151
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Brando PM, Soares-Filho B, Rodrigues L, Assunção A, Morton D, Tuchschneider D, Fernandes ECM, Macedo MN, Oliveira U, Coe MT. The gathering firestorm in southern Amazonia. SCIENCE ADVANCES 2020; 6:eaay1632. [PMID: 31950083 PMCID: PMC6954065 DOI: 10.1126/sciadv.aay1632] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 11/08/2019] [Indexed: 05/04/2023]
Abstract
Wildfires, exacerbated by extreme weather events and land use, threaten to change the Amazon from a net carbon sink to a net carbon source. Here, we develop and apply a coupled ecosystem-fire model to quantify how greenhouse gas-driven drying and warming would affect wildfires and associated CO2 emissions in the southern Brazilian Amazon. Regional climate projections suggest that Amazon fire regimes will intensify under both low- and high-emission scenarios. Our results indicate that projected climatic changes will double the area burned by wildfires, affecting up to 16% of the region's forests by 2050. Although these fires could emit as much as 17.0 Pg of CO2 equivalent to the atmosphere, avoiding new deforestation could cut total net fire emissions in half and help prevent fires from escaping into protected areas and indigenous lands. Aggressive efforts to eliminate ignition sources and suppress wildfires will be critical to conserve southern Amazon forests.
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Affiliation(s)
- P. M. Brando
- Department of Earth System, University of California, Irvine, CA 92697, USA
- Woods Hole Research Center, 149 Woods Hole Rd., Falmouth, MA 02540, USA
- Instituto de Pesquisa Ambiental da Amazônia (IPAM), SHIN, CA-5, Brasilia, DF 7500, Brazil
- Corresponding author.
| | - B. Soares-Filho
- Centro de Sensoriamento Remoto, Instituto de Geociências, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, CEP 31270-901, Belo Horizonte, MG, Brazil
| | - L. Rodrigues
- Centro de Sensoriamento Remoto, Instituto de Geociências, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, CEP 31270-901, Belo Horizonte, MG, Brazil
| | - A. Assunção
- Centro de Sensoriamento Remoto, Instituto de Geociências, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, CEP 31270-901, Belo Horizonte, MG, Brazil
| | - D. Morton
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - D. Tuchschneider
- Agriculture Global Practice, World Bank Group, 1818 H. St., NW, Washington, DC 20433, USA
| | - E. C. M. Fernandes
- Agriculture Global Practice, World Bank Group, 1818 H. St., NW, Washington, DC 20433, USA
| | - M. N. Macedo
- Woods Hole Research Center, 149 Woods Hole Rd., Falmouth, MA 02540, USA
- Instituto de Pesquisa Ambiental da Amazônia (IPAM), SHIN, CA-5, Brasilia, DF 7500, Brazil
| | - U. Oliveira
- Centro de Sensoriamento Remoto, Instituto de Geociências, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos 6627, CEP 31270-901, Belo Horizonte, MG, Brazil
| | - M. T. Coe
- Woods Hole Research Center, 149 Woods Hole Rd., Falmouth, MA 02540, USA
- Instituto de Pesquisa Ambiental da Amazônia (IPAM), SHIN, CA-5, Brasilia, DF 7500, Brazil
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152
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Papastefanou P, Zang CS, Pugh TAM, Liu D, Grams TEE, Hickler T, Rammig A. A Dynamic Model for Strategies and Dynamics of Plant Water-Potential Regulation Under Drought Conditions. FRONTIERS IN PLANT SCIENCE 2020; 11:373. [PMID: 32411150 PMCID: PMC7199548 DOI: 10.3389/fpls.2020.00373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/16/2020] [Indexed: 05/15/2023]
Abstract
Vegetation responds to drought through a complex interplay of plant hydraulic mechanisms, posing challenges for model development and parameterization. We present a mathematical model that describes the dynamics of leaf water-potential over time while considering different strategies by which plant species regulate their water-potentials. The model has two parameters: the parameter λ describing the adjustment of the leaf water potential to changes in soil water potential, and the parameter Δψww describing the typical 'well-watered' leaf water potentials at non-stressed (near-zero) levels of soil water potential. Our model was tested and calibrated on 110 time-series datasets containing the leaf- and soil water potentials of 66 species under drought and non-drought conditions. Our model successfully reproduces the measured leaf water potentials over time based on three different regulation strategies under drought. We found that three parameter sets derived from the measurement data reproduced the dynamics of 53% of an drought dataset, and 52% of a control dataset [root mean square error (RMSE) < 0.5 MPa)]. We conclude that, instead of quantifying water-potential-regulation of different plant species by complex modeling approaches, a small set of parameters may be sufficient to describe the water potential regulation behavior for large-scale modeling. Thus, our approach paves the way for a parsimonious representation of the full spectrum of plant hydraulic responses to drought in dynamic vegetation models.
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Affiliation(s)
- Phillip Papastefanou
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
- *Correspondence: Phillip Papastefanou, ;
| | - Christian S. Zang
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Thomas A. M. Pugh
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Institute of Forest Research, University of Birmingham, Birmingham, United Kingdom
| | - Daijun Liu
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Institute of Forest Research, University of Birmingham, Birmingham, United Kingdom
| | - Thorsten E. E. Grams
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Thomas Hickler
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt, Germany
- Department of Physical Geography, Goethe University, Frankfurt, Germany
| | - Anja Rammig
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
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153
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Tomasella M, Petrussa E, Petruzzellis F, Nardini A, Casolo V. The Possible Role of Non-Structural Carbohydrates in the Regulation of Tree Hydraulics. Int J Mol Sci 2019; 21:E144. [PMID: 31878253 PMCID: PMC6981889 DOI: 10.3390/ijms21010144] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/13/2019] [Accepted: 12/22/2019] [Indexed: 12/29/2022] Open
Abstract
The xylem is a complex system that includes a network of dead conduits ensuring long-distance water transport in plants. Under ongoing climate changes, xylem embolism is a major and recurrent cause of drought-induced tree mortality. Non-structural carbohydrates (NSC) play key roles in plant responses to drought and frost stress, and several studies putatively suggest their involvement in the regulation of xylem water transport. However, a clear picture on the roles of NSCs in plant hydraulics has not been drawn to date. We summarize the current knowledge on the involvement of NSCs during embolism formation and subsequent hydraulic recovery. Under drought, sugars are generally accumulated in xylem parenchyma and in xylem sap. At drought-relief, xylem functionality is putatively restored in an osmotically driven process involving wood parenchyma, xylem sap and phloem compartments. By analyzing the published data on stem hydraulics and NSC contents under drought/frost stress and subsequent stress relief, we found that embolism build-up positively correlated to stem NSC depletion, and that the magnitude of post-stress hydraulic recovery positively correlated to consumption of soluble sugars. These findings suggest a close relationship between hydraulics and carbohydrate dynamics. We call for more experiments on hydraulic and NSC dynamics in controlled and field conditions.
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Affiliation(s)
- Martina Tomasella
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Elisa Petrussa
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 91, 33100 Udine, Italy; (E.P.); (V.C.)
| | - Francesco Petruzzellis
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Andrea Nardini
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Valentino Casolo
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 91, 33100 Udine, Italy; (E.P.); (V.C.)
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154
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Sperry JS, Venturas MD, Todd HN, Trugman AT, Anderegg WRL, Wang Y, Tai X. The impact of rising CO 2 and acclimation on the response of US forests to global warming. Proc Natl Acad Sci U S A 2019; 116:25734-25744. [PMID: 31767760 PMCID: PMC6926066 DOI: 10.1073/pnas.1913072116] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The response of forests to climate change depends in part on whether the photosynthetic benefit from increased atmospheric CO2 (∆Ca = future minus historic CO2) compensates for increased physiological stresses from higher temperature (∆T). We predicted the outcome of these competing responses by using optimization theory and a mechanistic model of tree water transport and photosynthesis. We simulated current and future productivity, stress, and mortality in mature monospecific stands with soil, species, and climate sampled from 20 continental US locations. We modeled stands with and without acclimation to ∆Ca and ∆T, where acclimated forests adjusted leaf area, photosynthetic capacity, and stand density to maximize productivity while avoiding stress. Without acclimation, the ∆Ca-driven boost in net primary productivity (NPP) was compromised by ∆T-driven stress and mortality associated with vascular failure. With acclimation, the ∆Ca-driven boost in NPP and stand biomass (C storage) was accentuated for cooler futures but negated for warmer futures by a ∆T-driven reduction in NPP and biomass. Thus, hotter futures reduced forest biomass through either mortality or acclimation. Forest outcomes depended on whether projected climatic ∆Ca/∆T ratios were above or below physiological thresholds that neutralized the negative impacts of warming. Critically, if forests do not acclimate, the ∆Ca/∆T must be above ca 89 ppm⋅°C-1 to avoid chronic stress, a threshold met by 55% of climate projections. If forests do acclimate, the ∆Ca/∆T must rise above ca 67 ppm⋅°C-1 for NPP and biomass to increase, a lower threshold met by 71% of projections.
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Affiliation(s)
- John S Sperry
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
| | - Martin D Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112;
| | - Henry N Todd
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
| | - Anna T Trugman
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
- Department of Geography, University of California, Santa Barbara, CA 93106
| | | | - Yujie Wang
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
| | - Xiaonan Tai
- Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112
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155
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Cruz MV, Mori GM, Oh DH, Dassanayake M, Zucchi MI, Oliveira RS, Souza APD. Molecular responses to freshwater limitation in the mangrove tree Avicennia germinans (Acanthaceae). Mol Ecol 2019; 29:344-362. [PMID: 31834961 DOI: 10.1111/mec.15330] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/31/2022]
Abstract
Environmental variation along the geographical space can shape populations by natural selection. In the context of global warming and changing precipitation regimes, it is crucial to understand the role of environmental heterogeneity in tropical trees adaptation, given their disproportional contribution to water and carbon biogeochemical cycles. Here, we investigated how heterogeneity in freshwater availability along tropical wetlands has influenced molecular variations of the black mangrove (Avicennia germinans). A total of 57 trees were sampled at seven sites differing markedly in precipitation regime and riverine freshwater inputs. Using 2,297 genome-wide single nucleotide polymorphic markers, we found signatures of natural selection by the association between variations in allele frequencies and environmental variables, including the precipitation of the warmest quarter and the annual precipitation. Additionally, we found candidate loci for selection based on statistical deviations from neutral expectations of interpopulation differentiation. Most candidate loci within transcribed sequences were functionally associated with central aspects of drought tolerance or plant response to drought. Moreover, our results suggest the occurrence of the rapid evolution of a population, probably in response to sudden and persistent limitations in plant access to soil water, following a road construction in 1974. Observations supporting rapid evolution included the reduction in tree size and changes in allele frequencies and in transcript expression associated with increased drought tolerance through the accumulation of osmoprotectants and antioxidants, biosynthesis of cuticles, protection against protein degradation, stomatal closure, photorespiration and photosynthesis. We describe a major role of spatial heterogeneity in freshwater availability in the specialization of this typically tropical tree.
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Affiliation(s)
- Mariana Vargas Cruz
- Department of Plant Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, Brazil
| | | | - Dong-Ha Oh
- Department of Biological Sciences, Louisiana State University (LSU), Louisiana, LA, USA
| | - Maheshi Dassanayake
- Department of Biological Sciences, Louisiana State University (LSU), Louisiana, LA, USA
| | | | - Rafael Silva Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, Brazil
| | - Anete Pereira de Souza
- Department of Plant Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, Brazil
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156
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Waite PA, Schuldt B, Mathias Link R, Breidenbach N, Triadiati T, Hennings N, Saad A, Leuschner C. Soil moisture regime and palm height influence embolism resistance in oil palm. TREE PHYSIOLOGY 2019; 39:1696-1712. [PMID: 31135930 DOI: 10.1093/treephys/tpz061] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 04/29/2019] [Accepted: 05/03/2019] [Indexed: 06/09/2023]
Abstract
With the prospect of climate change and more frequent El Niño-related dry spells, the drought tolerance of oil palm (Elaeis guineensis Jacq.), one of the most important tropical crop species, is of major concern. We studied the influence of soil water availability and palm height on the plasticity of xylem anatomy of oil palm fronds and their embolism resistance at well-drained and seasonally flooded riparian sites in lowland Sumatra, Indonesia. We found overall mean P12 and P50 values, i.e., the xylem pressures at 12% or 50% loss of hydraulic conductance, of -1.05 and - 1.86 MPa, respectively, indicating a rather vulnerable frond xylem of oil palm. This matches diurnal courses of stomatal conductance, which in combination with the observed low xylem safety evidence a sensitive water loss regulation. While the xylem anatomical traits vessel diameter (Dh), vessel density and potential hydraulic conductivity (Kp) were not different between the sites, palms in the moister riparian plots had on average by 0.4 MPa higher P50 values than plants in the well-drained plots. This could largely be attributed to differences in palm height between systems. As a consequence, palms of equal height had 1.3 MPa less negative P50 values in the moister riparian plots than in the well-drained plots. While palm height was positively related to P50, Dh and Kp decreased with height. The high plasticity in embolism resistance may be an element of the drought response strategy of oil palm, which, as a monocot, has a relatively deterministic hydraulic architecture. We conclude that oil palm fronds develop a vulnerable water transport system, which may expose the palms to increasing drought stress in a warmer and drier climate. However, the risk of hydraulic failure may be reduced by considerable plasticity in the hydraulic system and the environmental control of embolism resistance, and a presumably large stem capacitance.
