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Qiu J, Crow WT, Wang S, Dong J, Li Y, Garcia M, Shangguan W. Microwave-based soil moisture improves estimates of vegetation response to drought in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157535. [PMID: 35872188 DOI: 10.1016/j.scitotenv.2022.157535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/17/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
The increased frequency and severity of drought has heightened concerns over the risk of hydraulic vegetative stress and the premature mortality of ecosystems globally. Unfortunately, most land surface models (LSMs) continue to underestimate ecosystem resilience to drought - which degrades the credibility of model-predicted ecohydrological responses to climate change. This study investigates the response of vegetation gross productivity to water-stress conditions using microwave-based vegetation optical depth (VOD) and soil moisture retrievals. Based on the estimated isohydric/anisohydric spectrum, we find that vegetation at isohydric state exhibits a larger decrease in gross primary productivity and higher water use efficiency than anisohydric vegetation due to their more rigorous stomatal control and higher tolerance of carbon starvation risk. In addition, the introduction of microwave soil moisture improves the accuracy of isohydricity/anisohydricity estimates compared to those obtained using microwave VOD alone (i.e., increases their Spearman rank correlation versus the benchmark of Global Biodiversity Information Facility dataset from 0.12 to 0.63). Results of this study provide clear justification for the use of microwave-based soil moisture retrievals to enhance stomatal conductance parameterization within LSMs.
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Affiliation(s)
- Jianxiu Qiu
- Guangdong Provincial Key Laboratory of Urbanization and Geo-simulation, School of Geography and Planning, Sun Yat-sen University, Guangzhou 510275, China.
| | - Wade T Crow
- USDA ARS Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705, USA
| | - Sheng Wang
- Agroecosystem Sustainability Center, Institute for Sustainability, Energy, and Environment, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jianzhi Dong
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Yan Li
- State Key Laboratory of Earth Surface Processes and Resources Ecology, Beijing Normal University, Beijing 100875, China
| | - Monica Garcia
- Research Centre for the Management of Agricultural and Environmental Risks, E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28015, Spain
| | - Wei Shangguan
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou 510275, China
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2
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Dong B, Yu Y, Pereira P. Non-growing season drought legacy effects on vegetation growth in southwestern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157334. [PMID: 35842151 DOI: 10.1016/j.scitotenv.2022.157334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/03/2022] [Accepted: 07/09/2022] [Indexed: 06/15/2023]
Abstract
Water availability influences terrestrial ecosystems' composition, structure, and function. Recently, climate change increased drought periods frequency and length in many parts of the world, including southwestern China, a biodiversity hotspot. Although the drought impacts on ecosystems are well known, studies are scarce in subtropical areas of China. This work studied the drought legacy effects on vegetation growth in southwestern China using Normalized Difference Vegetation Index (NDVI) and the Standardized Precipitation Evapotranspiration Index (SPEI), with a particular focus on non-growing season extreme drought events. Pervasive non-growing season drought legacy effects were found in the first growing season in most parts of southwestern China. The highest impacts were identified in forests, while the effects in grass were less severe. At the regional scale, horizontal and vertical spatial patterns of drought legacy effects were heterogeneous, and the highest impacts were found in warmer and wetter forests and alpine grasslands. Our study highlights that severe drought conditions may dramatically affect vegetation growth in southwestern China.
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Affiliation(s)
- Bogang Dong
- School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
| | - Yang Yu
- School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China; Jixian National Forest Ecosystem Observation and Research Station, CNERN, School of Soil and Water Conservation, Beijing Forestry University, China.
| | - Paulo Pereira
- Environmental Management Center, Mykolas Romeris University, Ateities g. 20, LT-08303 Vilnius, Lithuania
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3
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Su R, Liu H, Wang C, Zhang H, Cui J. Leaf turgor loss point is one of the best predictors of drought-induced tree mortality in tropical forest. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.974004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Accurately predicting global drought-induced tree mortality remains a major challenge facing plant science and ecology. Stem hydraulic safety margin (HSM, the difference between water potential at the minimum value and the value that causes xylem vulnerability to embolism) performs as one of the best hydraulic traits in predicting global drought-induced tree mortality, however, HSM is time-consuming and very difficult to measure. We proposed to use leaf turgor loss point (TLP, the water potential at which leaves start to wilt) as a proxy for HSM because HSM may be highly correlated to TLP, as both of them are tightly linked with water potential changes after stomatal closure. Since TLP is more easy and rapid to measure than HSM, if we find strong HSM-TLP relationships at the global scale, TLP can be used in predicting global drought-induced tree mortality. However, no study has quantified the relationships between HSM and TLP at the global scale. Here we draw together published data on HSM and TLP for 1,773 species from 370 sites worldwide to check whether HSM and TLP are highly associated. We found that HSMs and TLPs are merely highly related in tropical forests, thus TLP can be a reliable surrogate of HSM to predict drought-induced tree mortality in tropical forest. Here we are certainly not advocating for the use of TLP instead of HSM to predict drought-induced tree mortality in tropical forests, but simply for predicting drought-induced tree mortality in tropical forests in supplementary of HSM in the future.
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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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5
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Schmitt S, Trueba S, Coste S, Ducouret É, Tysklind N, Heuertz M, Bonal D, Burban B, Hérault B, Derroire G. Seasonal variation of leaf thickness: An overlooked component of functional trait variability. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:458-463. [PMID: 35120262 DOI: 10.1111/plb.13395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
The dry and wet seasons in the Neotropics have strong effects on soil water and nutrient availability, as well as on forest dynamics. Despite these major effects on forest ecology, little is known on how leaf traits vary throughout the seasons in tropical rainforest trees. Here, we investigated the influence of seasonal variations in climate and soil characteristics on leaf trait variation in two tropical tree species. We measured two leaf traits, thickness and water mass per area, in 401 individuals of two species of Symphonia (Clusiaceae) in the Paracou research station in French Guiana tropical lowland rainforest. We found a significant effect of seasonal variation on these two leaf traits. Soil relative extractable water was a strong environmental predictor of leaf trait variation in response to seasonal variation. Reduced soil water availability during the dry season was associated with increased leaf thickness and water mass per area, possibly as a result of stomatal closure. Our findings advocate the need to account for environmental seasonality when studying leaf traits in seasonal ecosystems such as tropical forests.
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Affiliation(s)
- S Schmitt
- CNRS, UMR EcoFoG (Agroparistech, Cirad, INRAE, Université des Antilles, Université de la Guyane), Campus Agronomique, Kourou, French Guiana
- Université de Bordeaux, INRAE, BIOGECO, Pessac, France
| | - S Trueba
- Université de Bordeaux, INRAE, BIOGECO, Allée Geoffroy St-Hilaire, Pessac, France
| | - S Coste
- Université de la Guyane, UMR EcoFoG (Agroparistech, Cirad, CNRS, INRAE, Université des Antilles), Campus Agronomique, Kourou, French Guiana
| | - É Ducouret
- Université de la Guyane, UMR EcoFoG (Agroparistech, Cirad, CNRS, INRAE, Université des Antilles), Campus Agronomique, Kourou, French Guiana
| | - N Tysklind
- INRAE, UMR EcoFoG (Agroparistech, CNRS, Cirad, Université des Antilles, Université de la Guyane), Campus Agronomique, Kourou, French Guiana
| | - M Heuertz
- Université de Bordeaux, INRAE, BIOGECO, Pessac, France
| | - D Bonal
- Université de Lorraine, AgroParisTech, INRAE, UMR Silva, Nancy, France
| | - B Burban
- INRAE, UMR EcoFoG (Agroparistech, CNRS, Cirad, Université des Antilles, Université de la Guyane), Campus Agronomique, Kourou, French Guiana
| | - B Hérault
- Forêts et Sociétés, Université de Montpellier, CIRAD, Montpellier, France
- Institut National Polytechnique Félix Houphouët-Boigny, INP-HB, Yamoussoukro, Côte d'Ivoire
| | - G Derroire
- Cirad, UMR EcoFoG (Agroparistech, CNRS, INRAE, Université des Antilles, Université de la Guyane), Campus Agronomique, Kourou, French Guiana
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Spanner GC, Gimenez BO, Wright CL, Menezes VS, Newman BD, Collins AD, Jardine KJ, Negrón-Juárez RI, Lima AJN, Rodrigues JR, Chambers JQ, Higuchi N, Warren JM. Dry Season Transpiration and Soil Water Dynamics in the Central Amazon. FRONTIERS IN PLANT SCIENCE 2022; 13:825097. [PMID: 35401584 PMCID: PMC8987125 DOI: 10.3389/fpls.2022.825097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
With current observations and future projections of more intense and frequent droughts in the tropics, understanding the impact that extensive dry periods may have on tree and ecosystem-level transpiration and concurrent carbon uptake has become increasingly important. Here, we investigate paired soil and tree water extraction dynamics in an old-growth upland forest in central Amazonia during the 2018 dry season. Tree water use was assessed via radial patterns of sap flow in eight dominant canopy trees, each a different species with a range in diameter, height, and wood density. Paired multi-sensor soil moisture probes used to quantify volumetric water content dynamics and soil water extraction within the upper 100 cm were installed adjacent to six of those trees. To link depth-specific water extraction patterns to root distribution, fine root biomass was assessed through the soil profile to 235 cm. To scale tree water use to the plot level (stand transpiration), basal area was measured for all trees within a 5 m radius around each soil moisture probe. The sensitivity of tree transpiration to reduced precipitation varied by tree, with some increasing and some decreasing in water use during the dry period. Tree-level water use scaled with sapwood area, from 11 to 190 L per day. Stand level water use, based on multiple plots encompassing sap flow and adjacent trees, varied from ∼1.7 to 3.3 mm per day, increasing linearly with plot basal area. Soil water extraction was dependent on root biomass, which was dense at the surface (i.e., 45% in the upper 5 cm) and declined dramatically with depth. As the dry season progressed and the upper soil dried, soil water extraction shifted to deeper levels and model projections suggest that much of the water used during the month-long dry-down could be extracted from the upper 2-3 m. Results indicate variation in rates of soil water extraction across the research area and, temporally, through the soil profile. These results provide key information on whole-tree contributions to transpiration by canopy trees as water availability changes. In addition, information on simultaneous stand level dynamics of soil water extraction that can inform mechanistic models that project tropical forest response to drought.
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Affiliation(s)
| | - Bruno O. Gimenez
- National Institute of Amazonian Research (INPA), Manaus, Brazil
- Smithsonian Tropical Research Institute (STRI), Panama City, Panama
| | - Cynthia L. Wright
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, TN, United States
| | | | - Brent D. Newman
- Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Adam D. Collins
- Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Kolby J. Jardine
- National Institute of Amazonian Research (INPA), Manaus, Brazil
- Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | | | | | | | - Jeffrey Q. Chambers
- National Institute of Amazonian Research (INPA), Manaus, Brazil
- Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Geography, University of California, Berkeley, Berkeley, CA, United States
| | - Niro Higuchi
- National Institute of Amazonian Research (INPA), Manaus, Brazil
| | - Jeffrey M. Warren
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, TN, United States
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Binks O, Cernusak LA, Liddell M, Bradford M, Coughlin I, Carle H, Bryant C, Dunn E, Oliveira R, Mencuccini M, Meir P. Forest system hydraulic conductance: partitioning tree and soil components. THE NEW PHYTOLOGIST 2022; 233:1667-1681. [PMID: 34861052 DOI: 10.1111/nph.17895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/23/2021] [Indexed: 06/13/2023]
Abstract
Soil-leaf hydraulic conductance determines canopy-atmosphere coupling in vegetation models, but it is typically derived from ex-situ measurements of stem segments and soil samples. Using a novel approach, we derive robust in-situ estimates for whole-tree conductance (ktree ), 'functional' soil conductance (ksoil ), and 'system' conductance (ksystem , water table to canopy), at two climatically different tropical rainforest sites. Hydraulic 'functional rooting depth', determined for each tree using profiles of soil water potential (Ψsoil ) and sap flux data, enabled a robust determination of ktree and ksoil . ktree was compared across species, size classes, seasons, height above nearest drainage (HAND), two field sites, and to alternative representations of ktree ; ksoil was analysed with respect to variations in site, season and HAND. ktree was lower and changed seasonally at the site with higher vapour pressure deficit (VPD) and rainfall; ktree differed little across species but scaled with tree circumference; rsoil (1/ksoil ) ranged from 0 in the wet season to 10× less than rtree (1/ktree ) in the dry season. VPD and not rainfall may influence plot-level k; leaf water potentials and sap flux can be used to determine ktree , ksoil and ksystem ; Ψsoil profiles can provide mechanistic insights into ecosystem-level water fluxes.
