ORCID Profile
0000-0002-8993-6168
Current Organisation
University of Leeds
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Publisher: Springer Science and Business Media LLC
Date: 10-03-2013
DOI: 10.1038/NGEO1741
Publisher: The Royal Society
Date: 14-12-2016
Abstract: Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high ersity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary ersity, ecosystem function and the response of tropical forests to global change.
Publisher: Springer Science and Business Media LLC
Date: 04-2021
DOI: 10.1038/S41559-021-01418-Y
Abstract: The forests of Amazonia are among the most bio erse plant communities on Earth. Given the immediate threats posed by climate and land-use change, an improved understanding of how this extraordinary bio ersity is spatially organized is urgently required to develop effective conservation strategies. Most Amazonian tree species are extremely rare but a few are common across the region. Indeed, just 227 'hyperdominant' species account for >50% of all in iduals >10 cm diameter at 1.3 m in height. Yet, the degree to which the phenomenon of hyperdominance is sensitive to tree size, the extent to which the composition of dominant species changes with size class and how evolutionary history constrains tree hyperdominance, all remain unknown. Here, we use a large floristic dataset to show that, while hyperdominance is a universal phenomenon across forest strata, different species dominate the forest understory, midstory and canopy. We further find that, although species belonging to a range of phylogenetically dispersed lineages have become hyperdominant in small size classes, hyperdominants in large size classes are restricted to a few lineages. Our results demonstrate that it is essential to consider all forest strata to understand regional patterns of dominance and composition in Amazonia. More generally, through the lens of 654 hyperdominant species, we outline a tractable pathway for understanding the functioning of half of Amazonian forests across vertical strata and geographical locations.
Publisher: Springer Science and Business Media LLC
Date: 2004
DOI: 10.1038/NATURE02121
Publisher: The Royal Society
Date: 27-11-2011
Abstract: The rate of above-ground woody biomass production, W P , in some western Amazon forests exceeds those in the east by a factor of 2 or more. Underlying causes may include climate, soil nutrient limitations and species composition. In this modelling paper, we explore the implications of allowing key nutrients such as N and P to constrain the photosynthesis of Amazon forests, and also we examine the relationship between modelled rates of photosynthesis and the observed gradients in W P . We use a model with current understanding of the underpinning biochemical processes as affected by nutrient availability to assess: (i) the degree to which observed spatial variations in foliar [N] and [P] across Amazonia affect stand-level photosynthesis and (ii) how these variations in forest photosynthetic carbon acquisition relate to the observed geographical patterns of stem growth across the Amazon Basin. We find nutrient availability to exert a strong effect on photosynthetic carbon gain across the Basin and to be a likely important contributor to the observed gradient in W P . Phosphorus emerges as more important than nitrogen in accounting for the observed variations in productivity. Implications of these findings are discussed in the context of future tropical forests under a changing climate.
Publisher: IEEE
Date: 07-2016
Publisher: Wiley
Date: 03-03-2014
DOI: 10.1111/ELE.12252
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-03-2017
Abstract: The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.
Publisher: Copernicus GmbH
Date: 05-05-2011
Publisher: Springer Science and Business Media LLC
Date: 04-03-2020
Publisher: Elsevier BV
Date: 11-2017
Publisher: Informa UK Limited
Date: 03-2013
Publisher: American Association for the Advancement of Science (AAAS)
Date: 16-10-1998
DOI: 10.1126/SCIENCE.282.5388.439
Abstract: The role of the world's forests as a “sink” for atmospheric carbon dioxide is the subject of active debate. Long-term monitoring of plots in mature humid tropical forests concentrated in South America revealed that biomass gain by tree growth exceeded losses from tree death in 38 of 50 Neotropical sites. These forest plots have accumulated 0.71 ton, plus or minus 0.34 ton, of carbon per hectare per year in recent decades. The data suggest that Neotropical forests may be a significant carbon sink, reducing the rate of increase in atmospheric carbon dioxide.
Publisher: Elsevier BV
Date: 2013
DOI: 10.1016/J.TPLANTS.2012.08.005
Abstract: Tree biomass influences biogeochemical cycles, climate, and bio ersity across local to global scales. Understanding the environmental control of tree biomass demands consideration of the drivers of in idual tree growth over their lifespan. This can be achieved by studies of tree growth in permanent s le plots (prospective studies) and tree ring analyses (retrospective studies). However, identification of growth trends and attribution of their drivers demands statistical control of the axiomatic co-variation of tree size and age, and avoiding s ling biases at the stand, forest, and regional scales. Tracking and predicting the effects of environmental change on tree biomass requires well-designed studies that address the issues that we have reviewed.
Publisher: Wiley
Date: 16-04-2018
DOI: 10.1111/ELE.12964
Publisher: Springer Science and Business Media LLC
Date: 17-01-2018
DOI: 10.1038/S41598-017-18927-1
Abstract: Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider this limitation, especially for large bio ersity assessments projects, when they are automatically generated without subsequent checking. Our pipeline provides a conservative estimate of a species’ area of occupancy, within an area slightly larger than its extent of occurrence, compatible to e.g. IUCN red list assessments.
Publisher: UN Sustainable Development Solutions Network (SDSN)
Date: 02-06-2022
DOI: 10.55161/XRVW6896
Abstract: El objetivo principal de este capítulo transversal es resumir el estado de la Amazonía como fuente o sumidero de carbono (C). Los procesos y estudios involucrados se detallan en otros capítulos del SPA.
Publisher: Springer Science and Business Media LLC
Date: 26-09-2023
Publisher: Springer Science and Business Media LLC
Date: 26-04-2023
DOI: 10.1038/S41586-023-05971-3
Abstract: Tropical forests face increasing climate risk 1,2 , yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for ex le, $$\\varPsi $$ Ψ 50 ) and hydraulic safety margins (for ex le, HSM 50 ) are important predictors of drought-induced mortality risk 3–5 , little is known about how these vary across Earth’s largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters $$\\varPsi $$ Ψ 50 and HSM 50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both $$\\varPsi $$ Ψ 50 and HSM 50 influence the biogeographical distribution of Amazon tree species. However, HSM 50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM 50 are gaining more biomass than are low HSM 50 forests. We propose that this may be associated with a growth–mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM 50 in the Amazon 6,7 , with strong implications for the Amazon carbon sink.
