Sun Z, Liu Q. Exploring carbon sequestration in broad-leaved Korean pine forests: Insights into photosynthetic and respiratory processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167421. [PMID: 37774859 DOI: 10.1016/j.scitotenv.2023.167421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/08/2023] [Accepted: 09/26/2023] [Indexed: 10/01/2023]
Abstract
A comprehensive understanding of carbon assimilation and sequestration in broad-leaved Korean pine forests is crucial for accurately estimating this significant aspect of temperate forests at a regional scale. In this study, we introduced a high-temporal resolution model designed for carbon assimilation insights at the plot scale, focusing on specific parameters such as leaf area dynamics, vertical leaf distribution, photosynthetically active radiation (PAR) fluctuations, and the photosynthetic traits of tree species. The findings reveal that most tree species in broad-leaved Korean pine forests exhibit an inverted U-shaped pattern in leaf area dynamics, with shorter leaf drop periods than leaf expansion events. Leaf distribution varies significantly among different canopy heights, with approximately 80 % of the leaves above 15 m. PAR decreases as canopy height decreases, with PAR at 25 m accounting for about 60 % of the PAR above the canopy. Our framework incorporates a leaf-scale light-response curve and empirical photosynthesis-temperature relationships to estimate forest carbon assimilation on daily and hourly scales accurately. Using the model, we assess the gross primary productivity (GPP), leaf net photosynthetic assimilation (LNPA), and carbon increment (ΔC) of broad-leaved Korean pine forests from 2017 to 2020. The results demonstrate GPP, LNPA, and ΔC values of 21.4 t·ha-1·a-1, 17.4 t·ha-1·a-1, and 4.0 t·ha-1·a-1, respectively. Regarding efficiency, GPP, LNPA, and ΔC per square meter of leaf per year are 179 g, 146 g, and 33 g, respectively. Notably, tree species in the canopy layer of the forest exhibit significantly higher efficiency than those in the understory layer. This research significantly contributes to our understanding of carbon cycling and the responses of forest ecosystems to climate change. Moreover, it provides a practical tool for forest management and the development of carbon sequestration strategies.
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Affiliation(s)
- Zhenzhao Xu
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Lihou Qin
- Academy of Inventory and Planning, National Forestry and Grassland Administration, Beijing 100714, China.
| | - Guang Zhou
- Jiangxi Academy of Forestry, Nanchang 330032, China; College of Forestry, Beijing Forestry University, Beijing 100083, China.
| | - Bilige SiQing
- Ordos Forestry and Grassland Development Center, Ordos 017000, China.
| | - Wenxian Du
- Zunyi Nature Reserve Management Service Center, Zunyi 563000, China.
| | - Shengwang Meng
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Jian Yu
- School of Landscape Architecture, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, China.
| | - Zhen Sun
- College of Forestry, Beijing Forestry University, Beijing 100083, China.
| | - Qijing Liu
- College of Forestry, Beijing Forestry University, Beijing 100083, China.
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2
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Paschalis A, De Kauwe MG, Sabot M, Fatichi S. When do plant hydraulics matter in terrestrial biosphere modelling? GLOBAL CHANGE BIOLOGY 2024; 30:e17022. [PMID: 37962234 PMCID: PMC10952296 DOI: 10.1111/gcb.17022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
The ascent of water from the soil to the leaves of vascular plants, described by the study of plant hydraulics, regulates ecosystem responses to environmental forcing and recovery from stress periods. Several approaches to model plant hydraulics have been proposed. In this study, we introduce four different versions of plant hydraulics representations in the terrestrial biosphere model T&C to understand the significance of plant hydraulics to ecosystem functioning. We tested representations of plant hydraulics, investigating plant water capacitance, and long-term xylem damages following drought. The four models we tested were a combination of representations including or neglecting capacitance and including or neglecting xylem damage legacies. Using the models at six case studies spanning semiarid to tropical ecosystems, we quantify how plant xylem flow, plant water storage and long-term xylem damage can modulate overall water and carbon dynamics across multiple time scales. We show that as drought develops, models with plant hydraulics predict a slower onset of plant water stress, and a diurnal variability of water and carbon fluxes closer to observations. Plant water storage was found to be particularly important for the diurnal dynamics of water and carbon fluxes, with models that include plant water capacitance yielding better results. Models including permanent damage to conducting plant tissues show an additional significant drought legacy effect, limiting plant productivity during the recovery phase following major droughts. However, when considering ecosystem responses to the observed climate variability, plant hydraulic modules alone cannot significantly improve the overall model performance, even though they reproduce more realistic water and carbon dynamics. This opens new avenues for model development, explicitly linking plant hydraulics with additional ecosystem processes, such as plant phenology and improved carbon allocation algorithms.
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Affiliation(s)
- Athanasios Paschalis
- Department of Civil and Environmental EngineeringImperial College LondonLondonUK
| | | | - Manon Sabot
- ARC Centre of Excellence for Climate Extremes and Climate Change Research CentreUniversity of New South WalesSydneyNew South WalesAustralia
| | - Simone Fatichi
- Department of Civil and Environmental EngineeringNational University of SingaporeSingaporeSingapore
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3
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Wilcox KR, Chen A, Avolio ML, Butler EE, Collins S, Fisher R, Keenan T, Kiang NY, Knapp AK, Koerner SE, Kueppers L, Liang G, Lieungh E, Loik M, Luo Y, Poulter B, Reich P, Renwick K, Smith MD, Walker A, Weng E, Komatsu KJ. Accounting for herbaceous communities in process-based models will advance our understanding of "grassy" ecosystems. GLOBAL CHANGE BIOLOGY 2023; 29:6453-6477. [PMID: 37814910 DOI: 10.1111/gcb.16950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/01/2023] [Indexed: 10/11/2023]
Abstract
Grassland and other herbaceous communities cover significant portions of Earth's terrestrial surface and provide many critical services, such as carbon sequestration, wildlife habitat, and food production. Forecasts of global change impacts on these services will require predictive tools, such as process-based dynamic vegetation models. Yet, model representation of herbaceous communities and ecosystems lags substantially behind that of tree communities and forests. The limited representation of herbaceous communities within models arises from two important knowledge gaps: first, our empirical understanding of the principles governing herbaceous vegetation dynamics is either incomplete or does not provide mechanistic information necessary to drive herbaceous community processes with models; second, current model structure and parameterization of grass and other herbaceous plant functional types limits the ability of models to predict outcomes of competition and growth for herbaceous vegetation. In this review, we provide direction for addressing these gaps by: (1) presenting a brief history of how vegetation dynamics have been developed and incorporated into earth system models, (2) reporting on a model simulation activity to evaluate current model capability to represent herbaceous vegetation dynamics and ecosystem function, and (3) detailing several ecological properties and phenomena that should be a focus for both empiricists and modelers to improve representation of herbaceous vegetation in models. Together, empiricists and modelers can improve representation of herbaceous ecosystem processes within models. In so doing, we will greatly enhance our ability to forecast future states of the earth system, which is of high importance given the rapid rate of environmental change on our planet.
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Affiliation(s)
- Kevin R Wilcox
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
- University of Wyoming, Laramie, Wyoming, USA
| | - Anping Chen
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Meghan L Avolio
- Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ethan E Butler
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
| | - Scott Collins
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Rosie Fisher
- CICERO Centre for International Cimate Research, Forskningsparken, Oslo, Norway
| | - Trevor Keenan
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nancy Y Kiang
- NASA Goddard Institute for Space Studies, New York, New York, USA
| | - Alan K Knapp
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Sally E Koerner
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
| | - Lara Kueppers
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Guopeng Liang
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
| | - Eva Lieungh
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Michael Loik
- Department of Environmental Studies, University of California, Santa Cruz, California, USA
| | - Yiqi Luo
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Ben Poulter
- Biospheric Sciences Lab, NASA GSFC, Greenbelt, Maryland, USA
| | - Peter Reich
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | | | - Melinda D Smith
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Anthony Walker
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Ensheng Weng
- NASA Goddard Institute for Space Studies, New York, New York, USA
- Center for Climate Systems Research, Columbia University, New York, New York, USA
| | - Kimberly J Komatsu
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
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4
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Feldman AF, Zhang Z, Yoshida Y, Gentine P, Chatterjee A, Entekhabi D, Joiner J, Poulter B. A multi-satellite framework to rapidly evaluate extreme biosphere cascades: The Western US 2021 drought and heatwave. GLOBAL CHANGE BIOLOGY 2023; 29:3634-3651. [PMID: 37070967 DOI: 10.1111/gcb.16725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 04/04/2023] [Indexed: 06/06/2023]
Abstract
The increasing frequency and intensity of climate extremes and complex ecosystem responses motivate the need for integrated observational studies at low latency to determine biosphere responses and carbon-climate feedbacks. Here, we develop a satellite-based rapid attribution workflow and demonstrate its use at a 1-2-month latency to attribute drivers of the carbon cycle feedbacks during the 2020-2021 Western US drought and heatwave. In the first half of 2021, concurrent negative photosynthesis anomalies and large positive column CO2 anomalies were detected with satellites. Using a simple atmospheric mass balance approach, we estimate a surface carbon efflux anomaly of 132 TgC in June 2021, a magnitude corroborated independently with a dynamic global vegetation model. Integrated satellite observations of hydrologic processes, representing the soil-plant-atmosphere continuum (SPAC), show that these surface carbon flux anomalies are largely due to substantial reductions in photosynthesis because of a spatially widespread moisture-deficit propagation through the SPAC between 2020 and 2021. A causal model indicates deep soil moisture stores partially drove photosynthesis, maintaining its values in 2020 and driving its declines throughout 2021. The causal model also suggests legacy effects may have amplified photosynthesis deficits in 2021 beyond the direct effects of environmental forcing. The integrated, observation framework presented here provides a valuable first assessment of a biosphere extreme response and an independent testbed for improving drought propagation and mechanisms in models. The rapid identification of extreme carbon anomalies and hotspots can also aid mitigation and adaptation decisions.
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Affiliation(s)
- Andrew F Feldman
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- NASA Postdoctoral Program, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Zhen Zhang
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA
| | - Yasuko Yoshida
- Science Systems and Applications, Inc. (SSAI), Lanham, Maryland, USA
| | - Pierre Gentine
- Department of Earth and Environmental Engineering, Columbia University, New York, New York, USA
| | - Abhishek Chatterjee
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Dara Entekhabi
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Joanna Joiner
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Benjamin Poulter
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
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5
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Xu H, Zhang Z, Oren R, Wu X. Hyposensitive canopy conductance renders ecosystems vulnerable to meteorological droughts. GLOBAL CHANGE BIOLOGY 2023; 29:1890-1904. [PMID: 36655411 DOI: 10.1111/gcb.16607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 01/07/2023] [Accepted: 01/11/2023] [Indexed: 05/28/2023]
Abstract
Increased meteorological drought intensity with rising atmospheric demand for water (hereafter vapor pressure deficit [VPD]) increases the risk of tree mortality and ecosystem dysfunction worldwide. Ecosystem-scale water-use strategy is increasingly recognized as a key factor in regulating drought-related ecosystem responses. However, the link between water-use strategy and ecosystem vulnerability to meteorological droughts is poorly established. Using the global flux observations, historic hydroclimatic data, remote-sensing products, and plant functional-trait archive, we identified potentially vulnerable ecosystems, examining how ecosystem water-use strategy, quantified by the percentage bias (δ) of the empirical canopy conductance sensitivity to VPD relative to the theoretical value, mediated ecosystem responses to droughts. We found that prevailing soil water availability substantially impacted δ in dryland regions where ecosystems with insufficient soil moisture usually showed conservative water-use strategy, while ecosystems in humid regions exhibited more pronounced climatic adaptability. Hyposensitive and hypersensitive ecosystems, classified based on δ falling below or above the theoretical sensitivity, respectively, achieved similar net ecosystem productivity during droughts, employing different structural and functional strategies. However, hyposensitive ecosystems, risking their hydraulic system with a permissive water-use strategy, were unable to recover from droughts as quickly as hypersensitive ones. Our findings highlight that processed-based models predicting current functions and future performance of vegetation should account for the greater vulnerability of hyposensitive ecosystems to intensifying atmospheric and soil droughts.