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Affiliation(s)
- Oliver Binks
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Lucas A Cernusak
- Centre for Tropical Environmental and Sustainability Science, College of Science and Engineering, James Cook University, Cairns, Qld, 4878, Australia
| | - Michael Liddell
- Centre for Tropical Environmental and Sustainability Science, College of Science and Engineering, James Cook University, Cairns, Qld, 4878, Australia
| | - Matt Bradford
- CSIRO Land and Water, Atherton, Qld, 4883, Australia
| | - Ingrid Coughlin
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Hannah Carle
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Callum Bryant
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Elliot Dunn
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Rafael Oliveira
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, Sao Paulo, 13083-970, Brazil
| | | | - Patrick Meir
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
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8
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Abdalla M, Ahmed MA, Cai G, Wankmüller F, Schwartz N, Litig O, Javaux M, Carminati A. Stomatal closure during water deficit is controlled by below-ground hydraulics. ANNALS OF BOTANY 2022; 129:161-170. [PMID: 34871349 PMCID: PMC8796668 DOI: 10.1093/aob/mcab141] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/16/2021] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Stomatal closure allows plants to promptly respond to water shortage. Although the coordination between stomatal regulation, leaf and xylem hydraulics has been extensively investigated, the impact of below-ground hydraulics on stomatal regulation remains unknown. METHODS We used a novel root pressure chamber to measure, during soil drying, the relation between transpiration rate (E) and leaf xylem water pressure (ψleaf-x) in tomato shoots grafted onto two contrasting rootstocks, a long and a short one. In parallel, we also measured the E(ψleaf-x) relation without pressurization. A soil-plant hydraulic model was used to reproduce the measurements. We hypothesize that (1) stomata close when the E(ψleaf-x) relation becomes non-linear and (2) non-linearity occurs at higher soil water contents and lower transpiration rates in short-rooted plants. KEY RESULTS The E(ψleaf-x) relation was linear in wet conditions and became non-linear as the soil dried. Changing below-ground traits (i.e. root system) significantly affected the E(ψleaf-x) relation during soil drying. Plants with shorter root systems required larger gradients in soil water pressure to sustain the same transpiration rate and exhibited an earlier non-linearity and stomatal closure. CONCLUSIONS We conclude that, during soil drying, stomatal regulation is controlled by below-ground hydraulics in a predictable way. The model suggests that the loss of hydraulic conductivity occurred in soil. These results prove that stomatal regulation is intimately tied to root and soil hydraulic conductances.
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Affiliation(s)
- Mohanned Abdalla
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Horticulture, Faculty of Agriculture, University of Khartoum, Khartoum North, Sudan
| | - Mutez Ali Ahmed
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Department of Land, Air and Water Resources, University of California Davis, Davis, USA
| | - Gaochao Cai
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Fabian Wankmüller
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Nimrod Schwartz
- Department of Soil and Water Science, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Or Litig
- Department of Soil and Water Science, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Mathieu Javaux
- Earth and Life Institute-Environmental Science, Université catholique de Louvain, Louvain-la-Neuve, Belgium
- Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
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Sun J, Ye C, Liu M, Wang Y, Chen J, Wang S, Lu X, Liu G, Xu M, Li R, Liu S, Zhou H, Du Z, Peng F, Tsunekawa A, Tsubo M. Response of net reduction rate in vegetation carbon uptake to climate change across a unique gradient zone on the Tibetan Plateau. ENVIRONMENTAL RESEARCH 2022; 203:111894. [PMID: 34418448 DOI: 10.1016/j.envres.2021.111894] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/22/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
The Tibetan Plateau (TP) has a variety of vegetation types that range from alpine tundra to tropic evergreen forest, which play an important role in the global carbon (C) cycle and is extremely vulnerable to climate change. The vegetation C uptake is crucial to the ecosystem C sequestration. Moreover, net reduction in vegetation C uptake (NRVCU) will strongly affect the C balance of terrestrial ecosystem. Until now, there is limited knowledge on the recovery process of vegetation net C uptake and the spatial-temporal patterns of NRVCU after the disturbance that caused by climate change and human activities. Here, we used the MODIS-derived net primary production to characterize the spatial-temporal patterns of NRVCU. We further explored the influence factors of the net reduction rate in vegetation C uptake (NRRVCU) and recovery processes of vegetation net C uptake across a unique gradient zone on the TP. Results showed that the total net reduction amount of vegetation C uptake gradually decreased from 2000 to 2015 on the TP (Slope = -0.002, P < 0.05). Specifically, an increasing gradient zone of multi-year average of net reduction rate in vegetation carbon uptake (MYANRRVCU) from east to west was observed. In addition, we found that the recovery of vegetation net C uptake after the disturbance caused by climate change and anthropogenic disturbance in the gradient zone were primarily dominated by precipitation and temperature. The findings revealed that the effects of climate change on MYANRRVCU and vegetation net C uptake recovery differed significantly across geographical space and vegetation types. Our results highlight that the biogeographic characteristics of the TP should be considered for combating future climate change.
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Affiliation(s)
- Jian Sun
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Chongchong Ye
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Miao Liu
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yi Wang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Ji Chen
- Department of Agroecology, Aarhus University, 8830, Tjele, Denmark; Aarhus University Centre for Circular Bioeconomy, Aarhus University, 8830, Tjele, Denmark; CLIMATE Interdisciplinary Centre for Climate Change, Aarhus University, 4000, Roskilde, Denmark.
| | - Shuai Wang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, China.
| | - Xuyang Lu
- Institute of Mountain Hazard and Environment, Chinese Academy of Sciences, Chengdu, 610041, China.
| | - Guohua Liu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, China.
| | - Ming Xu
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Renqiang Li
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Shiliang Liu
- School of Environment, Beijing Normal University, Beijing, 100875, China.
| | - Huakun Zhou
- Key Laboratory of Restoration Ecology for Cold Regions in Qinghai, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China.
| | - Zhong Du
- College of Land and Resources, China West Normal University, Nanchong, 637009, China.
| | - Fei Peng
- Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
| | - Atsushi Tsunekawa
- Arid Land Research Center, Tottori University, Tottori, 6800001, Japan.
| | - Mitsuru Tsubo
- Arid Land Research Center, Tottori University, Tottori, 6800001, Japan.
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10
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Kannenberg SA, Guo JS, Novick KA, Anderegg WRL, Feng X, Kennedy D, Konings AG, Martínez‐Vilalta J, Matheny AM. Opportunities, challenges and pitfalls in characterizing plant water‐use strategies. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13945] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
| | - Jessica S. Guo
- Department of Geology and Geophysics University of Utah Salt Lake City UT USA
- Arizona Experiment Station, College of Agriculture and Life Sciences University of Arizona Tucson AZ USA
| | - Kimberly A. Novick
- O’Neill School of Public and Environmental Affairs Indiana University Bloomington IN USA
| | | | - Xue Feng
- Department of Civil, Environmental, and Geo‐Engineering University of Minnesota Minneapolis MN USA
- Saint Anthony Falls Laboratory University of Minnesota Minneapolis MN USA
| | | | | | - Jordi Martínez‐Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès) Catalonia Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès) Catalonia Spain
| | - Ashley M. Matheny
- Department of Geological Sciences Jackson School of Geosciences University of Texas Austin TX USA
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11
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Impacts of Canopy and Understory Nitrogen Additions on Stomatal Conductance and Carbon Assimilation of Dominant Tree Species in a Temperate Broadleaved Deciduous Forest. Ecosystems 2021. [DOI: 10.1007/s10021-020-00595-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Gallup SM, Baker IT, Gallup JL, Restrepo‐Coupe N, Haynes KD, Geyer NM, Denning AS. Accurate Simulation of Both Sensitivity and Variability for Amazonian Photosynthesis: Is It Too Much to Ask? JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2021; 13:e2021MS002555. [PMID: 34594478 PMCID: PMC8459247 DOI: 10.1029/2021ms002555] [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: 04/01/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
Estimates of Amazon rainforest gross primary productivity (GPP) differ by a factor of 2 across a suite of three statistical and 18 process models. This wide spread contributes uncertainty to predictions of future climate. We compare the mean and variance of GPP from these models to that of GPP at six eddy covariance (EC) towers. Only one model's mean GPP across all sites falls within a 99% confidence interval for EC GPP, and only one model matches EC variance. The strength of model response to climate drivers is related to model ability to match the seasonal pattern of the EC GPP. Models with stronger seasonal swings in GPP have stronger responses to rain, light, and temperature than does EC GPP. The model to data comparison illustrates a trade-off inherent to deterministic models between accurate simulation of a mean (average) and accurate responsiveness to drivers. The trade-off exists because all deterministic models simplify processes and lack at least some consequential driver or interaction. If a model's sensitivities to included drivers and their interactions are accurate, then deterministically predicted outcomes have less variability than is realistic. If a GPP model has stronger responses to climate drivers than found in data, model predictions may match the observed variance and seasonal pattern but are likely to overpredict GPP response to climate change. High or realistic variability of model estimates relative to reference data indicate that the model is hypersensitive to one or more drivers.
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Affiliation(s)
- Sarah M. Gallup
- Graduate Degree Program in EcologyColorado State UniversityFort CollinsCOUSA
| | - Ian T. Baker
- Department of Atmospheric ScienceColorado State UniversityFort CollinsCOUSA
| | - John L. Gallup
- Department of EconomicsPortland State UniversityPortlandORUSA
| | - Natalia Restrepo‐Coupe
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonAZUSA
- School of Life SciencesUniversity of Technology SydneyUltimoNSWAustralia
| | | | - Nicholas M. Geyer
- Department of Atmospheric ScienceColorado State UniversityFort CollinsCOUSA
| | - A. Scott Denning
- Graduate Degree Program in EcologyColorado State UniversityFort CollinsCOUSA
- Department of Atmospheric ScienceColorado State UniversityFort CollinsCOUSA
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13
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Xu X, Konings AG, Longo M, Feldman A, Xu L, Saatchi S, Wu D, Wu J, Moorcroft P. Leaf surface water, not plant water stress, drives diurnal variation in tropical forest canopy water content. THE NEW PHYTOLOGIST 2021; 231:122-136. [PMID: 33539544 DOI: 10.1111/nph.17254] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/27/2021] [Indexed: 05/25/2023]
Abstract
Variation in canopy water content (CWC) that can be detected from microwave remote sensing of vegetation optical depth (VOD) has been proposed as an important measure of vegetation water stress. However, the contribution of leaf surface water (LWs ), arising from dew formation and rainfall interception, to CWC is largely unknown, particularly in tropical forests and other high-humidity ecosystems. We compared VOD data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and CWC predicted by a plant hydrodynamics model at four tropical sites in Brazil spanning a rainfall gradient. We assessed how LWs influenced the relationship between VOD and CWC. The analysis indicates that while CWC is strongly correlated with VOD (R2 = 0.62 across all sites), LWs accounts for 61-76% of the diurnal variation in CWC despite being < 10% of CWC. Ignoring LWs weakens the near-linear relationship between CWC and VOD and reduces the consistency in diurnal variation. The contribution of LWs to CWC variation, however, decreases at longer, seasonal to inter-annual, time scales. Our results demonstrate that diurnal patterns of dew formation and rainfall interception can be an important driver of diurnal variation in CWC and VOD over tropical ecosystems and therefore should be accounted for when inferring plant diurnal water stress from VOD measurements.
