Patrick Meir

University of Edinburgh

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Yadvinder Malhi

University of Oxford

103

Antônio C. L. da Costa

Universidade Federal do Pará

Lucy Rowland

University of Exeter

Maurizio Mencuccini

Centre for Research on Ecology and Forestry Applications

Norma Salinas

Pontifical Catholic University of Peru

David Galbraith

University of Leeds

Andrew T. Nottingham

Smithsonian Tropical Research Institute

Oliver L. Phillips

University of Leeds

Oliver Binks

Centre for Research on Ecology and Forestry Applications

Mathew Williams

University of Edinburgh

Cooperative Institutions

John Wiley & Sons (United States)

429

Ecological Society of America

419

IFC Research (United Kingdom)

318

National Institute of Amazonian Research

138

University of Edinburgh

134

Wyoming Game and Fish Department

120

Centre National de la Recherche Scientifique

114

University of Oxford

113

University of Leeds

105

Wageningen University & Research

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Effect of 7 yr of experimental drought on vegetation dynamics and biomass storage of an eastern Amazonian rainforest

New Phytologist (2010)

Antônio C. L. da Costa David Galbraith Samuel Almeida Bruno Takeshi Tanaka Portela Mauricio Costa

*At least one climate model predicts severe reductions of rainfall over Amazonia during this century. Long-term throughfall exclusion (TFE) experiments represent the best available means to investigate the resilience of the Amazon rainforest to such droughts. *Results are presented from a 7 yr TFE study at Caxiuanã National Forest, eastern Amazonia. We focus on the impacts of the drought on tree mortality, wood production and above-ground biomass. *Tree mortality in the TFE plot over the experimental period was 2.5% yr(-1), compared with 1.25% yr(-1) in a nearby control plot experiencing normal rainfall. Differences in stem mortality between plots were greatest in the largest (> 40 cm diameter at breast height (dbh)) size class (4.1% yr(-1) in the TFE and 1.4% yr(-1) in the control). Wood production in the TFE plot was c. 30% lower than in the control plot. Together, these changes resulted in a loss of 37.8 +/- 2.0 Mg carbon (C) ha(-1) in the TFE plot (2002-2008), compared with no change in the control. *These results are remarkably consistent with those from another TFE (at Tapajós National Forest), suggesting that eastern Amazonian forests may respond to prolonged drought in a predictable manner.

Forest dynamics

10.1111/j.1469-8137.2010.03309.x

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Citations (360)

Terrestrial Global Productivity: Past, Present and Future

Academic Press eBooks (2001)

J. P. Grace Yadvinder Malhi Níro Higuchi Patrick Meir

Source

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Citations (51)

Amazonian Deforestation and Climate

Alejandro Miranda Heloísa S. Miranda J. P. Grace Patrick Meir Jon Lloyd

Deforestation

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Citations (204)

Author Correction: Soil carbon loss by experimental warming in a tropical forest

Nature (2020)

Andrew T. Nottingham Patrick Meir Esther Velasquez Benjamin L. Turner

Tropical forest

Amendment

Carbon fibers

10.1038/s41586-020-2792-9

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Citations (3)

Stand dynamics modulate water cycling and mortality risk in droughted 1 tropical forest

Scientific Reports (2017)

A.C.L. Da Costa Lucy Rowland Rafael S. Oliveira Alexa A.R. Oliveira Oliver Binks

Cycling

Tropical forest

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Citations (0)

Asymmetric Responses of Primary Productivity to Altered Precipitation Simulated by Ecosystem Models across Three Longterm Grassland Sites