Publisher: Elsevier BV
Date: 06-2017
Publisher: Wiley
Date: 02-05-2023
Abstract: 1. Bio ersity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between bio ersity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall ersity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between ersity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis . Collectively, these results demonstrate that evenness is an integral component of the relationship between bio ersity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community ersity. Our research suggests that evenness is a fundamental component of bio ersity–ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions.
Publisher: Wiley
Date: 29-04-2004
Publisher: Informa UK Limited
Date: 17-09-2013
Publisher: Springer Science and Business Media LLC
Date: 09-11-2020
DOI: 10.1038/S41467-020-18996-3
Abstract: The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted—modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth–survival trade-off in driving tropical tree mortality.
Publisher: Springer Science and Business Media LLC
Date: 10-10-2019
DOI: 10.1038/S41597-019-0196-1
Abstract: Forest biomass is an essential indicator for monitoring the Earth’s ecosystems and climate. It is a critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies such as REDD+, among others. Wall-to-wall mapping of aboveground biomass (AGB) is now possible with satellite remote sensing (RS). However, RS methods require extant, up-to-date, reliable, representative and comparable in situ data for calibration and validation. Here, we present the Forest Observation System (FOS) initiative, an international cooperation to establish and maintain a global in situ forest biomass database. AGB and canopy height estimates with their associated uncertainties are derived at a 0.25 ha scale from field measurements made in permanent research plots across the world’s forests. All plot estimates are geolocated and have a size that allows for direct comparison with many RS measurements. The FOS offers the potential to improve the accuracy of RS-based biomass products while developing new synergies between the RS and ground-based ecosystem research communities.
Publisher: Springer Science and Business Media LLC
Date: 17-02-2023
DOI: 10.1038/S41598-023-28132-Y
Abstract: In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics.
Publisher: Copernicus GmbH
Date: 07-03-2022
Abstract: Abstract. The Moderate Resolution Imaging Spectroradiometer Vegetation Continuous Fields (MODIS VCF) Earth observation product is widely used to estimate forest cover changes and to parameterize vegetation and Earth system models and as a reference for validation or calibration where field data are limited. However, although limited independent validations of MODIS VCF have shown that MODIS VCF's accuracy decreases when estimating tree cover in sparsely vegetated areas such as tropical savannas, no study has yet assessed the impact this may have on the VCF-based tree cover data used by many in their research. Using tropical forest and savanna inventory data collected by the Tropical Biomes in Transition (TROBIT) project, we produce a series of calibration scenarios that take into account (i) the spatial disparity between the in situ plot size and the MODIS VCF pixel and (ii) the trees' spatial distribution within in situ plots. To identify if a disparity also exists in products trained using VCF, we used a similar approach to evaluate the finer-scale Landsat Tree Canopy Cover (TCC) product. For MODIS VCF, we then applied our calibrations to areas identified as forest or savanna in the International Geosphere-Biosphere Programme (IGBP) land cover mapping product. All IGBP classes identified as “savanna” show substantial increases in cover after calibration, indicating that the most recent version of MODIS VCF consistently underestimates woody cover in tropical savannas. We also found that these biases are propagated in the finer-scale Landsat TCC. Our scenarios suggest that MODIS VCF accuracy can vary substantially, with tree cover underestimation ranging from 0 % to 29 %. Models that use MODIS VCF as their benchmark could therefore be underestimating the carbon uptake in forest–savanna areas and misrepresenting forest–savanna dynamics. Because of the limited in situ plot number, our results are designed to be used as an indicator of where the product is potentially more or less reliable. Until more in situ data are available to produce more accurate calibrations, we recommend caution when using uncalibrated MODIS VCF data in tropical savannas.
Publisher: Copernicus GmbH
Date: 25-02-2009
Abstract: Abstract. Understanding the relationships between plant traits and ecosystem properties at large spatial scales is important for predicting how compositional change will affect carbon cycling in tropical forests. In this study, we examine the relationships between species wood density, maximum height and above-ground, coarse wood production of trees ≥10 cm diameter (CWP) for 60 Amazonian forest plots. Average species maximum height and wood density are lower in Western than Eastern Amazonia and are negatively correlated with CWP. To test the hypothesis that variation in these traits causes the variation in CWP, we generate plot-level estimates of CWP by res ling the full distribution of tree biomass growth rates whilst maintaining the appropriate tree-diameter and functional-trait distributions for each plot. These estimates are then compared with the observed values. Overall, the estimates do not predict the observed, regional-scale pattern of CWP, suggesting that the variation in community-level trait values does not determine variation in coarse wood productivity in Amazonian forests. Instead, the regional gradient in CWP is caused by higher biomass growth rates across all tree types in Western Amazonia. Therefore, the regional gradient in CWP is driven primarily by environmental factors, rather than the particular functional composition of each stand. These results contrast with previous findings for forest biomass, where variation in wood density, associated with variation in species composition, is an important driver of regional-scale patterns in above-ground biomass. Therefore, in tropical forests, above-ground wood productivity may be less sensitive than biomass to compositional change that alters community-level averages of these plant traits.
Publisher: Wiley
Date: 13-09-2022
DOI: 10.1111/ECOG.06125
Abstract: Tree ersity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well‐drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree ersity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1‐ha non‐flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha ersity, 2) the community‐weighted wood density mean (CWM‐wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree ersity depends on climate, being more evident in wetter forests, where ersity increases towards locations with well‐drained soils. CWM‐wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central‐Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the ersity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures.