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Affiliation(s)
- Xiangtao Xu
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14850, USA
| | - Alexandra G Konings
- Department of Earth System Science, Stanford University, Stanford, CA, 94305, USA
| | - Marcos Longo
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Andrew Feldman
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Liang Xu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Sassan Saatchi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
- Institute of Environment and Sustainability, University of California, Los Angeles, CA, 90024, USA
| | - Donghai Wu
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14850, USA
| | - Jin Wu
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Paul Moorcroft
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
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14
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Maréchaux I, Langerwisch F, Huth A, Bugmann H, Morin X, Reyer CP, Seidl R, Collalti A, Dantas de Paula M, Fischer R, Gutsch M, Lexer MJ, Lischke H, Rammig A, Rödig E, Sakschewski B, Taubert F, Thonicke K, Vacchiano G, Bohn FJ. Tackling unresolved questions in forest ecology: The past and future role of simulation models. Ecol Evol 2021; 11:3746-3770. [PMID: 33976773 PMCID: PMC8093733 DOI: 10.1002/ece3.7391] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/04/2021] [Accepted: 02/20/2021] [Indexed: 12/13/2022] Open
Abstract
Understanding the processes that shape forest functioning, structure, and diversity remains challenging, although data on forest systems are being collected at a rapid pace and across scales. Forest models have a long history in bridging data with ecological knowledge and can simulate forest dynamics over spatio-temporal scales unreachable by most empirical investigations.We describe the development that different forest modelling communities have followed to underpin the leverage that simulation models offer for advancing our understanding of forest ecosystems.Using three widely applied but contrasting approaches - species distribution models, individual-based forest models, and dynamic global vegetation models - as examples, we show how scientific and technical advances have led models to transgress their initial objectives and limitations. We provide an overview of recent model applications on current important ecological topics and pinpoint ten key questions that could, and should, be tackled with forest models in the next decade.Synthesis. This overview shows that forest models, due to their complementarity and mutual enrichment, represent an invaluable toolkit to address a wide range of fundamental and applied ecological questions, hence fostering a deeper understanding of forest dynamics in the context of global change.
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Affiliation(s)
| | - Fanny Langerwisch
- Department of Ecology and Environmental SciencesPalacký University OlomoucOlomoucCzech Republic
- Department of Water Resources and Environmental ModelingCzech University of Life SciencesPragueCzech Republic
| | - Andreas Huth
- Helmholtz Centre for Environmental Research ‐ UFZLeipzigGermany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐LeipzigLeipzigGermany
- Institute of Environmental Systems ResearchOsnabrück UniversityOsnabrückGermany
| | - Harald Bugmann
- Forest EcologyInstitute of Terrestrial EcosystemsETH ZürichZurichSwitzerland
| | - Xavier Morin
- EPHECEFECNRSUniv MontpellierUniv Paul Valéry MontpellierIRDMontpellierFrance
| | - Christopher P.O. Reyer
- Potsdam Institute for Climate Impact Research (PIK)Member of the Leibniz AssociationPotsdamGermany
| | - Rupert Seidl
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU)ViennaAustria
- TUM School of Life SciencesTechnical University of MunichFreisingGermany
| | - Alessio Collalti
- Forest Modelling LabInstitute for Agriculture and Forestry Systems in the MediterraneanNational Research Council of Italy (CNR‐ISAFOM)Perugia (PG)Italy
- Department of Innovation in Biological, Agro‐food and Forest SystemsUniversity of TusciaViterboItaly
| | | | - Rico Fischer
- Helmholtz Centre for Environmental Research ‐ UFZLeipzigGermany
| | - Martin Gutsch
- Potsdam Institute for Climate Impact Research (PIK)Member of the Leibniz AssociationPotsdamGermany
| | | | - Heike Lischke
- Dynamic MacroecologyLand Change ScienceSwiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
| | - Anja Rammig
- TUM School of Life SciencesTechnical University of MunichFreisingGermany
| | - Edna Rödig
- Helmholtz Centre for Environmental Research ‐ UFZLeipzigGermany
| | - Boris Sakschewski
- Potsdam Institute for Climate Impact Research (PIK)Member of the Leibniz AssociationPotsdamGermany
| | | | - Kirsten Thonicke
- Potsdam Institute for Climate Impact Research (PIK)Member of the Leibniz AssociationPotsdamGermany
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15
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Flack-Prain S, Meir P, Malhi Y, Smallman TL, Williams M. Does economic optimisation explain LAI and leaf trait distributions across an Amazon soil moisture gradient? GLOBAL CHANGE BIOLOGY 2021; 27:587-605. [PMID: 32979883 DOI: 10.1111/gcb.15368] [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: 03/06/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
Leaf area index (LAI) underpins terrestrial ecosystem functioning, yet our ability to predict LAI remains limited. Across Amazon forests, mean LAI, LAI seasonal dynamics and leaf traits vary with soil moisture stress. We hypothesise that LAI variation can be predicted via an optimality-based approach, using net canopy C export (NCE, photosynthesis minus the C cost of leaf growth and maintenance) as a fitness proxy. We applied a process-based terrestrial ecosystem model to seven plots across a moisture stress gradient with detailed in situ measurements, to determine nominal plant C budgets. For each plot, we then compared observations and simulations of the nominal (i.e. observed) C budget to simulations of alternative, experimental budgets. Experimental budgets were generated by forcing the model with synthetic LAI timeseries (across a range of mean LAI and LAI seasonality) and different leaf trait combinations (leaf mass per unit area, lifespan, photosynthetic capacity and respiration rate) operating along the leaf economic spectrum. Observed mean LAI and LAI seasonality across the soil moisture stress gradient maximised NCE, and were therefore consistent with optimality-based predictions. Yet, the predictive power of an optimality-based approach was limited due to the asymptotic response of simulated NCE to mean LAI and LAI seasonality. Leaf traits fundamentally shaped the C budget, determining simulated optimal LAI and total NCE. Long-lived leaves with lower maximum photosynthetic capacity maximised simulated NCE under aseasonal high mean LAI, with the reverse found for short-lived leaves and higher maximum photosynthetic capacity. The simulated leaf trait LAI trade-offs were consistent with observed distributions. We suggest that a range of LAI strategies could be equally economically viable at local level, though we note several ecological limitations to this interpretation (e.g. between-plant competition). In addition, we show how leaf trait trade-offs enable divergence in canopy strategies. Our results also allow an assessment of the usefulness of optimality-based approaches in simulating primary tropical forest functioning, evaluated against in situ data.
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Affiliation(s)
| | - Patrick Meir
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Thomas L Smallman
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
- National Centre for Earth Observation, University of Edinburgh, Edinburgh, UK
| | - Mathew Williams
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
- National Centre for Earth Observation, University of Edinburgh, Edinburgh, UK
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16
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Rowland L, Oliveira RS, Bittencourt PRL, Giles AL, Coughlin I, Costa PDB, Domingues T, Ferreira LV, Vasconcelos SS, Junior JAS, Oliveira AAR, da Costa ACL, Meir P, Mencuccini M. Plant traits controlling growth change in response to a drier climate. THE NEW PHYTOLOGIST 2021; 229:1363-1374. [PMID: 32981040 DOI: 10.1111/nph.16972] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
Plant traits are increasingly being used to improve prediction of plant function, including plant demography. However, the capability of plant traits to predict demographic rates remains uncertain, particularly in the context of trees experiencing a changing climate. Here we present data combining 17 plant traits associated with plant structure, metabolism and hydraulic status, with measurements of long-term mean, maximum and relative growth rates for 176 trees from the world's longest running tropical forest drought experiment. We demonstrate that plant traits can predict mean annual tree growth rates with moderate explanatory power. However, only combinations of traits associated more directly with plant functional processes, rather than more commonly employed traits like wood density or leaf mass per area, yield the power to predict growth. Critically, we observe a shift from growth being controlled by traits related to carbon cycling (assimilation and respiration) in well-watered trees, to traits relating to plant hydraulic stress in drought-stressed trees. We also demonstrate that even with a very comprehensive set of plant traits and growth data on large numbers of tropical trees, considerable uncertainty remains in directly interpreting the mechanisms through which traits influence performance in tropical forests.
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Affiliation(s)
- Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
| | - Rafael S Oliveira
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, SP, 13083-970, Brasil
- Biological Sciences, UWA, Perth, Crawle, WA, 6009, Australia
| | - Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
- Programa de Pós Graduação em Ecologia Institute of Biology, University of Campinas - UNICAMP 13083-970, PO Box 6109, Campinas, SP, Brazil
| | - Andre L Giles
- Programa de Pós Graduação em Ecologia Institute of Biology, University of Campinas - UNICAMP 13083-970, PO Box 6109, Campinas, SP, Brazil
| | - Ingrid Coughlin
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, SP, 14040-900, Brasil
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Patricia de Britto Costa
- Biological Sciences, UWA, Perth, Crawle, WA, 6009, Australia
- Programa de Pós Graduação em Biologia Vegetal Institute of Biology, University of Campinas - UNICAMP, PO Box 6109, Campinas, SP, 13083-970, Brazil
| | - Tomas Domingues
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, SP, 14040-900, Brasil
| | | | | | - João A S Junior
- Instituto de Geosciências, Universidade Federal do Pará, Belém, PA, 66075-110, Brasil
| | - Alex A R Oliveira
- School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Antonio C L da Costa
- Museu Paraense Emílio Goeldi, Belém, PA, 66040-170, Brasil
- EMBRAPA Amazônia Oriental, 14 Belém, PA, 66095-903, Brasil
| | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
- School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Maurizio Mencuccini
- CREAF, Campus UAB, Cerdanyola del Vallés, 08193, Spain
- ICREA, Barcelona, 08010, Spain
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17
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Tang ACI, Melling L, Stoy PC, Musin KK, Aeries EB, Waili JW, Shimizu M, Poulter B, Hirata R. A Bornean peat swamp forest is a net source of carbon dioxide to the atmosphere. GLOBAL CHANGE BIOLOGY 2020; 26:6931-6944. [PMID: 32881141 DOI: 10.1111/gcb.15332] [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: 11/03/2019] [Revised: 06/30/2020] [Accepted: 07/27/2020] [Indexed: 06/11/2023]
Abstract
Tropical peat forests are a globally important reservoir of carbon, but little is known about CO2 exchange on an annual basis. We measured CO2 exchange between the atmosphere and tropical peat swamp forest in Sarawak, Malaysia using the eddy covariance technique over 4 years from 2011 to 2014. The CO2 fluxes varied between seasons and years. A small carbon uptake took place during the rainy season at the beginning of 2011, while a substantial net efflux of >600 g C/m2 occurred over a 2 month period in the middle of the dry season. Conversely, the peat ecosystem was a source of carbon during both the dry and rainy seasons in subsequent years and more carbon was lost during the rainy season relative to the dry season. Our results demonstrate that the forest was a net source of CO2 to the atmosphere during every year of measurement with annual efflux ranging from 183 to 632 g C m-2 year-1 , noting that annual flux values were sensitive to gap filling methodology. This is in contrast to the typical view of tropical peat forests which must have acted as net C sinks over time scales of centuries to millennia to create the peat deposits. Path analyses revealed that the gross primary productivity (GPP) and ecosystem respiration (RE) were primarily affected by vapour pressure deficit (VPD). Results suggest that future increases in VPD could further reduce the C sink strength and result in additional net CO2 losses from this tropical peat swamp forest in the absence of plant acclimation to such changes in atmospheric dryness.