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Affiliation(s)
- Pierre-André Waite
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2,Goettingen, Germany
| | - Bernhard Schuldt
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2,Goettingen, Germany
- Chair of Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute for Biological Sciences, University of Wuerzburg, Julius-von-Sachs-Platz 3, Wuerzburg, Germany
| | - Roman Mathias Link
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2,Goettingen, Germany
- Chair of Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute for Biological Sciences, University of Wuerzburg, Julius-von-Sachs-Platz 3, Wuerzburg, Germany
| | - Natalie Breidenbach
- Department of Forest Genetic and Forest Tree Breeding, Forestry Faculty, Buesgen Institute, University of Goettingen, Buesgenweg 2, Goettingen, Germany
| | - Triadiati Triadiati
- Department of Biology, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Darmaga Campus, Bogor, Indonesia
| | - Nina Hennings
- Department of Soil Science of Temperate Ecosystems, Forestry Faculty, Buesgen Institute, University of Goettingen, Buesgenweg 2, Goettingen, Germany
| | - Asmadi Saad
- Department of Soil Science, University of Jambi, Jalan Raya Jambi Muara Bulian KM 15 Mandalo Darat, Jambi, Sumatra, Indonesia
| | - Christoph Leuschner
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2,Goettingen, Germany
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157
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Menezes‐Silva PE, Loram‐Lourenço L, Alves RDFB, Sousa LF, Almeida SEDS, Farnese FS. Different ways to die in a changing world: Consequences of climate change for tree species performance and survival through an ecophysiological perspective. Ecol Evol 2019; 9:11979-11999. [PMID: 31695903 PMCID: PMC6822037 DOI: 10.1002/ece3.5663] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 08/22/2019] [Accepted: 08/28/2019] [Indexed: 01/10/2023] Open
Abstract
Anthropogenic activities such as uncontrolled deforestation and increasing greenhouse gas emissions are responsible for triggering a series of environmental imbalances that affect the Earth's complex climate dynamics. As a consequence of these changes, several climate models forecast an intensification of extreme weather events over the upcoming decades, including heat waves and increasingly severe drought and flood episodes. The occurrence of such extreme weather will prompt profound changes in several plant communities, resulting in massive forest dieback events that can trigger a massive loss of biodiversity in several biomes worldwide. Despite the gravity of the situation, our knowledge regarding how extreme weather events can undermine the performance, survival, and distribution of forest species remains very fragmented. Therefore, the present review aimed to provide a broad and integrated perspective of the main biochemical, physiological, and morpho-anatomical disorders that may compromise the performance and survival of forest species exposed to climate change factors, particularly drought, flooding, and global warming. In addition, we also discuss the controversial effects of high CO2 concentrations in enhancing plant growth and reducing the deleterious effects of some extreme climatic events. We conclude with a discussion about the possible effects that the factors associated with the climate change might have on species distribution and forest composition.
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Affiliation(s)
| | - Lucas Loram‐Lourenço
- Laboratory of Plant EcophysiologyInstituto Federal Goiano – Campus Rio VerdeGoiásBrazil
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158
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A Spatial and Temporal Risk Assessment of the Impacts of El Niño on the Tropical Forest Carbon Cycle: Theoretical Framework, Scenarios, and Implications. ATMOSPHERE 2019. [DOI: 10.3390/atmos10100588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Strong El Niño events alter tropical climates and may lead to a negative carbon balance in tropical forests and consequently a disruption to the global carbon cycle. The complexity of tropical forests and the lack of data from these regions hamper the assessment of the spatial distribution of El Niño impacts on these ecosystems. Typically, maps of climate anomaly are used to detect areas of greater risk, ignoring baseline climate conditions and forest cover. Here, we integrated climate anomalies from the 1982–1983, 1997–1998, and 2015–2016 El Niño events with baseline climate and forest edge extent, using a risk assessment approach to hypothetically assess the spatial and temporal distributions of El Niño risk over tropical forests under several risk scenarios. The drivers of risk varied temporally and spatially. Overall, the relative risk of El Niño has been increasing driven mainly by intensified forest fragmentation that has led to a greater chance of fire ignition and increased mean annual air temperatures. We identified areas of repeated high risk, where conservation efforts and fire control measures should be focused to avoid future forest degradation and negative impacts on the carbon cycle.
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159
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Kannenberg SA, Novick KA, Alexander MR, Maxwell JT, Moore DJP, Phillips RP, Anderegg WRL. Linking drought legacy effects across scales: From leaves to tree rings to ecosystems. GLOBAL CHANGE BIOLOGY 2019; 25:2978-2992. [PMID: 31132225 DOI: 10.1111/gcb.14710] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/10/2019] [Accepted: 05/22/2019] [Indexed: 05/23/2023]
Abstract
Severe drought can cause lagged effects on tree physiology that negatively impact forest functioning for years. These "drought legacy effects" have been widely documented in tree-ring records and could have important implications for our understanding of broader scale forest carbon cycling. However, legacy effects in tree-ring increments may be decoupled from ecosystem fluxes due to (a) postdrought alterations in carbon allocation patterns; (b) temporal asynchrony between radial growth and carbon uptake; and (c) dendrochronological sampling biases. In order to link legacy effects from tree rings to whole forests, we leveraged a rich dataset from a Midwestern US forest that was severely impacted by a drought in 2012. At this site, we compiled tree-ring records, leaf-level gas exchange, eddy flux measurements, dendrometer band data, and satellite remote sensing estimates of greenness and leaf area before, during, and after the 2012 drought. After accounting for the relative abundance of tree species in the stand, we estimate that legacy effects led to ~10% reductions in tree-ring width increments in the year following the severe drought. Despite this stand-scale reduction in radial growth, we found that leaf-level photosynthesis, gross primary productivity (GPP), and vegetation greenness were not suppressed in the year following the 2012 drought. Neither temporal asynchrony between radial growth and carbon uptake nor sampling biases could explain our observations of legacy effects in tree rings but not in GPP. Instead, elevated leaf-level photosynthesis co-occurred with reduced leaf area in early 2013, indicating that resources may have been allocated away from radial growth in conjunction with postdrought upregulation of photosynthesis and repair of canopy damage. Collectively, our results indicate that tree-ring legacy effects were not observed in other canopy processes, and that postdrought canopy allocation could be an important mechanism that decouples tree-ring signals from GPP.
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Affiliation(s)
| | - Kimberly A Novick
- School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana
| | | | - Justin T Maxwell
- Department of Geography, Indiana University, Bloomington, Indiana
- Harvard Forest, Harvard University, Petersham, Massachusetts
| | - David J P Moore
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona
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160
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Conesa MÀ, Mus M, Galmés J. Leaf size as a key determinant of contrasting growth patterns in closely related Limonium (Plumbaginaceae) species. JOURNAL OF PLANT PHYSIOLOGY 2019; 240:152984. [PMID: 31207461 DOI: 10.1016/j.jplph.2019.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 06/09/2023]
Abstract
This study aims to analyze the importance of leaf size on plant growth capacity among an array of closely related Limonium species, and its impact on the underlying determinants of growth reduction under extreme water deficit conditions. To do so, thirteen Balearic Limonium species with contrasting leaf size were grown under long-term well-watered (WW) and severe water-deficit (WD) conditions in a common garden experiment. Fundamental growth traits were measured, including relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), leaf mass area (LMA) and leaf mass ratio (LMR). WD promoted small changes in leaf size, and species with larger leaves had higher RGR than species with smaller leaves, irrespective of the water treatment. Most RGR variation across species and treatments was explained by NAR, with comparatively much lower importance of LAR. The factorization of LAR underlying components denoted the importance of LMA in explaining RGR, whereas the impact of LMR on RGR was negligible in Limonium. Further, species with larger leaves had higher water consumption but also higher water use efficiency, especially under WD. Therefore, contrary to general trends in species from dry environments, increased leaf size is linked to increased growth capacity and also increased water use efficiency across closely related Limonium species.
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Affiliation(s)
- Miquel À Conesa
- Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia - INAGEA, Universitat de les Illes Balears, Carretera de Valldemossa km 7.5, E-07122, Palma, Balearic Islands, Spain.
| | - Maurici Mus
- Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia - INAGEA, Universitat de les Illes Balears, Carretera de Valldemossa km 7.5, E-07122, Palma, Balearic Islands, Spain
| | - Jeroni Galmés
- Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia - INAGEA, Universitat de les Illes Balears, Carretera de Valldemossa km 7.5, E-07122, Palma, Balearic Islands, Spain
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161
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Brodribb TJ, Cochard H, Dominguez CR. Measuring the pulse of trees; using the vascular system to predict tree mortality in the 21st century. CONSERVATION PHYSIOLOGY 2019; 7:coz046. [PMID: 31423313 PMCID: PMC6691484 DOI: 10.1093/conphys/coz046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/10/2019] [Accepted: 06/18/2019] [Indexed: 06/01/2023]
Abstract
Tree mortality during hot and dry conditions presents a stark reminder of the vulnerability of plant species to climatic extremes. The current global warming trend makes predicting the impacts of hot/dry events on species survival an urgent task; yet, the standard tools for this purpose lack a physiological basis. This review examines a diversity of recent evidence demonstrating how physiological attributes of plant vascular systems can explain not only why trees die during drought, but also their distributional limits according to rainfall. These important advances in the science of plant water transport physiology provide the basis for new hydraulic models that can provide credible predictions of not only how but when, where and which species will be impacted by changes in rainfall and temperature in the future. Applying a recently developed hydraulic model using realistic parameters, we show that even apparently safe mesic forest in central France is predicted to experience major forest mortality before the end of the century.
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Affiliation(s)
- Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Bag 55 ,Hobart, Tasmania, Australia
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162
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Zhu SD, Li RH, He PC, Siddiq Z, Cao KF, Ye Q. Large branch and leaf hydraulic safety margins in subtropical evergreen broadleaved forest. TREE PHYSIOLOGY 2019; 39:1405-1415. [PMID: 30901055 DOI: 10.1093/treephys/tpz028] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 02/21/2019] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
As a global biodiversity hotspot, the subtropical evergreen broadleaved forest (SEBF) in southern China is strongly influenced by the humid monsoon climate, with distinct hot-wet and cool-dry seasons. However, the hydraulic strategies of this forest are not well understood. Branch and leaf hydraulic safety margins (HSMbranch and HSMleaf, respectively), as well as seasonal changes in predawn and midday leaf water potential (Ψpd and Ψmd), stomatal conductance (Gs), leaf to sapwood area ratio (AL/AS) and turgor loss point (Ψtlp), were examined for woody species in a mature SEBF. For comparison, we compiled these traits of tropical dry forests (TDFs) and Mediterranean-type woodlands (MWs) from the literature because they experience a hot-dry season. We found that on average, SEBF showed larger HSMbranch and HSMleaf than TDF and MW. During the dry season, TDF and MW species displayed a significant decrease in Ψpd and Ψmd. However, SEBF species showed a slight decrease in Ψpd but an increase in Ψmd. Similar to TDF and MW species, Gs was substantially lower in the dry season for SEBF species, but this might be primarily because of the low atmospheric temperature (low vapor pressure deficit). On the other hand, AL/AS and Ψtlp were not significant different between seasons for any SEBF species. Most SEBF species had leaves that were more resistant to cavitation than branches. Additionally, species with stronger leaf-to-branch vulnerability segmentation tended to have smaller HSMleaf but larger HSMbranch. Our results suggest that SEBF is at low hydraulic risk under the current climate.
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Affiliation(s)
- Shi-Dan Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Daxuedong Road, Xixiangtang District, Nanning, Guangxi, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Daxuedong Road, Xixiangtang District, Nanning, Guangxi, China
| | - Rong-Hua Li
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road, Tianhe District, Guangzhou, Guangdong, China
| | - Peng-Cheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road, Tianhe District, Guangzhou, Guangdong, China
| | - Zafar Siddiq
- Department of Botany, Government College University, Katchery Road, Lahore, Pakistan
| | - Kun-Fang Cao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Daxuedong Road, Xixiangtang District, Nanning, Guangxi, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Daxuedong Road, Xixiangtang District, Nanning, Guangxi, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road, Tianhe District, Guangzhou, Guangdong, China
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163
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Chen Z, Li S, Luan J, Zhang Y, Zhu S, Wan X, Liu S. Prediction of temperate broadleaf tree species mortality in arid limestone habitats with stomatal safety margins. TREE PHYSIOLOGY 2019; 39:1428-1437. [PMID: 30977822 DOI: 10.1093/treephys/tpz045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/24/2019] [Accepted: 04/04/2019] [Indexed: 06/09/2023]
Abstract
A growing body of evidence highlights the occurrence of increased widespread tree mortality during climate change-associated severe droughts; however, in situ long-term drought experiments with multispecies communities for the prediction of tree mortality and exploration of related mechanisms are rather limited in natural environments. We conducted a 7-year afforestation trial with 20 drought-resistant broadleaf tree species in an arid limestone habitat in northern China, where the species displayed a broad range of survival rates. The stomatal and xylem hydraulic traits of all the species were measured. We found that species' stomatal closure points were strongly related to their xylem embolism resistance and xylem minimum water potential but not to their survival rates. Hydraulic failure of the vascular system appeared to be the main cause of tree mortality, and the stomatal safety margin was a better predictor of tree mortality than the traditionally considered xylem embolism resistance and hydraulic safety margin. We recommend the stomatal safety margin as the indicator for predicting drought-induced tree mortality and for selecting tree species in future forest restorations in arid regions.