Publisher: Emerald
Date: 12-03-2018
Abstract: The purpose of this paper is to examine the potential for eXtensible Business Reporting Language (XBRL) to go beyond static reporting. A taxonomy structure of information is developed for providing a knowledge base and insights for an XBRL taxonomy for integrated reporting (IR). Design Science (DS) research, as a pragmatic exploratory research approach, is embraced to create a new “artefact” and thematic content analysis is used to analyse IR in practice. Using XBRL for IR allows a shift from static and periodic reporting to more relevant and dynamic corporate disclosure for stakeholders, who can navigate and retrieve customised disclosure information according to their interest by exploiting the multidimensionality of IR and overcome some of its criticisms. The bi-dimensional taxonomy structure the authors’ present allows users to navigate disclosure from two different perspectives (content elements (CE) and capitals), display specific themes of interest, and drill down to more detailed information. Because of its evidence-based nature and levels of disaggregation, it provides flexibility to preparers and users of information. Additionally, the findings demonstrate the need to codify sector-specific information for the CE, so that to direct the efforts toward the development of sector-specific taxonomy extensions in developing an XBRL taxonomy for IR. The limitations of DS research are, first, the artefact design and, second, its effects in practice. The first limitation stems from the social actors’ perspective taken into account to develop the taxonomy structure, which derives from the analysis of the reporting practices rather than a pluralistic approach and dialogic engagement. The second limitation relates to the XBRL taxonomy development process because, since the study is limited to the “design” phase being codification and structuring the knowledge base for an XBRL taxonomy, there is a need to develop a taxonomy in XBRL and then apply it in practice to empirically demonstrate the potential and benefits of XBRL in the IR context. The taxonomy structure is targeted at entities interested in designing an XBRL taxonomy for IR. This is a call for academics and practitioners to explore the potential of technology to improve corporate disclosure and open up new projections for resurging themes on intellectual capital (IC) reporting with prospects for IC “fourth-stage” research focused on IC disclosure. This is an interdisciplinary research employing the DS approach, which is rooted in information systems research. It is the first academic study providing pragmatic results for using XBRL in the context of IC and IR.
Publisher: Springer Science and Business Media LLC
Date: 09-2023
Publisher: Elsevier BV
Date: 08-2021
Publisher: Wiley
Date: 05-05-2020
DOI: 10.1002/ECY.3052
Abstract: Competition among trees is an important driver of community structure and dynamics in tropical forests. Neighboring trees may impact an in idual tree’s growth rate and probability of mortality, but large‐scale geographic and environmental variation in these competitive effects has yet to be evaluated across the tropical forest biome. We quantified effects of competition on tree‐level basal area growth and mortality for trees ≥10‐cm diameter across 151 ~1‐ha plots in mature tropical forests in Amazonia and tropical Africa by developing nonlinear models that accounted for wood density, tree size, and neighborhood crowding. Using these models, we assessed how water availability (i.e., climatic water deficit) and soil fertility influenced the predicted plot‐level strength of competition (i.e., the extent to which growth is reduced, or mortality is increased, by competition across all in idual trees). On both continents, tree basal area growth decreased with wood density and increased with tree size. Growth decreased with neighborhood crowding, which suggests that competition is important. Tree mortality decreased with wood density and generally increased with tree size, but was apparently unaffected by neighborhood crowding. Across plots, variation in the plot‐level strength of competition was most strongly related to plot basal area (i.e., the sum of the basal area of all trees in a plot), with greater reductions in growth occurring in forests with high basal area, but in Amazonia, the strength of competition also varied with plot‐level wood density. In Amazonia, the strength of competition increased with water availability because of the greater basal area of wetter forests, but was only weakly related to soil fertility. In Africa, competition was weakly related to soil fertility and invariant across the shorter water availability gradient. Overall, our results suggest that competition influences the structure and dynamics of tropical forests primarily through effects on in idual tree growth rather than mortality and that the strength of competition largely depends on environment‐mediated variation in basal area.
Publisher: Frontiers Media SA
Date: 24-04-2020
Publisher: Springer Science and Business Media LLC
Date: 19-01-2018
DOI: 10.1038/S41467-018-02920-X
Abstract: The original version of this Article contained an error in the third sentence of the abstract and incorrectly read “Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha −1 year −1 (95% CI 0.14–0.72, mean period 1988–2010) above-ground live biomass”, rather than the correct “Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha −1 year −1 (95% CI 0.14–0.72, mean period 1988–2010) in above-ground live biomass carbon”. This has now been corrected in both the PDF and HTML versions of the Article.
Publisher: Wiley
Date: 21-04-2004
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-05-2020
Abstract: A key uncertainty in climate change models is the thermal sensitivity of tropical forests and how this value might influence carbon fluxes. Sullivan et al. measured carbon stocks and fluxes in permanent forest plots distributed globally. This synthesis of plot networks across climatic and biogeographic gradients shows that forest thermal sensitivity is dominated by high daytime temperatures. This extreme condition depresses growth rates and shortens the time that carbon resides in the ecosystem by killing trees under hot, dry conditions. The effect of temperature is worse above 32°C, and a greater magnitude of climate change thus risks greater loss of tropical forest carbon stocks. Nevertheless, forest carbon stocks are likely to remain higher under moderate climate change if they are protected from direct impacts such as clearance, logging, or fires. Science , this issue p. 869
Publisher: Wiley
Date: 05-08-0008
DOI: 10.1111/NPH.13253
Abstract: Leaf dark respiration ( R dark ) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of R dark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed‐effects models were used to disentangle sources of variation in R dark . Area‐based R dark at the prevailing average daily growth temperature ( T ) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8–28°C). By contrast, R dark at a standard T (25°C, R dark 25 ) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher R dark 25 at a given photosynthetic capacity ( V cmax 25 ) or leaf nitrogen concentration ([N]) than species at warmer sites. R dark 25 values at any given V cmax 25 or [N] were higher in herbs than in woody plants. The results highlight variation in R dark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of R dark in terrestrial biosphere models (TBMs) and associated land‐surface components of Earth system models (ESMs).
Publisher: Wiley
Date: 31-12-2019
DOI: 10.1111/GCB.14904
Abstract: Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to bio ersity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on in idual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
Publisher: Copernicus GmbH
Date: 21-05-2015
Publisher: Oxford University PressOxford
Date: 30-06-2007
DOI: 10.1093/ACPROF:OSO/9780198567066.003.0010
Abstract: Previous work found that tree turnover, biomass, and large liana densities increased in mature tropical forests in the late 20th century, indicating a concerted shift in forest ecological processes. However, the findings have proved controversial. Here, regional-scale patterns of tree turnover are characterized, using improved datasets available for Amazonia that span the last twenty-five years. The main findings include: trees at least 10 cm in diameter recruit and die twice as fast on the richer soils of western Amazonia compared to trees on the poorer soils of eastern Amazonia turnover rates have increased throughout Amazonia over the last two decades mortality and recruitment rates have tended to increase in every region and environmental zone recruitment rates consistently exceed mortality rates and increases in recruitment and mortality rates are greatest in western Amazonia. These patterns and trends are not caused by obvious artefacts in the data or the analyses, and cannot be directly driven by a mortality driver such as increased drought because the biomass in these forests has simultaneously increased. Apparently, therefore, widespread environmental changes are stimulating the growth and productivity of Amazon forests.