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Affiliation(s)
- Angela C I Tang
- Sarawak Tropical Peat Research Institute, Kota Samarahan, Sarawak, Malaysia
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
| | - Lulie Melling
- Sarawak Tropical Peat Research Institute, Kota Samarahan, Sarawak, Malaysia
| | - Paul C Stoy
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
- Department of Biological Systems Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Kevin K Musin
- Sarawak Tropical Peat Research Institute, Kota Samarahan, Sarawak, Malaysia
| | - Edward B Aeries
- Sarawak Tropical Peat Research Institute, Kota Samarahan, Sarawak, Malaysia
| | - Joseph W Waili
- Sarawak Tropical Peat Research Institute, Kota Samarahan, Sarawak, Malaysia
| | - Mariko Shimizu
- Civil Engineering Research Institute for Cold Region, Sapporo, Japan
| | - Benjamin Poulter
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Ryuichi Hirata
- Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Japan
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18
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Stand-Level Transpiration Increases after Eastern Redcedar (Juniperus virginiana L.) Encroachment into the Midstory of Oak Forests. FORESTS 2020. [DOI: 10.3390/f11090901] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Eastern redcedar (Juniperus virginiana L., redcedar) encroachment is transitioning the oak-dominated Cross-Timbers of the southern Great Plain of the USA into mixed-species forests. However, it remains unknown how the re-assemblage of tree species in a semiarid to sub-humid climate affects species-specific water use and competition, and ultimately the ecosystem-level water budget. We selected three sites representative of oak, redcedar, and oak and redcedar mixed stands with a similar total basal area (BA) in a Cross-Timbers forest near Stillwater, Oklahoma. Sap flow sensors were installed in a subset of trees in each stand representing the distribution of diameter at breast height (DBH). Sap flow of each selected tree was continuously monitored over a period of 20 months, encompassing two growing seasons between May 2017 and December 2018. Results showed that the mean sap flow density (Sd) of redcedar was usually higher than post oaks (Quercus stellata Wangenh.). A structural equation model showed a significant correlation between Sd and shallow soil moisture for redcedar but not for post oak. At the stand level, the annual water use of the mixed species stand was greater than the redcedar or oak stand of similar total BA. The transition of oak-dominated Cross-Timbers to redcedar and oak mixed forest will increase stand-level transpiration, potentially reducing the water available for runoff or recharge to groundwater.
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19
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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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20
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Differences in Near Isohydric and Anisohydric Behavior of Contrasting Poplar Hybrids (I-101 (Populus alba L.) × 84K (Populus alba L. × Populus glandulosa Uyeki)) under Drought-Rehydration Treatments. FORESTS 2020. [DOI: 10.3390/f11040402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Carbon starvation and hydraulic failure are considered important factors in determining the mechanisms associated with tree mortality. In this study, iso/anisohydric classification was used to assess drought resistance and mortality mechanisms in two contrasting poplar species, as it is generally believed that isohydric species are more susceptible to carbon starvation, while anisohydric species are more susceptible to hydraulic failure. However, these assumptions are rarely tested in poplar genotypes with contrasting growth strategies. Thus, we subjected potted poplar genotypes (I-101 (Populus alba L.) × 84K (Populus alba L. × Populus glandulosa Uyeki)) with fast and slow growth rates to drought–rehydration treatments. The slow-growing genotype maintained higher stomatal conductance and lower predawn leaf water potential than the fast-growing genotype, thus exhibiting a near-anisohydric stomatal behavior throughout the treatment period. The nonstructural carbohydrate (NSC) content indicated that the two genotypes had the same trend of carbon change (e.g., the NSC content in the leaves increased with drought and then decreased). However, when NSC content data were combined with the growth and photosynthetic data, it was observed that the slow-growing genotype mobilized carbon to maintain hydraulic safety, while the NSC content of the fast-growing genotype among tissues was static. The percent loss of hydraulic conductivity in the branches during treatments indicated that the fast-growing genotype could recover more quickly from xylem embolism than the slow-growing genotype. The slow-growing genotype with a slow growth recovery after rehydration showed a significant increase in carbon consumption, combined with a significant increase in the hydraulic safety threshold value, indicating that there may be drought tolerance. In comparison, the fast-growing genotype showed a faster hydraulic recovery ability that had no effect on the NSC content in the leaves and roots. Our findings demonstrate intraspecific isohydric behavior in poplar; however, the trade-off between carbon distribution and stomatal regulation should be considered separately within genotypes of the same species. In addition, NSC plays an important role in water–carbon balance in the drought–rehydration cycle.
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21
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Recurrence Analysis of Vegetation Indices for Highlighting the Ecosystem Response to Drought Events: An Application to the Amazon Forest. REMOTE SENSING 2020. [DOI: 10.3390/rs12060907] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Forests are important in sequestering CO2 and therefore play a significant role in climate change. However, the CO2 cycle is conditioned by drought events that alter the rate of photosynthesis, which is the principal physiological action of plants in transforming CO2 into biological energy. This study applied recurrence quantification analysis (RQA) to describe the evolution of photosynthesis-related indices to highlight disturbance alterations produced by the Atlantic Multidecadal Oscillation (AMO, years 2005 and 2010) and the El Niño-Southern Oscillation (ENSO, year 2015) in the Amazon forest. The analysis was carried out using Moderate Resolution Imaging Spectroradiometer (MODIS) images to build time series of the enhanced vegetation index (EVI), the normalized difference water index (NDWI), and the land surface temperature (LST) covering the period 2001–2018. The results did not show significant variations produced by AMO throughout the study area, while a disruption due to the global warming phase linked to the extreme ENSO event occurred, and the forest was able to recover. In addition, spatial differences in the response of the forest to the ENSO event were found. These findings show that the application of RQA to the time series of vegetation indices supports the evaluation of the forest ecosystem response to disruptive events. This approach provides information on the capacity of the forest to recover after a disruptive event and, therefore is useful to estimate the resilience of this particular ecosystem.
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22
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Yoshifuji N, Kumagai T, Ichie T, Kume T, Tateishi M, Inoue Y, Yoneyama A, Nakashizuka T. Limited stomatal regulation of the largest-size class of Dryobalanops aromatica in a Bornean tropical rainforest in response to artificial soil moisture reduction. JOURNAL OF PLANT RESEARCH 2020; 133:175-191. [PMID: 31858360 DOI: 10.1007/s10265-019-01161-3] [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: 04/05/2019] [Accepted: 12/08/2019] [Indexed: 06/10/2023]
Abstract
The physiological response of trees to drought is crucial for understanding the risk of mortality and its feedbacks to climate under the increase in droughts due to climate change, especially for the largest trees in tropical rainforests because of their large contribution to total carbon storage and water use. We determined the response of the mean canopy stomatal conductance per unit leaf area (gs) and whole-tree hydraulic conductance (Gp) of the largest individuals (38-53 m in height) of a typical canopy tree species in a Bornean tropical rainforest, Dryobalanops aromatica C.F.Gaertn., to soil moisture reduction by a 4-month rainfall exclusion experiment (REE) based on the measurements of sap flux and leaf water potentials at midday and dawn. In the mesic condition, the gs at vapor pressure deficit (D) = 1 kPa (gsref) was small compared with the reported values in various biomes. The sensitivity of gs to D (m) at a given gsref (m/gsref) was ≥ 0.6 irrespective of soil moisture conditions, indicating intrinsically sensitive stomatal control with increasing D. The REE caused greater soil drought and decreased the mean leaf water potentials at midday and dawn to the more negative values than the control under the relatively dry conditions due to natural reduction in rainfall. However, the REE did not cause a greater decrease in gs nor any clear alteration in the sensitivity of gs to D compared with the control, and induced greater decreases in Gp during REE than the control. Thus, though the small gs and the sensitive stomatal response to D indicate the water saving characteristics of the studied trees under usual mesic conditions, their limited stomatal regulation in response to soil drought by REE and the resulting decline in Gp might suggest a poor resistance to the unusually severe drought expected in the future.
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Affiliation(s)
- Natsuko Yoshifuji
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.
- Kasuya Research Forest, Kyushu University, Sasaguri, Fukuoka, 811-2415, Japan.
| | - Tomo'omi Kumagai
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Aichi, 464-8601, Japan
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Tomoaki Ichie
- Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Kochi, 783-8502, Japan
| | - Tomonori Kume
- Kasuya Research Forest, Kyushu University, Sasaguri, Fukuoka, 811-2415, Japan
| | - Makiko Tateishi
- Kyoto University Research Administration Office, Kyoto, 606-8501, Japan
| | - Yuta Inoue
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime, 790-8566, Japan
| | - Aogu Yoneyama
- Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Kochi, 783-8502, Japan
| | - Tohru Nakashizuka
- Research Institute for Humanity and Nature, Kamigamo-Motoyama, Kyoto, 603-8047, Japan
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23
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Tang ACI, Stoy PC, Hirata R, Musin KK, Aeries EB, Wenceslaus J, Shimizu M, Melling L. The exchange of water and energy between a tropical peat forest and the atmosphere: Seasonal trends and comparison against other tropical rainforests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 683:166-174. [PMID: 31132697 DOI: 10.1016/j.scitotenv.2019.05.217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 06/09/2023]
Abstract
Tropical rainforests control the exchange of water and energy between the land surface and the atmosphere near the equator and thus play an important role in the global climate system. Measurements of latent (LE) and sensible heat exchange (H) have not been synthesized across global tropical rainforests to date, which can help place observations from individual tropical forests in a global context. We measured LE and H for four years in a tropical peat forest ecosystem in Sarawak, Malaysian Borneo using eddy covariance, and hypothesize that the study ecosystem will exhibit less seasonal variability in turbulent fluxes than other tropical ecosystems as soil water is not expected to be limiting in a tropical forested wetland. LE and H show little variability across seasons in the study ecosystem, with LE values on the order of 11 MJ m-2 day and H on the order of 3 MJ m-2 day-1. Annual evapotranspiration (ET) did not differ among years and averaged 1579 ± 47 mm year-1. LE exceeded characteristic values from other tropical rainforest ecosystems in the FLUXNET2015 database with the exception of GF-Guy near coastal French Guyana, which averaged 8-11 MJ m-2 day-1. The Bowen ratio (Bo) in tropical rainforests in the FLUXNET2015 database either exhibited little seasonal trend, one seasonal peak, or two peaks. Volumetric water content (VWC) and VPD explained a trivial amount of the variability of LE and Bo in some of the tropical rainforests including the study ecosystem, but were strong controls in others, suggesting differences in stomatal regulation and/or the partitioning between evaporation and transpiration. Results demonstrate important differences in the seasonal patterns in water and energy exchange across different tropical rainforest ecosystems that need to be understood to quantify how ongoing changes in tropical rainforest extent will impact the global climate system.
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Affiliation(s)
- Angela C I Tang
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA; Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Paul C Stoy
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA.
| | - Ryuichi Hirata
- Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
| | - Kevin K Musin
- Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Edward B Aeries
- Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Joseph Wenceslaus
- Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Mariko Shimizu
- Civil Engineering Research Institute for Cold Region, Sapporo 062-8602, Japan
| | - Lulie Melling
- Sarawak Tropical Peat Research Institute, Lot 6035, Kuching-Kota Samarahan Expressway, 94300 Kota Samarahan, Sarawak, Malaysia
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24
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Mencuccini M, Manzoni S, Christoffersen B. Modelling water fluxes in plants: from tissues to biosphere. THE NEW PHYTOLOGIST 2019; 222:1207-1222. [PMID: 30636295 DOI: 10.1111/nph.15681] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 12/18/2018] [Indexed: 05/02/2023]
Abstract
Contents Summary 1207 I. Introduction 1207 II. A brief history of modelling plant water fluxes 1208 III. Main components of plant water transport models 1208 IV. Stand-scale water fluxes and coupling to climate and soil 1213 V. Water fluxes in terrestrial biosphere models and feedbacks to community dynamics 1215 VI. Outstanding challenges in modelling water fluxes in the soil-plant-atmosphere continuum 1217 Acknowledgements 1218 References 1218 SUMMARY: Models of plant water fluxes have evolved from studies focussed on understanding the detailed structure and functioning of specific components of the soil-plant-atmosphere (SPA) continuum to architectures often incorporated inside eco-hydrological and terrestrial biosphere (TB) model schemes. We review here the historical evolution of this field, examine the basic structure of a simplified individual-based model of plant water transport, highlight selected applications for specific ecological problems and conclude by examining outstanding issues requiring further improvements in modelling vegetation water fluxes. We particularly emphasise issues related to the scaling from tissue-level traits to individual-based predictions of water transport, the representation of nonlinear and hysteretic behaviour in soil-xylem hydraulics and the need to incorporate knowledge of hydraulics within broader frameworks of plant ecological strategies and their consequences for predicting community demography and dynamics.