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Affiliation(s)
- Zhicheng Chen
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing, China
| | - Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, China
| | - Junwei Luan
- Institute for Resources and Environment, International Centre for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, National Forestry and Grassland Administration, Beijing, China
- Department of Natural Resource Sciences, Macdonald Campus, McGill University, Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, Canada
| | - Yongtao Zhang
- Mountain Tai Forest Ecosystem Research Station of National Forestry and Grassland Administration, Forestry College of Shandong Agricultural University, Taian, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Xianchong Wan
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing, China
| | - Shirong Liu
- Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
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164
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Sapes G, Roskilly B, Dobrowski S, Maneta M, Anderegg WRL, Martinez-Vilalta J, Sala A. Plant water content integrates hydraulics and carbon depletion to predict drought-induced seedling mortality. TREE PHYSIOLOGY 2019; 39:1300-1312. [PMID: 31135927 DOI: 10.1093/treephys/tpz062] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/29/2019] [Accepted: 05/13/2019] [Indexed: 05/25/2023]
Abstract
Widespread drought-induced forest mortality (DIM) is expected to increase with climate change and drought, and is expected to have major impacts on carbon and water cycles. For large-scale assessment and management, it is critical to identify variables that integrate the physiological mechanisms of DIM and signal risk of DIM. We tested whether plant water content, a variable that can be remotely sensed at large scales, is a useful indicator of DIM risk at the population level. We subjected Pinus ponderosa Douglas ex C. Lawson seedlings to experimental drought using a point of no return experimental design. Periodically during the drought, independent sets of seedlings were sampled to measure physiological state (volumetric water content (VWC), percent loss of conductivity (PLC) and non-structural carbohydrates) and to estimate population-level probability of mortality through re-watering. We show that plant VWC is a good predictor of population-level DIM risk and exhibits a threshold-type response that distinguishes plants at no risk from those at increasing risk of mortality. We also show that plant VWC integrates the mechanisms involved in individual tree death: hydraulic failure (PLC), carbon depletion across organs and their interaction. Our results are promising for landscape-level monitoring of DIM risk.
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Affiliation(s)
- Gerard Sapes
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Beth Roskilly
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Solomon Dobrowski
- Department of Forest Management, University of Montana, Missoula, MT 59812, USA
| | - Marco Maneta
- Department of Geosciences, University of Montana, Missoula, MT 59812, USA
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84103, USA
| | - Jordi Martinez-Vilalta
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF) Cerdanyola del Vallès 08193 Barcelona, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193 Barcelona, Spain
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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165
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Barros FDV, Bittencourt PRL, Brum M, Restrepo-Coupe N, Pereira L, Teodoro GS, Saleska SR, Borma LS, Christoffersen BO, Penha D, Alves LF, Lima AJN, Carneiro VMC, Gentine P, Lee JE, Aragão LEOC, Ivanov V, Leal LSM, Araujo AC, Oliveira RS. Hydraulic traits explain differential responses of Amazonian forests to the 2015 El Niño-induced drought. THE NEW PHYTOLOGIST 2019; 223:1253-1266. [PMID: 31077396 DOI: 10.1111/nph.15909] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 04/28/2019] [Indexed: 05/12/2023]
Abstract
Reducing uncertainties in the response of tropical forests to global change requires understanding how intra- and interannual climatic variability selects for different species, community functional composition and ecosystem functioning, so that the response to climatic events of differing frequency and severity can be predicted. Here we present an extensive dataset of hydraulic traits of dominant species in two tropical Amazon forests with contrasting precipitation regimes - low seasonality forest (LSF) and high seasonality forest (HSF) - and relate them to community and ecosystem response to the El Niño-Southern Oscillation (ENSO) of 2015. Hydraulic traits indicated higher drought tolerance in the HSF than in the LSF. Despite more intense drought and lower plant water potentials in HSF during the 2015-ENSO, greater xylem embolism resistance maintained similar hydraulic safety margin as in LSF. This likely explains how ecosystem-scale whole-forest canopy conductance at HSF maintained a similar response to atmospheric drought as at LSF, despite their water transport systems operating at different water potentials. Our results indicate that contrasting precipitation regimes (at seasonal and interannual time scales) select for assemblies of hydraulic traits and taxa at the community level, which may have a significant role in modulating forest drought response at ecosystem scales.
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Affiliation(s)
- Fernanda de V Barros
- Department of Plant Biology, Institute of Biology, CP 6109, University of Campinas- UNICAMP, Campinas, SP, 13083-970, Brazil
| | - Paulo R L Bittencourt
- Department of Plant Biology, Institute of Biology, CP 6109, University of Campinas- UNICAMP, Campinas, SP, 13083-970, Brazil
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK
| | - Mauro Brum
- Department of Plant Biology, Institute of Biology, CP 6109, University of Campinas- UNICAMP, Campinas, SP, 13083-970, Brazil
| | - Natalia Restrepo-Coupe
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- School of Life Science, University of Technology Sydney, Sydney, NSW, 2006, Australia
| | - Luciano Pereira
- Department of Plant Biology, Institute of Biology, CP 6109, University of Campinas- UNICAMP, Campinas, SP, 13083-970, Brazil
| | - Grazielle S Teodoro
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, 66075-110, Brazil
| | - Scott R Saleska
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Laura S Borma
- Earth System Science Centre, National Institute for Space Research, Av. dos Astronautas, 1.758, São José dos Campos, SP, 12227-010, Brazil
| | - Bradley O Christoffersen
- Department of Biology and School of Earth, Environmental and Marine Sciences, University of Texas Rio Grande Valley, Edinburg, TX, 78539, USA
| | - Deliane Penha
- Society, Nature and Development Department, Federal University of Western Pará (UFOPA), Santarém, PA, 68035-110, Brazil
| | - Luciana F Alves
- Center for Tropical Research, Institute of the Environment and Sustainability, University of California - Los Angeles, Los Angeles, CA, 90095, USA
| | - Adriano J N Lima
- Laboratório de Manejo Florestal, Instituto Nacional de Pesquisas na Amazônia - INPA, Manaus, AM, 69.067-375, Brazil
| | - Vilany M C Carneiro
- Laboratório de Manejo Florestal, Instituto Nacional de Pesquisas na Amazônia - INPA, Manaus, AM, 69.067-375, Brazil
| | - Pierre Gentine
- Department of Earth and Environmental Engineering, Columbia University, New York, NY, 10027, USA
| | - Jung-Eun Lee
- Department of Earth and Planetary Sciences, Brown University Providence, 324 Brook Street, Providence, RI, 02912, USA
| | - Luiz E O C Aragão
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK
- Remote Sensing Division, National Institute for Space Research, Av. dos Astronautas, 1.758, São José dos Campos, SP, 12227-010, Brazil
| | - Valeriy Ivanov
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, 48019, USA
| | - Leila S M Leal
- Laboratory of Sustainable Systems Analyses, Oriental Amazon Embrapa, Belém, Pará, 66083-156, Brazil
| | - Alessandro C Araujo
- LBA Program Micrometeorology Group, INPA, Manaus, Amazonas, 69.067-375, Brazil
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, CP 6109, University of Campinas- UNICAMP, Campinas, SP, 13083-970, Brazil
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166
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Chen Y, Uriarte M, Wright SJ, Yu S. Effects of neighborhood trait composition on tree survival differ between drought and postdrought periods. Ecology 2019; 100:e02766. [PMID: 31161620 DOI: 10.1002/ecy.2766] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/25/2019] [Accepted: 04/23/2019] [Indexed: 12/22/2022]
Abstract
Although direct tree demographic responses to drought are widely recognized, studies of drought-mediated changes in tree interactions are rare. We hypothesize that drought exacerbates soil-water limitation and intensifies competition for water, but reduces light limitation and competition for light. We predict that competition would be stronger for trees (1) consuming more water or more susceptible to water deficits during drought and (2) intercepting more light or more susceptible to shade during postdrought periods. We tested these predictions in a 50-ha tropical forest plot by quantifying the effects of neighborhood mean trait values on tree survival during versus after a severe drought. We used wood density (WD) and leaf mass per area (LMA) as proxies for water and light use strategies, respectively. Tree survival was lower, canopy loss was greater, and sapling recruitment was greater during the drought relative to postdrought census intervals. This suggests that drought pushed water deficits to lethal extremes and increased understory light availability. Relationships between survival and neighborhood WD were independent of drought, which is inconsistent with our first prediction. In contrast, relationships between survival and neighborhood LMA differed strongly with drought. Survival time was unaffected by neighborhood LMA during drought, but was longer for trees of all sizes in low-LMA neighborhoods in the postdrought census interval, consistent with the prediction of reduced competition for light during drought. Our results suggest that severe drought might increase light availability and reduce competition for light in moist tropical forests.
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Affiliation(s)
- Yuxin Chen
- School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterhurerstrasse 190, Zurich, CH-8057, Switzerland
| | - María Uriarte
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, 10027, USA
| | | | - Shixiao Yu
- School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China
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167
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Rosas T, Mencuccini M, Barba J, Cochard H, Saura-Mas S, Martínez-Vilalta J. Adjustments and coordination of hydraulic, leaf and stem traits along a water availability gradient. THE NEW PHYTOLOGIST 2019; 223:632-646. [PMID: 30636323 DOI: 10.1111/nph.15684] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 01/08/2019] [Indexed: 05/18/2023]
Abstract
Trait variability in space and time allows plants to adjust to changing environmental conditions. However, we know little about how this variability is distributed and coordinated at different organizational levels. For six dominant tree species in northeastern Spain (three Fagaceae and three Pinaceae) we quantified the inter- and intraspecific variability of a set of traits along a water availability gradient. We measured leaf mass per area (LMA), leaf nitrogen (N) concentration, carbon isotope composition in leaves (δ13 C), stem wood density, the Huber value (Hv, the ratio of cross-sectional sapwood area to leaf area), sapwood-specific and leaf-specific stem hydraulic conductivity, vulnerability to xylem embolism (P50 ) and the turgor loss point (Ptlp ). Differences between families explained the largest amount of variability for most traits, although intraspecific variability was also relevant. Species occupying wetter sites showed higher N, P50 and Ptlp , and lower LMA, δ13 C and Hv. However, when trait relationships with water availability were assessed within species they held only for Hv and Ptlp . Overall, our results indicate that intraspecific adjustments along the water availability gradient relied primarily on changes in resource allocation between sapwood and leaf area and in leaf water relations.
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Affiliation(s)
- Teresa Rosas
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Maurizio Mencuccini
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- ICREA, 08010, Barcelona, Spain
| | - Josep Barba
- Plant and Soil Sciences Department, University of Delaware, Newark, DE, 19716, USA
| | - Hervé Cochard
- INRA, PIAF, Université Clermont-Auvergne, Site de Crouël 5, chemin de Beaulieu, 63000, Clermont-Ferrand, France
| | - Sandra Saura-Mas
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Spain
| | - Jordi Martínez-Vilalta
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Spain
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168
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Gimenez BO, Jardine KJ, Higuchi N, Negrón-Juárez RI, Sampaio-Filho IDJ, Cobello LO, Fontes CG, Dawson TE, Varadharajan C, Christianson DS, Spanner GC, Araújo AC, Warren JM, Newman BD, Holm JA, Koven CD, McDowell NG, Chambers JQ. Species-Specific Shifts in Diurnal Sap Velocity Dynamics and Hysteretic Behavior of Ecophysiological Variables During the 2015-2016 El Niño Event in the Amazon Forest. FRONTIERS IN PLANT SCIENCE 2019; 10:830. [PMID: 31316536 PMCID: PMC6611341 DOI: 10.3389/fpls.2019.00830] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 06/07/2019] [Indexed: 05/11/2023]
Abstract
Current climate change scenarios indicate warmer temperatures and the potential for more extreme droughts in the tropics, such that a mechanistic understanding of the water cycle from individual trees to landscapes is needed to adequately predict future changes in forest structure and function. In this study, we contrasted physiological responses of tropical trees during a normal dry season with the extreme dry season due to the 2015-2016 El Niño-Southern Oscillation (ENSO) event. We quantified high resolution temporal dynamics of sap velocity (Vs), stomatal conductance (gs) and leaf water potential (ΨL) of multiple canopy trees, and their correlations with leaf temperature (Tleaf) and environmental conditions [direct solar radiation, air temperature (Tair) and vapor pressure deficit (VPD)]. The experiment leveraged canopy access towers to measure adjacent trees at the ZF2 and Tapajós tropical forest research (near the cities of Manaus and Santarém). The temporal difference between the peak of gs (late morning) and the peak of VPD (early afternoon) is one of the major regulators of sap velocity hysteresis patterns. Sap velocity displayed species-specific diurnal hysteresis patterns reflected by changes in Tleaf. In the morning, Tleaf and sap velocity displayed a sigmoidal relationship. In the afternoon, stomatal conductance declined as Tleaf approached a daily peak, allowing ΨL to begin recovery, while sap velocity declined with an exponential relationship with Tleaf. In Manaus, hysteresis indices of the variables Tleaf-Tair and ΨL-Tleaf were calculated for different species and a significant difference (p < 0.01, α = 0.05) was observed when the 2015 dry season (ENSO period) was compared with the 2017 dry season ("control scenario"). In some days during the 2015 ENSO event, Tleaf approached 40°C for all studied species and the differences between Tleaf and Tair reached as high at 8°C (average difference: 1.65 ± 1.07°C). Generally, Tleaf was higher than Tair during the middle morning to early afternoon, and lower than Tair during the early morning, late afternoon and night. Our results support the hypothesis that partial stomatal closure allows for a recovery in ΨL during the afternoon period giving an observed counterclockwise hysteresis pattern between ΨL and Tleaf.