Donghai Wu Philippe Ciais Nicolas Viovy Alan K. Knapp Kevin R. Wilcox

Abstract. Changes in precipitation variability are known to influence grassland growth. Field measurements of aboveground net primary productivity (ANPP) in temperate grasslands suggest that both positive and negative asymmetric responses to changes in precipitation may occur. Under normally variable precipitation regimes, wet years typically result in ANPP gains being larger than ANPP declines in dry years (positive asymmetry), whereas increases in ANPP are lower in magnitude in extreme wet years compared to reductions during extreme drought (negative asymmetry). Whether ecosystem models that couple carbon-water system in grasslands are capable of simulating these non-symmetrical ANPP responses is an unresolved question. In this study, we evaluated the simulated responses of temperate grassland primary productivity to scenarios of altered precipitation with fourteen ecosystem models at three sites, Shortgrass Steppe (SGS), Konza Prairie (KNZ) and Stubai Valley meadow (STU), spanning a rainfall gradient from dry to moist. We found that: (1) Gross primary productivity (GPP), NPP, ANPP and belowground NPP (BNPP) showed concave-down nonlinear response curves to altered precipitation in all the models, but with different curvatures and mean values. (2) The slopes of spatial relationships (across sites) between modeled primary productivity and precipitation were steeper than the temporal slopes obtained from inter-annual variations, consistent with empirical data. (3) The asymmetry of the responses of modeled primary productivity under normal inter-annual precipitation variability differed among models, and the median of the model-ensemble suggested a negative asymmetry across the three sites, in contrast to empirical studies. (4) The median sensitivity of modeled productivity to rainfall consistently suggested greater negative impacts with reduced precipitation than positive effects with increased precipitation under extreme conditions. This study indicates that most models overestimate the extent of negative drought effects and/or underestimate the impacts of increased precipitation on primary productivity under normal climate conditions, highlighting the need for improving eco-hydrological processes in models.

Steppe

Grassland ecosystem

10.5194/bg-2018-53

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Citations (5)

New insights into large tropical tree mass and structure from direct harvest and terrestrial lidar

bioRxiv (Cold Spring Harbor Laboratory) (2020)

Andrew Burt Matheus Boni Vicari Antônio C. L. da Costa Ingrid Coughlin Patrick Meir

Abstract A large portion of the terrestrial vegetation carbon stock is stored in the above-ground biomass (AGB) of tropical forests, but the exact amount remains uncertain, partly due to the lack of measurements. To date, accessible peer-reviewed data are available for just 10 large tropical trees in the Amazon that have been harvested and directly measured entirely via weighing. Here, we harvested four large tropical rainforest trees (stem diameter: 0.6–1.2m, height: 30–46m, AGB: 3960–18 584 kg) in intact old-growth forest in East Amazonia, and measured above-ground green mass, moisture content and woody tissue density. We first present rare ecological insights provided by these data, including unsystematic intra-tree variations in density, with both height and radius. We also found the majority of AGB was usually found in the crown, but varied from 42–62%. We then compare non-destructive approaches for estimating the AGB of these trees, using both classical allometry, and new lidar-based methods. Terrestrial lidar point clouds were collected pre-harvest, on which we fitted cylinders to model woody structure, enabling retrieval of volume-derived AGB. Estimates from this approach were more accurate than allometric counterparts (mean tree-scale relative error: 3% vs. 15%), and error decreased when up-scaling to the cumulative AGB of the four trees (1% vs. 15%). Further, whilst allometric error increased four-fold with tree size over the diameter range, lidar error remained constant. This suggests error in these lidar-derived estimates is random and additive. Were these results transferable across forest scenes, terrestrial lidar methods would reduce uncertainty in stand-scale AGB estimates, and therefore advance our understanding of the role of tropical forests in the global carbon cycle.