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Affiliation(s)
| | - Stefano Manzoni
- Stockholm University, Stockholm, 10691, Sweden
- Bolin Centre for Climate Research, Stockholm University, SE-10691, Stockholm, Sweden
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25
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Feng X, Ackerly DD, Dawson TE, Manzoni S, McLaughlin B, Skelton RP, Vico G, Weitz AP, Thompson SE. Beyond isohydricity: The role of environmental variability in determining plant drought responses. PLANT, CELL & ENVIRONMENT 2019; 42:1104-1111. [PMID: 30513545 DOI: 10.1111/pce.13486] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/04/2018] [Accepted: 11/20/2018] [Indexed: 05/21/2023]
Abstract
Despite the appeal of the iso/anisohydric framework for classifying plant drought responses, recent studies have shown that such classifications can be strongly affected by a plant's environment. Here, we present measured in situ drought responses to demonstrate that apparent isohydricity can be conflated with environmental conditions that vary over space and time. In particular, we (a) use data from an oak species (Quercus douglasii) during the 2012-2015 extreme drought in California to demonstrate how temporal and spatial variability in the environment can influence plant water potential dynamics, masking the role of traits; (b) explain how these environmental variations might arise from climatic, topographic, and edaphic variability; (c) illustrate, through a "common garden" thought experiment, how existing trait-based or response-based isohydricity metrics can be confounded by these environmental variations, leading to Type-1 (false positive) and Type-2 (false negative) errors; and (d) advocate for the use of model-based approaches for formulating alternate classification schemes. Building on recent insights from greenhouse and vineyard studies, we offer additional evidence across multiple field sites to demonstrate the importance of spatial and temporal drivers of plants' apparent isohydricity. This evidence challenges the use of isohydricity indices, per se, to characterize plant water relations at the global scale.
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Affiliation(s)
- Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - David D Ackerly
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, 94720, USA
| | - Todd E Dawson
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, 94720, USA
- Department of Environmental Sciences, Policy, and Management, University of California, Berkeley, Berkeley, California, 94720, USA
| | - Stefano Manzoni
- Department of Physical Geography, Stockholm University, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm, Sweden
| | | | - Robert P Skelton
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, 94720, USA
| | - Giulia Vico
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Andrew P Weitz
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, 94720, USA
| | - Sally E Thompson
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California, 94720, USA
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26
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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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27
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McDowell N, Allen CD, Anderson-Teixeira K, Brando P, Brienen R, Chambers J, Christoffersen B, Davies S, Doughty C, Duque A, Espirito-Santo F, Fisher R, Fontes CG, Galbraith D, Goodsman D, Grossiord C, Hartmann H, Holm J, Johnson DJ, Kassim AR, Keller M, Koven C, Kueppers L, Kumagai T, Malhi Y, McMahon SM, Mencuccini M, Meir P, Moorcroft P, Muller-Landau HC, Phillips OL, Powell T, Sierra CA, Sperry J, Warren J, Xu C, Xu X. Drivers and mechanisms of tree mortality in moist tropical forests. THE NEW PHYTOLOGIST 2018; 219:851-869. [PMID: 29451313 DOI: 10.1111/nph.15027] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/19/2017] [Indexed: 05/22/2023]
Abstract
Tree mortality rates appear to be increasing in moist tropical forests (MTFs) with significant carbon cycle consequences. Here, we review the state of knowledge regarding MTF tree mortality, create a conceptual framework with testable hypotheses regarding the drivers, mechanisms and interactions that may underlie increasing MTF mortality rates, and identify the next steps for improved understanding and reduced prediction. Increasing mortality rates are associated with rising temperature and vapor pressure deficit, liana abundance, drought, wind events, fire and, possibly, CO2 fertilization-induced increases in stand thinning or acceleration of trees reaching larger, more vulnerable heights. The majority of these mortality drivers may kill trees in part through carbon starvation and hydraulic failure. The relative importance of each driver is unknown. High species diversity may buffer MTFs against large-scale mortality events, but recent and expected trends in mortality drivers give reason for concern regarding increasing mortality within MTFs. Models of tropical tree mortality are advancing the representation of hydraulics, carbon and demography, but require more empirical knowledge regarding the most common drivers and their subsequent mechanisms. We outline critical datasets and model developments required to test hypotheses regarding the underlying causes of increasing MTF mortality rates, and improve prediction of future mortality under climate change.
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Affiliation(s)
- Nate McDowell
- Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Craig D Allen
- US Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, NM, 87544, USA
| | - Kristina Anderson-Teixeira
- Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Washington, DC, 20036, USA
- Conservation Ecology Center, Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA, 22630, USA
| | - Paulo Brando
- Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA, 02450, USA
- Instituto de Pesquisa Ambiental de Amazonia, Lago Norte, Brasilia, Brazil
| | - Roel Brienen
- School of Geography, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Jeff Chambers
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Brad Christoffersen
- Department of Biology and School of Earth, Environmental and Marine Sciences, University of Texas Rio Grande Valley, Edinburg, TX, 78539, USA
| | - Stuart Davies
- Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Washington, DC, 20036, USA
| | - Chris Doughty
- SICCS, Northern Arizona University, Flagstaff, AZ, 86001, USA
| | - Alvaro Duque
- Departmento de Ciencias Forestales, Universidad Nacional de Columbia, Medellín, Columbia
| | | | - Rosie Fisher
- National Center for Atmospheric Research, Boulder, CO, 80305, USA
| | - Clarissa G Fontes
- Department of Integrative Biology, University of California at Berkeley, Berkeley, CA, 94720, USA
| | - David Galbraith
- School of Geography, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Devin Goodsman
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | | | - Henrik Hartmann
- Department of Biogeochemical Processes, Max Plank Institute for Biogeochemistry, 07745, Jena, Germany
| | - Jennifer Holm
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Abd Rahman Kassim
- Geoinformation Programme, Forestry and Environment Division, Forest Research Institute Malaysia, Selangor, Malaysia
| | - Michael Keller
- International Institute of Tropical Forestry, USDA Jardin Botanico Sur, 1201 Calle Ceiba, San Juan, 00926, Puerto Rico
- Embrapa Agricultural Informatics, Parque Estacao Biologica, Brasilia DF, 70770, Brazil
- Jet Propulsion Laboratory, Pasadena, CA, 91109, USA
| | - Charlie Koven
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lara Kueppers
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Energy and Resources Group, University of California, Berkeley, CA, 94720, USA
| | - Tomo'omi Kumagai
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 7 Chome-3-1 Hongo, Bunkyo, Tokyo, 113-8654, Japan
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, OX1 2JD, UK
| | - Sean M McMahon
- Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Washington, DC, 20036, USA
| | - Maurizio Mencuccini
- ICREA, CREAF, University of Barcelona, Gran Via de les Corts Catalenes, 585 08007, Barcelona, Spain
| | - Patrick Meir
- Australian National University, Acton, Canberra, ACT, 2601, Australia
- School of Geosciences, University of Edinburgh, Old College, South Bridge, Edinburgh, EH8 9YL, UK
| | | | - Helene C Muller-Landau
- Smithsonian Tropical Research Institute, Apartado Postal, 0843-03092, Panamá, República de Panamá
| | - Oliver L Phillips
- School of Geography, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Thomas Powell
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Carlos A Sierra
- Department of Biogeochemical Processes, Max Plank Institute for Biogeochemistry, 07745, Jena, Germany
| | - John Sperry
- University of Utah, Salt Lake City, UT, 84112, USA
| | - Jeff Warren
- Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Chonggang Xu
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Xiangtao Xu
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
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28
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Fisher RA, Koven CD, Anderegg WRL, Christoffersen BO, Dietze MC, Farrior CE, Holm JA, Hurtt GC, Knox RG, Lawrence PJ, Lichstein JW, Longo M, Matheny AM, Medvigy D, Muller-Landau HC, Powell TL, Serbin SP, Sato H, Shuman JK, Smith B, Trugman AT, Viskari T, Verbeeck H, Weng E, Xu C, Xu X, Zhang T, Moorcroft PR. Vegetation demographics in Earth System Models: A review of progress and priorities. GLOBAL CHANGE BIOLOGY 2018; 24:35-54. [PMID: 28921829 DOI: 10.1111/gcb.13910] [Citation(s) in RCA: 183] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 08/12/2017] [Accepted: 08/17/2017] [Indexed: 05/24/2023]
Abstract
Numerous current efforts seek to improve the representation of ecosystem ecology and vegetation demographic processes within Earth System Models (ESMs). These developments are widely viewed as an important step in developing greater realism in predictions of future ecosystem states and fluxes. Increased realism, however, leads to increased model complexity, with new features raising a suite of ecological questions that require empirical constraints. Here, we review the developments that permit the representation of plant demographics in ESMs, and identify issues raised by these developments that highlight important gaps in ecological understanding. These issues inevitably translate into uncertainty in model projections but also allow models to be applied to new processes and questions concerning the dynamics of real-world ecosystems. We argue that stronger and more innovative connections to data, across the range of scales considered, are required to address these gaps in understanding. The development of first-generation land surface models as a unifying framework for ecophysiological understanding stimulated much research into plant physiological traits and gas exchange. Constraining predictions at ecologically relevant spatial and temporal scales will require a similar investment of effort and intensified inter-disciplinary communication.
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Affiliation(s)
- Rosie A Fisher
- National Center for Atmospheric Research, Boulder, CO, USA
| | | | | | | | - Michael C Dietze
- Department of Earth and Environment, Boston University, Boston, MA, USA
| | - Caroline E Farrior
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | | | - George C Hurtt
- Department of Geographical Sciences, University of Maryland, College Park, MD, USA
| | - Ryan G Knox
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | | | - Marcos Longo
- Embrapa Agricultural Informatics, Campinas, Brazil
| | - Ashley M Matheny
- Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA
| | - David Medvigy
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | | | | | - Shawn P Serbin
- Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, USA
| | - Hisashi Sato
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan
| | | | - Benjamin Smith
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Anna T Trugman
- Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, USA
| | - Toni Viskari
- Smithsonian Tropical Research Institute, Panamá, Panamá
| | - Hans Verbeeck
- Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Ensheng Weng
- Center for Climate Systems Research, Columbia University, New York, NY, USA
| | - Chonggang Xu
- Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Xiangtao Xu
- Department of Geosciences, Princeton University, Princeton, NJ, USA
| | - Tao Zhang
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Paul R Moorcroft
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
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29
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Wu X, Tang Y, Chen Y, Wen J, Xie Y, Lu S. Sap flow characteristics and responses to summer rainfall for Pinus tabulaeformis and Hippophae rhamnoides in the Loess hilly region of China. Ecol Evol 2018; 8:617-630. [PMID: 29321898 PMCID: PMC5756875 DOI: 10.1002/ece3.3639] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/15/2017] [Accepted: 10/08/2017] [Indexed: 11/10/2022] Open
Abstract
As a major driving element of the structure and function of arid and semiarid ecosystems, rainfall is the essential factor limiting plant biological processes. To clarify the characteristics of transpiration and responses to summer rainfall, sap flow density (Fd) of Pinus tabulaeformis and Hippophae rhamnoides was monitored using thermal dissipation probes. In addition, midday leaf water potential (ψm) and leaf stomatal conductance (Gs) were also analyzed to determine water use strategies. The results indicated that the diurnal variation in the normalized Fd values exhibited a single-peak curve for P. tabulaeformis, while H. rhamnoides showed multiple peaks. The normalized Fd for P. tabulaeformis remained relatively stable regardless of rainfall events. However, there was also a significant increase in the normalized Fd for H. rhamnoides in response to rainfall in June and August (p < .05), although no significant differences were observed in July. The normalized Fd values for P. tabulaeformis and H. rhamnoides fitted well with the derived variable of transpiration, an integrated index calculated from the vapor pressure deficit and solar radiation (Rs), using an exponential saturation function. The differences in fitting coefficients suggested that H. rhamnoides showed more sensitivity to summer rainfall (p < .01) than P. tabulaeformis. Furthermore, during the study period, P. tabulaeformis reduced Gs as soil water decreased, maintaining a relatively constant ψm; while H. rhamnoides allowed large fluctuations in ψm to maintain Gs. Therefore, P. tabulaeformis and H. rhamnoides should be considered isohydric and anisohydric species, respectively. And more consideration should be taken for H. rhamnoides in the afforestation activities and the local plantation management under the context of the frequently seasonal drought in the loess hilly region.