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Affiliation(s)
| | - Kolby J. Jardine
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Niro Higuchi
- National Institute of Amazonian Research (INPA), Manaus, Brazil
| | - Robinson I. Negrón-Juárez
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | | | | | - Clarissa G. Fontes
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Todd E. Dawson
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Charuleka Varadharajan
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Danielle S. Christianson
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | | | | | - Jeffrey M. Warren
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Brent D. Newman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Jennifer A. Holm
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Charles D. Koven
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Nate G. McDowell
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Jeffrey Q. Chambers
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Geography, University of California, Berkeley, Berkeley, CA, United States
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169
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Umebayashi T, Sperry JS, Smith DD, Love DM. 'Pressure fatigue': the influence of sap pressure cycles on cavitation vulnerability in Acer negundo. TREE PHYSIOLOGY 2019; 39:740-746. [PMID: 30799506 DOI: 10.1093/treephys/tpy148] [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: 10/04/2018] [Revised: 12/13/2018] [Accepted: 12/19/2018] [Indexed: 05/11/2023]
Abstract
Vulnerability-to-cavitation curves (VCs) can vary within a tree crown in relation to position or branch age. We tested the hypothesis that VC variation can arise from differential susceptibility to the number of diurnal sap pressure cycles experienced. We designed a method to distinguish between effects of cycling vs exposure time to negative pressure, and tested the influence of sap pressure cycles on cavitation vulnerability between upper and lower branches in Acer negundo L. trees using static and flow centrifuge, and air-injection methods. Branches from the upper crown had greater hydraulic conductivity and were more resistant to cavitation than branches from the lower crown. Upper branches also showed little change after exposure to 10 or 20 pressure cycles between -0.5 MPa and -2.0 MPa. Lower branches, however, showed a marked increase in vulnerability to cavitation after pressure-cycling. This result suggests that 'cavitation fatigue' can occur without the actual induction (and reversal) of cavitation as documented previously, but simply from the cycling of pressures in the sub-cavitation range. This 'pressure fatigue' may explain age-related shifts in VCs that could eventually induce dieback in suppressed branches or trees. Pressure fatigue may help explain developmental variation in hydraulic capacity of branches within individuals.
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Affiliation(s)
- Toshihiro Umebayashi
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - Duncan D Smith
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - David M Love
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
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170
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Dickman LT, McDowell NG, Grossiord C, Collins AD, Wolfe BT, Detto M, Wright SJ, Medina-Vega JA, Goodsman D, Rogers A, Serbin SP, Wu J, Ely KS, Michaletz ST, Xu C, Kueppers L, Chambers JQ. Homoeostatic maintenance of nonstructural carbohydrates during the 2015-2016 El Niño drought across a tropical forest precipitation gradient. PLANT, CELL & ENVIRONMENT 2019; 42:1705-1714. [PMID: 30537216 DOI: 10.1111/pce.13501] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/26/2018] [Accepted: 12/02/2018] [Indexed: 06/09/2023]
Abstract
Nonstructural carbohydrates (NSCs) are essential for maintenance of plant metabolism and may be sensitive to short- and long-term climatic variation. NSC variation in moist tropical forests has rarely been studied, so regulation of NSCs in these systems is poorly understood. We measured foliar and branch NSC content in 23 tree species at three sites located across a large precipitation gradient in Panama during the 2015-2016 El Niño to examine how short- and long-term climatic variation impact carbohydrate dynamics. There was no significant difference in total NSCs as the drought progressed (leaf P = 0.32, branch P = 0.30) nor across the rainfall gradient (leaf P = 0.91, branch P = 0.96). Foliar soluble sugars decreased while starch increased over the duration of the dry period, suggesting greater partitioning of NSCs to storage than metabolism or transport as drought progressed. There was a large variation across species at all sites, but total foliar NSCs were positively correlated with leaf mass per area, whereas branch sugars were positively related to leaf temperature and negatively correlated with daily photosynthesis and wood density. The NSC homoeostasis across a wide range of conditions suggests that NSCs are an allocation priority in moist tropical forests.
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Affiliation(s)
- Lee Turin Dickman
- Earth & Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Nate G McDowell
- Earth Systems Analysis & Modeling, Pacific Northwest National Laboratory, Richland, Washington
| | - Charlotte Grossiord
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Forest Dynamics Research Unit, Birmensdorf, Switzerland
| | - Adam D Collins
- Earth & Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Brett T Wolfe
- Smithsonian Tropical Research Institute, Balboa, Panama
| | - Matteo Detto
- Ecology and Evolutionary Biology Department, Princeton University, Princeton, New Jersey
| | | | - José A Medina-Vega
- Smithsonian Tropical Research Institute, Balboa, Panama
- Forest Ecology and Forest Management Group, Wageningen University and Research, Wageningen, The Netherlands
| | - Devin Goodsman
- Earth & Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Alistair Rogers
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, New York, New York
| | - Shawn P Serbin
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, New York, New York
| | - Jin Wu
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, New York, New York
| | - Kim S Ely
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, New York, New York
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chonggang Xu
- Earth & Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico
| | - Lara Kueppers
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Jeffrey Q Chambers
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, California
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171
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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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172
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Schwartz NB, Budsock AM, Uriarte M. Fragmentation, forest structure, and topography modulate impacts of drought in a tropical forest landscape. Ecology 2019; 100:e02677. [PMID: 30825323 DOI: 10.1002/ecy.2677] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 01/23/2019] [Accepted: 02/04/2019] [Indexed: 02/02/2023]
Abstract
Climate models predict increases in drought conditions in many parts of the tropics. Yet the response of tropical forests to drought remains highly uncertain, especially with regards to the factors that generate spatial heterogeneity in drought response across landscapes. In this study, we used Landsat imagery to assess the impacts of a severe drought in 2015 across an ~80,000-ha landscape in Puerto Rico. Specifically, we asked whether drought effects varied systematically with topography and with forest age, height, and fragmentation. We quantified drought impacts using anomalies of two vegetation indices, the enhanced vegetation index (EVI) and normalized difference water index (NDWI), and fit random forest models of these metrics including slope, aspect, forest age, canopy height, and two indices of fragmentation as predictors. Drought effects were more severe on drier topographic positions, that is, steeper slopes and southwest-facing aspects, and in second-growth forests. Shorter and more fragmented forests were also more strongly affected by drought. We also assessed which factors were associated with stronger recovery from drought. Factors associated with more negative drought anomalies were also associated with more positive postdrought anomalies, suggesting that increased light availability as a result of drought led to high rates of recovery in forests more severely affected by drought. In general, recovery from drought was rapid across the landscape, with postdrought anomalies at or above average across the study area. This suggests that forests in Puerto Rico might be resilient to a single-year drought, though vulnerability to drought varies depending on forest characteristics and landscape position.
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Affiliation(s)
- Naomi B Schwartz
- Department of Geography, University of British Columbia, 1984 West Mall, Vancouver, British Columbia, V6T 1Z2, Canada.,Department of Ecology, Evolution, and Behavior, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota, 55108, USA.,Department of Ecology Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, New York, 10027, USA
| | - Andrew M Budsock
- Department of Ecology Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, New York, 10027, USA
| | - María Uriarte
- Department of Ecology Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, New York, 10027, USA
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173
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van der Sande MT, Poorter L, Schnitzer SA, Engelbrecht BMJ, Markesteijn L. The hydraulic efficiency-safety trade-off differs between lianas and trees. Ecology 2019; 100:e02666. [PMID: 30801680 PMCID: PMC6850011 DOI: 10.1002/ecy.2666] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 11/14/2018] [Accepted: 01/14/2019] [Indexed: 11/17/2022]
Abstract
Hydraulic traits are important for woody plant functioning and distribution. Associations among hydraulic traits, other leaf and stem traits, and species’ performance are relatively well understood for trees, but remain poorly studied for lianas. We evaluated the coordination among hydraulic efficiency (i.e., maximum hydraulic conductivity), hydraulic safety (i.e., cavitation resistance), a suite of eight morphological and physiological traits, and species’ abundances for saplings of 24 liana species and 27 tree species in wet tropical forests in Panama. Trees showed a strong trade‐off between hydraulic efficiency and hydraulic safety, whereas efficiency and safety were decoupled in lianas. Hydraulic efficiency was strongly and similarly correlated with acquisitive traits for lianas and trees (e.g., positively with gas exchange rates and negatively with wood density). Hydraulic safety, however, showed no correlations with other traits in lianas, but with several in trees (e.g., positively with leaf dry matter content and wood density and negatively with gas exchange rates), indicating that in lianas hydraulic efficiency is an anchor trait because it is correlated with many other traits, while in trees both efficiency and safety are anchor traits. Traits related to shade tolerance (e.g., low specific leaf area and high wood density) were associated with high local tree sapling abundance, but not with liana abundance. Our results suggest that different, yet unknown mechanisms determine hydraulic safety and local‐scale abundance for lianas compared to trees. For trees, the trade‐off between efficiency and safety will provide less possibilities for ecological strategies. For lianas, however, the uncoupling of efficiency and safety could allow them to have high hydraulic efficiency, and hence high growth rates, without compromising resistance to cavitation under drought, thus allowing them to thrive and outperform trees under drier conditions.
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Affiliation(s)
- Masha T van der Sande
- Department of Community Ecology, Helmholtz Centre for Environmental Research - UFZ, Theodor-Lieser-Straße 4, 06120, Halle (Saale), Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany.,Forest Ecology and Forest Management Group, Wageningen University and Research, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.,Department of Biological Sciences, Florida Institute of Technology, Melbourne, Florida, FL 32901, USA.,Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University and Research, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
| | - Stefan A Schnitzer
- Department of Biological Sciences, Marquette University, PO Box 1881, Milwaukee, Wisconsin, 53201 USA.,Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Republic of Panama
| | - Bettina M J Engelbrecht
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Republic of Panama.,Department of Plant Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440, Bayreuth, Germany
| | - Lars Markesteijn
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Republic of Panama.,School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2DG, United Kingdom
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174
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van der Sande MT, Gosling W, Correa-Metrio A, Prado-Junior J, Poorter L, Oliveira RS, Mazzei L, Bush MB. A 7000-year history of changing plant trait composition in an Amazonian landscape; the role of humans and climate. Ecol Lett 2019; 22:925-935. [PMID: 30883016 PMCID: PMC6850629 DOI: 10.1111/ele.13251] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/28/2018] [Accepted: 02/17/2019] [Indexed: 01/20/2023]
Abstract
Tropical forests are shifting in species and trait composition, but the main underlying causes remain unclear because of the short temporal scales of most studies. Here, we develop a novel approach by linking functional trait data with 7000 years of forest dynamics from a fossil pollen record of Lake Sauce in the Peruvian Amazon. We evaluate how climate and human disturbances affect community trait composition. We found weak relationships between environmental conditions and traits at the taxon level, but strong effects for community‐mean traits. Overall, community‐mean traits were more responsive to human disturbances than to climate change; human‐induced erosion increased the dominance of dense‐wooded, non‐zoochorous species with compound leaves, and human‐induced fire increased the dominance of tall, zoochorous taxa with large seeds and simple leaves. This information can help to enhance our understanding of forest responses to past environmental changes, and improve predictions of future changes in tropical forest composition.