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Affiliation(s)
- Hang Xu
- Jixian National Forest Ecosystem Observation and Research Station, CNERN, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of Soil and Water Conservation and Desertification Combating, State Forestry and Grassland Administration, Beijing Forestry University, Beijing, China
| | - Zhiqiang Zhang
- Jixian National Forest Ecosystem Observation and Research Station, CNERN, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of Soil and Water Conservation and Desertification Combating, State Forestry and Grassland Administration, Beijing Forestry University, Beijing, China
| | - Ram Oren
- Nicholas School of the Environment and Pratt School of Engineering, Duke University, North Carolina, Durham, USA
- Department of Forest Science, University of Helsinki, Helsinki, Finland
| | - Xiaoyun Wu
- Jixian National Forest Ecosystem Observation and Research Station, CNERN, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of Soil and Water Conservation and Desertification Combating, State Forestry and Grassland Administration, Beijing Forestry University, Beijing, China
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6
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Tracking 21 st century anthropogenic and natural carbon fluxes through model-data integration. Nat Commun 2022; 13:5516. [PMID: 36163167 PMCID: PMC9512848 DOI: 10.1038/s41467-022-32456-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 08/01/2022] [Indexed: 12/01/2022] Open
Abstract
Monitoring the implementation of emission commitments under the Paris agreement relies on accurate estimates of terrestrial carbon fluxes. Here, we assimilate a 21st century observation-based time series of woody vegetation carbon densities into a bookkeeping model (BKM). This approach allows us to disentangle the observation-based carbon fluxes by terrestrial woody vegetation into anthropogenic and environmental contributions. Estimated emissions (from land-use and land cover changes) between 2000 and 2019 amount to 1.4 PgC yr−1, reducing the difference to other carbon cycle model estimates by up to 88% compared to previous estimates with the BKM (without the data assimilation). Our estimates suggest that the global woody vegetation carbon sink due to environmental processes (1.5 PgC yr−1) is weaker and more susceptible to interannual variations and extreme events than estimated by state-of-the-art process-based carbon cycle models. These findings highlight the need to advance model-data integration to improve estimates of the terrestrial carbon cycle under the Global Stocktake. Accurate estimates of carbon fluxes are important to our understanding of the carbon cycle. Here, via model-data integration, the authors disentangle anthropogenic and environmental carbon flux contributions of terrestrial woody vegetation, and find that environmental processes are weaker and more susceptible to interannual variations and extreme events in the 21st century than previously estimated.
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7
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Effect of tree demography and flexible root water uptake for modeling the carbon and water cycles of Amazonia. Ecol Modell 2022. [DOI: 10.1016/j.ecolmodel.2022.109969] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Hartmann H, Bastos A, Das AJ, Esquivel-Muelbert A, Hammond WM, Martínez-Vilalta J, McDowell NG, Powers JS, Pugh TAM, Ruthrof KX, Allen CD. Climate Change Risks to Global Forest Health: Emergence of Unexpected Events of Elevated Tree Mortality Worldwide. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:673-702. [PMID: 35231182 DOI: 10.1146/annurev-arplant-102820-012804] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Recent observations of elevated tree mortality following climate extremes, like heat and drought, raise concerns about climate change risks to global forest health. We currently lack both sufficient data and understanding to identify whether these observations represent a global trend toward increasing tree mortality. Here, we document events of sudden and unexpected elevated tree mortality following heat and drought events in ecosystems that previously were considered tolerant or not at risk of exposure. These events underscore the fact that climate change may affect forests with unexpected force in the future. We use the events as examples to highlight current difficulties and challenges for realistically predicting such tree mortality events and the uncertainties about future forest condition. Advances in remote sensing technology and greater availably of high-resolution data, from both field assessments and satellites, are needed to improve both understanding and prediction of forest responses to future climate change.
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Affiliation(s)
- Henrik Hartmann
- Max Planck Institute for Biogeochemistry, Department of Biogeochemical Processes, Jena, Germany;
| | - Ana Bastos
- Max Planck Institute for Biogeochemistry, Department of Biogeochemical Integration, Jena, Germany
| | - Adrian J Das
- US Geological Survey, Western Ecological Research Center, Three Rivers, Sequoia and Kings Canyon Field Station, California, USA
| | - Adriane Esquivel-Muelbert
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - William M Hammond
- Agronomy Department, University of Florida, Gainesville, Florida, USA
| | - Jordi Martínez-Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Lab, Richland, Washington, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Jennifer S Powers
- Departments of Ecology, Evolution and Behavior and Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
| | - Thomas A M Pugh
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Katinka X Ruthrof
- Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia
- Murdoch University, Murdoch, Western Australia, Australia
| | - Craig D Allen
- Department of Geography and Environmental Studies, University of New Mexico, Albuquerque, New Mexico, USA
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9
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A deep learning-based hybrid model of global terrestrial evaporation. Nat Commun 2022; 13:1912. [PMID: 35395845 PMCID: PMC8993934 DOI: 10.1038/s41467-022-29543-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 03/22/2022] [Indexed: 12/21/2022] Open
Abstract
Terrestrial evaporation (E) is a key climatic variable that is controlled by a plethora of environmental factors. The constraints that modulate the evaporation from plant leaves (or transpiration, Et) are particularly complex, yet are often assumed to interact linearly in global models due to our limited knowledge based on local studies. Here, we train deep learning algorithms using eddy covariance and sap flow data together with satellite observations, aiming to model transpiration stress (St), i.e., the reduction of Et from its theoretical maximum. Then, we embed the new St formulation within a process-based model of E to yield a global hybrid E model. In this hybrid model, the St formulation is bidirectionally coupled to the host model at daily timescales. Comparisons against in situ data and satellite-based proxies demonstrate an enhanced ability to estimate St and E globally. The proposed framework may be extended to improve the estimation of E in Earth System Models and enhance our understanding of this crucial climatic variable. Global evaporation is a key climatic process that remains highly uncertain. Here, the authors shed light on this process with a novel hybrid model that integrates a deep learning representation of ecosystem stress within a physics-based framework.
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10
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Saunders A, Drew DM. Stomatal responses of Eucalyptus spp. under drought can be predicted with a gain-risk optimization model. TREE PHYSIOLOGY 2022; 42:815-830. [PMID: 34791492 DOI: 10.1093/treephys/tpab145] [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: 09/10/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
The frequency and severity of drought events are expected to increase due to climate change, with optimal environmental conditions for forestry likely to shift. Modeling plant responses to a changing climate is therefore vital. We tested the process-based gain-risk model to predict stomatal responses to drought of two Eucalyptus hybrids. The process-based gain-risk model has the advantage that all the parameters used within the model are based on measurable plant traits. The gain-risk model proposes that plants optimize photosynthetic gain while minimizing a hydraulic cost. Previous versions of the model used hydraulic risk as a cost function; however, they did not account for delayed or reduced hydraulic recovery rates from embolism post-drought. Hydraulic recovery has been seen in many species, however it is still unclear how this inclusion of a partial or delayed hydraulic recovery would affect the predictive power of the gain-risk model. Many hydraulic parameters required by the model are also difficult to measure and are not freely available. We therefore tested a simplified gain-risk model that includes a delayed or reduced hydraulic recovery component post-drought. The simplified gain-risk model performed well at predicting stomatal responses in both Eucalyptus grandis × camaldulensis (GC) and Eucalyptus urophylla × grandis (UG). In this study two distinct strategies were seen between GC and UG, with GC being more resistant to embolism formation, however it could not recover hydraulic conductance compared with UG. The inclusion of a delayed or reduced hydraulic recovery component slightly improved model predictions for GC, however not for UG, which can be related to UG being able to recover lost hydraulic conductance and therefore can maintain stomatal conductance regardless of hydraulic risk. Even though the gain-risk model shows promise in predicting plant responses, more information is needed regarding hydraulic recovery after drought.
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Affiliation(s)
- Alta Saunders
- Department of Forest and Wood Science, Stellenbosch University, Paul Sauer Building, Bosman St, Stellenbosch Central, Stellenbosch, 7599, South Africa
| | - David M Drew
- Department of Forest and Wood Science, Stellenbosch University, Paul Sauer Building, Bosman St, Stellenbosch Central, Stellenbosch, 7599, South Africa
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11
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Wang Y, Xiao J, Li X, Niu S. Global evidence on the asymmetric response of gross primary productivity to interannual precipitation changes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 814:152786. [PMID: 34990664 DOI: 10.1016/j.scitotenv.2021.152786] [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: 09/17/2021] [Revised: 12/24/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
Understanding gross primary productivity (GPP) response to precipitation (PPT) changes is essential for predicting land carbon uptake under increasing PPT variability and extremes. Previous studies found that ecosystem GPP may have an asymmetric response to PPT changes, leading to the inconsistency of GPP gains in wet years compared to GPP declines in dry years. However, it is unclear how the asymmetric responses vary among vegetation types and under different PPT variabilities. This study evaluated the global patterns of asymmetries of GPP response to different PPT changes using two state-of-science global GPP datasets. The result shows that under mild PPT changes (|ΔPPT| ≤ 25%), grasslands, savannas, shrublands, and tundra show positive asymmetric responses (i.e., larger GPP gains in wet years than GPP losses in dry years), while other vegetation types show negative asymmetric responses (i.e., larger GPP losses in dry years than GPP gains in wet years). Conversely, all vegetation types show negative GPP asymmetric responses to moderate (25% < |ΔPPT| ≤ 50%) and extreme (|ΔPPT| > 50%) PPT changes. Thus, we propose a new non-linear asymmetric GPP-PPT model that incorporates three modes with regards to vegetation types. Meanwhile, we found that the spatial patterns of asymmetry were mainly driven by PPT amount and variability. Stronger and negative asymmetries were found in areas with smaller PPT amount and variability, while positive asymmetries were found in areas with higher PPT variability. These findings promote our understanding of carbon dynamics under increased PPT variability and extremes and provide new insights for land models to better predict future carbon uptake and its feedback to climate change.
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Affiliation(s)
- Yiheng Wang
- Key Laboratory of Ecosystem Network Observation and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; School of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingfeng Xiao
- Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA
| | - Xing Li
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Shuli Niu
- Key Laboratory of Ecosystem Network Observation and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; School of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
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12
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Light and Water Conditions Co-Regulated Stomata and Leaf Relative Uptake Rate (LRU) during Photosynthesis and COS Assimilation: A Meta-Analysis. SUSTAINABILITY 2022. [DOI: 10.3390/su14052840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
As a trace gas involved in hydration during plant photosynthesis, carbonyl sulfide (COS) and its leaf relative uptake rate (LRU) is used to reduce the uncertainties in simulations of gross primary productivity (GPP). In this study, 101 independent observations were collected from 22 studies. We extracted the LRU, stomatal conductance (gs), canopy COS and carbon dioxide (CO2) fluxes, and relevant environmental conditions (i.e., light, temperature, and humidity), as well as the atmospheric COS and CO2 concentrations (Ca,COS and Ca,CO2). Although no evidence was found showing that gs regulates LRU, they responded in opposite ways to diurnal variations of environmental conditions in both mixed forests (LRU: Hedges’d = −0.901, LnRR = −0.189; gs: Hedges’d = 0.785, LnRR = 0.739) and croplands dominated by C3 plants (Hedges’d = −0.491, LnRR = −0.371; gs: Hedges’d = 1.066, LnRR = 0.322). In this process, the stomata play an important role in COS assimilation (R2 = 0.340, p = 0.020) and further influence the interrelationship of COS and CO2 fluxes (R2 = 0.650, p = 0.000). Slight increases in light intensity (R2 = 1, p = 0.002) and atmospheric drought (R2 = 0.885, p = 0.005) also decreased the LRU. The LRU saturation points of Ca,COS and Ca,CO2 were observed when ΔCa,COS ≈ 13 ppt (R2 = 0.580, p = 0.050) or ΔCa,CO2 ≈ −18 ppm (R2 = 0.970, p = 0.003). This study concluded that during plant photosynthesis and COS assimilation, light and water conditions co-regulated the stomata and LRU.
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Impact of Ice-Storms and Subsequent Salvage Logging on the Productivity of Cunninghamia lanceolata (Chinese Fir) Forests. FORESTS 2022. [DOI: 10.3390/f13020296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The impacts of ice-storms on forests have received growing attention in recent years. Although there is a wide agreement that ice-storms significantly affect forest structure and functions, how frequent ice-storms and subsequent salvage logging impact productivity of subtropical coniferous forests in the future still remains poorly understood. In this study, we used the Ecosystem Demography model, Version 2.2 (ED-2.2), to project the impact of salvage logging of ice-storm-damaged trees on the productivity of Cunninghamia lanceolata-dominated coniferous forest and C. lanceolata-dominated mixed coniferous and broadleaved forests. The results show that forest productivity recovery is delayed in coniferous forests when there is no shade-tolerant broadleaved species invasion after ice-storms, and C. lanceolata could continue to dominate the canopy in the mixed coniferous and broadleaved forests under high-frequency ice-storms and subsequent salvage logging. The resistance and resilience of the mixed coniferous and broadleaved forests to high-frequency ice-storms and subsequent salvage logging were stronger compared to coniferous forests. Although conifers could continue to dominate the canopy under shade-tolerant broadleaved species invasion, we could not rule out the possibility of a future forest community dominated by shade-tolerant broadleaf trees because there were few coniferous saplings and shade-tolerant broadleaf species dominated the understory. Our results highlight that post-disaster forest management should be continued after high-frequency ice-storms and subsequent salvage logging in C. lanceolata forests to prevent possible shade-tolerant, late successional broadleaf trees from dominating the canopy in the future.