Allometry

Tree Allometry

Tropical rain forest

10.1101/2020.09.29.317198

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Citations (2)

Differences in xylem and leaf hydraulic traits explain differences in drought tolerance among mature Amazon rainforest trees

Global Change Biology (2017)

Thomas L. Powell James K. Wheeler Alex Oliveira Antônio C. L. da Costa S. R. Saleska

Abstract Considerable uncertainty surrounds the impacts of anthropogenic climate change on the composition and structure of Amazon forests. Building upon results from two large‐scale ecosystem drought experiments in the eastern Brazilian Amazon that observed increases in mortality rates among some tree species but not others, in this study we investigate the physiological traits underpinning these differential demographic responses. Xylem pressure at 50% conductivity (xylem‐P 50 ), leaf turgor loss point ( TLP ), cellular osmotic potential (π o ), and cellular bulk modulus of elasticity (ε), all traits mechanistically linked to drought tolerance, were measured on upper canopy branches and leaves of mature trees from selected species growing at the two drought experiment sites. Each species was placed a priori into one of four plant functional type ( PFT ) categories: drought‐tolerant versus drought‐intolerant based on observed mortality rates, and subdivided into early‐ versus late‐successional based on wood density. We tested the hypotheses that the measured traits would be significantly different between the four PFT s and that they would be spatially conserved across the two experimental sites. Xylem‐P 50 , TLP , and π o , but not ε, occurred at significantly higher water potentials for the drought‐intolerant PFT compared to the drought‐tolerant PFT ; however, there were no significant differences between the early‐ and late‐successional PFT s. These results suggest that these three traits are important for determining drought tolerance, and are largely independent of wood density—a trait commonly associated with successional status. Differences in these physiological traits that occurred between the drought‐tolerant and drought‐intolerant PFT s were conserved between the two research sites, even though they had different soil types and dry‐season lengths. This more detailed understanding of how xylem and leaf hydraulic traits vary between co‐occuring drought‐tolerant and drought‐intolerant tropical tree species promises to facilitate a much‐needed improvement in the representation of plant hydraulics within terrestrial ecosystem and biosphere models, which will enhance our ability to make robust predictions of how future changes in climate will affect tropical forests.

Drought Tolerance

Turgor pressure

Plant functional type

10.1111/gcb.13731

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Citations (90)

Fluxes of carbon, water and energy over Brazilian cerrado: an analysis using eddy covariance and stable isotopes

Plant Cell & Environment (1997)

Antônio Carlos de Oliveira Miranda Heloísa S. Miranda Jon Lloyd J. Grace R. J. Francey

ABSTRACT We present the energy and mass balance of cerrado sensu stricto (a Brazilian form of savanna), in which a mixture of shrubs, trees and grasses forms a vegetation with a leaf area index of 1·0 in the wet season and 0·4 in the dry season. In the wet season the available energy was equally dissipated between sensible heat and evaporation, but in the dry season at high irradiance the sensible heat greatly exceeded evaporation. Ecosystem surface conductance g s in the wet season rose abruptly to 0·3 mol m −2 s −1 and fell gradually as the day progressed. Much of the total variation in g s was associated with variation in the leaf‐to‐air vapour pressure deficit of water and the solar irradiance. In the dry season the maximal g s values were only 0·1 mol m −2 s −1 . Maximal net ecosystem fluxes of CO 2 in the wet and dry season were –10 and –15 μmol CO 2 m −2 s −1 , respectively (sign convention: negative denotes fluxes from atmosphere to vegetation). The canopy was well coupled to the atmosphere, and there was rarely a significant build‐up of respiratory CO 2 during the night. For observations in the wet season, the vegetation was a carbon dioxide sink, of maximal strength 0·15 mol m −2 d −1 . However, it was a source of carbon dioxide for a brief period at the height of the dry season. Leaf carbon isotopic composition showed all the grasses except for one species to be C 4 , and all the palms and woody plants to be C 3 . The CO 2 coming from the soil had an isotopic composition that suggested 40% of it was of C 4 origin.

Dry season

Bowen ratio

Carbon sink

Wet season

Tropical savanna climate

Growing season

10.1046/j.1365-3040.1997.d01-80.x

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Citations (238)

Manipulative experiments demonstrate how long-term soil moisture changes alter controls of plant water use

Environmental and Experimental Botany (2017)

Charlotte Grossiord Sanna Sevanto Jean‐Marc Limousin Patrick Meir Maurizio Mencuccini

10.1016/j.envexpbot.2017.12.010

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Citations (60)