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Affiliation(s)
- Masha T van der Sande
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL, USA.,Institute for Biodiversity & Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands.,Forest Ecology and Forest Management Group, Wageningen University and Research, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
| | - William Gosling
- Institute for Biodiversity & Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Alexander Correa-Metrio
- Instituto de Geología, Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México, CP 04510, Mexico
| | | | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University and Research, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, CP 6109, University of Campinas- UNICAMP, 13083-970, Campinas, SP, Brazil
| | - Lucas Mazzei
- Embrapa Amazônia Oriental, Travessa Enéas Pinheiro, S/N° 100 Belém, CEP 66095, Pará, Brazil
| | - Mark B Bush
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL, USA
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175
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Hogan JA, McMahon SM, Buzzard V, Michaletz ST, Enquist BJ, Thompson J, Swenson NG, Zimmerman JK. Drought and the interannual variability of stem growth in an aseasonal, everwet forest. Biotropica 2019. [DOI: 10.1111/btp.12624] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- J. Aaron Hogan
- Department of Biological Sciences Department of Biological Sciences International Center for Tropical Botany Florida International University Miami Florida
- Department of Environmental Sciences University of Puerto Rico – Río Piedras San Juan Puerto Rico
| | - Sean M. McMahon
- Smithsonian Environmental Research Center Edgewater Maryland
| | - Vanessa Buzzard
- Department of Ecology and Evolutionary Biology University of Arizona Tucson Arizona
| | - Sean T. Michaletz
- Department of Ecology and Evolutionary Biology University of Arizona Tucson Arizona
- Biosphere 2 University of Arizona Tucson Arizona
- Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver British Columbia Canada
| | - Brian J. Enquist
- Department of Ecology and Evolutionary Biology University of Arizona Tucson Arizona
| | - Jill Thompson
- Centre for Ecology & Hydrology Penicuik Midlothian UK
| | - Nathan G. Swenson
- Department of Ecology and Evolutionary Biology University of Maryland College Park Maryland
| | - Jess K. Zimmerman
- Department of Environmental Sciences University of Puerto Rico – Río Piedras San Juan Puerto Rico
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176
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Oliveira RS, Costa FRC, van Baalen E, de Jonge A, Bittencourt PR, Almanza Y, Barros FDV, Cordoba EC, Fagundes MV, Garcia S, Guimaraes ZTM, Hertel M, Schietti J, Rodrigues-Souza J, Poorter L. Embolism resistance drives the distribution of Amazonian rainforest tree species along hydro-topographic gradients. THE NEW PHYTOLOGIST 2019; 221:1457-1465. [PMID: 30295938 DOI: 10.1111/nph.15463] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/23/2018] [Indexed: 05/08/2023]
Abstract
Species distribution is strongly driven by local and global gradients in water availability but the underlying mechanisms are not clear. Vulnerability to xylem embolism (P50 ) is a key trait that indicates how species cope with drought and might explain plant distribution patterns across environmental gradients. Here we address its role on species sorting along a hydro-topographical gradient in a central Amazonian rainforest and examine its variance at the community scale. We measured P50 for 28 tree species, soil properties and estimated the hydrological niche of each species using an indicator of distance to the water table (HAND). We found a large hydraulic diversity, covering as much as 44% of the global angiosperm variation in P50 . We show that P50 : contributes to species segregation across a hydro-topographic gradient in the Amazon, and thus to species coexistence; is the result of repeated evolutionary adaptation within closely related taxa; is associated with species tolerance to P-poor soils, suggesting the evolution of a stress-tolerance syndrome to nutrients and drought; and is higher for trees in the valleys than uplands. The large observed hydraulic diversity and its association with topography has important implications for modelling and predicting forest and species resilience to climate change.
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Affiliation(s)
- Rafael S Oliveira
- Department of Plant Biology, Instituto de Biologia, University of Campinas, Caixa Postal 6109, CEP 13083-970, Campinas, SP, Brazil
| | - Flavia R C Costa
- Coordenação de Pesquisa em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Caixa Postal 2223, CEP 69080-971, Manaus, Brazil
| | - Emma van Baalen
- Coordenação de Pesquisa em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Caixa Postal 2223, CEP 69080-971, Manaus, Brazil
- Forest Ecology and Forest Management Group, Wageningen University and Research, PO Box 47, 6700 AA, Wageningen, the Netherlands
| | - Arjen de Jonge
- Coordenação de Pesquisa em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Caixa Postal 2223, CEP 69080-971, Manaus, Brazil
- Forest Ecology and Forest Management Group, Wageningen University and Research, PO Box 47, 6700 AA, Wageningen, the Netherlands
| | - Paulo R Bittencourt
- Department of Plant Biology, Instituto de Biologia, University of Campinas, Caixa Postal 6109, CEP 13083-970, Campinas, SP, Brazil
| | - Yanina Almanza
- Instituto de Biociencias, Universidade Federal de Mato Grosso, Av. Fernando Correa, CEP 78060-900, Cuiabá, Brazil
| | - Fernanda de V Barros
- Department of Plant Biology, Instituto de Biologia, University of Campinas, Caixa Postal 6109, CEP 13083-970, Campinas, SP, Brazil
| | - Edher C Cordoba
- Coordenação de Pesquisa em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Caixa Postal 2223, CEP 69080-971, Manaus, Brazil
| | - Marina V Fagundes
- Restoration Ecology Research Group, Department of Ecology, Universidade Federal do Rio Grande do Norte, CEP 59072970, Natal, RN, Brazil
| | - Sabrina Garcia
- Coordenação de Pesquisa em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Caixa Postal 2223, CEP 69080-971, Manaus, Brazil
| | - Zilza T M Guimaraes
- Programa de Pós-Graduação em Ciências de Florestas Tropicais, Instituto Nacional de Pesquisas da Amazônia, CEP 69080-971, Manaus, Brazil
| | - Mariana Hertel
- Laboratório de Fisiologia Vegetal, Universidade Estadual de Londrina, Londrina, CEP 86097850, PR, Brazil
| | - Juliana Schietti
- Coordenação de Pesquisa em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Caixa Postal 2223, CEP 69080-971, Manaus, Brazil
| | - Jefferson Rodrigues-Souza
- Coordenação de Pesquisa em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Caixa Postal 2223, CEP 69080-971, Manaus, Brazil
| | - Lourens Poorter
- Coordenação de Pesquisa em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Caixa Postal 2223, CEP 69080-971, Manaus, Brazil
- Forest Ecology and Forest Management Group, Wageningen University and Research, PO Box 47, 6700 AA, Wageningen, the Netherlands
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177
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Salmon Y, Dietrich L, Sevanto S, Hölttä T, Dannoura M, Epron D. Drought impacts on tree phloem: from cell-level responses to ecological significance. TREE PHYSIOLOGY 2019; 39:173-191. [PMID: 30726983 DOI: 10.1093/treephys/tpy153] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 12/03/2018] [Accepted: 01/25/2019] [Indexed: 06/09/2023]
Abstract
On-going climate change is increasing the risk of drought stress across large areas worldwide. Such drought events decrease ecosystem productivity and have been increasingly linked to tree mortality. Understanding how trees respond to water shortage is key to predicting the future of ecosystem functions. Phloem is at the core of the tree functions, moving resources such as non-structural carbohydrates, nutrients, and defence and information molecules across the whole plant. Phloem function and ability to transport resources is tightly controlled by the balance of carbon and water fluxes within the tree. As such, drought is expected to impact phloem function by decreasing the amount of available water and new photoassimilates. Yet, the effect of drought on the phloem has received surprisingly little attention in the last decades. Here we review existing knowledge on drought impacts on phloem transport from loading and unloading processes at cellular level to possible effects on long-distance transport and consequences to ecosystems via ecophysiological feedbacks. We also point to new research frontiers that need to be explored to improve our understanding of phloem function under drought. In particular, we show how phloem transport is affected differently by increasing drought intensity, from no response to a slowdown, and explore how severe drought might actually disrupt the phloem transport enough to threaten tree survival. Because transport of resources affects other organisms interacting with the tree, we also review the ecological consequences of phloem response to drought and especially predatory, mutualistic and competitive relations. Finally, as phloem is the main path for carbon from sources to sink, we show how drought can affect biogeochemical cycles through changes in phloem transport. Overall, existing knowledge is consistent with the hypotheses that phloem response to drought matters for understanding tree and ecosystem function. However, future research on a large range of species and ecosystems is urgently needed to gain a comprehensive understanding of the question.
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Affiliation(s)
- Yann Salmon
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, Gustaf Hällströmin katu 2b, University of Helsinki, Helsinki, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, Latokartanonkaari 7, University of Helsinki, Helsinki, Finland
| | - Lars Dietrich
- Department of Environmental Sciences, University of Basel, Schönbeinstrasse 6, Basel, Switzerland
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, PO Box 1663 MA 495, Los Alamos, NM, USA
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, Latokartanonkaari 7, University of Helsinki, Helsinki, Finland
| | - Masako Dannoura
- Kyoto University, Laboratory of Ecosystem Production and Dynamics, Graduate School of Global Environmental Studies, Kyoto, Japan
- Kyoto University, Laboratory of Forest Utilization, Graduate School of Agriculture, Kyoto, Japan
| | - Daniel Epron
- Université de Lorraine, AgroParisTech, INRA, UMR Silva, Faculté des Sciences et Technologies, Nancy, France
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178
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Dynamics of Socioeconomic Exposure, Vulnerability and Impacts of Recent Droughts in Argentina. GEOSCIENCES 2019. [DOI: 10.3390/geosciences9010039] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
During the last 20 years, Argentina experienced several extreme and widespread droughts in many different regions, including the core cropland areas. The most devastating recent events were recorded in the years 2006, 2009 and 2011. Reported impacts of the main events induced losses of more than 4 billion U.S. dollars and more than 1 million persons were reported to be directly or indirectly affected. In this paper, we analyse the drought risk in Argentina, taking into account recent information on drought hazard, exposure and vulnerability. Accordingly, we identified the most severe droughts in Argentina during the 2000–2015 period using a combination of drought hazard indicators and exposure layers. Three main events were identified: (1) during spring 2006 droughts peaked in the northeast of Argentina, (2) in 2009 precipitation deficits indicated a drought epicenter in the central Argentinian plains, and (3) in 2011 the northern Patagonia region experienced a combination of natural disasters due to severe drought conditions and a devastating volcanic eruption. Furthermore, we analysed the dynamics of drought exposure for the population and the main economic sectors affected by municipality, i.e., agriculture and livestock production. Assets exposed to droughts have been identified with several records of drought impacts and declarations of farming emergencies. We show that by combining exposure and vulnerability with drought intensity it is feasible to detect the likelihood of regional impacts in different sectors.
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179
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Kono Y, Ishida A, Saiki ST, Yoshimura K, Dannoura M, Yazaki K, Kimura F, Yoshimura J, Aikawa SI. Initial hydraulic failure followed by late-stage carbon starvation leads to drought-induced death in the tree Trema orientalis. Commun Biol 2019; 2:8. [PMID: 30623104 PMCID: PMC6323055 DOI: 10.1038/s42003-018-0256-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 12/07/2018] [Indexed: 11/09/2022] Open
Abstract
Drought-induced tree death has become a serious problem in global forest ecosystems. Two nonexclusive hypotheses, hydraulic failure and carbon starvation, have been proposed to explain tree die-offs. To clarify the mechanisms, we investigated the physiological processes of drought-induced tree death in saplings with contrasting Huber values (sapwood area/total leaf area). First, hydraulic failure and reduced respiration were found in the initial process of tree decline, and in the last stage carbon starvation led to tree death. The carbohydrate reserves at the stem bases, low in healthy trees, accumulated at the beginning of the declining process due to phloem transport failure, and then decreased just before dying. The concentrations of non-structural carbohydrates at the stem bases are a good indicator of tree damage. The physiological processes and carbon sink-source dynamics that occur during lethal drought provide important insights into the adaptive measures underlying forest die-offs under global warming conditions.
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Affiliation(s)
- Yuri Kono
- Center for Ecological Research, Kyoto University, Otsu, Shiga 520-2113 Japan
| | - Atsushi Ishida
- Center for Ecological Research, Kyoto University, Otsu, Shiga 520-2113 Japan
| | - Shin-Taro Saiki
- Center for Ecological Research, Kyoto University, Otsu, Shiga 520-2113 Japan
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687 Japan
| | - Kenichi Yoshimura
- Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata 997-8555 Japan
| | - Masako Dannoura
- Kyoto University Graduate School of Global Environmental Studies, Kyoto, Kyoto 606-8502 Japan
- Faculty of Agriculture, Kyoto University, Kyoto, Kyoto 606-8502 Japan
| | - Kenichi Yazaki
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687 Japan
| | - Fuku Kimura
- Graduate School of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-0880 Japan
| | - Jin Yoshimura
- Graduate School of Science and Technology and Department of Mathematical and Systems Engineering, Shizuoka University, Naka-Ku, Hamamatsu Shizuoka, 432-8561 Japan
- Department of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210 USA
- Marine Biosystems Research Center, Chiba University, Kamogawa, Chiba 299-5502 Japan
| | - Shin-ichi Aikawa
- Japan Forest Technology Association, Chiyoda, Tokyo 102-5281 Japan
- Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397 Japan
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180
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Esquivel‐Muelbert A, Baker TR, Dexter KG, Lewis SL, Brienen RJW, Feldpausch TR, Lloyd J, Monteagudo‐Mendoza A, Arroyo L, Álvarez-Dávila E, Higuchi N, Marimon BS, Marimon-Junior BH, Silveira M, Vilanova E, Gloor E, Malhi Y, Chave J, Barlow J, Bonal D, Davila Cardozo N, Erwin T, Fauset S, Hérault B, Laurance S, Poorter L, Qie L, Stahl C, Sullivan MJP, ter Steege H, Vos VA, Zuidema PA, Almeida E, Almeida de Oliveira E, Andrade A, Vieira SA, Aragão L, Araujo‐Murakami A, Arets E, Aymard C GA, Baraloto C, Camargo PB, Barroso JG, Bongers F, Boot R, Camargo JL, Castro W, Chama Moscoso V, Comiskey J, Cornejo Valverde F, Lola da Costa AC, del Aguila Pasquel J, Di Fiore A, Fernanda Duque L, Elias F, Engel J, Flores Llampazo G, Galbraith D, Herrera Fernández R, Honorio Coronado E, Hubau W, Jimenez‐Rojas E, Lima AJN, Umetsu RK, Laurance W, Lopez‐Gonzalez G, Lovejoy T, Aurelio Melo Cruz O, Morandi PS, Neill D, Núñez Vargas P, Pallqui Camacho NC, Parada Gutierrez A, Pardo G, Peacock J, Peña‐Claros M, Peñuela‐Mora MC, Petronelli P, Pickavance GC, Pitman N, Prieto A, Quesada C, Ramírez‐Angulo H, Réjou‐Méchain M, Restrepo Correa Z, Roopsind A, Rudas A, Salomão R, Silva N, Silva Espejo J, Singh J, Stropp J, Terborgh J, Thomas R, Toledo M, Torres‐Lezama A, Valenzuela Gamarra L, van de Meer PJ, van der Heijden G, van der Hout P, Vasquez Martinez R, Vela C, Vieira ICG, Phillips OL. Compositional response of Amazon forests to climate change. GLOBAL CHANGE BIOLOGY 2019; 25:39-56. [PMID: 30406962 PMCID: PMC6334637 DOI: 10.1111/gcb.14413] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 06/27/2018] [Accepted: 07/04/2018] [Indexed: 05/05/2023]
Abstract
Most of the planet's diversity is concentrated in the tropics, which includes many regions undergoing rapid climate change. Yet, while climate-induced biodiversity changes are widely documented elsewhere, few studies have addressed this issue for lowland tropical ecosystems. Here we investigate whether the floristic and functional composition of intact lowland Amazonian forests have been changing by evaluating records from 106 long-term inventory plots spanning 30 years. We analyse three traits that have been hypothesized to respond to different environmental drivers (increase in moisture stress and atmospheric CO2 concentrations): maximum tree size, biogeographic water-deficit affiliation and wood density. Tree communities have become increasingly dominated by large-statured taxa, but to date there has been no detectable change in mean wood density or water deficit affiliation at the community level, despite most forest plots having experienced an intensification of the dry season. However, among newly recruited trees, dry-affiliated genera have become more abundant, while the mortality of wet-affiliated genera has increased in those plots where the dry season has intensified most. Thus, a slow shift to a more dry-affiliated Amazonia is underway, with changes in compositional dynamics (recruits and mortality) consistent with climate-change drivers, but yet to significantly impact whole-community composition. The Amazon observational record suggests that the increase in atmospheric CO2 is driving a shift within tree communities to large-statured species and that climate changes to date will impact forest composition, but long generation times of tropical trees mean that biodiversity change is lagging behind climate change.