Publisher: Oxford University PressOxford
Date: 30-06-2007
DOI: 10.1093/ACPROF:OSO/9780198567066.003.0011
Abstract: This chapter discusses a previous study by Phillips et al. (1998) on biomass changes in Amazonian permanent s le plots which has been used to infer the presence of a regional carbon sink, generating vigorous debate about s ling and methodological issues. A new analysis of biomass change in old-growth Amazonian forest plots is presented here using new inventory data. It has been found that across fifty-nine sites, the above-ground dry biomass in trees of more than 10 cm in diameter has increased since plot establishment by about 1.22 Mg per hectare per year, or about 0.98 Mg per hectare per year if in idual plot values are weighted by the number of hectare years of monitoring. This significant increase is not confounded by spatial or temporal variation in wood specific gravity, nor does it depend on the allometric equation used to estimate biomass. Overall, these results suggest a slightly greater rate of net stand-level change than reported in 1998, and indicate the presence of a significant regional-scale carbon sink in old-growth Amazonian forests during the past two decades.
Publisher: Wiley
Date: 10-10-2018
DOI: 10.1111/GEB.12803
Abstract: Large tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and field inventories. To close this gap, we propose a new pan‐tropical model to predict plot‐level forest structure properties and biomass from only the largest trees. Pan‐tropical. Early 21st century. Woody plants. Using a dataset of 867 plots distributed among 118 sites across the tropics, we tested the prediction of the quadratic mean diameter, basal area, Lorey's height, community wood density and aboveground biomass (AGB) from the i th largest trees. Measuring the largest trees in tropical forests enables unbiased predictions of plot‐ and site‐level forest structure. The 20 largest trees per hectare predicted quadratic mean diameter, basal area, Lorey's height, community wood density and AGB with 12, 16, 4, 4 and 17.7% of relative error, respectively. Most of the remaining error in biomass prediction is driven by differences in the proportion of total biomass held in medium‐sized trees (50–70 cm diameter at breast height), which shows some continental dependency, with American tropical forests presenting the highest proportion of total biomass in these intermediate‐diameter classes relative to other continents. Our approach provides new information on tropical forest structure and can be used to generate accurate field estimates of tropical forest carbon stocks to support the calibration and validation of current and forthcoming space missions. It will reduce the cost of field inventories and contribute to scientific understanding of tropical forest ecosystems and response to climate change.
Publisher: Springer Science and Business Media LLC
Date: 05-2019
DOI: 10.1038/S41586-019-1128-0
Abstract: The identity of the dominant root-associated microbial symbionts in a forest determines the ability of trees to access limiting nutrients from atmospheric or soil pools
Publisher: Springer Science and Business Media LLC
Date: 18-05-2022
DOI: 10.1038/S41586-022-04737-7
Abstract: Evidence exists that tree mortality is accelerating in some regions of the tropics
Publisher: Wiley
Date: 24-09-2023
DOI: 10.1111/NPH.19276
Publisher: Elsevier BV
Date: 03-2022
Publisher: Cold Spring Harbor Laboratory
Date: 04-2021
DOI: 10.1101/2021.03.31.437717
Abstract: In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics.
Publisher: Wiley
Date: 03-2019
DOI: 10.1111/JVS.12710
Publisher: Elsevier BV
Date: 03-2021
Publisher: American Association for the Advancement of Science (AAAS)
Date: 06-10-2023
Publisher: Springer Science and Business Media LLC
Date: 28-04-2015
DOI: 10.1038/NCOMMS7857
Abstract: While Amazonian forests are extraordinarily erse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant’ species. In addition to their ersity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region.
Publisher: Wiley
Date: 08-07-2020
DOI: 10.1111/GEB.13123
Publisher: Wiley
Date: 28-11-2021
DOI: 10.1111/GCB.15982
Abstract: A better understanding of how climate affects growth in tree species is essential for improved predictions of forest dynamics under climate change. Long‐term climate averages (mean climate) drive spatial variations in species’ baseline growth rates, whereas deviations from these averages over time (anomalies) can create growth variation around the local baseline. However, the rarity of long‐term tree census data spanning climatic gradients has so far limited our understanding of their respective role, especially in tropical systems. Furthermore, tree growth sensitivity to climate is likely to vary widely among species, and the ecological strategies underlying these differences remain poorly understood. Here, we utilize an exceptional dataset of 49 years of growth data for 509 tree species across 23 tropical rainforest plots along a climatic gradient to examine how multiannual tree growth responds to both climate means and anomalies, and how species’ functional traits mediate these growth responses to climate. We show that anomalous increases in atmospheric evaporative demand and solar radiation consistently reduced tree growth. Drier forests and fast‐growing species were more sensitive to water stress anomalies. In addition, species traits related to water use and photosynthesis partly explained differences in growth sensitivity to both climate means and anomalies. Our study demonstrates that both climate means and anomalies shape tree growth in tropical forests and that species traits can provide insights into understanding these demographic responses to climate change, offering a promising way forward to forecast tropical forest dynamics under different climate trajectories.
Publisher: Springer Science and Business Media LLC
Date: 23-10-2023
Publisher: Wiley
Date: 04-03-2019
DOI: 10.1111/ELE.13243
Abstract: Climatic changes have profound effects on the distribution of bio ersity, but untangling the links between climatic change and ecosystem functioning is challenging, particularly in high ersity systems such as tropical forests. Tropical forests may also show different responses to a changing climate, with baseline climatic conditions potentially inducing differences in the strength and timing of responses to droughts. Trait-based approaches provide an opportunity to link functional composition, ecosystem function and environmental changes. We demonstrate the power of such approaches by presenting a novel analysis of long-term responses of different tropical forest to climatic changes along a rainfall gradient. We explore how key ecosystem's biogeochemical properties have shifted over time as a consequence of multi-decadal drying. Notably, we find that drier tropical forests have increased their deciduous species abundance and generally changed more functionally than forests growing in wetter conditions, suggesting an enhanced ability to adapt ecologically to a drying environment.