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14
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Exploring the ecosystem resilience concept with land surface model scenarios. Ecol Modell 2022. [DOI: 10.1016/j.ecolmodel.2021.109817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Meunier F, Visser MD, Shiklomanov A, Dietze MC, Guzmán Q. JA, Sanchez‐Azofeifa GA, De Deurwaerder HPT, Krishna Moorthy SM, Schnitzer SA, Marvin DC, Longo M, Liu C, Broadbent EN, Almeyda Zambrano AM, Muller‐Landau HC, Detto M, Verbeeck H. Liana optical traits increase tropical forest albedo and reduce ecosystem productivity. GLOBAL CHANGE BIOLOGY 2022; 28:227-244. [PMID: 34651375 PMCID: PMC9298317 DOI: 10.1111/gcb.15928] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/30/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Lianas are a key growth form in tropical forests. Their lack of self-supporting tissues and their vertical position on top of the canopy make them strong competitors of resources. A few pioneer studies have shown that liana optical traits differ on average from those of colocated trees. Those trait discrepancies were hypothesized to be responsible for the competitive advantage of lianas over trees. Yet, in the absence of reliable modelling tools, it is impossible to unravel their impact on the forest energy balance, light competition, and on the liana success in Neotropical forests. To bridge this gap, we performed a meta-analysis of the literature to gather all published liana leaf optical spectra, as well as all canopy spectra measured over different levels of liana infestation. We then used a Bayesian data assimilation framework applied to two radiative transfer models (RTMs) covering the leaf and canopy scales to derive tropical tree and liana trait distributions, which finally informed a full dynamic vegetation model. According to the RTMs inversion, lianas grew thinner, more horizontal leaves with lower pigment concentrations. Those traits made the lianas very efficient at light interception and significantly modified the forest energy balance and its carbon cycle. While forest albedo increased by 14% in the shortwave, light availability was reduced in the understorey (-30% of the PAR radiation) and soil temperature decreased by 0.5°C. Those liana-specific traits were also responsible for a significant reduction of tree (-19%) and ecosystem (-7%) gross primary productivity (GPP) while lianas benefited from them (their GPP increased by +27%). This study provides a novel mechanistic explanation to the increase in liana abundance, new evidence of the impact of lianas on forest functioning, and paves the way for the evaluation of the large-scale impacts of lianas on forest biogeochemical cycles.
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Affiliation(s)
- Félicien Meunier
- CAVElab—Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
- Department of Earth and EnvironmentBoston UniversityBostonMassachusettsUSA
| | - Marco D. Visser
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNew JerseyUSA
- Institute of Environmental SciencesLeiden UniversityLeidenThe Netherlands
| | | | - Michael C. Dietze
- Department of Earth and EnvironmentBoston UniversityBostonMassachusettsUSA
| | - J. Antonio Guzmán Q.
- Centre for Earth Observation Sciences (CEOS)Earth and Atmospheric Sciences DepartmentUniversity of AlbertaEdmontonAlbertaCanada
| | - G. Arturo Sanchez‐Azofeifa
- Centre for Earth Observation Sciences (CEOS)Earth and Atmospheric Sciences DepartmentUniversity of AlbertaEdmontonAlbertaCanada
- Smithsonian Tropical Research InstituteBalboaPanama
| | | | - Sruthi M. Krishna Moorthy
- CAVElab—Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
| | - Stefan A. Schnitzer
- Smithsonian Tropical Research InstituteBalboaPanama
- Department of Biological SciencesMarquette UniversityMilwaukeeWisconsinUSA
| | | | - Marcos Longo
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCaliforniaUSA
| | - Chang Liu
- CAVElab—Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
| | - Eben N. Broadbent
- Spatial Ecology and Conservation (SPEC) Lab, School of Forest, Fisheries, and Geomatics SciencesUniversity of FloridaGainesvilleFloridaUSA
- Spatial Ecology and Conservation (SPEC) Lab, Center for Latin American StudiesUniversity of FloridaGainesvilleFloridaUSA
| | - Angelica M. Almeyda Zambrano
- Spatial Ecology and Conservation (SPEC) Lab, Center for Latin American StudiesUniversity of FloridaGainesvilleFloridaUSA
| | | | - Matteo Detto
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNew JerseyUSA
- Smithsonian Tropical Research InstituteBalboaPanama
| | - Hans Verbeeck
- CAVElab—Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
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16
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Liu Q, Peng C, Schneider R, Cyr D, Liu Z, Zhou X, Kneeshaw D. TRIPLEX-Mortality model for simulating drought-induced tree mortality in boreal forests: Model development and evaluation. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2021.109652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Chitra‐Tarak R, Xu C, Aguilar S, Anderson‐Teixeira KJ, Chambers J, Detto M, Faybishenko B, Fisher RA, Knox RG, Koven CD, Kueppers LM, Kunert N, Kupers SJ, McDowell NG, Newman BD, Paton SR, Pérez R, Ruiz L, Sack L, Warren JM, Wolfe BT, Wright C, Wright SJ, Zailaa J, McMahon SM. Hydraulically-vulnerable trees survive on deep-water access during droughts in a tropical forest. THE NEW PHYTOLOGIST 2021; 231:1798-1813. [PMID: 33993520 PMCID: PMC8457149 DOI: 10.1111/nph.17464] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 04/29/2021] [Indexed: 05/24/2023]
Abstract
Deep-water access is arguably the most effective, but under-studied, mechanism that plants employ to survive during drought. Vulnerability to embolism and hydraulic safety margins can predict mortality risk at given levels of dehydration, but deep-water access may delay plant dehydration. Here, we tested the role of deep-water access in enabling survival within a diverse tropical forest community in Panama using a novel data-model approach. We inversely estimated the effective rooting depth (ERD, as the average depth of water extraction), for 29 canopy species by linking diameter growth dynamics (1990-2015) to vapor pressure deficit, water potentials in the whole-soil column, and leaf hydraulic vulnerability curves. We validated ERD estimates against existing isotopic data of potential water-access depths. Across species, deeper ERD was associated with higher maximum stem hydraulic conductivity, greater vulnerability to xylem embolism, narrower safety margins, and lower mortality rates during extreme droughts over 35 years (1981-2015) among evergreen species. Species exposure to water stress declined with deeper ERD indicating that trees compensate for water stress-related mortality risk through deep-water access. The role of deep-water access in mitigating mortality of hydraulically-vulnerable trees has important implications for our predictive understanding of forest dynamics under current and future climates.
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18
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Jiang M, Kelly JWG, Atwell BJ, Tissue DT, Medlyn BE. Drought by CO 2 interactions in trees: a test of the water savings mechanism. THE NEW PHYTOLOGIST 2021; 230:1421-1434. [PMID: 33496969 DOI: 10.1111/nph.17233] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
Elevated atmospheric CO2 (eCa ) may benefit plants during drought by reducing stomatal conductance (gs ) but any 'water savings effect' could be neutralized by concurrent stimulation of leaf area. We investigated whether eCa enhanced water savings, thereby ameliorating the impact of drought on carbon and water relations in trees. We report leaf-level gas exchange and whole-plant and soil water relations during a short-term dry-down in two Eucalyptus species with contrasting drought tolerance. Plants had previously been established for 9 to 11 months in steady-state conditions of ambient atmospheric CO2 (aCa ) and eCa , with half of each treatment group exposed to sustained drought for 5 to 7 months. The lower stomatal conductance under eCa did not lead to soil moisture savings during the dry-down due to the counteractive effect of increased whole-plant leaf area. Nonetheless, eCa -grown plants maintained higher photosynthetic rates and leaf water potentials, making them less stressed during the dry-down, despite being larger. These effects were more pronounced in the xeric species than the mesic species, and in previously water-stressed plants. Our findings indicate that eCa may enhance plant performance during drought despite a lack of soil water savings, especially in species with more conservative growth and water-use strategies.
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Affiliation(s)
- Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Jeff W G Kelly
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
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19
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Restrepo-Coupe N, Albert LP, Longo M, Baker I, Levine NM, Mercado LM, da Araujo AC, Christoffersen BO, Costa MH, Fitzjarrald DR, Galbraith D, Imbuzeiro H, Malhi Y, von Randow C, Zeng X, Moorcroft P, Saleska SR. Understanding water and energy fluxes in the Amazonia: Lessons from an observation-model intercomparison. GLOBAL CHANGE BIOLOGY 2021; 27:1802-1819. [PMID: 33565692 DOI: 10.1111/gcb.15555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 01/18/2021] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Tropical forests are an important part of global water and energy cycles, but the mechanisms that drive seasonality of their land-atmosphere exchanges have proven challenging to capture in models. Here, we (1) report the seasonality of fluxes of latent heat (LE), sensible heat (H), and outgoing short and longwave radiation at four diverse tropical forest sites across Amazonia-along the equator from the Caxiuanã and Tapajós National Forests in the eastern Amazon to a forest near Manaus, and from the equatorial zone to the southern forest in Reserva Jaru; (2) investigate how vegetation and climate influence these fluxes; and (3) evaluate land surface model performance by comparing simulations to observations. We found that previously identified failure of models to capture observed dry-season increases in evapotranspiration (ET) was associated with model overestimations of (1) magnitude and seasonality of Bowen ratios (relative to aseasonal observations in which sensible was only 20%-30% of the latent heat flux) indicating model exaggerated water limitation, (2) canopy emissivity and reflectance (albedo was only 10%-15% of incoming solar radiation, compared to 0.15%-0.22% simulated), and (3) vegetation temperatures (due to underestimation of dry-season ET and associated cooling). These partially compensating model-observation discrepancies (e.g., higher temperatures expected from excess Bowen ratios were partially ameliorated by brighter leaves and more interception/evaporation) significantly biased seasonal model estimates of net radiation (Rn ), the key driver of water and energy fluxes (LE ~ 0.6 Rn and H ~ 0.15 Rn ), though these biases varied among sites and models. A better representation of energy-related parameters associated with dynamic phenology (e.g., leaf optical properties, canopy interception, and skin temperature) could improve simulations and benchmarking of current vegetation-atmosphere exchange and reduce uncertainty of regional and global biogeochemical models.
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Affiliation(s)
- Natalia Restrepo-Coupe
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
| | - Loren P Albert
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
- Biology Department, West Virginia University, Morgantown, WV, USA
| | - Marcos Longo
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Ian Baker
- Colorado State University, Atmospheric Science, Fort Collins, CO, USA
| | - Naomi M Levine
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- College of Letters, Arts, and Science, University of Southern California, Los Angeles, CA, USA
| | - Lina M Mercado
- University of Exeter, College of Life and Environmental Sciences, Exeter, Devon, UK
- Centre for Ecology and Hydrology, Wallingford, Oxfordshire, UK
| | - Alessandro C da Araujo
- Embrapa Amazônia Oriental, Belém, Pará, Brazil
- Programa LBA, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil
| | - Bradley O'Donnell Christoffersen
- Department of Biology, University of Texas Rio Grande Valley, Edinburg, TX, USA
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Marcos H Costa
- Department of Agricultural Engineering, Federal University of Vicosa, Vicosa, Mato Grosso, Brazil
| | | | | | - Hewlley Imbuzeiro
- Department of Agricultural Engineering, Federal University of Vicosa, Vicosa, Mato Grosso, Brazil
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Celso von Randow
- National Institute for Space Research (INPE), Center for Earth Systems Science, São José dos Campos, São Pablo, Brazil
| | - Xubin Zeng
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
| | - Paul Moorcroft
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Scott R Saleska
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
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20
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Assessment of SITE for CO2 and Energy Fluxes Simulations in a Seasonally Dry Tropical Forest (Caatinga Ecosystem). FORESTS 2021. [DOI: 10.3390/f12010086] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Although seasonally dry tropical forests are considered invaluable to a greater understanding of global carbon fluxes, they remain as one of the ecosystems with the fewest observations. In this context, ecological and ecosystem models can be used as alternative methods to answer questions related to the interactions between the biosphere and the atmosphere in dry forests. The objective of this study was to calibrate the simple tropical ecosystem model (SITE) and evaluate its performance in characterizing the annual and seasonal behavior of the energy and carbon fluxes in a preserved fragment of the Caatinga biome. The SITE model exhibited reasonable applicability to simulate variations in CO2 and energy fluxes (r > 0.7). Results showed that the calibrated set of vegetation parameters adequately simulated gross primary productivity (GPP) and net ecosystem CO2 exchange (NEE). The SITE model was also able to accurately retrieve the time at which daily GPP and NEE peaked. The model was able to simulate the partition of the available energy into sensible and latent heat fluxes and soil heat flux when the calibrated parameters were used. Therefore, changes in the dynamics of dry forests should be taken into consideration in the modeling of ecosystem carbon balances.