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181
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Ammer C. Diversity and forest productivity in a changing climate. THE NEW PHYTOLOGIST 2019; 221:50-66. [PMID: 29905960 DOI: 10.1111/nph.15263] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/13/2018] [Indexed: 06/08/2023]
Abstract
Contents Summary 50 I. Introduction 50 II. Drivers of the diversity-productivity relationship 51 III. Patterns of the diversity-productivity relationship 55 IV. Responses of mixed stands to climate change 57 V. Conclusions 60 Acknowledgements 61 References 61 SUMMARY: Although the relationship between species diversity and biomass productivity has been extensively studied in grasslands, the impact of tree species diversity on forest productivity, as well as the main drivers of this relationship, are still under discussion. It is widely accepted that the magnitude of the relationship between tree diversity and forest stand productivity is context specific and depends on environmental conditions, but the underlying mechanisms of this relationship are still not fully understood. Competition reduction and facilitation have been identified as key mechanisms driving the diversity-productivity relationship. However, contrasting results have been reported with respect to the extent to which competition reduction and facilitation determine the diversity-productivity relationship. They appear to depend on regional climate, soil fertility, functional diversity of the tree species involved, and developmental stage of the forest. The purpose of this review is to summarize current knowledge and to suggest a conceptual framework to explain the various processes leading to higher productivity of species-rich forests compared with average yields of their respective monocultures. This framework provides three pathways for possible development of the diversity-productivity relationship under a changing climate.
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Affiliation(s)
- Christian Ammer
- Silviculture and Forest Ecology of the Temperate Zones, Faculty of Forest Sciences, University of Göttingen, Büsgenweg 1, D-37077, Göttingen, Germany
- Centre of Biodiversity and Sustainable Land-use, University of Göttingen, Büsgenweg 1, D-37077, Göttingen, Germany
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182
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Tng DYP, Apgaua DMG, Ishida YF, Mencuccini M, Lloyd J, Laurance WF, Laurance SGW. Rainforest trees respond to drought by modifying their hydraulic architecture. Ecol Evol 2018; 8:12479-12491. [PMID: 30619559 PMCID: PMC6308889 DOI: 10.1002/ece3.4601] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/03/2018] [Accepted: 09/05/2018] [Indexed: 02/06/2023] Open
Abstract
Increased drought is forecasted for tropical regions, with severe implications for the health and function of forest ecosystems. How mature forest trees will respond to water deficit is poorly known. We investigated wood anatomy and leaf traits in lowland tropical forest trees after 24 months of experimental rainfall exclusion. Sampling sun-exposed young canopy branches from target species, we found species-specific systematic variation in hydraulic-related wood anatomy and leaf traits in response to drought stress. Relative to controls, drought-affected individuals of different tree species variously exhibited trait measures consistent with increasing hydraulic safety. These included narrower or less vessels, reduced vessel groupings, lower theoretical water conductivities, less water storage tissue and more abundant fiber in their wood, and more occluded vessels. Drought-affected individuals also had thinner leaves, and more negative pre-dawn or mid-day leaf water potentials. Future studies examining both wood and leaf hydraulic traits should improve the representation of plant hydraulics within terrestrial ecosystem and biosphere models, and help fine-tune predictions of how future climate changes will affect tropical forests globally.
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Affiliation(s)
- David Y. P. Tng
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
- Instituto de BiologiaUniversidade Federal da BahiaSalvadorBahiaBrazil
| | - Deborah M. G. Apgaua
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Yoko F. Ishida
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Maurizio Mencuccini
- ICREAPg. Lluís CompanysBarcelonaSpain
- CREAFUniversidad Autonoma de BarcelonaBarcelonaSpain
| | - Jon Lloyd
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
- Department of Life SciencesImperial College LondonAscotUK
- Faculdade de Filosofia, Ciencias e Letras de Ribeirao PretoUniversidade de Sao PauloRibeirao PretoBrazil
| | - William F. Laurance
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Susan G. W. Laurance
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
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183
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When Short Stature Is an Asset in Trees. Trends Ecol Evol 2018; 34:193-199. [PMID: 30447938 DOI: 10.1016/j.tree.2018.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/18/2018] [Accepted: 10/23/2018] [Indexed: 11/20/2022]
Abstract
With their imposing grandeur, the small number of very tall tree species attract a disproportionate amount of scientific study. We right this bias by focusing here on the shorter trees, which often grow in the shade of the giants and many other places besides. That tall trees are so restricted in distribution indicates that there are far more habitats available for small trees. We discuss some leading candidates for the mechanisms that limit maximum plant height in any given habitat, as well as why every habitat has a range of plant sizes. At least two attributes - greater adaptation capacity and higher drought resistance - suggest that the forests of the future belong to short trees.
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184
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Extreme Drought Events over the Amazon Basin: The Perspective from the Reconstruction of South American Hydroclimate. WATER 2018. [DOI: 10.3390/w10111594] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Amazon basin has experienced severe drought events for centuries, mainly associated with climate variability connected to tropical North Atlantic and Pacific sea surface temperature anomalous warming. Recently, these events are becoming more frequent, more intense and widespread. Because of the Amazon droughts environmental and socioeconomic impacts, there is an increased demand for understanding the characteristics of such extreme events in the region. In that regard, regional models instead of the general circulation models provide a promising strategy to generate more detailed climate information of extreme events, seeking better representation of physical processes. Due to uneven spatial distribution and gaps found in station data in tropical South America, and the need of more refined climate assessment in those regions, satellite-enhanced regional downscaling for applied studies (SRDAS) is used in the reconstruction of South American hydroclimate, with hourly to monthly outputs from January 1998. Accordingly, this research focuses on the analyses of recent extreme drought events in the years of 2005 and 2010 in the Amazon Basin, using the SRDAS monthly means of near-surface temperature and relative humidity, precipitation and vertically integrated soil moisture fields. Results from this analysis corroborate spatial and temporal patterns found in previous studies on extreme drought events in the region, displaying the distinctive features of the 2005 and 2010 drought events.
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185
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Zuidema PA, Poulter B, Frank DC. A Wood Biology Agenda to Support Global Vegetation Modelling. TRENDS IN PLANT SCIENCE 2018; 23:1006-1015. [PMID: 30209023 DOI: 10.1016/j.tplants.2018.08.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/31/2018] [Accepted: 08/03/2018] [Indexed: 05/06/2023]
Abstract
Realistic forecasting of forest responses to climate change critically depends on key advancements in global vegetation modelling. Compared with traditional 'big-leaf' models that simulate forest stands, 'next-generation' vegetation models aim to track carbon-, light-, water-, and nutrient-limited growth of individual trees. Wood biology can play an important role in delivering the required knowledge at tissue-to-individual levels, at minute-to-century scales and for model parameterization and benchmarking. We propose a wood biology research agenda that contributes to filling six knowledge gaps: sink versus source limitation, drivers of intra-annual growth, drought impacts, functional wood traits, dynamic biomass allocation, and nutrient cycling. Executing this agenda will expedite model development and increase the ability of models to forecast global change impact on forest dynamics.
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Affiliation(s)
- Pieter A Zuidema
- Forest Ecology and Forest Management, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands.
| | | | - David C Frank
- Laboratory of Tree-Ring Research, University of Arizona, 1215 E Lowell Street, Tucson, AZ 85721, USA
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186
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Bittencourt PRL, Pereira L, Oliveira RS. Pneumatic Method to Measure Plant Xylem Embolism. Bio Protoc 2018; 8:e3059. [PMID: 34532525 DOI: 10.21769/bioprotoc.3059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 09/30/2018] [Accepted: 10/04/2018] [Indexed: 11/02/2022] Open
Abstract
Embolism, the formation of air bubbles in the plant water transport system, has a major impact on plant water relations. Embolism formation in the water transport system of plants disrupts plant water transport capacity, impairing plant functioning and triggering plant mortality. Measuring embolism with traditional hydraulic methods is both time-consuming and requires large amounts of plant material. While the stem hydraulic methods measure loss of xylem hydraulic conductance due to embolism formation, the pneumatic method directly quantifies the amount of emboli inside the xylem as changes in xylem air content. The pneumatic method is an easy and fast (8+ embolism curves per day) method to measure plant embolism requiring minimal plant material. Here, we provide detailed descriptions and recent technical improvements on the pneumatic method.