Publisher: Wiley
Date: 08-11-2018
DOI: 10.1111/GCB.14413
Publisher: Springer Science and Business Media LLC
Date: 31-08-2025
DOI: 10.1038/S41467-017-01997-0
Abstract: Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha −1 per year (95% CI 0.14–0.72, mean period 1988–2010) in above-ground live biomass carbon. These results closely match those from African and Amazonian plot networks, suggesting that the world’s remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997–1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere.
Publisher: Springer Science and Business Media LLC
Date: 23-08-2023
DOI: 10.1038/S41586-023-06440-7
Abstract: Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species 1,2 . Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies 3,4 . Here, leveraging global tree databases 5–7 , we explore how the phylogenetic and functional ersity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native ersity, with higher ersity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional ersity have a critical role in the establishment and spread of subsequent invasions.
Publisher: The Royal Society
Date: 29-03-2004
Abstract: Previous work has shown that tree turnover, tree biomass and large liana densities have increased in mature tropical forest plots in the late twentieth century. These results point to a concerted shift in forest ecological processes that may already be having significant impacts on terrestrial carbon stocks, fluxes and bio ersity. However, the findings have proved controversial, partly because a rather limited number of permanent plots have been monitored for rather short periods. The aim of this paper is to characterize regional–scale patterns of ‘tree turnover’ (the rate with which trees die and recruit into a population) by using improved datasets now available for Amazonia that span the past 25 years. Specifically, we assess whether concerted changes in turnover are occurring, and if so whether they are general throughout the Amazon or restricted to one region or environmental zone. In addition, we ask whether they are driven by changes in recruitment, mortality or both. We find that: (i) trees 10 cm or more in diameter recruit and die twice as fast on the richer soils of southern and western Amazonia than on the poorer soils of eastern and central Amazonia (ii) turnover rates have increased throughout Amazonia over the past two decades (iii) mortality and recruitment rates have both increased significantly in every region and environmental zone, with the exception of mortality in eastern Amazonia (iv) recruitment rates have consistently exceeded mortality rates (v) absolute increases in recruitment and mortality rates are greatest in western Amazonian sites and (vi) mortality appears to be lagging recruitment at regional scales. These spatial patterns and temporal trends are not caused by obvious artefacts in the data or the analyses. The trends cannot be directly driven by a mortality driver (such as increased drought or fragmentation–related death) because the biomass in these forests has simultaneously increased. Our findings therefore indicate that long–acting and widespread environmental changes are stimulating the growth and productivity of Amazon forests.
Publisher: Copernicus GmbH
Date: 10-08-2009
Abstract: Abstract. Leaf size influences many aspects of tree function such as rates of transpiration and photosynthesis and, consequently, often varies in a predictable way in response to environmental gradients. The recent development of pan-Amazonian databases based on permanent botanical plots has now made it possible to assess trends in leaf size across environmental gradients in Amazonia. Previous plot-based studies have shown that the community structure of Amazonian trees breaks down into at least two major ecological gradients corresponding with variations in soil fertility (decreasing from southwest to northeast) and length of the dry season (increasing from northwest to south and east). Here we describe the geographic distribution of leaf size categories based on 121 plots distributed across eight South American countries. We find that the Amazon forest is predominantly populated by tree species and in iduals in the mesophyll size class (20.25–182.25 cm2). The geographic distribution of species and in iduals with large leaves ( .25 cm2) is complex but is generally characterized by a higher proportion of such trees in the northwest of the region. Spatially corrected regressions reveal weak correlations between the proportion of large-leaved species and metrics of water availability. We also find a significant negative relationship between leaf size and wood density.
Publisher: Springer Science and Business Media LLC
Date: 16-05-2022
DOI: 10.1038/S41559-022-01747-6
Abstract: Tropical forests are some of the most bio erse ecosystems in the world, yet their functioning is threatened by anthropogenic disturbances and climate change. Global actions to conserve tropical forests could be enhanced by having local knowledge on the forests' functional ersity and functional redundancy as proxies for their capacity to respond to global environmental change. Here we create estimates of plant functional ersity and redundancy across the tropics by combining a dataset of 16 morphological, chemical and photosynthetic plant traits s led from 2,461 in idual trees from 74 sites distributed across four continents together with local climate data for the past half century. Our findings suggest a strong link between climate and functional ersity and redundancy with the three trait groups responding similarly across the tropics and climate gradient. We show that drier tropical forests are overall less functionally erse than wetter forests and that functional redundancy declines with increasing soil water and vapour pressure deficits. Areas with high functional ersity and high functional redundancy tend to better maintain ecosystem functioning, such as aboveground biomass, after extreme weather events. Our predictions suggest that the lower functional ersity and lower functional redundancy of drier tropical forests, in comparison with wetter forests, may leave them more at risk of shifting towards alternative states in face of further declines in water availability across tropical regions.
Publisher: Springer Science and Business Media LLC
Date: 23-06-2020
DOI: 10.1038/S41598-020-66686-3
Abstract: Amazonian forests are extraordinarily erse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated in iduals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete s le of all tree species, rigorous field c aigns may be needed but the number of trees in Amazonia will remain an estimate for years to come.