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21
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Meunier F, Verbeeck H, Cowdery B, Schnitzer SA, Smith‐Martin CM, Powers JS, Xu X, Slot M, De Deurwaerder HPT, Detto M, Bonal D, Longo M, Santiago LS, Dietze M. Unraveling the relative role of light and water competition between lianas and trees in tropical forests: A vegetation model analysis. THE JOURNAL OF ECOLOGY 2021; 109:519-540. [PMID: 33536686 PMCID: PMC7839527 DOI: 10.1111/1365-2745.13540] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 10/16/2020] [Indexed: 05/05/2023]
Abstract
Despite their low contribution to forest carbon stocks, lianas (woody vines) play an important role in the carbon dynamics of tropical forests. As structural parasites, they hinder tree survival, growth and fecundity; hence, they negatively impact net ecosystem productivity and long-term carbon sequestration.Competition (for water and light) drives various forest processes and depends on the local abundance of resources over time. However, evaluating the relative role of resource availability on the interactions between lianas and trees from empirical observations is particularly challenging. Previous approaches have used labour-intensive and ecosystem-scale manipulation experiments, which are infeasible in most situations.We propose to circumvent this challenge by evaluating the uncertainty of water and light capture processes of a process-based vegetation model (ED2) including the liana growth form. We further developed the liana plant functional type in ED2 to mechanistically simulate water uptake and transport from roots to leaves, and start the model from prescribed initial conditions. We then used the PEcAn bioinformatics platform to constrain liana parameters and run uncertainty analyses.Baseline runs successfully reproduced ecosystem gas exchange fluxes (gross primary productivity and latent heat) and forest structural features (leaf area index, aboveground biomass) in two sites (Barro Colorado Island, Panama and Paracou, French Guiana) characterized by different rainfall regimes and levels of liana abundance.Model uncertainty analyses revealed that water limitation was the factor driving the competition between trees and lianas at the drier site (BCI), and during the relatively short dry season of the wetter site (Paracou). In young patches, light competition dominated in Paracou but alternated with water competition between the wet and the dry season on BCI according to the model simulations.The modelling workflow also identified key liana traits (photosynthetic quantum efficiency, stomatal regulation parameters, allometric relationships) and processes (water use, respiration, climbing) driving the model uncertainty. They should be considered as priorities for future data acquisition and model development to improve predictions of the carbon dynamics of liana-infested forests. Synthesis. Competition for water plays a larger role in the interaction between lianas and trees than previously hypothesized, as demonstrated by simulations from a process-based vegetation model.
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Affiliation(s)
- Félicien Meunier
- Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
- Department of Earth and EnvironmentBoston UniversityBostonMAUSA
| | - Hans Verbeeck
- Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
| | - Betsy Cowdery
- Department of Earth and EnvironmentBoston UniversityBostonMAUSA
| | - Stefan A. Schnitzer
- Smithsonian Tropical Research InstituteApartadoPanama
- Department of Biological SciencesMarquette UniversityMilwaukeeWIUSA
| | - Chris M. Smith‐Martin
- Department of Ecology, Evolution and Evolutionary BiologyColumbia UniversityNew YorkNYUSA
| | - Jennifer S. Powers
- Smithsonian Tropical Research InstituteApartadoPanama
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
| | - Xiangtao Xu
- Department of Ecology and Evolutionary BiologyCornell UniversityIthacaNYUSA
| | - Martijn Slot
- Smithsonian Tropical Research InstituteApartadoPanama
| | - Hannes P. T. De Deurwaerder
- Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNJUSA
| | - Matteo Detto
- Smithsonian Tropical Research InstituteApartadoPanama
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNJUSA
| | - Damien Bonal
- Université de LorraineAgroParisTechINRAEUMR SilvaNancyFrance
| | - Marcos Longo
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Louis S. Santiago
- Smithsonian Tropical Research InstituteApartadoPanama
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCAUSA
| | - Michael Dietze
- Department of Earth and EnvironmentBoston UniversityBostonMAUSA
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22
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Wilcox KR, Komatsu KJ, Avolio ML. Improving collaborations between empiricists and modelers to advance grassland community dynamics in ecosystem models. THE NEW PHYTOLOGIST 2020; 228:1467-1471. [PMID: 33460147 DOI: 10.1111/nph.16900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Kevin R Wilcox
- Department of Ecosystem Science and Management, University of Wyoming, Laramie, WY, 82071, USA
| | | | - Meghan L Avolio
- Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, 21218, USA
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23
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De Kauwe MG, Medlyn BE, Ukkola AM, Mu M, Sabot MEB, Pitman AJ, Meir P, Cernusak LA, Rifai SW, Choat B, Tissue DT, Blackman CJ, Li X, Roderick M, Briggs PR. Identifying areas at risk of drought-induced tree mortality across South-Eastern Australia. GLOBAL CHANGE BIOLOGY 2020; 26:5716-5733. [PMID: 32512628 DOI: 10.1111/gcb.15215] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
South-East Australia has recently been subjected to two of the worst droughts in the historical record (Millennium Drought, 2000-2009 and Big Dry, 2017-2019). Unfortunately, a lack of forest monitoring has made it difficult to determine whether widespread tree mortality has resulted from these droughts. Anecdotal observations suggest the Big Dry may have led to more significant tree mortality than the Millennium drought. Critically, to be able to robustly project future expected climate change effects on Australian vegetation, we need to assess the vulnerability of Australian trees to drought. Here we implemented a model of plant hydraulics into the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model. We parameterized the drought response behaviour of five broad vegetation types, based on a common garden dry-down experiment with species originating across a rainfall gradient (188-1,125 mm/year) across South-East Australia. The new hydraulics model significantly improved (~35%-45% reduction in root mean square error) CABLE's previous predictions of latent heat fluxes during periods of water stress at two eddy covariance sites in Australia. Landscape-scale predictions of the greatest percentage loss of hydraulic conductivity (PLC) of about 40%-60%, were broadly consistent with satellite estimates of regions of the greatest change in both droughts. In neither drought did CABLE predict that trees would have reached critical PLC in widespread areas (i.e. it projected a low mortality risk), although the model highlighted critical levels near the desert regions of South-East Australia where few trees live. Overall, our experimentally constrained model results imply significant resilience to drought conferred by hydraulic function, but also highlight critical data and scientific gaps. Our approach presents a promising avenue to integrate experimental data and make regional-scale predictions of potential drought-induced hydraulic failure.
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Affiliation(s)
- Martin G De Kauwe
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
- Evolution & Ecology Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Anna M Ukkola
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
| | - Mengyuan Mu
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Manon E B Sabot
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
- Evolution & Ecology Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Andrew J Pitman
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Patrick Meir
- Research School of Biology, The Australian National University, Acton, ACT, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, Australia
| | - Sami W Rifai
- Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Chris J Blackman
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Ximeng Li
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Michael Roderick
- ARC Centre of Excellence for Climate Extremes, Sydney, NSW, Australia
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
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Braghiere RK, Gérard F, Evers JB, Pradal C, Pagès L. Simulating the effects of water limitation on plant biomass using a 3D functional-structural plant model of shoot and root driven by soil hydraulics. ANNALS OF BOTANY 2020; 126:713-728. [PMID: 32249296 PMCID: PMC7489072 DOI: 10.1093/aob/mcaa059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 04/02/2020] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS Improved modelling of carbon assimilation and plant growth to low soil moisture requires evaluation of underlying mechanisms in the soil, roots, and shoots. The feedback between plants and their local environment throughout the whole spectrum soil-root-shoot-environment is crucial to accurately describe and evaluate the impact of environmental changes on plant development. This study presents a 3D functional structural plant model, in which shoot and root growth are driven by radiative transfer, photosynthesis, and soil hydrodynamics through different parameterisation schemes relating soil water deficit and carbon assimilation. The new coupled model is used to evaluate the impact of soil moisture availability on plant productivity for two different groups of flowering plants under different spatial configurations. METHODS In order to address different aspects of plant development due to limited soil water availability, a 3D FSP model including root, shoot, and soil was constructed by linking three different well-stablished models of airborne plant, root architecture, and reactive transport in the soil. Different parameterisation schemes were used in order to integrate photosynthetic rate with root water uptake within the coupled model. The behaviour of the model was assessed on how the growth of two different types of plants, i.e. monocot and dicot, is impacted by soil water deficit under different competitive conditions: isolated (no competition), intra, and interspecific competition. KEY RESULTS The model proved to be capable of simulating carbon assimilation and plant development under different growing settings including isolated monocots and dicots, intra, and interspecific competition. The model predicted that (1) soil water availability has a larger impact on photosynthesis than on carbon allocation; (2) soil water deficit has an impact on root and shoot biomass production by up to 90 % for monocots and 50 % for dicots; and (3) the improved dicot biomass production in interspecific competition was highly related to root depth and plant transpiration. CONCLUSIONS An integrated model of 3D shoot architecture and biomass development with a 3D root system representation, including light limitation and water uptake considering soil hydraulics, was presented. Plant-plant competition and regulation on stomatal conductance to drought were able to be predicted by the model. In the cases evaluated here, water limitation impacted plant growth almost 10 times more than the light environment.
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Affiliation(s)
- Renato K Braghiere
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- Joint Institute for Regional Earth System Science and Engineering, University of California at Los Angeles, Los Angeles, CA, USA
- Eco&Sols, Univ. Montpellier, CIRAD, INRAE, IRD, SupAgro, Montpellier, France
| | - Frédéric Gérard
- Eco&Sols, Univ. Montpellier, CIRAD, INRAE, IRD, SupAgro, Montpellier, France
| | - Jochem B Evers
- Centre for Crop Systems Analysis (CSA), Wageningen University, Wageningen, The Netherlands
| | - Christophe Pradal
- CIRAD, UMR AGAP, Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRAE, SupAgro, Montpellier, France
- INRIA, Univ. Montpellier, France
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25
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Longo M, Saatchi S, Keller M, Bowman K, Ferraz A, Moorcroft PR, Morton DC, Bonal D, Brando P, Burban B, Derroire G, dos‐Santos MN, Meyer V, Saleska S, Trumbore S, Vincent G. Impacts of Degradation on Water, Energy, and Carbon Cycling of the Amazon Tropical Forests. JOURNAL OF GEOPHYSICAL RESEARCH. BIOGEOSCIENCES 2020; 125:e2020JG005677. [PMID: 32999796 PMCID: PMC7507752 DOI: 10.1029/2020jg005677] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/28/2020] [Accepted: 06/02/2020] [Indexed: 05/31/2023]
Abstract
Selective logging, fragmentation, and understory fires directly degrade forest structure and composition. However, studies addressing the effects of forest degradation on carbon, water, and energy cycles are scarce. Here, we integrate field observations and high-resolution remote sensing from airborne lidar to provide realistic initial conditions to the Ecosystem Demography Model (ED-2.2) and investigate how disturbances from forest degradation affect gross primary production (GPP), evapotranspiration (ET), and sensible heat flux (H). We used forest structural information retrieved from airborne lidar samples (13,500 ha) and calibrated with 817 inventory plots (0.25 ha) across precipitation and degradation gradients in the eastern Amazon as initial conditions to ED-2.2 model. Our results show that the magnitude and seasonality of fluxes were modulated by changes in forest structure caused by degradation. During the dry season and under typical conditions, severely degraded forests (biomass loss ≥66%) experienced water stress with declines in ET (up to 34%) and GPP (up to 35%) and increases of H (up to 43%) and daily mean ground temperatures (up to 6.5°C) relative to intact forests. In contrast, the relative impact of forest degradation on energy, water, and carbon cycles markedly diminishes under extreme, multiyear droughts, as a consequence of severe stress experienced by intact forests. Our results highlight that the water and energy cycles in the Amazon are driven by not only climate and deforestation but also the past disturbance and changes of forest structure from degradation, suggesting a much broader influence of human land use activities on the tropical ecosystems.