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Affiliation(s)
- Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.,Department of Plant Biology, Institute of Biology, State University of Campinas-UNICAMP, Campinas, Brazil
| | - Luciano Pereira
- Laboratory of Plant Physiology "Coaracy M. Franco", Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas SP, Brazil
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, State University of Campinas-UNICAMP, Campinas, Brazil
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187
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Eller CB, Rowland L, Oliveira RS, Bittencourt PRL, Barros FV, da Costa ACL, Meir P, Friend AD, Mencuccini M, Sitch S, Cox P. Modelling tropical forest responses to drought and El Niño with a stomatal optimization model based on xylem hydraulics. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170315. [PMID: 30297470 PMCID: PMC6178424 DOI: 10.1098/rstb.2017.0315] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2018] [Indexed: 11/12/2022] Open
Abstract
The current generation of dynamic global vegetation models (DGVMs) lacks a mechanistic representation of vegetation responses to soil drought, impairing their ability to accurately predict Earth system responses to future climate scenarios and climatic anomalies, such as El Niño events. We propose a simple numerical approach to model plant responses to drought coupling stomatal optimality theory and plant hydraulics that can be used in dynamic global vegetation models (DGVMs). The model is validated against stand-scale forest transpiration (E) observations from a long-term soil drought experiment and used to predict the response of three Amazonian forest sites to climatic anomalies during the twentieth century. We show that our stomatal optimization model produces realistic stomatal responses to environmental conditions and can accurately simulate how tropical forest E responds to seasonal, and even long-term soil drought. Our model predicts a stronger cumulative effect of climatic anomalies in Amazon forest sites exposed to soil drought during El Niño years than can be captured by alternative empirical drought representation schemes. The contrasting responses between our model and empirical drought factors highlight the utility of hydraulically-based stomatal optimization models to represent vegetation responses to drought and climatic anomalies in DGVMs.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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Affiliation(s)
- Cleiton B Eller
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | - Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | - Fernanda V Barros
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | | | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, Australia
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - Andrew D Friend
- Department of Geography, University of Cambridge, Cambridge, UK
| | | | - Stephen Sitch
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Peter Cox
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
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188
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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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189
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Berenguer E, Malhi Y, Brando P, Cardoso Nunes Cordeiro A, Ferreira J, França F, Chesini Rossi L, Maria Moraes de Seixas M, Barlow J. Tree growth and stem carbon accumulation in human-modified Amazonian forests following drought and fire. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2017.0308. [PMID: 30297467 DOI: 10.1098/rstb.2017.0308] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2018] [Indexed: 11/12/2022] Open
Abstract
Human-modified forests are an ever-increasing feature across the Amazon Basin, but little is known about how stem growth is influenced by extreme climatic events and the resulting wildfires. Here we assess for the first time the impacts of human-driven disturbance in combination with El Niño-mediated droughts and fires on tree growth and carbon accumulation. We found that after 2.5 years of continuous measurements, there was no difference in stem carbon accumulation between undisturbed and human-modified forests. Furthermore, the extreme drought caused by the El Niño did not affect carbon accumulation rates in surviving trees. In recently burned forests, trees grew significantly more than in unburned ones, regardless of their history of previous human disturbance. Wood density was the only significant factor that helped explain the difference in growth between trees in burned and unburned forests, with low wood-density trees growing significantly more in burned sites. Our results suggest stem carbon accumulation is resistant to human disturbance and one-off extreme drought events, and it is stimulated immediately after wildfires. However, these results should be seen with caution-without accounting for carbon losses, recruitment and longer-term changes in species composition, we cannot fully understand the impacts of drought and fire in the carbon balance of human-modified forests.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Nino on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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Affiliation(s)
- Erika Berenguer
- Environmental Change Institute, University of Oxford, Oxford OX1 3QY, UK .,Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Yadvinder Malhi
- Environmental Change Institute, University of Oxford, Oxford OX1 3QY, UK
| | - Paulo Brando
- The Woods Hole Research Center, 149 Woods Hole Road, 02540-1644 Falmouth, MA, USA.,Instituto de Pesquisa Ambiental da Amazônia, Lago Norte, Brasília, DF, Brazil
| | - Amanda Cardoso Nunes Cordeiro
- Programa de Pós-Graduação em Ciências Ambientais, Instituto de Geociências, Universidade Federal do Pará, 66075-110 Belém, PA, Brazil
| | - Joice Ferreira
- Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro, s/n, CP 48, 66095-100 Belém, PA, Brazil
| | - Filipe França
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.,Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro, s/n, CP 48, 66095-100 Belém, PA, Brazil.,Instituto Federal de Minas Gerais, Rodovia Bambuí/Medeiros, Km-05, 38900-000 Bambuí, MG, Brazil
| | - Liana Chesini Rossi
- Departamento de Ecologia, Universidade Estadual Paulista, 13506-900 Rio Claro, SP, Brazil
| | | | - Jos Barlow
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.,MCT/Museu Paraense Emílio Goeldi, Av. Magalhães Barata 376, São Braz, 66040-170 Belém, PA, Brazil
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190
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Brum M, Gutiérrez López J, Asbjornsen H, Licata J, Pypker T, Sanchez G, Oiveira RS. ENSO effects on the transpiration of eastern Amazon trees. Philos Trans R Soc Lond B Biol Sci 2018; 373:20180085. [PMID: 30297479 PMCID: PMC6178436 DOI: 10.1098/rstb.2018.0085] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2018] [Indexed: 11/12/2022] Open
Abstract
Tree transpiration is important in the recycling of precipitation in the Amazon and might be negatively affected by El Niño-Southern Oscillation (ENSO)-induced droughts. To investigate the relative importance of soil moisture deficits versus increasing atmospheric demand (VPD) and determine if these drivers exert different controls over tree transpiration during the wet season versus the dry season (DS), we conducted sap flow measurements in a primary lowland tropical forest in eastern Amazon during the most extreme ENSO-induced drought (2015/2016) recorded in the Amazon. We also assessed whether trees occupying different canopy strata contribute equally to the overall stand transpiration (Tstand). Canopy trees were the primary source of Tstand However, subcanopy trees are still important as they transpired an amount similar to other biomes around the globe. Tree water use was higher during the DS, indicating that during extreme drought trees did not reduce transpiration in response to low soil moisture. Photosynthetically active radiation and VPD exerted an overriding effect on water use patterns relative to soil moisture during extreme drought, indicating that light and atmospheric constraints play a critical role in controlling ecosystem fluxes of water. Our study highlights the importance of canopy and subcanopy trees to the regional water balance and highlights the resilience to droughts that these trees show during an extreme ENSO event.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)
- Mauro Brum
- Department of Plant Biology, Institute of Biology, CP 6109, State University of Campinas - UNICAMP, Campinas, São Paulo 13083-970, Brazil
| | - Jose Gutiérrez López
- Earth Systems Research Center, University of New Hampshire, Durham, NH 03824, USA
| | - Heidi Asbjornsen
- Earth Systems Research Center, University of New Hampshire, Durham, NH 03824, USA
| | - Julian Licata
- Instituto Nacional de Tecnología Agropecuaria, Estación Experimental Concordia, Concordia, Entre Ríos, Argentina
| | - Thomas Pypker
- Department of Natural Resource Sciences, Thompson Rivers University, Kamloops, British Columbia, Canada V2C0C8
| | - Gilson Sanchez
- AGROPALMA Company, PA-150 Highway, No Number, Km 74, Tailândia, Pará 68695-000, Brazil
| | - Rafael S Oiveira
- Department of Plant Biology, Institute of Biology, CP 6109, State University of Campinas - UNICAMP, Campinas, São Paulo 13083-970, Brazil
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191
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Collalti A, Trotta C, Keenan TF, Ibrom A, Bond‐Lamberty B, Grote R, Vicca S, Reyer CPO, Migliavacca M, Veroustraete F, Anav A, Campioli M, Scoccimarro E, Šigut L, Grieco E, Cescatti A, Matteucci G. Thinning Can Reduce Losses in Carbon Use Efficiency and Carbon Stocks in Managed Forests Under Warmer Climate. JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2018; 10:2427-2452. [PMID: 31007835 PMCID: PMC6472666 DOI: 10.1029/2018ms001275] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 09/10/2018] [Accepted: 09/16/2018] [Indexed: 05/10/2023]
Abstract
Forest carbon use efficiency (CUE, the ratio of net to gross primary productivity) represents the fraction of photosynthesis that is not used for plant respiration. Although important, it is often neglected in climate change impact analyses. Here we assess the potential impact of thinning on projected carbon cycle dynamics and implications for forest CUE and its components (i.e., gross and net primary productivity and plant respiration), as well as on forest biomass production. Using a detailed process-based forest ecosystem model forced by climate outputs of five Earth System Models under four representative climate scenarios, we investigate the sensitivity of the projected future changes in the autotrophic carbon budget of three representative European forests. We focus on changes in CUE and carbon stocks as a result of warming, rising atmospheric CO2 concentration, and forest thinning. Results show that autotrophic carbon sequestration decreases with forest development, and the decrease is faster with warming and in unthinned forests. This suggests that the combined impacts of climate change and changing CO2 concentrations lead the forests to grow faster, mature earlier, and also die younger. In addition, we show that under future climate conditions, forest thinning could mitigate the decrease in CUE, increase carbon allocation into more recalcitrant woody pools, and reduce physiological-climate-induced mortality risks. Altogether, our results show that thinning can improve the efficacy of forest-based mitigation strategies and should be carefully considered within a portfolio of mitigation options.
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Affiliation(s)
- Alessio Collalti
- Impacts on Agriculture, Forests and Ecosystem Services DivisionFoundation Euro‐Mediterranean Center on Climate Change (CMCC)ViterboItaly
- National Research Council of ItalyInstitute for Agriculture and Forestry Systems in the Mediterranean (CNR‐ISAFOM)RendeItaly
| | - Carlo Trotta
- Department for Innovation in Biological, Agro‐food and Forest SystemsUniversity of TusciaViterboItaly
| | - Trevor F. Keenan
- Earth Sciences DivisionLawrence Berkeley National LaboratoryBerkeleyCAUSA
- Department of Environmental Science Policy and ManagementUniversity of CaliforniaBerkeleyCAUSA
| | - Andreas Ibrom
- Department Environmental EngineeringTechnical University of Denmark (DTU)LyngbyDenmark
| | - Ben Bond‐Lamberty
- Pacific Northwest National LaboratoryJoint Global Change Research Institute at the University of Maryland‐College ParkCollege ParkMDUSA
| | - Ruediger Grote
- Institute of Meteorology and Climate Research (IMK‐IFU)Karlsruhe Institute of TechnologyKarlsruheGermany
| | - Sara Vicca
- Centre of Excellence PLECO (Pant and Vegetation Ecology), Department of BiologyUniversity of AntwerpAntwerpBelgium
| | | | | | | | - Alessandro Anav
- College of Engineering, Mathematics and Physical SciencesUniversity of ExeterExeterUK
| | - Matteo Campioli
- Department Environmental EngineeringTechnical University of Denmark (DTU)LyngbyDenmark
| | - Enrico Scoccimarro
- Climate Simulation and Prediction DivisionFoundation Euro‐Mediterranean Center on Climate Change (CMCC)BolognaItaly
| | - Ladislav Šigut
- Department of Matter and Energy FluxesGlobal Change Research Institute CASBrnoCzech Republic
| | - Elisa Grieco
- Impacts on Agriculture, Forests and Ecosystem Services DivisionFoundation Euro‐Mediterranean Center on Climate Change (CMCC)ViterboItaly
| | - Alessandro Cescatti
- Directorate for Sustainable ResourcesEuropean Commission, Joint Research CentreIspraItaly
| | - Giorgio Matteucci
- National Research Council of ItalyInstitute for Agriculture and Forestry Systems in the Mediterranean (CNR‐ISAFOM)RendeItaly
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192
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Taylor TC, McMahon SM, Smith MN, Boyle B, Violle C, van Haren J, Simova I, Meir P, Ferreira LV, de Camargo PB, da Costa ACL, Enquist BJ, Saleska SR. Isoprene emission structures tropical tree biogeography and community assembly responses to climate. THE NEW PHYTOLOGIST 2018; 220:435-446. [PMID: 29974469 DOI: 10.1111/nph.15304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/02/2018] [Indexed: 06/08/2023]
Abstract
The prediction of vegetation responses to climate requires a knowledge of how climate-sensitive plant traits mediate not only the responses of individual plants, but also shifts in the species and functional compositions of whole communities. The emission of isoprene gas - a trait shared by one-third of tree species - is known to protect leaf biochemistry under climatic stress. Here, we test the hypothesis that isoprene emission shapes tree species compositions in tropical forests by enhancing the tolerance of emitting trees to heat and drought. Using forest inventory data, we estimated the proportional abundance of isoprene-emitting trees (pIE) at 103 lowland tropical sites. We also quantified the temporal composition shifts in three tropical forests - two natural and one artificial - subjected to either anomalous warming or drought. Across the landscape, pIE increased with site mean annual temperature, but decreased with dry season length. Through time, pIE strongly increased under high temperatures, and moderately increased following drought. Our analysis shows that isoprene emission is a key plant trait determining species responses to climate. For species adapted to seasonal dry periods, isoprene emission may tradeoff with alternative strategies, such as leaf deciduousness. Community selection for isoprene-emitting species is a potential mechanism for enhanced forest resilience to climatic change.
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Affiliation(s)
- Tyeen C Taylor
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Sean M McMahon
- Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Environmental Research Center, Edgewater, MD, 21307, USA
| | - Marielle N Smith
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Brad Boyle
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Hardner & Gullison Associates, LLC, 15 Woodland Drive, Amherst, NH, 03031, USA
| | - Cyrille Violle
- Centre d'Écologie Fonctionnelle et Évolutive (UMR 5175), CNRS - Université de Montpellier - Université Paul Valéry Montpellier, EPHE, Montpellier, France
| | - Joost van Haren
- Biosphere 2, University of Arizona, 32540 S. Biosphere Road, Oracle, AZ, 85623, USA
| | - Irena Simova
- Center for Theoretical Study, Charles University, Praha, 11636, Czech Republic
- Department of Ecology, Faculty of Science, Charles University, 12844, Praha, Czech Republic
| | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, EH8 9XP, UK
| | - Leandro V Ferreira
- Coordenação de Botânica, Museu Paraense Emílio Goeldi, 66040-170, Belém, PA, Brazil
| | - Plinio B de Camargo
- Laboratório de Ecologia Isotópica, Centro de Energia Nuclear na Agricultura (CENA), Universidade de São Paulo, 13400-970, Piracicaba, São Paulo, Brazil
| | - Antonio C L da Costa
- Centro de Geociências, Universidade Federal do Pará, 66017-970, Belém, PA, Brazil
| | - Brian J Enquist
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, 87501, USA
| | - Scott R Saleska
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
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193
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Rungwattana K, Kasemsap P, Phumichai T, Kanpanon N, Rattanawong R, Hietz P. Trait evolution in tropical rubber (Hevea brasiliensis) trees is related to dry season intensity. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13203] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kanin Rungwattana
- Institute of BotanyUniversity of Natural Resources and Life Sciences Vienna Austria
| | - Poonpipope Kasemsap
- Hevea Research Platform in PartnershipDORAS CentreKasetsart University Bangkok Thailand
- Department of HorticultureFaculty of AgricultureKasetsart University Bangkok Thailand
| | | | - Nicha Kanpanon
- Department of HorticultureFaculty of AgricultureKasetsart University Bangkok Thailand
- UMR 1137, Ecologie et Ecophysiologie ForestièresFaculté des SciencesUniversité de Lorraine Vandoeure‐les‐Nancy France
| | - Ratchanee Rattanawong
- Nong Khai Rubber Research CenterRubber Research Institute of Thailand Rattanawapi District Nong Khai Thailand
| | - Peter Hietz
- Institute of BotanyUniversity of Natural Resources and Life Sciences Vienna Austria
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194
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Jin Y, Li J, Liu C, Liu Y, Zhang Y, Sha L, Wang Z, Song Q, Lin Y, Zhou R, Chen A, Li P, Fei X, Grace J. Carbohydrate dynamics of three dominant species in a Chinese savanna under precipitation exclusion. TREE PHYSIOLOGY 2018; 38:1371-1383. [PMID: 29474710 DOI: 10.1093/treephys/tpy017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/06/2018] [Indexed: 06/08/2023]
Abstract
The potential impact of drought on the carbon balance in plants has gained great attention. Non-structural carbohydrate (NSC) dynamics have been suggested as an important trait reflecting carbon balance under drought conditions. However, NSC dynamics under drought and the response mechanisms of NSC to drought remain unclear, especially in water-limited savanna ecosystems. A precipitation exclusion experiment was performed to simulate different drought intensities in a savanna ecosystem in Yuanjiang valley in southwestern China. Growth, total NSC concentration and diurnal change of NSC were determined for the leaves and non-photosynthetic organs of three dominant species (Lannea coromandelica, Polyalthia cerasoides and Heteropogon contortus) throughout the growing season. Drought significantly reduced the growth of all the three species. Total NSC concentration averaged ~8.1%, varying with species, organ and sampling period, and did not significantly decrease under drought stress. By contrast, the diurnal change of NSC in these three species increased under drought stress. These results indicate that these three dominant species did not undergo carbon limitation. Thus, relative change in NSC is a more sensitive and effective indicator than carbon reserves in evaluation of plant carbon balance. These findings provide new insights for the understanding of carbon balance and the mechanisms of carbon starvation.