Publisher: Copernicus GmbH
Date: 22-06-2018
Abstract: Abstract. Borneo contains some of the world's most bio erse and carbon-dense tropical forest, but this 750 000 km2 island has lost 62 % of its old-growth forests within the last 40 years. Efforts to protect and restore the remaining forests of Borneo hinge on recognizing the ecosystem services they provide, including their ability to store and sequester carbon. Airborne laser scanning (ALS) is a remote sensing technology that allows forest structural properties to be captured in great detail across vast geographic areas. In recent years ALS has been integrated into statewide assessments of forest carbon in Neotropical and African regions, but not yet in Asia. For this to happen new regional models need to be developed for estimating carbon stocks from ALS in tropical Asia, as the forests of this region are structurally and compositionally distinct from those found elsewhere in the tropics. By combining ALS imagery with data from 173 permanent forest plots spanning the lowland rainforests of Sabah on the island of Borneo, we develop a simple yet general model for estimating forest carbon stocks using ALS-derived canopy height and canopy cover as input metrics. An advanced feature of this new model is the propagation of uncertainty in both ALS- and ground-based data, allowing uncertainty in hectare-scale estimates of carbon stocks to be quantified robustly. We show that the model effectively captures variation in aboveground carbon stocks across extreme disturbance gradients spanning tall dipterocarp forests and heavily logged regions and clearly outperforms existing ALS-based models calibrated for the tropics, as well as currently available satellite-derived products. Our model provides a simple, generalized and effective approach for mapping forest carbon stocks in Borneo and underpins ongoing efforts to safeguard and facilitate the restoration of its unique tropical forests.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-10-2013
Abstract: Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record ersity of these forests have h ered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots s ling all major lowland forest types to explore patterns of commonness, rarity, and richness. The ~6-million-km 2 Amazonian lowlands were ided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify s ling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting the mean rank-abundance data to Fisher’s log-series distribution. Our analyses suggest that lowland Amazonia harbors 3.9 × 10 11 trees and ~16,000 tree species. We found 227 “hyperdominant” species (1.4% of the total) to be so common that together they account for half of all trees in Amazonia, whereas the rarest 11,000 species account for just 0.12% of trees. Most hyperdominants are habitat specialists that have large geographic ranges but are only dominant in one or two regions of the basin, and a median of 41% of trees in in idual plots belong to hyperdominants. A disproportionate number of hyperdominants are palms, Myristicaceae, and Lecythidaceae. The finding that Amazonia is dominated by just 227 tree species implies that most biogeochemical cycling in the world’s largest tropical forest is performed by a tiny sliver of its ersity. The causes underlying hyperdominance in these species remain unknown. Both competitive superiority and widespread pre-1492 cultivation by humans are compelling hypotheses that deserve testing. Although the data suggest that spatial models can effectively forecast tree community composition and structure of unstudied sites in Amazonia, incorporating environmental data may yield substantial improvements. An appreciation of how thoroughly common species dominate the basin has the potential to simplify research in Amazonian biogeochemistry, ecology, and vegetation mapping. Such advances are urgently needed in light of the ,000 rare, poorly known, and potentially threatened tree species in the Amazon.
Publisher: Springer Science and Business Media LLC
Date: 03-2015
DOI: 10.1038/NATURE14283
Abstract: Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink erges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.
Publisher: Wiley
Date: 08-07-2016
DOI: 10.1111/NPH.14079
Abstract: We examined whether variations in photosynthetic capacity are linked to variations in the environment and/or associated leaf traits for tropical moist forests ( TMF s) in the Andes/western Amazon regions of Peru. We compared photosynthetic capacity (maximal rate of carboxylation of Rubisco ( V cmax ), and the maximum rate of electron transport ( J max )), leaf mass, nitrogen (N) and phosphorus (P) per unit leaf area ( M a , N a and P a , respectively), and chlorophyll from 210 species at 18 field sites along a 3300‐m elevation gradient. Western blots were used to quantify the abundance of the CO 2 ‐fixing enzyme Rubisco. Area‐ and N‐based rates of photosynthetic capacity at 25°C were higher in upland than lowland TMF s, underpinned by greater investment of N in photosynthesis in high‐elevation trees. Soil [P] and leaf P a were key explanatory factors for models of area‐based V cmax and J max but did not account for variations in photosynthetic N‐use efficiency. At any given N a and P a , the fraction of N allocated to photosynthesis was higher in upland than lowland species. For a small subset of lowland TMF trees examined, a substantial fraction of Rubisco was inactive. These results highlight the importance of soil‐ and leaf‐P in defining the photosynthetic capacity of TMF s, with variations in N allocation and Rubisco activation state further influencing photosynthetic rates and N‐use efficiency of these critically important forests.
Publisher: Copernicus GmbH
Date: 10-08-2009
Abstract: Abstract. Leaves in tropical forests come in an enormous variety of sizes and shapes, each of which can be ultimately viewed as an adaptation to the complex problem of optimising the capture of light for photosynthesis. However, the fact that many different shape "strategies" coexist within a habitat demonstrate that there are many other intrinsic and extrinsic factors involved, such as the differential investment in support tissues required for different leaf lamina shapes. Here, we take a macrogeographic approach to understanding the function of different lamina shape categories. Specifically, we use 106 permanent plots spread across the Amazon rainforest basin to: 1) describe the geographic distribution of some simple metrics of lamina shape in plots from across Amazonia, and 2) identify and quantify relationships between key environmental parameters and lamina shape in tropical forests. Because the plots are not randomly distributed across the study area, achieving this latter objective requires the use of statistics that can account for spatial auto-correlation. We found that between 60–70% of the 2791 species and 83 908 in idual trees in the dataset could be classified as having elliptic leaves (= the widest part of the leaf is on an axis in the middle fifth of the long axis of the leaf). Furthermore, the average Amazonian tree leaf is 2.5 times longer than it is wide and has an entire margin. Contrary to theoretical expectations we found little support for the hypothesis that narrow leaves are an adaptation to dry conditions. However, we did find strong regional patterns in leaf lamina length-width ratios and several significant correlations with precipitation variables suggesting that water availability may be exerting an as yet unrecognised selective pressure on leaf shape of rainforest trees. Some support was found for the hypothesis that narrow leaves are an adaptation to low nutrient soils. Furthermore, we found a strong correlation between the proportion of trees with non-entire laminas (dissected, toothed, etc.) and mean annual temperature once again supporting the well documented association that provides a basis for reconstructing past temperature regimes.
Publisher: Wiley
Date: 26-07-2019
DOI: 10.1111/ELE.13357
Publisher: Springer Science and Business Media LLC
Date: 28-06-2019
DOI: 10.1038/S41586-019-1342-9
Abstract: In this Letter, a middle initial and additional affiliation have been added for author G. J. Nabuurs two statements have been added to the Supplementary Acknowledgements and a citation to the French National Institute has been added to the Methods see accompanying Author Correction for further details.