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Affiliation(s)
- Marcos Longo
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Sassan Saatchi
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
- Institute of Environment and SustainabilityUniversity of CaliforniaLos AngelesCAUSA
| | - Michael Keller
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
- International Institute of Tropical ForestryUSDA Forest ServiceRio PiedrasPuerto Rico
- Embrapa Informática AgropecuáriaCampinasBrazil
| | - Kevin Bowman
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - António Ferraz
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
- Institute of Environment and SustainabilityUniversity of CaliforniaLos AngelesCAUSA
| | - Paul R. Moorcroft
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMAUSA
| | | | - Damien Bonal
- Université de Lorraine, INRAE, AgroParisTech, UMR SilvaNancyFrance
| | - Paulo Brando
- Department of Earth System ScienceUniversity of CaliforniaIrvineCAUSA
- Woods Hole Research CenterWoods HoleMAUSA
- Instituto de Pesquisa Ambiental da AmazôniaBrasíliaBrazil
| | - Benoît Burban
- Institut National de Recherche en Agriculture, Alimentation et Environnement (INRAE), UMR 0745 EcoFoG, Campus AgronomiqueKourouFrance
| | - Géraldine Derroire
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UMR EcoFoG (Agroparistech, CNRS, INRAE, Université des Antilles, Université de Guyane), Campus AgronomiqueKourouFrance
| | | | - Victoria Meyer
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Scott Saleska
- Ecology and Evolutionary BiologyUniversity of ArizonaTucsonAZUSA
| | | | - Grégoire Vincent
- AMAP, Univ Montpellier, IRD, CIRAD, CNRS, INRAEMontpellierFrance
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26
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Paschalis A, Fatichi S, Zscheischler J, Ciais P, Bahn M, Boysen L, Chang J, De Kauwe M, Estiarte M, Goll D, Hanson PJ, Harper AB, Hou E, Kigel J, Knapp AK, Larsen KS, Li W, Lienert S, Luo Y, Meir P, Nabel JEMS, Ogaya R, Parolari AJ, Peng C, Peñuelas J, Pongratz J, Rambal S, Schmidt IK, Shi H, Sternberg M, Tian H, Tschumi E, Ukkola A, Vicca S, Viovy N, Wang YP, Wang Z, Williams K, Wu D, Zhu Q. Rainfall manipulation experiments as simulated by terrestrial biosphere models: Where do we stand? GLOBAL CHANGE BIOLOGY 2020; 26:3336-3355. [PMID: 32012402 DOI: 10.1111/gcb.15024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 01/22/2020] [Indexed: 06/10/2023]
Abstract
Changes in rainfall amounts and patterns have been observed and are expected to continue in the near future with potentially significant ecological and societal consequences. Modelling vegetation responses to changes in rainfall is thus crucial to project water and carbon cycles in the future. In this study, we present the results of a new model-data intercomparison project, where we tested the ability of 10 terrestrial biosphere models to reproduce the observed sensitivity of ecosystem productivity to rainfall changes at 10 sites across the globe, in nine of which, rainfall exclusion and/or irrigation experiments had been performed. The key results are as follows: (a) Inter-model variation is generally large and model agreement varies with timescales. In severely water-limited sites, models only agree on the interannual variability of evapotranspiration and to a smaller extent on gross primary productivity. In more mesic sites, model agreement for both water and carbon fluxes is typically higher on fine (daily-monthly) timescales and reduces on longer (seasonal-annual) scales. (b) Models on average overestimate the relationship between ecosystem productivity and mean rainfall amounts across sites (in space) and have a low capacity in reproducing the temporal (interannual) sensitivity of vegetation productivity to annual rainfall at a given site, even though observation uncertainty is comparable to inter-model variability. (c) Most models reproduced the sign of the observed patterns in productivity changes in rainfall manipulation experiments but had a low capacity in reproducing the observed magnitude of productivity changes. Models better reproduced the observed productivity responses due to rainfall exclusion than addition. (d) All models attribute ecosystem productivity changes to the intensity of vegetation stress and peak leaf area, whereas the impact of the change in growing season length is negligible. The relative contribution of the peak leaf area and vegetation stress intensity was highly variable among models.
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Affiliation(s)
- Athanasios Paschalis
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
| | - Simone Fatichi
- Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland
| | - Jakob Zscheischler
- Climate and Environmental Physics, University of Bern, Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette, France
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Lena Boysen
- Max Planck Institute for Meteorology, Hamburg, Germany
| | - Jinfeng Chang
- Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette, France
| | - Martin De Kauwe
- ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, NSW, Australia
| | - Marc Estiarte
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, Catalonia, Spain
| | - Daniel Goll
- Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette, France
- Department of Geography, University of Augsburg, Augsburg, Germany
| | - Paul J Hanson
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Anna B Harper
- Department of Mathematics, University of Exeter, Exeter, UK
| | - Enqing Hou
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Jaime Kigel
- Institute for Plant Sciences and Genetics, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Alan K Knapp
- Graduate Degree Program in Ecology, Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Klaus S Larsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark
| | - Wei Li
- Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette, France
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
| | - Sebastian Lienert
- Climate and Environmental Physics, University of Bern, Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Yiqi Luo
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Patrick Meir
- Research School of Biology, Australian National University, Acton, ACT, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | | | - Romà Ogaya
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, Catalonia, Spain
| | - Anthony J Parolari
- Department of Civil, Construction, and Environmental Engineering, Marquette University, Milwaukee, WI, USA
| | - Changhui Peng
- Department of Biology Sciences, University of Quebec at Montreal, Montreal, QC, Canada
| | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, Catalonia, Spain
| | - Julia Pongratz
- Department of Geography, Ludwig Maximilian University of Munich, Munchen, Germany
| | - Serge Rambal
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, Montpellier, France
| | - Inger K Schmidt
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark
| | - Hao Shi
- International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, USA
| | - Marcelo Sternberg
- School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Hanqin Tian
- International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, USA
| | - Elisabeth Tschumi
- Climate and Environmental Physics, University of Bern, Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Anna Ukkola
- ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, NSW, Australia
| | - Sara Vicca
- Centre of Excellence PLECO (Plants and Ecosystems), Biology Department, University of Antwerp, Wilrijk, Belgium
| | - Nicolas Viovy
- Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette, France
| | - Ying-Ping Wang
- CSIRO Marine and Atmospheric Research and Centre for Australian Weather and Climate Research, Aspendale, Vic., Australia
| | - Zhuonan Wang
- International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, USA
| | | | - Donghai Wu
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Qiuan Zhu
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Xianyang, China
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27
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Anderegg WRL, Venturas MD. Plant hydraulics play a critical role in Earth system fluxes. THE NEW PHYTOLOGIST 2020; 226:1535-1538. [PMID: 32259286 DOI: 10.1111/nph.16548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Martin D Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
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28
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Eller CB, Rowland L, Mencuccini M, Rosas T, Williams K, Harper A, Medlyn BE, Wagner Y, Klein T, Teodoro GS, Oliveira RS, Matos IS, Rosado BHP, Fuchs K, Wohlfahrt G, Montagnani L, Meir P, Sitch S, Cox PM. Stomatal optimization based on xylem hydraulics (SOX) improves land surface model simulation of vegetation responses to climate. THE NEW PHYTOLOGIST 2020; 226:1622-1637. [PMID: 31916258 PMCID: PMC7318565 DOI: 10.1111/nph.16419] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/03/2020] [Indexed: 05/23/2023]
Abstract
Land surface models (LSMs) typically use empirical functions to represent vegetation responses to soil drought. These functions largely neglect recent advances in plant ecophysiology that link xylem hydraulic functioning with stomatal responses to climate. We developed an analytical stomatal optimization model based on xylem hydraulics (SOX) to predict plant responses to drought. Coupling SOX to the Joint UK Land Environment Simulator (JULES) LSM, we conducted a global evaluation of SOX against leaf- and ecosystem-level observations. SOX simulates leaf stomatal conductance responses to climate for woody plants more accurately and parsimoniously than the existing JULES stomatal conductance model. An ecosystem-level evaluation at 70 eddy flux sites shows that SOX decreases the sensitivity of gross primary productivity (GPP) to soil moisture, which improves the model agreement with observations and increases the predicted annual GPP by 30% in relation to JULES. SOX decreases JULES root-mean-square error in GPP by up to 45% in evergreen tropical forests, and can simulate realistic patterns of canopy water potential and soil water dynamics at the studied sites. SOX provides a parsimonious way to incorporate recent advances in plant hydraulics and optimality theory into LSMs, and an alternative to empirical stress factors.
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Affiliation(s)
- Cleiton B. Eller
- College of Life and Environmental SciencesUniversity of ExeterExeterEX4 4QFUK
- Department of Plant BiologyUniversity of CampinasCampinas13083‐862Brazil
| | - Lucy Rowland
- College of Life and Environmental SciencesUniversity of ExeterExeterEX4 4QFUK
| | - Maurizio Mencuccini
- CREAFBellaterra08193BarcelonaSpain
- ICREAPg. Lluís Companys 2308010BarcelonaSpain
| | - Teresa Rosas
- CREAFBellaterra08193BarcelonaSpain
- ICREAPg. Lluís Companys 2308010BarcelonaSpain
| | | | - Anna Harper
- College of Engineering, Mathematics and Physical SciencesUniversity of ExeterExeterEX4 4QFUK
| | - Belinda E. Medlyn
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - Yael Wagner
- Department of Plant & Environmental SciencesWeizmann Institute of Science76100RehovotIsrael
| | - Tamir Klein
- Department of Plant & Environmental SciencesWeizmann Institute of Science76100RehovotIsrael
| | | | - Rafael S. Oliveira
- Department of Plant BiologyUniversity of CampinasCampinas13083‐862Brazil
| | - Ilaine S. Matos
- Department of Ecology – IBRAGRio de Janeiro State University (UERJ)Rio de Janeiro20550‐013Brazil
| | - Bruno H. P. Rosado
- Department of Ecology – IBRAGRio de Janeiro State University (UERJ)Rio de Janeiro20550‐013Brazil
| | - Kathrin Fuchs
- Department of Environmental Systems ScienceETH ZurichUniversitätstrasse 28092ZurichSwitzerland
| | - Georg Wohlfahrt
- Department of EcologyUniversity of InnsbruckInnsbruck6020Austria
| | - Leonardo Montagnani
- Forest ServicesAutonomous Province of BolzanoVia Brennero 639100BolzanoItaly
| | - Patrick Meir
- Research School of BiologyThe Australian National UniversityActonACT2601Australia
- School of GeosciencesUniversity of EdinburghEdinburghEH9 3FFUK
| | - Stephen Sitch
- College of Life and Environmental SciencesUniversity of ExeterExeterEX4 4QFUK
| | - Peter M. Cox
- College of Engineering, Mathematics and Physical SciencesUniversity of ExeterExeterEX4 4QFUK
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29
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Schumacher DL, Keune J, Miralles DG. Atmospheric heat and moisture transport to energy- and water-limited ecosystems. Ann N Y Acad Sci 2020; 1472:123-138. [PMID: 32383259 PMCID: PMC7496078 DOI: 10.1111/nyas.14357] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/11/2020] [Accepted: 04/14/2020] [Indexed: 12/03/2022]
Abstract
The land biosphere is a crucial component of the Earth system that interacts with the atmosphere in a complex manner through manifold feedback processes. These relationships are bidirectional, as climate affects our terrestrial ecosystems, which, in turn, influence climate. Great progress has been made in understanding the local interactions between the terrestrial biosphere and climate, but influences from remote regions through energy and water influxes to downwind ecosystems remain less explored. Using a Lagrangian trajectory model driven by atmospheric reanalysis data, we show how heat and moisture advection affect gross carbon production at interannual scales and in different ecoregions across the globe. For water‐limited regions, results show a detrimental effect on ecosystem productivity during periods of enhanced heat and reduced moisture advection. These periods are typically associated with winds that disproportionately come from continental source regions, as well as positive sensible heat flux and negative latent heat flux anomalies in those upwind locations. Our results underline the vulnerability of ecosystems to the occurrence of upwind climatic extremes and highlight the importance of the latter for the spatiotemporal propagation of ecosystem disturbances.
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Affiliation(s)
| | - Jessica Keune
- Hydro-Climate Extremes Lab, Ghent University, Ghent, Belgium
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30
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Tropical carbon sink accelerated by symbiotic dinitrogen fixation. Nat Commun 2019; 10:5637. [PMID: 31822758 PMCID: PMC6904724 DOI: 10.1038/s41467-019-13656-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 11/18/2019] [Indexed: 11/30/2022] Open
Abstract
A major uncertainty in the land carbon cycle is whether symbiotic nitrogen fixation acts to enhance the tropical forest carbon sink. Nitrogen-fixing trees can supply vital quantities of the growth-limiting nutrient nitrogen, but the extent to which the resulting carbon–nitrogen feedback safeguards ecosystem carbon sequestration remains unclear. We combine (i) field observations from 112 plots spanning 300 years of succession in Panamanian tropical forests, and (ii) a new model that resolves nitrogen and light competition at the scale of individual trees. Fixation doubled carbon accumulation in early succession and enhanced total carbon in mature forests by ~10% (~12MgC ha−1) through two mechanisms: (i) a direct fixation effect on tree growth, and (ii) an indirect effect on the successional sequence of non-fixing trees. We estimate that including nitrogen-fixing trees in Neotropical reforestation projects could safeguard the sequestration of 6.7 Gt CO2 over the next 20 years. Our results highlight the connection between functional diversity of plant communities and the critical ecosystem service of carbon sequestration for mitigating climate change. The contribution of symbiotic dinitrogen fixation to the forest carbon sink could change throughout forest succession. Here the authors model nitrogen cycling and light competition between trees based on data from Panamanian forest plots, showing that fixation contributes substantially to the carbon sink in early successional stages.
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31
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Trugman AT, Anderegg LDL, Sperry JS, Wang Y, Venturas M, Anderegg WRL. Leveraging plant hydraulics to yield predictive and dynamic plant leaf allocation in vegetation models with climate change. GLOBAL CHANGE BIOLOGY 2019; 25:4008-4021. [PMID: 31465580 DOI: 10.1111/gcb.14814] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Plant functional traits provide a link in process-based vegetation models between plant-level physiology and ecosystem-level responses. Recent advances in physiological understanding and computational efficiency have allowed for the incorporation of plant hydraulic processes in large-scale vegetation models. However, a more mechanistic representation of water limitation that determines ecosystem responses to plant water stress necessitates a re-evaluation of trait-based constraints for plant carbon allocation, particularly allocation to leaf area. In this review, we examine model representations of plant allocation to leaves, which is often empirically set by plant functional type-specific allometric relationships. We analyze the evolution of the representation of leaf allocation in models of different scales and complexities. We show the impacts of leaf allocation strategy on plant carbon uptake in the context of recent advancements in modeling hydraulic processes. Finally, we posit that deriving allometry from first principles using mechanistic hydraulic processes is possible and should become standard practice, rather than using prescribed allometries. The representation of allocation as an emergent property of scarce resource constraints is likely to be critical to representing how global change processes impact future ecosystem dynamics and carbon fluxes and may reduce the number of poorly constrained parameters in vegetation models.