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Affiliation(s)
- Xu Wu
- State Key Laboratory of Soil Erosion and Dry‐Land Farming on the Loess PlateauInstitute of Soil and Water ConservationChinese Academy of SciencesMinistry of Water ResourcesYanglingShaanxiChina
- University of Chinese Academy of ScienceBeijingChina
| | - Yakun Tang
- Institute of Soil and Water ConservationNorthwest Agriculture and Forestry UniversityYanglingShaanxiChina
| | - Yunming Chen
- State Key Laboratory of Soil Erosion and Dry‐Land Farming on the Loess PlateauInstitute of Soil and Water ConservationChinese Academy of SciencesMinistry of Water ResourcesYanglingShaanxiChina
- Institute of Soil and Water ConservationNorthwest Agriculture and Forestry UniversityYanglingShaanxiChina
| | - Jie Wen
- College of ForestryNorthwest Agriculture and Forestry UniversityYanglingShaanxiChina
| | - Yuli Xie
- State Key Laboratory of Soil Erosion and Dry‐Land Farming on the Loess PlateauInstitute of Soil and Water ConservationChinese Academy of SciencesMinistry of Water ResourcesYanglingShaanxiChina
- University of Chinese Academy of ScienceBeijingChina
| | - Senbao Lu
- College of ForestryNorthwest Agriculture and Forestry UniversityYanglingShaanxiChina
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30
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Powell TL, Wheeler JK, de Oliveira AAR, da Costa ACL, Saleska SR, Meir P, Moorcroft PR. Differences in xylem and leaf hydraulic traits explain differences in drought tolerance among mature Amazon rainforest trees. GLOBAL CHANGE BIOLOGY 2017; 23:4280-4293. [PMID: 28426175 DOI: 10.1111/gcb.13731] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/23/2017] [Indexed: 05/24/2023]
Abstract
Considerable uncertainty surrounds the impacts of anthropogenic climate change on the composition and structure of Amazon forests. Building upon results from two large-scale ecosystem drought experiments in the eastern Brazilian Amazon that observed increases in mortality rates among some tree species but not others, in this study we investigate the physiological traits underpinning these differential demographic responses. Xylem pressure at 50% conductivity (xylem-P50 ), leaf turgor loss point (TLP), cellular osmotic potential (πo ), and cellular bulk modulus of elasticity (ε), all traits mechanistically linked to drought tolerance, were measured on upper canopy branches and leaves of mature trees from selected species growing at the two drought experiment sites. Each species was placed a priori into one of four plant functional type (PFT) categories: drought-tolerant versus drought-intolerant based on observed mortality rates, and subdivided into early- versus late-successional based on wood density. We tested the hypotheses that the measured traits would be significantly different between the four PFTs and that they would be spatially conserved across the two experimental sites. Xylem-P50 , TLP, and πo , but not ε, occurred at significantly higher water potentials for the drought-intolerant PFT compared to the drought-tolerant PFT; however, there were no significant differences between the early- and late-successional PFTs. These results suggest that these three traits are important for determining drought tolerance, and are largely independent of wood density-a trait commonly associated with successional status. Differences in these physiological traits that occurred between the drought-tolerant and drought-intolerant PFTs were conserved between the two research sites, even though they had different soil types and dry-season lengths. This more detailed understanding of how xylem and leaf hydraulic traits vary between co-occuring drought-tolerant and drought-intolerant tropical tree species promises to facilitate a much-needed improvement in the representation of plant hydraulics within terrestrial ecosystem and biosphere models, which will enhance our ability to make robust predictions of how future changes in climate will affect tropical forests.
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Affiliation(s)
- Thomas L Powell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Earth and Environmental Sciences Area, Lawrence Berkeley National Lab, Berkeley, CA, USA
| | - James K Wheeler
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Alex A R de Oliveira
- Museu Paraense Emílio Goeldi, Programa de Pós-Graduação em Biodiversidade e Evolução, Belém, Pará, Brazil
| | | | - Scott R Saleska
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, ACT, Australia
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - Paul R Moorcroft
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
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Esquivel-Muelbert A, Galbraith D, Dexter KG, Baker TR, Lewis SL, Meir P, Rowland L, Costa ACLD, Nepstad D, Phillips OL. Biogeographic distributions of neotropical trees reflect their directly measured drought tolerances. Sci Rep 2017; 7:8334. [PMID: 28827613 PMCID: PMC5567183 DOI: 10.1038/s41598-017-08105-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/10/2017] [Indexed: 11/09/2022] Open
Abstract
High levels of species diversity hamper current understanding of how tropical forests may respond to environmental change. In the tropics, water availability is a leading driver of the diversity and distribution of tree species, suggesting that many tropical taxa may be physiologically incapable of tolerating dry conditions, and that their distributions along moisture gradients can be used to predict their drought tolerance. While this hypothesis has been explored at local and regional scales, large continental-scale tests are lacking. We investigate whether the relationship between drought-induced mortality and distributions holds continentally by relating experimental and observational data of drought-induced mortality across the Neotropics to the large-scale bioclimatic distributions of 115 tree genera. Across the different experiments, genera affiliated to wetter climatic regimes show higher drought-induced mortality than dry-affiliated ones, even after controlling for phylogenetic relationships. This pattern is stronger for adult trees than for saplings or seedlings, suggesting that the environmental filters exerted by drought impact adult tree survival most strongly. Overall, our analysis of experimental, observational, and bioclimatic data across neotropical forests suggests that increasing moisture-stress is indeed likely to drive significant changes in floristic composition.
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Affiliation(s)
| | - David Galbraith
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
| | - Kyle G Dexter
- Royal Botanic Garden of Edinburgh, EH3 5LR, Edinburgh, UK
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - Timothy R Baker
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
| | - Simon L Lewis
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
- Department of Geography, University College London, London, UK
| | - Patrick Meir
- School of Geosciences, University of Edinburgh, Edinburgh, UK
- Research School of Biology, Australian National University, Canberra, Australia
| | - Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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Tuzet A, Granier A, Betsch P, Peiffer M, Perrier A. Modelling hydraulic functioning of an adult beech stand under non-limiting soil water and severe drought condition. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Konings AG, Gentine P. Global variations in ecosystem-scale isohydricity. GLOBAL CHANGE BIOLOGY 2017; 23:891-905. [PMID: 27334054 DOI: 10.1111/gcb.13389] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 05/30/2016] [Indexed: 05/21/2023]
Abstract
Droughts are expected to become more frequent and more intense under climate change. Plant mortality rates and biomass declines in response to drought depend on stomatal and xylem flow regulation. Plants operate on a continuum of xylem and stomatal regulation strategies from very isohydric (strict regulation) to very anisohydric. Coexisting species may display a variety of isohydricity behaviors. As such, it can be difficult to predict how to model the degree of isohydricity at the ecosystem scale by aggregating studies of individual species. This is nonetheless essential for accurate prediction of ecosystem drought resilience. In this study, we define a metric for the degree of isohydricity at the ecosystem scale in analogy with a recent metric introduced at the species level. Using data from the AMSR-E satellite, this metric is evaluated globally based on diurnal variations in microwave vegetation optical depth (VOD), which is directly related to leaf water potential. Areas with low annual mean radiation are found to be more anisohydric. Except for evergreen broadleaf forests in the tropics, which are very isohydric, and croplands, which are very anisohydric, land cover type is a poor predictor of ecosystem isohydricity, in accordance with previous species-scale observations. It is therefore also a poor basis for parameterizing water stress response in land-surface models. For taller ecosystems, canopy height is correlated with higher isohydricity (so that rainforests are mostly isohydric). Highly anisohydric areas show either high or low underlying water use efficiency. In seasonally dry locations, most ecosystems display a more isohydric response (increased stomatal regulation) during the dry season. In several seasonally dry tropical forests, this trend is reversed, as dry-season leaf-out appears to coincide with a shift toward more anisohydric strategies. The metric developed in this study allows for detailed investigations of spatial and temporal variations in plant water behavior.
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Affiliation(s)
- Alexandra G Konings
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, 10027, USA
- Department of Earth System Science, Stanford University, Stanford, CA, 94305, USA
| | - Pierre Gentine
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, 10027, USA
- Earth Institute, Columbia University, New York, NY, 10027, USA
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Atkin O. New Phytologist: bridging the 'plant function - climate modelling divide'. THE NEW PHYTOLOGIST 2016; 209:1329-1332. [PMID: 26840246 DOI: 10.1111/nph.13876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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Berdanier AB, Clark JS. Multiyear drought-induced morbidity preceding tree death in southeastern U.S. forests. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2016; 26:17-23. [PMID: 27039506 DOI: 10.1890/15-0274] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Recent forest diebacks, combined with threats of future drought, focus attention on the extent to which tree death is caused by catastrophic events as opposed to chronic declines in health that accumulate over years. While recent attention has focused on large-scale diebacks, there is concern that increasing drought stress and chronic morbidity may have pervasive impacts on forest composition in many regions. Here we use long-term, whole-stand inventory data from southeastern U.S. forests to show that trees exposed to drought experience multiyear declines in growth prior to mortality. Following a severe, multiyear drought, 72% of trees that did not recover their pre-drought growth rates died within 10 yr. This pattern was mediated by local moisture availability. As an index of morbidity prior to death, we calculated the difference in cumulative growth after drought relative to surviving conspecifics. The strength of drought-induced morbidity varied among species and was correlated with drought tolerance. These findings support the ability of trees to avoid death during drought events but indicate shifts that could occur over decades. Tree mortality following drought is predictable in these ecosystems based on growth declines, highlighting an opportunity to address multiyear drought-induced morbidity in models, experiments, and management decisions.
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Rowland L, da Costa ACL, Galbraith DR, Oliveira RS, Binks OJ, Oliveira AAR, Pullen AM, Doughty CE, Metcalfe DB, Vasconcelos SS, Ferreira LV, Malhi Y, Grace J, Mencuccini M, Meir P. Death from drought in tropical forests is triggered by hydraulics not carbon starvation. Nature 2015; 528:119-22. [DOI: 10.1038/nature15539] [Citation(s) in RCA: 370] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 09/02/2015] [Indexed: 11/09/2022]
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Bonal D, Burban B, Stahl C, Wagner F, Hérault B. The response of tropical rainforests to drought-lessons from recent research and future prospects. ANNALS OF FOREST SCIENCE 2015; 73:27-44. [PMID: 27069374 PMCID: PMC4810888 DOI: 10.1007/s13595-015-0522-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 08/24/2015] [Indexed: 05/10/2023]
Abstract
KEY MESSAGE We review the recent findings on the influence of drought on tree mortality, growth or ecosystem functioning in tropical rainforests. Drought plays a major role in shaping tropical rainforests and the response mechanisms are highly diverse and complex. The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical rainforests on the three continents. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance. CONTEXT Tropical rainforest ecosystems are characterized by high annual rainfall. Nevertheless, rainfall regularly fluctuates during the year and seasonal soil droughts do occur. Over the past decades, a number of extreme droughts have hit tropical rainforests, not only in Amazonia but also in Asia and Africa. The influence of drought events on tree mortality and growth or on ecosystem functioning (carbon and water fluxes) in tropical rainforest ecosystems has been studied intensively, but the response mechanisms are complex. AIMS Herein, we review the recent findings related to the response of tropical forest ecosystems to seasonal and extreme droughts and the current knowledge about the future of these ecosystems. RESULTS This review emphasizes the progress made over recent years and the importance of the studies conducted under extreme drought conditions or in through-fall exclusion experiments in understanding the response of these ecosystems. It also points to the great diversity and complexity of the response of tropical rainforest ecosystems to drought. CONCLUSION The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical forest regions. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance.