Publisher: Proceedings of the National Academy of Sciences
Date: 23-03-2022
Publisher: Wiley
Date: 04-2002
Publisher: Springer Science and Business Media LLC
Date: 04-01-2021
DOI: 10.1038/S41467-020-20537-X
Abstract: A Correction to this paper has been published: 0.1038/s41467-020-20537-x
Publisher: Cold Spring Harbor Laboratory
Date: 09-06-2021
DOI: 10.1101/2021.06.08.447571
Abstract: A better understanding of how climate affects growth in tree species is essential for improved predictions of forest dynamics under climate change. Long-term climate averages (mean climate) and short-term deviations from these averages (anomalies) both influence tree growth, but the rarity of long-term data integrating climatic gradients with tree censuses has so far limited our understanding of their respective role, especially in tropical systems. Here, we combined 49 years of growth data for 509 tree species across 23 tropical rainforest plots along a climatic gradient to examine how tree growth responds to both climate means and anomalies, and how species functional traits mediate these tree growth responses to climate. We showed that short-term, anomalous increases in atmospheric evaporative demand and solar radiation consistently reduced tree growth. Drier forests and fast-growing species were more sensitive to water stress anomalies. In addition, species traits related to water use and photosynthesis partly explained differences in growth sensitivity to both long-term and short-term climate variations. Our study demonstrates that both climate means and anomalies shape tree growth in tropical forests, and that species traits can be leveraged to understand these demographic responses to climate change, offering a promising way forward to forecast tropical forest dynamics under different climate trajectories.
Publisher: Wiley
Date: 11-11-2011
Publisher: Routledge
Date: 16-10-2015
Publisher: Wiley
Date: 12-12-2020
DOI: 10.1111/GEB.13231
Publisher: Springer Science and Business Media LLC
Date: 08-2017
Publisher: Wiley
Date: 24-10-2022
DOI: 10.1111/GEB.13596
Abstract: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser‐availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource‐availability hypothesis). Tree‐inventory plots established between 1934 and 2019. Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree‐inventory plots across terra‐firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance‐weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra‐firme forests (excluding podzols) compared to flooded forests. The disperser‐availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types.
Publisher: UN Sustainable Development Solutions Network (SDSN)
Date: 12-11-2021
DOI: 10.55161/VNBV7494
Abstract: The main objective of this cross-chapter is to summarize the status of the Amazon as a source or sink of carbon (C). The processes and studies involved are detailed in other SPA chapters. The major challenge of determining the Amazon’s status as a net C source or sink at a continental scale is that many complex processes contribute to C fluxes. Unlike in other regions, emissions from the burning of fossil fuels are minor contributors to Amazonian fluxes. Instead, the major sinks and sources of C to the atmosphere are associated with the net accumulation or loss of biomass, with losses including deforestation, biomass burning, and tree mortality followed by decomposition. Biomass accumulates in areas where tree growth exceeds losses. The Amazon includes not only intact forests, also but degraded and logged forests, natural non-forests, agricultural and urban areas, and aquatic systems including wetlands that all contribute to regional carbon cycling.
Publisher: The Royal Society
Date: 29-03-2004
Abstract: A previous study by Phillips et al . of changes in the biomass of permanent s le plots in Amazonian forests was used to infer the presence of a regional carbon sink. However, these results generated a vigorous debate about s ling and methodological issues. Therefore we present a new analysis of biomass change in old–growth Amazonian forest plots using updated inventory data. We find that across 59 sites, the above–ground dry biomass in trees that are more than 10 cm in diameter (AGB) has increased since plot establishment by 1.22 ± 0.43 Mg per hectare per year (ha −1 yr −1 ), where 1 ha = 10 4 m 2 ), or 0.98 ± 0.38 Mg ha −1 yr −1 if in idual plot values are weighted by the number of hectare years of monitoring. This significant increase is neither confounded by spatial or temporal variation in wood specific gravity, nor dependent on the allometric equation used to estimate AGB. The conclusion is also robust to uncertainty about diameter measurements for problematic trees: for 34 plots in western Amazon forests a significant increase in AGB is found even with a conservative assumption of zero growth for all trees where diameter measurements were made using optical methods and/or growth rates needed to be estimated following fieldwork. Overall, our results suggest a slightly greater rate of net stand–level change than was reported by Phillips et al . Considering the spatial and temporal scale of s ling and associated studies showing increases in forest growth and stem turnover, the results presented here suggest that the total biomass of these plots has on average increased and that there has been a regional–scale carbon sink in old–growth Amazonian forests during the previous two decades.
Publisher: Wiley
Date: 27-07-2020
DOI: 10.1111/GEB.13158
Publisher: Wiley
Date: 30-06-2023
DOI: 10.1111/GCB.16821
Abstract: For more than three decades, major efforts in s ling and analyzing tree ersity in South America have focused almost exclusively on trees with stems of at least 10 and 2.5 cm diameter, showing highest species ersity in the wetter western and northern Amazon forests. By contrast, little attention has been paid to patterns and drivers of ersity in the largest canopy and emergent trees, which is surprising given these have dominant ecological functions. Here, we use a machine learning approach to quantify the importance of environmental factors and apply it to generate spatial predictions of the species ersity of all trees (dbh ≥ 10 cm) and for very large trees (dbh ≥ 70 cm) using data from 243 forest plots (108,450 trees and 2832 species) distributed across different forest types and biogeographic regions of the Brazilian Amazon. The ersity of large trees and of all trees was significantly associated with three environmental factors, but in contrasting ways across regions and forest types. Environmental variables associated with disturbances, for ex le, the lightning flash rate and wind speed, as well as the fraction of photosynthetically active radiation, tend to govern the ersity of large trees. Upland rainforests in the Guiana Shield and Roraima regions had a high ersity of large trees. By contrast, variables associated with resources tend to govern tree ersity in general. Places such as the province of Imeri and the northern portion of the province of Madeira stand out for their high ersity of species in general. Climatic and topographic stability and functional adaptation mechanisms promote ideal conditions for species ersity. Finally, we mapped general patterns of tree species ersity in the Brazilian Amazon, which differ substantially depending on size class.