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Affiliation(s)
- Anna T Trugman
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA, USA
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Leander D L Anderegg
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Yujie Wang
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Martin Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
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32
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The impact of rising CO 2 and acclimation on the response of US forests to global warming. Proc Natl Acad Sci U S A 2019; 116:25734-25744. [PMID: 31767760 DOI: 10.1073/pnas.1913072116] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The response of forests to climate change depends in part on whether the photosynthetic benefit from increased atmospheric CO2 (∆Ca = future minus historic CO2) compensates for increased physiological stresses from higher temperature (∆T). We predicted the outcome of these competing responses by using optimization theory and a mechanistic model of tree water transport and photosynthesis. We simulated current and future productivity, stress, and mortality in mature monospecific stands with soil, species, and climate sampled from 20 continental US locations. We modeled stands with and without acclimation to ∆Ca and ∆T, where acclimated forests adjusted leaf area, photosynthetic capacity, and stand density to maximize productivity while avoiding stress. Without acclimation, the ∆Ca-driven boost in net primary productivity (NPP) was compromised by ∆T-driven stress and mortality associated with vascular failure. With acclimation, the ∆Ca-driven boost in NPP and stand biomass (C storage) was accentuated for cooler futures but negated for warmer futures by a ∆T-driven reduction in NPP and biomass. Thus, hotter futures reduced forest biomass through either mortality or acclimation. Forest outcomes depended on whether projected climatic ∆Ca/∆T ratios were above or below physiological thresholds that neutralized the negative impacts of warming. Critically, if forests do not acclimate, the ∆Ca/∆T must be above ca 89 ppm⋅°C-1 to avoid chronic stress, a threshold met by 55% of climate projections. If forests do acclimate, the ∆Ca/∆T must rise above ca 67 ppm⋅°C-1 for NPP and biomass to increase, a lower threshold met by 71% of projections.
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33
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Szejner P, Belmecheri S, Ehleringer JR, Monson RK. Recent increases in drought frequency cause observed multi-year drought legacies in the tree rings of semi-arid forests. Oecologia 2019; 192:241-259. [DOI: 10.1007/s00442-019-04550-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 10/29/2019] [Indexed: 01/07/2023]
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34
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di Porcia e Brugnera M, Meunier F, Longo M, Krishna Moorthy SM, De Deurwaerder H, Schnitzer SA, Bonal D, Faybishenko B, Verbeeck H. Modeling the impact of liana infestation on the demography and carbon cycle of tropical forests. GLOBAL CHANGE BIOLOGY 2019; 25:3767-3780. [PMID: 31310429 PMCID: PMC6856694 DOI: 10.1111/gcb.14769] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 05/21/2023]
Abstract
There is mounting empirical evidence that lianas affect the carbon cycle of tropical forests. However, no single vegetation model takes into account this growth form, although such efforts could greatly improve the predictions of carbon dynamics in tropical forests. In this study, we incorporated a novel mechanistic representation of lianas in a dynamic global vegetation model (the Ecosystem Demography Model). We developed a liana-specific plant functional type and mechanisms representing liana-tree interactions (such as light competition, liana-specific allometries, and attachment to host trees) and parameterized them according to a comprehensive literature meta-analysis. We tested the model for an old-growth forest (Paracou, French Guiana) and a secondary forest (Gigante Peninsula, Panama). The resulting model simulations captured many features of the two forests characterized by different levels of liana infestation as revealed by a systematic comparison of the model outputs with empirical data, including local census data from forest inventories, eddy flux tower data, and terrestrial laser scanner-derived forest vertical structure. The inclusion of lianas in the simulations reduced the secondary forest net productivity by up to 0.46 tC ha-1 year-1 , which corresponds to a limited relative reduction of 2.6% in comparison with a reference simulation without lianas. However, this resulted in significantly reduced accumulated above-ground biomass after 70 years of regrowth by up to 20 tC /ha (19% of the reference simulation). Ultimately, the simulated negative impact of lianas on the total biomass was almost completely cancelled out when the forest reached an old-growth successional stage. Our findings suggest that lianas negatively influence the forest potential carbon sink strength, especially for young, disturbed, liana-rich sites. In light of the critical role that lianas play in the profound changes currently experienced by tropical forests, this new model provides a robust numerical tool to forecast the impact of lianas on tropical forest carbon sinks.
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Affiliation(s)
| | - Félicien Meunier
- CAVElab – Computational and Applied Vegetation EcologyGhent UniversityGhentBelgium
- Ecological Forecasting LabDepartment of Earth and EnvironmentBoston UniversityBostonMAUSA
| | - Marcos Longo
- Embrapa Agricultural InformaticsCampinasSPBrazil
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | | | | | - Stefan A. Schnitzer
- Smithsonian Tropical Research InstituteBalboaAnconPanama
- Department of Biological SciencesMarquette UniversityMilwaukeeWIUSA
| | - Damien Bonal
- UMR SilvaUniversité de Lorraine, AgroParisTech, INRANancyFrance
| | - Boris Faybishenko
- Earth and Environmental Science AreaLawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Hans Verbeeck
- CAVElab – Computational and Applied Vegetation EcologyGhent UniversityGhentBelgium
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35
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McCulloh KA, Domec JC, Johnson DM, Smith DD, Meinzer FC. A dynamic yet vulnerable pipeline: Integration and coordination of hydraulic traits across whole plants. PLANT, CELL & ENVIRONMENT 2019; 42:2789-2807. [PMID: 31273812 DOI: 10.1111/pce.13607] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 06/09/2023]
Abstract
The vast majority of measurements in the field of plant hydraulics have been on small-diameter branches from woody species. These measurements have provided considerable insight into plant functioning, but our understanding of plant physiology and ecology would benefit from a broader view, because branch hydraulic properties are influenced by many factors. Here, we discuss the influence that other components of the hydraulic network have on branch vulnerability to embolism propagation. We also modelled the impact of changes in the ratio of root-to-leaf areas and soil texture on vulnerability to hydraulic failure along the soil-to-leaf continuum and showed that hydraulic function is better maintained through changes in root vulnerability and root-to-leaf area ratio than in branch vulnerability. Differences among species in the stringency with which they regulate leaf water potential and in reliance on stored water to buffer changes in water potential also affect the need to construct embolism resistant branches. Many approaches, such as measurements on fine roots, small individuals, combining sap flow and psychrometry techniques, and modelling efforts, could vastly improve our understanding of whole-plant hydraulic functioning. A better understanding of how traits are coordinated across the whole plant will improve predictions for plant function under future climate conditions.
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Affiliation(s)
| | - Jean-Christophe Domec
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, 33175, Gradignan Cedex, France
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Duncan D Smith
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR, 97331, USA
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Kannenberg SA, Novick KA, Alexander MR, Maxwell JT, Moore DJP, Phillips RP, Anderegg WRL. Linking drought legacy effects across scales: From leaves to tree rings to ecosystems. GLOBAL CHANGE BIOLOGY 2019; 25:2978-2992. [PMID: 31132225 DOI: 10.1111/gcb.14710] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/10/2019] [Accepted: 05/22/2019] [Indexed: 05/23/2023]
Abstract
Severe drought can cause lagged effects on tree physiology that negatively impact forest functioning for years. These "drought legacy effects" have been widely documented in tree-ring records and could have important implications for our understanding of broader scale forest carbon cycling. However, legacy effects in tree-ring increments may be decoupled from ecosystem fluxes due to (a) postdrought alterations in carbon allocation patterns; (b) temporal asynchrony between radial growth and carbon uptake; and (c) dendrochronological sampling biases. In order to link legacy effects from tree rings to whole forests, we leveraged a rich dataset from a Midwestern US forest that was severely impacted by a drought in 2012. At this site, we compiled tree-ring records, leaf-level gas exchange, eddy flux measurements, dendrometer band data, and satellite remote sensing estimates of greenness and leaf area before, during, and after the 2012 drought. After accounting for the relative abundance of tree species in the stand, we estimate that legacy effects led to ~10% reductions in tree-ring width increments in the year following the severe drought. Despite this stand-scale reduction in radial growth, we found that leaf-level photosynthesis, gross primary productivity (GPP), and vegetation greenness were not suppressed in the year following the 2012 drought. Neither temporal asynchrony between radial growth and carbon uptake nor sampling biases could explain our observations of legacy effects in tree rings but not in GPP. Instead, elevated leaf-level photosynthesis co-occurred with reduced leaf area in early 2013, indicating that resources may have been allocated away from radial growth in conjunction with postdrought upregulation of photosynthesis and repair of canopy damage. Collectively, our results indicate that tree-ring legacy effects were not observed in other canopy processes, and that postdrought canopy allocation could be an important mechanism that decouples tree-ring signals from GPP.
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Affiliation(s)
| | - Kimberly A Novick
- School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana
| | | | - Justin T Maxwell
- Department of Geography, Indiana University, Bloomington, Indiana
- Harvard Forest, Harvard University, Petersham, Massachusetts
| | - David J P Moore
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona
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37
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Wang Y, Sperry JS, Venturas MD, Trugman AT, Love DM, Anderegg WRL. The stomatal response to rising CO2 concentration and drought is predicted by a hydraulic trait-based optimization model. TREE PHYSIOLOGY 2019; 39:1416-1427. [PMID: 30949697 DOI: 10.1093/treephys/tpz038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/29/2019] [Accepted: 03/22/2019] [Indexed: 06/09/2023]
Abstract
Modeling stomatal control is critical for predicting forest responses to the changing environment and hence the global water and carbon cycles. A trait-based stomatal control model that optimizes carbon gain while avoiding hydraulic risk has been shown to perform well in response to drought. However, the model's performance against changes in atmospheric CO2, which is rising rapidly due to human emissions, has yet to be evaluated. The present study tested the gain-risk model's ability to predict the stomatal response to CO2 concentration with potted water birch (Betula occidentalis Hook.) saplings in a growth chamber. The model's performance in predicting stomatal response to changes in atmospheric relative humidity and soil moisture was also assessed. The gain-risk model predicted the photosynthetic assimilation, transpiration rate and leaf xylem pressure under different CO2 concentrations, having a mean absolute percentage error (MAPE) of 25%. The model also predicted the responses to relative humidity and soil drought with a MAPE of 21.9% and 41.9%, respectively. Overall, the gain-risk model had an MAPE of 26.8% compared with the 37.5% MAPE obtained by a standard empirical model of stomatal conductance. Importantly, unlike empirical models, the optimization model relies on measurable physiological traits as inputs and performs well in predicting responses to novel environmental conditions without empirical corrections. Incorporating the optimization model in larger scale models has the potential for improving the simulation of water and carbon cycles.
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Affiliation(s)
- Yujie Wang
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Martin D Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Anna T Trugman
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - David M Love
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, E Green Street, Athens, GA, USA
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38
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Baker IT, Denning A, Dazlich DA, Harper AB, Branson MD, Randall DA, Phillips MC, Haynes KD, Gallup SM. Surface-Atmosphere Coupling Scale, the Fate of Water, and Ecophysiological Function in a Brazilian Forest. JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2019; 11:2523-2546. [PMID: 31749898 PMCID: PMC6851591 DOI: 10.1029/2019ms001650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/10/2019] [Accepted: 07/16/2019] [Indexed: 06/10/2023]
Abstract
Tropical South America plays a central role in global climate. Bowen ratio teleconnects to circulation and precipitation processes far afield, and the global CO2 growth rate is strongly influenced by carbon cycle processes in South America. However, quantification of basin-wide seasonality of flux partitioning between latent and sensible heat, the response to anomalies around climatic norms, and understanding of the processes and mechanisms that control the carbon cycle remains elusive. Here, we investigate simulated surface-atmosphere interaction at a single site in Brazil, using models with different representations of precipitation and cloud processes, as well as differences in scale of coupling between the surface and atmosphere. We find that the model with parameterized clouds/precipitation has a tendency toward unrealistic perpetual light precipitation, while models with explicit treatment of clouds produce more intense and less frequent rain. Models that couple the surface to the atmosphere on the scale of kilometers, as opposed to tens or hundreds of kilometers, produce even more realistic distributions of rainfall. Rainfall intensity has direct consequences for the "fate of water," or the pathway that a hydrometeor follows once it interacts with the surface. We find that the model with explicit treatment of cloud processes, coupled to the surface at small scales, is the most realistic when compared to observations. These results have implications for simulations of global climate, as the use of models with explicit (as opposed to parameterized) cloud representations becomes more widespread.