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Affiliation(s)
- Damien Bonal
- />INRA, UMR « Ecologie et Ecophysiologie Forestières », Université de Lorraine-INRA, F-54280 Champenoux, France
| | - Benoit Burban
- />INRA, UMR «Ecologie des Forêts de Guyane», AgroParisTech-CIRAD-INRA-CNRS-Université de Guyane-Université des Antilles, Campus Agronomique, 97387 Kourou, Guyane Française France
| | - Clément Stahl
- />CIRAD, UMR « Ecologie des Forêts de Guyane », AgroParisTech- CIRAD-INRA-CNRS-Université de Guyane-Université des Antilles, Campus Agronomique, 97387 Kourou, Guyane Française France
- />University of Antwerpen, Campus Agronomique, 97387 Kourou, Guyane Française France
| | - Fabien Wagner
- />National Institute for Space Research (INPE), São José dos Campos, SP 12227-010 Brazil
| | - Bruno Hérault
- />CIRAD, UMR « Ecologie des Forêts de Guyane », AgroParisTech- CIRAD-INRA-CNRS-Université de Guyane-Université des Antilles, Campus Agronomique, 97387 Kourou, Guyane Française France
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Meir P, Wood TE, Galbraith DR, Brando PM, Da Costa ACL, Rowland L, Ferreira LV. Threshold Responses to Soil Moisture Deficit by Trees and Soil in Tropical Rain Forests: Insights from Field Experiments. Bioscience 2015; 65:882-892. [PMID: 26955085 PMCID: PMC4777016 DOI: 10.1093/biosci/biv107] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many tropical rain forest regions are at risk of increased future drought. The net effects of drought on forest ecosystem functioning will be substantial if important ecological thresholds are passed. However, understanding and predicting these effects is challenging using observational studies alone. Field-based rainfall exclusion (canopy throughfall exclusion; TFE) experiments can offer mechanistic insight into the response to extended or severe drought and can be used to help improve model-based simulations, which are currently inadequate. Only eight TFE experiments have been reported for tropical rain forests. We examine them, synthesizing key results and focusing on two processes that have shown threshold behavior in response to drought: (1) tree mortality and (2) the efflux of carbon dioxdie from soil, soil respiration. We show that: (a) where tested using large-scale field experiments, tropical rain forest tree mortality is resistant to long-term soil moisture deficit up to a threshold of 50% of the water that is extractable by vegetation from the soil, but high mortality occurs beyond this value, with evidence from one site of increased autotrophic respiration, and (b) soil respiration reaches its peak value in response to soil moisture at significantly higher soil moisture content for clay-rich soils than for clay-poor soils. This first synthesis of tropical TFE experiments offers the hypothesis that low soil moisture–related thresholds for key stress responses in soil and vegetation may prove to be widely applicable across tropical rain forests despite the diversity of these forests.
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Affiliation(s)
- Patrick Meir
- Patrick Meir is affiliated with the Research School of Biology at Australian National University, in Canberra, and with the School of Geosciences at the University of Edinburgh, in the United Kingdom. Tana E. Wood is affiliated with the US Department of Agriculture Forest Service's International Institute of Tropical Forestry, in Rio Piedras, Puerto Rico, and with the Fundación Puertorriqueña de Conservación, in San Juan, Puerto Rico. David R. Galbraith is affiliated with the School of Geography at the University of Leeds, in the United Kingdom. Paulo M. Brando is with the Instituto Pesquisa Ambiental Amazonia, in Belém, Brazil. Antonio C. L. da Costa is affiliated with the Universidade Federal de Para, in Belém, Brazil. Lucy Rowland is with the Research School of Biology at Australian National University, in Canberra. Leandro V. Ferreira is affiliated with the Museu Paraense Emílio Goeldi, in Belém, Brazil
| | - Tana E Wood
- Patrick Meir is affiliated with the Research School of Biology at Australian National University, in Canberra, and with the School of Geosciences at the University of Edinburgh, in the United Kingdom. Tana E. Wood is affiliated with the US Department of Agriculture Forest Service's International Institute of Tropical Forestry, in Rio Piedras, Puerto Rico, and with the Fundación Puertorriqueña de Conservación, in San Juan, Puerto Rico. David R. Galbraith is affiliated with the School of Geography at the University of Leeds, in the United Kingdom. Paulo M. Brando is with the Instituto Pesquisa Ambiental Amazonia, in Belém, Brazil. Antonio C. L. da Costa is affiliated with the Universidade Federal de Para, in Belém, Brazil. Lucy Rowland is with the Research School of Biology at Australian National University, in Canberra. Leandro V. Ferreira is affiliated with the Museu Paraense Emílio Goeldi, in Belém, Brazil
| | - David R Galbraith
- Patrick Meir is affiliated with the Research School of Biology at Australian National University, in Canberra, and with the School of Geosciences at the University of Edinburgh, in the United Kingdom. Tana E. Wood is affiliated with the US Department of Agriculture Forest Service's International Institute of Tropical Forestry, in Rio Piedras, Puerto Rico, and with the Fundación Puertorriqueña de Conservación, in San Juan, Puerto Rico. David R. Galbraith is affiliated with the School of Geography at the University of Leeds, in the United Kingdom. Paulo M. Brando is with the Instituto Pesquisa Ambiental Amazonia, in Belém, Brazil. Antonio C. L. da Costa is affiliated with the Universidade Federal de Para, in Belém, Brazil. Lucy Rowland is with the Research School of Biology at Australian National University, in Canberra. Leandro V. Ferreira is affiliated with the Museu Paraense Emílio Goeldi, in Belém, Brazil
| | - Paulo M Brando
- Patrick Meir is affiliated with the Research School of Biology at Australian National University, in Canberra, and with the School of Geosciences at the University of Edinburgh, in the United Kingdom. Tana E. Wood is affiliated with the US Department of Agriculture Forest Service's International Institute of Tropical Forestry, in Rio Piedras, Puerto Rico, and with the Fundación Puertorriqueña de Conservación, in San Juan, Puerto Rico. David R. Galbraith is affiliated with the School of Geography at the University of Leeds, in the United Kingdom. Paulo M. Brando is with the Instituto Pesquisa Ambiental Amazonia, in Belém, Brazil. Antonio C. L. da Costa is affiliated with the Universidade Federal de Para, in Belém, Brazil. Lucy Rowland is with the Research School of Biology at Australian National University, in Canberra. Leandro V. Ferreira is affiliated with the Museu Paraense Emílio Goeldi, in Belém, Brazil
| | - Antonio C L Da Costa
- Patrick Meir is affiliated with the Research School of Biology at Australian National University, in Canberra, and with the School of Geosciences at the University of Edinburgh, in the United Kingdom. Tana E. Wood is affiliated with the US Department of Agriculture Forest Service's International Institute of Tropical Forestry, in Rio Piedras, Puerto Rico, and with the Fundación Puertorriqueña de Conservación, in San Juan, Puerto Rico. David R. Galbraith is affiliated with the School of Geography at the University of Leeds, in the United Kingdom. Paulo M. Brando is with the Instituto Pesquisa Ambiental Amazonia, in Belém, Brazil. Antonio C. L. da Costa is affiliated with the Universidade Federal de Para, in Belém, Brazil. Lucy Rowland is with the Research School of Biology at Australian National University, in Canberra. Leandro V. Ferreira is affiliated with the Museu Paraense Emílio Goeldi, in Belém, Brazil
| | - Lucy Rowland
- Patrick Meir is affiliated with the Research School of Biology at Australian National University, in Canberra, and with the School of Geosciences at the University of Edinburgh, in the United Kingdom. Tana E. Wood is affiliated with the US Department of Agriculture Forest Service's International Institute of Tropical Forestry, in Rio Piedras, Puerto Rico, and with the Fundación Puertorriqueña de Conservación, in San Juan, Puerto Rico. David R. Galbraith is affiliated with the School of Geography at the University of Leeds, in the United Kingdom. Paulo M. Brando is with the Instituto Pesquisa Ambiental Amazonia, in Belém, Brazil. Antonio C. L. da Costa is affiliated with the Universidade Federal de Para, in Belém, Brazil. Lucy Rowland is with the Research School of Biology at Australian National University, in Canberra. Leandro V. Ferreira is affiliated with the Museu Paraense Emílio Goeldi, in Belém, Brazil
| | - Leandro V Ferreira
- Patrick Meir is affiliated with the Research School of Biology at Australian National University, in Canberra, and with the School of Geosciences at the University of Edinburgh, in the United Kingdom. Tana E. Wood is affiliated with the US Department of Agriculture Forest Service's International Institute of Tropical Forestry, in Rio Piedras, Puerto Rico, and with the Fundación Puertorriqueña de Conservación, in San Juan, Puerto Rico. David R. Galbraith is affiliated with the School of Geography at the University of Leeds, in the United Kingdom. Paulo M. Brando is with the Instituto Pesquisa Ambiental Amazonia, in Belém, Brazil. Antonio C. L. da Costa is affiliated with the Universidade Federal de Para, in Belém, Brazil. Lucy Rowland is with the Research School of Biology at Australian National University, in Canberra. Leandro V. Ferreira is affiliated with the Museu Paraense Emílio Goeldi, in Belém, Brazil
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Maréchaux I, Bartlett MK, Sack L, Baraloto C, Engel J, Joetzjer E, Chave J. Drought tolerance as predicted by leaf water potential at turgor loss point varies strongly across species within an Amazonian forest. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12452] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Isabelle Maréchaux
- CNRS Université Paul Sabatier, ENFA; UMR5174 EDB (Laboratoire Evolution et Diversité Biologique) 118 route de NarbonneToulouse F‐31062 France
- AgroParisTech‐ENGREF 19 avenue du Maine Paris F‐75015 France
| | - Megan K. Bartlett
- Department of Ecology and Evolution University of California Los Angeles 621 Charles E. Young Drive South Los Angeles CA 90095 USA
| | - Lawren Sack
- Department of Ecology and Evolution University of California Los Angeles 621 Charles E. Young Drive South Los Angeles CA 90095 USA
| | - Christopher Baraloto
- International Center for Tropical Botany Department of Biological Sciences Florida International University Miami FL 33199 USA
| | - Julien Engel
- INRA UMR ‘Ecologie des Forêts de Guyane’ 97387 Kourou Cedex French Guiana
| | - Emilie Joetzjer
- CNRM‐GAME – URA1357 42 avenue G. Coriolis Toulouse 31057 France
| | - Jérôme Chave
- CNRS Université Paul Sabatier, ENFA; UMR5174 EDB (Laboratoire Evolution et Diversité Biologique) 118 route de NarbonneToulouse F‐31062 France
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Kenzo T, Inoue Y, Yoshimura M, Yamashita M, Tanaka-Oda A, Ichie T. Height-related changes in leaf photosynthetic traits in diverse Bornean tropical rain forest trees. Oecologia 2014; 177:191-202. [PMID: 25362582 DOI: 10.1007/s00442-014-3126-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/17/2014] [Indexed: 10/24/2022]
Abstract
Knowledge of variations in morphophysiological leaf traits with forest height is essential for quantifying carbon and water fluxes from forest ecosystems. Here, we examined changes in leaf traits with forest height in diverse tree species and their role in environmental acclimation in a tropical rain forest in Borneo that does not experience dry spells. Height-related changes in leaf physiological and morphological traits [e.g., maximum photosynthetic rate (Amax), stomatal conductance (gs), dark respiration rate (Rd), carbon isotope ratio (δ(13)C), nitrogen (N) content, and leaf mass per area (LMA)] from understory to emergent trees were investigated in 104 species in 29 families. We found that many leaf area-based physiological traits (e.g., A(max-area), Rd, gs), N, δ(13)C, and LMA increased linearly with tree height, while leaf mass-based physiological traits (e.g., A(max-mass)) only increased slightly. These patterns differed from other biomes such as temperate and tropical dry forests, where trees usually show decreased photosynthetic capacity (e.g., A(max-area), A(max-mass)) with height. Increases in photosynthetic capacity, LMA, and δ(13)C are favored under bright and dry upper canopy conditions with higher photosynthetic productivity and drought tolerance, whereas lower R d and LMA may improve shade tolerance in lower canopy trees. Rapid recovery of leaf midday water potential to theoretical gravity potential during the night supports the idea that the majority of trees do not suffer from strong drought stress. Overall, leaf area-based photosynthetic traits were associated with tree height and the degree of leaf drought stress, even in diverse tropical rain forest trees.