Publisher: Informa UK Limited
Date: 14-03-2014
Publisher: American Geophysical Union (AGU)
Date: 09-06-2015
DOI: 10.1002/2015GL063719
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 07-2004
DOI: 10.1038/NATURE02719
Publisher: Wiley
Date: 22-05-2006
Publisher: Wiley
Date: 02-05-2017
DOI: 10.1111/ELE.12771
Abstract: One of the major challenges in ecology is to understand how ecosystems respond to changes in environmental conditions, and how taxonomic and functional ersity mediate these changes. In this study, we use a trait-spectra and in idual-based model, to analyse variation in forest primary productivity along a 3.3 km elevation gradient in the Amazon-Andes. The model accurately predicted the magnitude and trends in forest productivity with elevation, with solar radiation and plant functional traits (leaf dry mass per area, leaf nitrogen and phosphorus concentration, and wood density) collectively accounting for productivity variation. Remarkably, explicit representation of temperature variation with elevation was not required to achieve accurate predictions of forest productivity, as trait variation driven by species turnover appears to capture the effect of temperature. Our semi-mechanistic model suggests that spatial variation in traits can potentially be used to estimate spatial variation in productivity at the landscape scale.
Publisher: Springer Science and Business Media LLC
Date: 11-11-2019
DOI: 10.1038/S41559-019-1007-Y
Abstract: Higher levels of taxonomic and evolutionary ersity are expected to maximize ecosystem function, yet their relative importance in driving variation in ecosystem function at large scales in erse forests is unknown. Using 90 inventory plots across intact, lowland, terra firme, Amazonian forests and a new phylogeny including 526 angiosperm genera, we investigated the association between taxonomic and evolutionary metrics of ersity and two key measures of ecosystem function: aboveground wood productivity and biomass storage. While taxonomic and phylogenetic ersity were not important predictors of variation in biomass, both emerged as independent predictors of wood productivity. Amazon forests that contain greater evolutionary ersity and a higher proportion of rare species have higher productivity. While climatic and edaphic variables are together the strongest predictors of productivity, our results show that the evolutionary ersity of tree species in erse forest stands also influences productivity. As our models accounted for wood density and tree size, they also suggest that additional, unstudied, evolutionarily correlated traits have significant effects on ecosystem function in tropical forests. Overall, our pan-Amazonian analysis shows that greater phylogenetic ersity translates into higher levels of ecosystem function: tropical forest communities with more distantly related taxa have greater wood productivity.
Publisher: Wiley
Date: 28-03-2008
Publisher: Informa UK Limited
Date: 02-10-2012
Publisher: Springer Science and Business Media LLC
Date: 08-08-2022
DOI: 10.1038/S41559-022-01831-X
Abstract: The latitudinal ersity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with in idual tree information and local biophysical characteristics from ~1.3 million s le plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of bio ersity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers.
Publisher: Springer Science and Business Media LLC
Date: 25-08-2021
DOI: 10.1038/S41586-021-03728-4
Abstract: Tropical forests store 40-50 per cent of terrestrial vegetation carbon
Publisher: Wiley
Date: 09-05-2016
DOI: 10.1111/NPH.13992
Abstract: Leaf dark respiration ( R dark ) represents an important component controlling the carbon balance in tropical forests. Here, we test how nitrogen (N) and phosphorus (P) affect R dark and its relationship with photosynthesis using three widely separated tropical forests which differ in soil fertility. R dark was measured on 431 rainforest canopy trees, from 182 species, in French Guiana, Peru and Australia. The variation in R dark was examined in relation to leaf N and P content, leaf structure and maximum photosynthetic rates at ambient and saturating atmospheric CO 2 concentration. We found that the site with the lowest fertility (French Guiana) exhibited greater rates of R dark per unit leaf N, P and photosynthesis. The data from Australia, for which there were no phylogenetic overlaps with the s les from the South American sites, yielded the most distinct relationships of R dark with the measured leaf traits. Our data indicate that no single universal scaling relationship accounts for variation in R dark across this large biogeographical space. Variability between sites in the absolute rates of R dark and the R dark : photosynthesis ratio were driven by variations in N‐ and P‐use efficiency, which were related to both taxonomic and environmental variability.
Publisher: The Royal Society
Date: 08-10-2018
Abstract: Meteorological extreme events such as El Niño events are expected to affect tropical forest net primary production (NPP) and woody growth, but there has been no large-scale empirical validation of this expectation. We collected a large high–temporal resolution dataset (for 1–13 years depending upon location) of more than 172 000 stem growth measurements using dendrometer bands from across 14 regions spanning Amazonia, Africa and Borneo in order to test how much month-to-month variation in stand-level woody growth of adult tree stems (NPP stem ) can be explained by seasonal variation and interannual meteorological anomalies. A key finding is that woody growth responds differently to meteorological variation between tropical forests with a dry season (where monthly rainfall is less than 100 mm), and aseasonal wet forests lacking a consistent dry season. In seasonal tropical forests, a high degree of variation in woody growth can be predicted from seasonal variation in temperature, vapour pressure deficit, in addition to anomalies of soil water deficit and shortwave radiation. The variation of aseasonal wet forest woody growth is best predicted by the anomalies of vapour pressure deficit, water deficit and shortwave radiation. In total, we predict the total live woody production of the global tropical forest biome to be 2.16 Pg C yr −1 , with an interannual range 1.96–2.26 Pg C yr −1 between 1996–2016, and with the sharpest declines during the strong El Niño events of 1997/8 and 2015/6. There is high geographical variation in hotspots of El Niño–associated impacts, with weak impacts in Africa, and strongly negative impacts in parts of Southeast Asia and extensive regions across central and eastern Amazonia. Overall, there is high correlation ( r = −0.75) between the annual anomaly of tropical forest woody growth and the annual mean of the El Niño 3.4 index, driven mainly by strong correlations with anomalies of soil water deficit, vapour pressure deficit and shortwave radiation. This article is part of the discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Oliver Phillips.