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Affiliation(s)
- Ian T. Baker
- Atmospheric Science DepartmentColorado State UniversityFort CollinsCOUSA
| | - A.Scott Denning
- Atmospheric Science DepartmentColorado State UniversityFort CollinsCOUSA
| | - Don A. Dazlich
- Atmospheric Science DepartmentColorado State UniversityFort CollinsCOUSA
| | - Anna B. Harper
- College of Engineering, Mathematics, and Physical SciencesUniversity of ExeterExeterEngland
| | - Mark D. Branson
- Atmospheric Science DepartmentColorado State UniversityFort CollinsCOUSA
| | - David A. Randall
- Atmospheric Science DepartmentColorado State UniversityFort CollinsCOUSA
| | - Morgan C. Phillips
- Atmospheric Science DepartmentColorado State UniversityFort CollinsCOUSA
| | | | - Sarah M. Gallup
- Atmospheric Science DepartmentColorado State UniversityFort CollinsCOUSA
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39
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Anderegg WRL, Anderegg LDL, Huang CY. Testing early warning metrics for drought-induced tree physiological stress and mortality. GLOBAL CHANGE BIOLOGY 2019; 25:2459-2469. [PMID: 30983066 DOI: 10.1111/gcb.14655] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
Climate change-driven drought stress has triggered numerous large-scale tree mortality events in recent decades. Advances in mechanistic understanding and prediction are greatly limited by an inability to detect in situ where trees are likely to die in order to take timely measurements and actions. Thus, algorithms of early warning and detection of drought-induced tree stress and mortality could have major scientific and societal benefits. Here, we leverage two consecutive droughts in the southwestern United States to develop and test a set of early warning metrics. Using Landsat satellite data, we constructed early warning metrics from the first drought event. We then tested these metrics' ability to predict spatial patterns in tree physiological stress and mortality from the second drought. To test the broader applicability of these metrics, we also examined a separate drought in the Amazon rainforest. The early warning metrics successfully explained subsequent tree mortality in the second drought in the southwestern US, as well as mortality in the independent drought in tropical forests. The metrics also strongly correlated with spatial patterns in tree hydraulic stress underlying mortality, which provides a strong link between tree physiological stress and remote sensing during the severe drought and indicates that the loss of hydraulic function during drought likely mediated subsequent mortality. Thus, early warning metrics provide a critical foundation for elucidating the physiological mechanisms underpinning tree mortality in mature forests and guiding management responses to these climate-induced disturbances.
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Affiliation(s)
| | - Leander D L Anderegg
- Department of Integrative Biology, UC Berkeley, Berkeley, California
- Department of Global Ecology, Carnegie Institution for Science, Stanford, California
| | - Cho-Ying Huang
- Department of Geography, National Taiwan University, Taipei, Taiwan
- Research Center for Future Earth, National Taiwan University, Taipei, Taiwan
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40
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Zhou SX, Prentice IC, Medlyn BE. Bridging Drought Experiment and Modeling: Representing the Differential Sensitivities of Leaf Gas Exchange to Drought. FRONTIERS IN PLANT SCIENCE 2019; 9:1965. [PMID: 30697222 PMCID: PMC6340983 DOI: 10.3389/fpls.2018.01965] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 12/18/2018] [Indexed: 05/15/2023]
Abstract
Global climate change is expected to increase drought duration and intensity in certain regions while increasing rainfall in others. The quantitative consequences of increased drought for ecosystems are not easy to predict. Process-based models must be informed by experiments to determine the resilience of plants and ecosystems from different climates. Here, we demonstrate what and how experimentally derived quantitative information can improve the representation of stomatal and non-stomatal photosynthetic responses to drought in large-scale vegetation models. In particular, we review literature on the answers to four key questions: (1) Which photosynthetic processes are affected under short-term drought? (2) How do the stomatal and non-stomatal responses to short-term drought vary among species originating from different hydro-climates? (3) Do plants acclimate to prolonged water stress, and do mesic and xeric species differ in their degree of acclimation? (4) Does inclusion of experimentally based plant functional type specific stomatal and non-stomatal response functions to drought help Land Surface Models to reproduce key features of ecosystem responses to drought? We highlighted the need for evaluating model representations of the fundamental eco-physiological processes under drought. Taking differential drought sensitivity of different vegetation into account is necessary for Land Surface Models to accurately model drought responses, or the drought impacts on vegetation in drier environments may be over-estimated.
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Affiliation(s)
- Shuang-Xi Zhou
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- The New Zealand Institute for Plant and Food Research Ltd., Hawke’s Bay, New Zealand
| | - I. Colin Prentice
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- AXA Chair of Biosphere and Climate Impacts, Grand Challenges in Ecosystems and the Environment and Grantham Institute – Climate Change and the Environment, Department of Life Sciences, Imperial College London, Ascot, United Kingdom
| | - Belinda E. Medlyn
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
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41
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Miralles DG, Gentine P, Seneviratne SI, Teuling AJ. Land-atmospheric feedbacks during droughts and heatwaves: state of the science and current challenges. Ann N Y Acad Sci 2019; 1436:19-35. [PMID: 29943456 PMCID: PMC6378599 DOI: 10.1111/nyas.13912] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 05/29/2018] [Accepted: 06/01/2018] [Indexed: 11/30/2022]
Abstract
Droughts and heatwaves cause agricultural loss, forest mortality, and drinking water scarcity, especially when they occur simultaneously as combined events. Their predicted increase in recurrence and intensity poses serious threats to future food security. Still today, the knowledge of how droughts and heatwaves start and evolve remains limited, and so does our understanding of how climate change may affect them. Droughts and heatwaves have been suggested to intensify and propagate via land-atmosphere feedbacks. However, a global capacity to observe these processes is still lacking, and climate and forecast models are immature when it comes to representing the influences of land on temperature and rainfall. Key open questions remain in our goal to uncover the real importance of these feedbacks: What is the impact of the extreme meteorological conditions on ecosystem evaporation? How do these anomalies regulate the atmospheric boundary layer state (event self-intensification) and contribute to the inflow of heat and moisture to other regions (event self-propagation)? Can this knowledge on the role of land feedbacks, when available, be exploited to develop geo-engineering mitigation strategies that prevent these events from aggravating during their early stages? The goal of our perspective is not to present a convincing answer to these questions, but to assess the scientific progress to date, while highlighting new and innovative avenues to keep advancing our understanding in the future.
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Affiliation(s)
- Diego G. Miralles
- Laboratory of Hydrology and Water ManagementGhent UniversityGhentBelgium
| | - Pierre Gentine
- Earth and Environmental EngineeringColumbia UniversityNew YorkNew York
| | | | - Adriaan J. Teuling
- Hydrology and Quantitative Water Management GroupWageningen University and ResearchWageningenthe Netherlands
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42
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Arellano G, Medina NG, Tan S, Mohamad M, Davies SJ. Crown damage and the mortality of tropical trees. THE NEW PHYTOLOGIST 2019; 221:169-179. [PMID: 30067290 DOI: 10.1111/nph.15381] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 07/10/2018] [Indexed: 06/08/2023]
Abstract
What causes individual tree death in tropical forests remains a major gap in our understanding of the biology of tropical trees and leads to significant uncertainty in predicting global carbon cycle dynamics. We measured individual characteristics (diameter at breast height, wood density, growth rate, crown illumination and crown form) and environmental conditions (soil fertility and habitat suitability) for 26 425 trees ≥ 10 cm diameter at breast height belonging to 416 species in a 52-ha plot in Lambir Hills National Park, Malaysia. We used structural equation models to investigate the relationships among the different factors and tree mortality. Crown form (a proxy for mechanical damage and other stresses) and prior growth were the two most important factors related to mortality. The effect of all variables on mortality (except habitat suitability) was substantially greater than expected by chance. Tree death is the result of interactions between factors, including direct and indirect effects. Crown form/damage and prior growth mediated most of the effect of tree size, wood density, fertility and habitat suitability on mortality. Large-scale assessment of crown form or status may result in improved prediction of individual tree death at the landscape scale.
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Affiliation(s)
- Gabriel Arellano
- CTFS-ForestGEO, Smithsonian Tropical Research Institute, PO Box 37012, Washington, DC, 20013-7012, USA
| | - Nagore G Medina
- Department of Botany, University of South Bohemia, Na Zlate stoce 1, České Budjovice, 370 05, Czech Republic
| | - Sylvester Tan
- Sarawak Forest Department, Kuching, Sarawak, 93050, Malaysia
| | - Mohizah Mohamad
- Sarawak Forest Department, Kuching, Sarawak, 93050, Malaysia
| | - Stuart J Davies
- CTFS-ForestGEO, Smithsonian Tropical Research Institute, PO Box 37012, Washington, DC, 20013-7012, USA
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43
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Wang S, Zhuang Q, Lähteenoja O, Draper FC, Cadillo-Quiroz H. Potential shift from a carbon sink to a source in Amazonian peatlands under a changing climate. Proc Natl Acad Sci U S A 2018; 115:12407-12412. [PMID: 30455319 PMCID: PMC6298090 DOI: 10.1073/pnas.1801317115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Amazonian peatlands store a large amount of soil organic carbon (SOC), and its fate under a future changing climate is unknown. Here, we use a process-based peatland biogeochemistry model to quantify the carbon accumulation for peatland and nonpeatland ecosystems in the Pastaza-Marañon foreland basin (PMFB) in the Peruvian Amazon from 12,000 y before present to AD 2100. Model simulations indicate that warming accelerates peat SOC loss, while increasing precipitation accelerates peat SOC accumulation at millennial time scales. The uncertain parameters and spatial variation of climate are significant sources of uncertainty to modeled peat carbon accumulation. Under warmer and presumably wetter conditions over the 21st century, SOC accumulation rate in the PMFB slows down to 7.9 (4.3-12.2) g⋅C⋅m-2⋅y-1 from the current rate of 16.1 (9.1-23.7) g⋅C⋅m-2⋅y-1, and the region may turn into a carbon source to the atmosphere at -53.3 (-66.8 to -41.2) g⋅C⋅m-2⋅y-1 (negative indicates source), depending on the level of warming. Peatland ecosystems show a higher vulnerability than nonpeatland ecosystems, as indicated by the ratio of their soil carbon density changes (ranging from 3.9 to 5.8). This is primarily due to larger peatlands carbon stocks and more dramatic responses of their aerobic and anaerobic decompositions in comparison with nonpeatland ecosystems under future climate conditions. Peatland and nonpeatland soils in the PMFB may lose up to 0.4 (0.32-0.52) Pg⋅C by AD 2100 with the largest loss from palm swamp. The carbon-dense Amazonian peatland may switch from a current carbon sink into a source in the 21st century.
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Affiliation(s)
- Sirui Wang
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN 47907
- Department of Agronomy, Purdue University, West Lafayette, IN 47907
| | - Qianlai Zhuang
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN 47907;
- Department of Agronomy, Purdue University, West Lafayette, IN 47907
| | - Outi Lähteenoja
- School of Life Sciences, Arizona State University, Tempe, AZ 85281
| | - Frederick C Draper
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA 94305
- International Center for Tropical Botany, Florida International University, Miami, FL 33199
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Limiting the high impacts of Amazon forest dieback with no-regrets science and policy action. Proc Natl Acad Sci U S A 2018; 115:11671-11679. [PMID: 30397144 DOI: 10.1073/pnas.1721770115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Large uncertainties still dominate the hypothesis of an abrupt large-scale shift of the Amazon forest caused by climate change [Amazonian forest dieback (AFD)] even though observational evidence shows the forest and regional climate changing. Here, we assess whether mitigation or adaptation action should be taken now, later, or not at all in light of such uncertainties. No action/later action would result in major social impacts that may influence migration to large Amazonian cities through a causal chain of climate change and forest degradation leading to lower river-water levels that affect transportation, food security, and health. Net-present value socioeconomic damage over a 30-year period after AFD is estimated between US dollar (USD) $957 billion (×109) and $3,589 billion (compared with Gross Brazilian Amazon Product of USD $150 billion per year), arising primarily from changes in the provision of ecosystem services. Costs of acting now would be one to two orders of magnitude lower than economic damages. However, while AFD mitigation alternatives-e.g., curbing deforestation-are attainable (USD $64 billion), their efficacy in achieving a forest resilience that prevents AFD is uncertain. Concurrently, a proposed set of 20 adaptation measures is also attainable (USD $122 billion) and could bring benefits even if AFD never occurs. An interdisciplinary research agenda to fill lingering knowledge gaps and constrain the risk of AFD should focus on developing sound experimental and modeling evidence regarding its likelihood, integrated with socioeconomic assessments to anticipate its impacts and evaluate the feasibility and efficacy of mitigation/adaptation options.
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45
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Venturas MD, Sperry JS, Love DM, Frehner EH, Allred MG, Wang Y, Anderegg WRL. A stomatal control model based on optimization of carbon gain versus hydraulic risk predicts aspen sapling responses to drought. THE NEW PHYTOLOGIST 2018; 220:836-850. [PMID: 29998567 DOI: 10.1111/nph.15333] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/08/2018] [Indexed: 05/27/2023]
Abstract
Empirical models of plant drought responses rely on parameters that are difficult to specify a priori. We test a trait- and process-based model to predict environmental responses from an optimization of carbon gain vs hydraulic risk. We applied four drought treatments to aspen (Populus tremuloides) saplings in a research garden. First we tested the optimization algorithm by using predawn xylem pressure as an input. We then tested the full model which calculates root-zone water budget and xylem pressure hourly throughout the growing season. The optimization algorithm performed well when run from measured predawn pressures. The per cent mean absolute error (MAE) averaged 27.7% for midday xylem pressure, transpiration, net assimilation, leaf temperature, sapflow, diffusive conductance and soil-canopy hydraulic conductance. Average MAE was 31.2% for the same observations when the full model was run from irrigation and rain data. Saplings that died were projected to exceed 85% loss in soil-canopy hydraulic conductance, whereas surviving plants never reached this threshold. The model fit was equivalent to that of an empirical model, but with the advantage that all inputs are specific traits. Prediction is empowered because knowing these traits allows knowing the response to climatic stress.