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Affiliation(s)
- Yanqiang Jin
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jing Li
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chenggang Liu
- Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | - Yuntong Liu
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | - Yiping Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | - Liqing Sha
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | - Zhe Wang
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Qinghai Song
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
| | - Youxing Lin
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ruiwu Zhou
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Aiguo Chen
- Yuanjiang Savanna Ecosystem Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yuanjiang, China
| | - Peiguang Li
- Yellow River Delta Ecological Research Station of Coastal Wetland, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Xuehai Fei
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, China
- University of Chinese Academy of Sciences, Beijing, China
| | - John Grace
- School of Geosciences, University of Edinburgh, Edinburgh, UK
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195
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Santos VAHFD, Ferreira MJ, Rodrigues JVFC, Garcia MN, Ceron JVB, Nelson BW, Saleska SR. Causes of reduced leaf-level photosynthesis during strong El Niño drought in a Central Amazon forest. GLOBAL CHANGE BIOLOGY 2018; 24:4266-4279. [PMID: 29723915 DOI: 10.1111/gcb.14293] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 03/18/2018] [Accepted: 04/16/2018] [Indexed: 06/08/2023]
Abstract
Sustained drought and concomitant high temperature may reduce photosynthesis and cause tree mortality. Possible causes of reduced photosynthesis include stomatal closure and biochemical inhibition, but their relative roles are unknown in Amazon trees during strong drought events. We assessed the effects of the recent (2015) strong El Niño drought on leaf-level photosynthesis of Central Amazon trees via these two mechanisms. Through four seasons of 2015, we measured leaf gas exchange, chlorophyll a fluorescence parameters, chlorophyll concentration, and nutrient content in leaves of 57 upper canopy and understory trees of a lowland terra firme forest on well-drained infertile oxisol. Photosynthesis decreased 28% in the upper canopy and 17% in understory trees during the extreme dry season of 2015, relative to other 2015 seasons and was also lower than the climatically normal dry season of the following non-El Niño year. Photosynthesis reduction under extreme drought and high temperature in the 2015 dry season was related only to stomatal closure in both upper canopy and understory trees, and not to chlorophyll a fluorescence parameters, chlorophyll, or leaf nutrient concentration. The distinction is important because stomatal closure is a transient regulatory response that can reverse when water becomes available, whereas the other responses reflect more permanent changes or damage to the photosynthetic apparatus. Photosynthesis decrease due to stomatal closure during the 2015 extreme dry season was followed 2 months later by an increase in photosynthesis as rains returned, indicating a margin of resilience to one-off extreme climatic events in Amazonian forests.
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Affiliation(s)
| | | | | | - Maquelle Neves Garcia
- Environmental Dynamics Department, Brazil's National Institute for Amazon Research, Manaus, Brazil
| | - João Vitor Barbosa Ceron
- Environmental Dynamics Department, Brazil's National Institute for Amazon Research, Manaus, Brazil
| | - Bruce Walker Nelson
- Environmental Dynamics Department, Brazil's National Institute for Amazon Research, Manaus, Brazil
| | - Scott Reid Saleska
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona
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196
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Drought Sensitiveness on Forest Growth in Peninsular Spain and the Balearic Islands. FORESTS 2018. [DOI: 10.3390/f9090524] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Drought is one of the key natural hazards impacting net primary production and tree growth in forest ecosystems. Nonetheless, tree species show different responses to drought events, which make it difficult to adopt fixed tools for monitoring drought impacts under contrasting environmental and climatic conditions. In this study, we assess the response of forest growth and a satellite proxy of the net primary production (NPP) to drought in peninsular Spain and the Balearic Islands, a region characterized by complex climatological, topographical, and environmental characteristics. Herein, we employed three different indicators based on in situ measurements and satellite image-derived vegetation information (i.e., tree-ring width, maximum annual greenness, and an indicator of NPP). We used seven different climate drought indices to assess drought impacts on the tree variables analyzed. The selected drought indices include four versions of the Palmer Drought Severity Index (PDSI, Palmer Hydrological Drought Index (PHDI), Z-index, and Palmer Modified Drought Index (PMDI)) and three multi-scalar indices (Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Precipitation Index (SPI), and Standardized Precipitation Drought Index (SPDI)). Our results suggest that—irrespective of drought index and tree species—tree-ring width shows a stronger response to interannual variability of drought, compared to the greenness and the NPP. In comparison to other drought indices (e.g., PDSI), and our results demonstrate that multi-scalar drought indices (e.g., SPI, SPEI) are more advantageous in monitoring drought impacts on tree-ring growth, maximum greenness, and NPP. This finding suggests that multi-scalar indices are more appropriate for monitoring and modelling forest drought in peninsular Spain and the Balearic Islands.
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197
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Feng X, Ackerly DD, Dawson TE, Manzoni S, Skelton RP, Vico G, Thompson SE. The ecohydrological context of drought and classification of plant responses. Ecol Lett 2018; 21:1723-1736. [DOI: 10.1111/ele.13139] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/12/2018] [Accepted: 07/16/2018] [Indexed: 01/20/2023]
Affiliation(s)
- Xue Feng
- Department of Civil, Environmental, and Geo‐Engineering University of Minnesota Minneapolis MN USA
| | - David D. Ackerly
- Department of Integrative Biology University of California Berkeley CA USA
| | - Todd E. Dawson
- Department of Integrative Biology University of California Berkeley CA USA
- Department of Environmental Sciences, Policy, and Management University of California Berkeley CA USA
| | - Stefano Manzoni
- Department of Physical Geography Stockholm University Stockholm Sweden
- Bolin Centre for Climate Research Stockholm Sweden
| | - Rob P. Skelton
- Department of Integrative Biology University of California Berkeley CA USA
| | - Giulia Vico
- Department of Crop Production Ecology Swedish University of Agricultural Sciences (SLU) Uppsala Sweden
| | - Sally E. Thompson
- Department of Civil and Environmental Engineering University of California Berkeley CA USA
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198
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Maréchaux I, Bonal D, Bartlett MK, Burban B, Coste S, Courtois EA, Dulormne M, Goret J, Mira E, Mirabel A, Sack L, Stahl C, Chave J. Dry‐season decline in tree sapflux is correlated with leaf turgor loss point in a tropical rainforest. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13188] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Isabelle Maréchaux
- Laboratoire Evolution et Diversité Biologique UMR5174, CNRS, Université Paul Sabatier, IRD Toulouse Cedex 9 France
- AMAP, INRA, University of Montpellier, IRD, CIRAD, CNRS Montpellier France
- AgroParisTech‐ENGREF Paris France
| | - Damien Bonal
- Université de Lorraine, AgroParisTech, INRA, UMR Silva Nancy France
| | - Megan K. Bartlett
- Department of Ecology and Evolution University of California Los Angeles Los Angeles California
- Princeton Environmental Institute, Princeton University Princeton New Jersey
| | - Benoît Burban
- INRA, UMR EcoFoG, AgroParisTech, CNRS, CIRAD, Université des Antilles, Université de Guyane Kourou France
| | - Sabrina Coste
- Université de Guyane, UMR EcoFoG, AgroParisTech, CNRS, CIRAD, INRA, Université des Antilles Cayenne France
| | - Elodie A. Courtois
- Department of Biology University of Antwerp Wilrijk Belgium
- Laboratoire Écologie, évolution, interactions des systèmes amazoniens (LEEISA) Université de Guyane, CNRS Guyane Cayenne France
| | - Maguy Dulormne
- Université des Antilles, UMR EcoFoG, AgroParisTech, CNRS, CIRAD, INRA, Université de Guyane Pointe à Pitre France
| | - Jean‐Yves Goret
- INRA, UMR EcoFoG, AgroParisTech, CNRS, CIRAD, Université des Antilles, Université de Guyane Kourou France
| | - Eléonore Mira
- Université des Antilles, UMR EcoFoG, AgroParisTech, CNRS, CIRAD, INRA, Université de Guyane Pointe à Pitre France
| | - Ariane Mirabel
- Université de Guyane, UMR EcoFoG, AgroParisTech, CNRS, CIRAD, INRA, Université des Antilles Cayenne France
| | - Lawren Sack
- Department of Ecology and Evolution University of California Los Angeles Los Angeles California
| | - Clément Stahl
- INRA, UMR EcoFoG, AgroParisTech, CNRS, CIRAD, Université des Antilles, Université de Guyane Kourou France
- Department of Biology University of Antwerp Wilrijk Belgium
| | - Jérôme Chave
- Laboratoire Evolution et Diversité Biologique UMR5174, CNRS, Université Paul Sabatier, IRD Toulouse Cedex 9 France
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199
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Trugman AT, Detto M, Bartlett MK, Medvigy D, Anderegg WRL, Schwalm C, Schaffer B, Pacala SW. Tree carbon allocation explains forest drought-kill and recovery patterns. Ecol Lett 2018; 21:1552-1560. [DOI: 10.1111/ele.13136] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/29/2018] [Accepted: 07/12/2018] [Indexed: 12/18/2022]
Affiliation(s)
- A. T. Trugman
- Department of Biology; University of Utah; Salt Lake City UT 84112 USA
| | - M. Detto
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ 08544 USA
| | - M. K. Bartlett
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ 08544 USA
| | - D. Medvigy
- Department of Biological Sciences; University of Notre Dame; Notre Dame IN 46556 USA
| | - W. R. L. Anderegg
- Department of Biology; University of Utah; Salt Lake City UT 84112 USA
| | - C. Schwalm
- Center for Ecosystem Science and Society; Northern Arizona University; Flagstaff AZ 86001 USA
- Woods Hole Research Center; Falmouth MA 02540 USA
| | - B. Schaffer
- Department of Civil and Environmental Engineering; Princeton University; Princeton NJ 08544 USA
| | - S. W. Pacala
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ 08544 USA
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200
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Yang Y, Saatchi SS, Xu L, Yu Y, Choi S, Phillips N, Kennedy R, Keller M, Knyazikhin Y, Myneni RB. Post-drought decline of the Amazon carbon sink. Nat Commun 2018; 9:3172. [PMID: 30093640 PMCID: PMC6085357 DOI: 10.1038/s41467-018-05668-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 07/04/2018] [Indexed: 01/01/2023] Open
Abstract
Amazon forests have experienced frequent and severe droughts in the past two decades. However, little is known about the large-scale legacy of droughts on carbon stocks and dynamics of forests. Using systematic sampling of forest structure measured by LiDAR waveforms from 2003 to 2008, here we show a significant loss of carbon over the entire Amazon basin at a rate of 0.3 ± 0.2 (95% CI) PgC yr−1 after the 2005 mega-drought, which continued persistently over the next 3 years (2005–2008). The changes in forest structure, captured by average LiDAR forest height and converted to above ground biomass carbon density, show an average loss of 2.35 ± 1.80 MgC ha−1 a year after (2006) in the epicenter of the drought. With more frequent droughts expected in future, forests of Amazon may lose their role as a robust sink of carbon, leading to a significant positive climate feedback and exacerbating warming trends. Forests of the Amazon Basin have experienced frequent and severe droughts in recent years with significant impacts on their carbon cycling. Here, using satellite LiDAR samples from 2003 to 2008, the authors show the long-term legacy of these droughts with persistent loss of carbon stocks after the 2005 drought.
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Affiliation(s)
- Yan Yang
- Institute of Environment and Sustainability, University of California, Los Angeles, CA, USA. .,Department of Earth and Environment, Boston University, Boston, MA, USA. .,Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
| | - Sassan S Saatchi
- Institute of Environment and Sustainability, University of California, Los Angeles, CA, USA.,Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Liang Xu
- Institute of Environment and Sustainability, University of California, Los Angeles, CA, USA.,Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Yifan Yu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Sungho Choi
- Department of Earth and Environment, Boston University, Boston, MA, USA
| | - Nathan Phillips
- Department of Earth and Environment, Boston University, Boston, MA, USA
| | - Robert Kennedy
- Dept. of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Michael Keller
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.,Int. Institute of Tropical Forestry & Int. Programs, USDA Forest Service, Washington, USA
| | - Yuri Knyazikhin
- Department of Earth and Environment, Boston University, Boston, MA, USA
| | - Ranga B Myneni
- Department of Earth and Environment, Boston University, Boston, MA, USA
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