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Affiliation(s)
- Tanaka Kenzo
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki, 305-8687, Japan,
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Klein T. The variability of stomatal sensitivity to leaf water potential across tree species indicates a continuum between isohydric and anisohydric behaviours. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12289] [Citation(s) in RCA: 298] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Tamir Klein
- Institute of Botany; University of Basel; Schönbeinstrasse 6 Basel 4056 Switzerland
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Rowland L, Hill TC, Stahl C, Siebicke L, Burban B, Zaragoza-Castells J, Ponton S, Bonal D, Meir P, Williams M. Evidence for strong seasonality in the carbon storage and carbon use efficiency of an Amazonian forest. GLOBAL CHANGE BIOLOGY 2014; 20:979-91. [PMID: 23996917 PMCID: PMC4298765 DOI: 10.1111/gcb.12375] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 08/14/2013] [Indexed: 05/25/2023]
Abstract
The relative contribution of gross primary production and ecosystem respiration to seasonal changes in the net carbon flux of tropical forests remains poorly quantified by both modelling and field studies. We use data assimilation to combine nine ecological time series from an eastern Amazonian forest, with mass balance constraints from an ecosystem carbon cycle model. The resulting analysis quantifies, with uncertainty estimates, the seasonal changes in the net carbon flux of a tropical rainforest which experiences a pronounced dry season. We show that the carbon accumulation in this forest was four times greater in the dry season than in the wet season and that this was accompanied by a 5% increase in the carbon use efficiency. This seasonal response was caused by a dry season increase in gross primary productivity, in response to radiation and a similar magnitude decrease in heterotrophic respiration, in response to drying soils. The analysis also predicts increased carbon allocation to leaves and wood in the wet season, and greater allocation to fine roots in the dry season. This study demonstrates implementation of seasonal variations in parameters better enables models to simulate observed patterns in data. In particular, we highlight the necessity to simulate the seasonal patterns of heterotrophic respiration to accurately simulate the net carbon flux seasonal tropical forest.
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Affiliation(s)
- Lucy Rowland
- School of Geosciences, University of EdinburghEdinburgh, EH9 3JN, UK
| | | | | | | | | | | | - Stephane Ponton
- INRA, UMR 1137 Ecologie et Ecophysiologie ForestièresChampenoux, 54280, France
| | - Damien Bonal
- INRA, UMR 1137 Ecologie et Ecophysiologie ForestièresChampenoux, 54280, France
| | - Patrick Meir
- School of Geosciences, University of EdinburghEdinburgh, EH9 3JN, UK
- Research School of Biology, Division of Plant Sciences, Australian National UniversityCanberra, ACT, 0200, Australia
| | - Mathew Williams
- School of Geosciences, University of EdinburghEdinburgh, EH9 3JN, UK
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Klein T, Yakir D, Buchmann N, Grünzweig JM. Towards an advanced assessment of the hydrological vulnerability of forests to climate change-induced drought. THE NEW PHYTOLOGIST 2014; 201:712-716. [PMID: 24117758 DOI: 10.1111/nph.12548] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- Tamir Klein
- Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot, Israel
- Institute of Botany, University of Basel, Basel, Switzerland
| | - Dan Yakir
- Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot, Israel
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zürich, Zürich, Switzerland
| | - José M Grünzweig
- Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Rehovot, Israel
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Powell TL, Galbraith DR, Christoffersen BO, Harper A, Imbuzeiro HMA, Rowland L, Almeida S, Brando PM, da Costa ACL, Costa MH, Levine NM, Malhi Y, Saleska SR, Sotta E, Williams M, Meir P, Moorcroft PR. Confronting model predictions of carbon fluxes with measurements of Amazon forests subjected to experimental drought. THE NEW PHYTOLOGIST 2013; 200:350-365. [PMID: 23844931 DOI: 10.1111/nph.12390] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 05/20/2013] [Indexed: 05/08/2023]
Abstract
Considerable uncertainty surrounds the fate of Amazon rainforests in response to climate change. Here, carbon (C) flux predictions of five terrestrial biosphere models (Community Land Model version 3.5 (CLM3.5), Ecosystem Demography model version 2.1 (ED2), Integrated BIosphere Simulator version 2.6.4 (IBIS), Joint UK Land Environment Simulator version 2.1 (JULES) and Simple Biosphere model version 3 (SiB3)) and a hydrodynamic terrestrial ecosystem model (the Soil-Plant-Atmosphere (SPA) model) were evaluated against measurements from two large-scale Amazon drought experiments. Model predictions agreed with the observed C fluxes in the control plots of both experiments, but poorly replicated the responses to the drought treatments. Most notably, with the exception of ED2, the models predicted negligible reductions in aboveground biomass in response to the drought treatments, which was in contrast to an observed c. 20% reduction at both sites. For ED2, the timing of the decline in aboveground biomass was accurate, but the magnitude was too high for one site and too low for the other. Three key findings indicate critical areas for future research and model development. First, the models predicted declines in autotrophic respiration under prolonged drought in contrast to measured increases at one of the sites. Secondly, models lacking a phenological response to drought introduced bias in the sensitivity of canopy productivity and respiration to drought. Thirdly, the phenomenological water-stress functions used by the terrestrial biosphere models to represent the effects of soil moisture on stomatal conductance yielded unrealistic diurnal and seasonal responses to drought.
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Affiliation(s)
- Thomas L Powell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - David R Galbraith
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, OX1 3QY, UK
| | | | - Anna Harper
- College of Engineering, Mathematics, and Physical Science, University of Exeter, Exeter, EX4 4QF, UK
- Department of Atmospheric Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Hewlley M A Imbuzeiro
- Grupo de Pesquisas em Interação Atmosfera-Biosfera, Universidade Federal de Viçosa, Viçosa, CEP 36570-000, Minas Gerias, Brazil
| | - Lucy Rowland
- School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, UK
| | - Samuel Almeida
- Museu Paraense Emilio Goeldi, Belém, CEP 66077-530, Pará, Brazil
| | - Paulo M Brando
- Instituto de Pesquisa Ambiental da Amazônia, CEP 71503-505, Brasília, Distrito Federal, Brazil
| | | | - Marcos Heil Costa
- Grupo de Pesquisas em Interação Atmosfera-Biosfera, Universidade Federal de Viçosa, Viçosa, CEP 36570-000, Minas Gerias, Brazil
| | - Naomi M Levine
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, OX1 3QY, UK
| | - Scott R Saleska
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | | | - Mathew Williams
- School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, UK
| | - Patrick Meir
- School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, UK
| | - Paul R Moorcroft
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
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Stahl C, Hérault B, Rossi V, Burban B, Bréchet C, Bonal D. Depth of soil water uptake by tropical rainforest trees during dry periods: does tree dimension matter? Oecologia 2013; 173:1191-201. [PMID: 23852028 DOI: 10.1007/s00442-013-2724-6] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 06/25/2013] [Indexed: 11/29/2022]
Abstract
Though the root biomass of tropical rainforest trees is concentrated in the upper soil layers, soil water uptake by deep roots has been shown to contribute to tree transpiration. A precise evaluation of the relationship between tree dimensions and depth of water uptake would be useful in tree-based modelling approaches designed to anticipate the response of tropical rainforest ecosystems to future changes in environmental conditions. We used an innovative dual-isotope labelling approach (deuterium in surface soil and oxygen at 120-cm depth) coupled with a modelling approach to investigate the role of tree dimensions in soil water uptake in a tropical rainforest exposed to seasonal drought. We studied 65 trees of varying diameter and height and with a wide range of predawn leaf water potential (Ψpd) values. We confirmed that about half of the studied trees relied on soil water below 100-cm depth during dry periods. Ψpd was negatively correlated with depth of water extraction and can be taken as a rough proxy of this depth. Some trees showed considerable plasticity in their depth of water uptake, exhibiting an efficient adaptive strategy for water and nutrient resource acquisition. We did not find a strong relationship between tree dimensions and depth of water uptake. While tall trees preferentially extract water from layers below 100-cm depth, shorter trees show broad variations in mean depth of water uptake. This precludes the use of tree dimensions to parameterize functional models.
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Affiliation(s)
- Clément Stahl
- INRA, UMR Ecologie des Forêts de Guyane, Campus Agronomique, BP 709, 97387, Kourou Cedex, French Guiana
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Janka E, Körner O, Rosenqvist E, Ottosen CO. High temperature stress monitoring and detection using chlorophyll a fluorescence and infrared thermography in chrysanthemum (Dendranthema grandiflora). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2013; 67:87-94. [PMID: 23545206 DOI: 10.1016/j.plaphy.2013.02.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 02/26/2013] [Indexed: 05/03/2023]
Abstract
Modern highly insulated greenhouses are more energy efficient than conventional types. Furthermore applying dynamic greenhouse climate control regimes will increase energy efficiency relatively more in modern structures. However, this combination may result in higher air and crop temperatures. Too high temperature affects the plant photosynthetic responses, resulting in a lower rate of photosynthesis. To predict and analyse physiological responses as stress indicators, two independent experiments were conducted, to detect the effect of high temperature on photosynthesis: analysing photosystem II (PSII) and stomatal conductance (gs). A combination of chlorophyll a fluorescence, gas exchange measurements and infrared thermography was applied using Chrysanthemum (Dendranthema grandiflora Tzvelev) 'Coral Charm' as a model species. Increasing temperature had a highly significant effect on PSII when the temperature exceeded 38 °C for a period of 7 (±1.8) days. High temperature decreased the maximum photochemical efficiency of PSII (Fv/Fm), the conformation term for primary photochemistry (Fv/Fo) and performance index (PI), as well as increased minimal fluorescence (Fo). However, at elevated CO2 of 1000 μmol mol(-1) and with a photosynthetic photon flux density (PPFD) of 800 μmol m(-2) s(-1), net photosynthesis (Pn) reached its maximum at 35 °C. The thermal index (IG), calculated from the leaf temperature and the temperature of a dry and wet reference leaf, showed a strong correlation with gs. We conclude that 1) chlorophyll a fluorescence and a combination of fluorescence parameters can be used as early stress indicators as well as to detect the temperature limit of PSII damage, and 2) the strong relation between gs and IG enables gs to be estimated non-invasively, which is an important first step in modelling leaf temperature to predict unfavourable growing conditions in a (dynamic) semi closed greenhouse.
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Affiliation(s)
- Eshetu Janka
- Department of Food Science, Aarhus University, Kirstinebjergvej 10, DK-5792 Årslev, Denmark.
| | - Oliver Körner
- AgroTech A/S, Institute for Agri Technology and Food Innovation, Højbakkegård Allé 21, DK-2630 Taastrup, Denmark
| | - Eva Rosenqvist
- Department of Plant and Environmental Sciences, Crop Science, Copenhagen University, Højbakkegård Allé 9, DK-2630 Taastrup, Denmark
| | - Carl-Otto Ottosen
- Department of Food Science, Aarhus University, Kirstinebjergvej 10, DK-5792 Årslev, Denmark
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49
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Structural Uncertainty in Model-Simulated Trends of Global Gross Primary Production. REMOTE SENSING 2013. [DOI: 10.3390/rs5031258] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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50
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Wright JK, Williams M, Starr G, McGee J, Mitchell RJ. Measured and modelled leaf and stand-scale productivity across a soil moisture gradient and a severe drought. PLANT, CELL & ENVIRONMENT 2013; 36:467-483. [PMID: 22882366 DOI: 10.1111/j.1365-3040.2012.02590.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Environmental controls on carbon dynamics operate at a range of interacting scales from the leaf to landscape. The key questions of this study addressed the influence of water and nitrogen (N) availability on Pinus palustris (Mill.) physiology and primary productivity across leaf and canopy scales, linking the soil-plant-atmosphere (SPA) model to leaf and stand-scale flux and leaf trait/canopy data. We present previously unreported ecophysiological parameters (e.g. V(cmax) and J(max)) for P. palustris and the first modelled estimates of its annual gross primary productivity (GPP) across xeric and mesic sites and under extreme drought. Annual mesic site P. palustris GPP was ∼23% greater than at the xeric site. However, at the leaf level, xeric trees had higher net photosynthetic rates, and water and light use efficiency. At the canopy scale, GPP was limited by light interception (canopy level), but co-limited by nitrogen and water at the leaf level. Contrary to expectations, the impacts of an intense growing season drought were greater at the mesic site. Modelling indicated a 10% greater decrease in mesic GPP compared with the xeric site. Xeric P. palustris trees exhibited drought-tolerant behaviour that contrasted with mesic trees' drought-avoidance behaviour.
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Affiliation(s)
- J K Wright
- School of Geosciences, University of Edinburgh, Edinburgh, UK.
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