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Affiliation(s)
- Martin D Venturas
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - John S Sperry
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - David M Love
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - Ethan H Frehner
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - Michael G Allred
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - Yujie Wang
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - William R L Anderegg
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
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46
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Zuidema PA, Poulter B, Frank DC. A Wood Biology Agenda to Support Global Vegetation Modelling. TRENDS IN PLANT SCIENCE 2018; 23:1006-1015. [PMID: 30209023 DOI: 10.1016/j.tplants.2018.08.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/31/2018] [Accepted: 08/03/2018] [Indexed: 05/06/2023]
Abstract
Realistic forecasting of forest responses to climate change critically depends on key advancements in global vegetation modelling. Compared with traditional 'big-leaf' models that simulate forest stands, 'next-generation' vegetation models aim to track carbon-, light-, water-, and nutrient-limited growth of individual trees. Wood biology can play an important role in delivering the required knowledge at tissue-to-individual levels, at minute-to-century scales and for model parameterization and benchmarking. We propose a wood biology research agenda that contributes to filling six knowledge gaps: sink versus source limitation, drivers of intra-annual growth, drought impacts, functional wood traits, dynamic biomass allocation, and nutrient cycling. Executing this agenda will expedite model development and increase the ability of models to forecast global change impact on forest dynamics.
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Affiliation(s)
- Pieter A Zuidema
- Forest Ecology and Forest Management, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands.
| | | | - David C Frank
- Laboratory of Tree-Ring Research, University of Arizona, 1215 E Lowell Street, Tucson, AZ 85721, USA
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47
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Eller CB, Rowland L, Oliveira RS, Bittencourt PRL, Barros FV, da Costa ACL, Meir P, Friend AD, Mencuccini M, Sitch S, Cox P. Modelling tropical forest responses to drought and El Niño with a stomatal optimization model based on xylem hydraulics. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170315. [PMID: 30297470 PMCID: PMC6178424 DOI: 10.1098/rstb.2017.0315] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2018] [Indexed: 11/12/2022] Open
Abstract
The current generation of dynamic global vegetation models (DGVMs) lacks a mechanistic representation of vegetation responses to soil drought, impairing their ability to accurately predict Earth system responses to future climate scenarios and climatic anomalies, such as El Niño events. We propose a simple numerical approach to model plant responses to drought coupling stomatal optimality theory and plant hydraulics that can be used in dynamic global vegetation models (DGVMs). The model is validated against stand-scale forest transpiration (E) observations from a long-term soil drought experiment and used to predict the response of three Amazonian forest sites to climatic anomalies during the twentieth century. We show that our stomatal optimization model produces realistic stomatal responses to environmental conditions and can accurately simulate how tropical forest E responds to seasonal, and even long-term soil drought. Our model predicts a stronger cumulative effect of climatic anomalies in Amazon forest sites exposed to soil drought during El Niño years than can be captured by alternative empirical drought representation schemes. The contrasting responses between our model and empirical drought factors highlight the utility of hydraulically-based stomatal optimization models to represent vegetation responses to drought and climatic anomalies in DGVMs.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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Affiliation(s)
- Cleiton B Eller
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | - Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | - Fernanda V Barros
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | | | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, Australia
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - Andrew D Friend
- Department of Geography, University of Cambridge, Cambridge, UK
| | | | - Stephen Sitch
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Peter Cox
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
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48
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Rifai SW, Girardin CAJ, Berenguer E, Del Aguila-Pasquel J, Dahlsjö CAL, Doughty CE, Jeffery KJ, Moore S, Oliveras I, Riutta T, Rowland LM, Murakami AA, Addo-Danso SD, Brando P, Burton C, Ondo FE, Duah-Gyamfi A, Amézquita FF, Freitag R, Pacha FH, Huasco WH, Ibrahim F, Mbou AT, Mihindou VM, Peixoto KS, Rocha W, Rossi LC, Seixas M, Silva-Espejo JE, Abernethy KA, Adu-Bredu S, Barlow J, da Costa ACL, Marimon BS, Marimon-Junior BH, Meir P, Metcalfe DB, Phillips OL, White LJT, Malhi Y. ENSO Drives interannual variation of forest woody growth across the tropics. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2017.0410. [PMID: 30297475 DOI: 10.1098/rstb.2017.0410] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2018] [Indexed: 01/05/2023] Open
Abstract
Meteorological extreme events such as El Niño events are expected to affect tropical forest net primary production (NPP) and woody growth, but there has been no large-scale empirical validation of this expectation. We collected a large high-temporal resolution dataset (for 1-13 years depending upon location) of more than 172 000 stem growth measurements using dendrometer bands from across 14 regions spanning Amazonia, Africa and Borneo in order to test how much month-to-month variation in stand-level woody growth of adult tree stems (NPPstem) can be explained by seasonal variation and interannual meteorological anomalies. A key finding is that woody growth responds differently to meteorological variation between tropical forests with a dry season (where monthly rainfall is less than 100 mm), and aseasonal wet forests lacking a consistent dry season. In seasonal tropical forests, a high degree of variation in woody growth can be predicted from seasonal variation in temperature, vapour pressure deficit, in addition to anomalies of soil water deficit and shortwave radiation. The variation of aseasonal wet forest woody growth is best predicted by the anomalies of vapour pressure deficit, water deficit and shortwave radiation. In total, we predict the total live woody production of the global tropical forest biome to be 2.16 Pg C yr-1, with an interannual range 1.96-2.26 Pg C yr-1 between 1996-2016, and with the sharpest declines during the strong El Niño events of 1997/8 and 2015/6. There is high geographical variation in hotspots of El Niño-associated impacts, with weak impacts in Africa, and strongly negative impacts in parts of Southeast Asia and extensive regions across central and eastern Amazonia. Overall, there is high correlation (r = -0.75) between the annual anomaly of tropical forest woody growth and the annual mean of the El Niño 3.4 index, driven mainly by strong correlations with anomalies of soil water deficit, vapour pressure deficit and shortwave radiation.This article is part of the discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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Affiliation(s)
- Sami W Rifai
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
| | - Cécile A J Girardin
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
| | - Erika Berenguer
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK.,Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | | | - Cecilia A L Dahlsjö
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
| | - Christopher E Doughty
- School of Informatics, Computing and Cyber systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Kathryn J Jeffery
- Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK.,Institut de Recherche en Écologie Tropicale, CENAREST, BP 842, Libreville, Gabon.,Agence Nationale des Parcs Nationaux (ANPN), BP 20379, Libreville, Gabon
| | - Sam Moore
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
| | - Imma Oliveras
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
| | - Terhi Riutta
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
| | - Lucy M Rowland
- Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Exeter EX4 4RJ, UK
| | - Alejandro Araujo Murakami
- Museo de Historia Natural Noel Kempff Mercado Universidad Autónoma Gabriel Rene Moreno, Avenida Irala 565 Casilla Postal 2489, Santa Cruz, Bolivia
| | | | - Paulo Brando
- Woods Hole Research Center, Falmouth, MA, USA.,Amazon Environmental Research Institute (IPAM), Canarana, Mato Grosso, Brazil
| | - Chad Burton
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
| | - Fidèle Evouna Ondo
- Agence Nationale des Parcs Nationaux (ANPN), BP 20379, Libreville, Gabon
| | | | | | - Renata Freitag
- Programa de Pós-graduação em Ecologia e Conservação, Universidade do Estado de Mato Grosso, CEP 78690-000, Nova Xavantina, MT, Brazil
| | | | - Walter Huaraca Huasco
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
| | | | - Armel T Mbou
- Centro Euro-Mediterraneo sui Cambiamente Climatici, Leece, Italy
| | - Vianet Mihindou Mihindou
- Agence Nationale des Parcs Nationaux (ANPN), BP 20379, Libreville, Gabon.,Ministère de la Forêt et de l'Environnement, BP199, Libreville, Gabon
| | - Karine S Peixoto
- Programa de Pós-graduação em Ecologia e Conservação, Universidade do Estado de Mato Grosso, CEP 78690-000, Nova Xavantina, MT, Brazil
| | - Wanderley Rocha
- Amazon Environmental Research Institute (IPAM), Canarana, Mato Grosso, Brazil
| | - Liana C Rossi
- Departamento de Ecologia, Universidade Estadual Paulista, 13506-900, Rio Claro, SP, Brazil
| | - Marina Seixas
- Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro, s/n, CP 48, 66095-100, Belém, PA, Brazil
| | | | - Katharine A Abernethy
- Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK.,Institut de Recherche en Écologie Tropicale, CENAREST, BP 842, Libreville, Gabon
| | | | - Jos Barlow
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | | | - Beatriz S Marimon
- Programa de Pós-graduação em Ecologia e Conservação, Universidade do Estado de Mato Grosso, CEP 78690-000, Nova Xavantina, MT, Brazil
| | - Ben H Marimon-Junior
- Programa de Pós-graduação em Ecologia e Conservação, Universidade do Estado de Mato Grosso, CEP 78690-000, Nova Xavantina, MT, Brazil
| | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia.,School of Geosciences, University of Edinburgh, Edinburgh EH93FF, UK
| | - Daniel B Metcalfe
- Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | | | - Lee J T White
- Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK.,Institut de Recherche en Écologie Tropicale, CENAREST, BP 842, Libreville, Gabon
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
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49
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Meir P, Mencuccini M, Binks O, da Costa AL, Ferreira L, Rowland L. Short-term effects of drought on tropical forest do not fully predict impacts of repeated or long-term drought: gas exchange versus growth. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170311. [PMID: 30297468 PMCID: PMC6178433 DOI: 10.1098/rstb.2017.0311] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2018] [Indexed: 11/12/2022] Open
Abstract
Are short-term responses by tropical rainforest to drought (e.g. during El Niño) sufficient to predict changes over the long-term, or from repeated drought? Using the world's only long-term (16-year) drought experiment in tropical forest we examine predictability from short-term measurements (1-2 years). Transpiration was maximized in droughted forest: it consumed all available throughfall throughout the 16 years of study. Leaf photosynthetic capacity [Formula: see text] was maintained, but only when averaged across tree size groups. Annual transpiration in droughted forest was less than in control, with initial reductions (at high biomass) imposed by foliar stomatal control. Tree mortality increased after year three, leading to an overall biomass loss of 40%; over the long-term, the main constraint on transpiration was thus imposed by the associated reduction in sapwood area. Altered tree mortality risk may prove predictable from soil and plant hydraulics, but additional monitoring is needed to test whether future biomass will stabilize or collapse. Allocation of assimilate differed over time: stem growth and reproductive output declined in the short-term, but following mortality-related changes in resource availability, both showed long-term resilience, with partial or full recovery. Understanding and simulation of these phenomena and related trade-offs in allocation will advance more effectively through greater use of optimization and probabilistic modelling approaches.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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Affiliation(s)
- Patrick Meir
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
- School of Geosciences, University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3FF, UK
| | - Maurizio Mencuccini
- CREAF, Campus UAB, Cerdanyola del Vallés 08193, Spain
- ICREA, Barcelona 08193, Spain
| | - Oliver Binks
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Antonio Lola da Costa
- Instituto de Geosciências, Universidade Federal do Pará, Belém, PA 66075-110, Brazil
| | | | - Lucy Rowland
- Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Exeter EX4 4RJ, UK
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50
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Feng X, Ackerly DD, Dawson TE, Manzoni S, Skelton RP, Vico G, Thompson SE. The ecohydrological context of drought and classification of plant responses. Ecol Lett 2018; 21:1723-1736. [DOI: 10.1111/ele.13139] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/12/2018] [Accepted: 07/16/2018] [Indexed: 01/20/2023]
Affiliation(s)
- Xue Feng
- Department of Civil, Environmental, and Geo‐Engineering University of Minnesota Minneapolis MN USA
| | - David D. Ackerly
- Department of Integrative Biology University of California Berkeley CA USA
| | - Todd E. Dawson
- Department of Integrative Biology University of California Berkeley CA USA
- Department of Environmental Sciences, Policy, and Management University of California Berkeley CA USA
| | - Stefano Manzoni
- Department of Physical Geography Stockholm University Stockholm Sweden
- Bolin Centre for Climate Research Stockholm Sweden
| | - Rob P. Skelton
- Department of Integrative Biology University of California Berkeley CA USA
| | - Giulia Vico
- Department of Crop Production Ecology Swedish University of Agricultural Sciences (SLU) Uppsala Sweden
| | - Sally E. Thompson
- Department of Civil and Environmental Engineering University of California Berkeley CA USA
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