27 results on '"Phillips, Oliver L."'
Search Results
2. Large Lianas as Hyperdynamic Elements of the Tropical Forest Canopy
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Phillips, Oliver L., Martínez, Rodolfo Vásquez, Mendoza, Abel Monteagudo, Baker, Timothy R., and Vargas, Percy Núñez
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- 2005
3. Recent Changes in Amazon Forest Biomass and Dynamics
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Phillips, Oliver L., Lewis, Simon L., Higuchi, Niro, Baker, Tim, Caldwell, Martyn M., Series editor, Díaz, Sandra, Series editor, Heldmaier, Gerhard, Series editor, Jackson, Robert B., Series editor, Lange, Otto L., Series editor, Levia, Delphis F., Series editor, Mooney, Harold A., Series editor, Schulze, Ernst-Detlef, Series editor, Sommer, Ulrich, Series editor, Nagy, Laszlo, editor, Forsberg, Bruce R., editor, and Artaxo, Paulo, editor
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- 2016
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4. Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology
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Pos, Edwin, de Souza Coelho, Luiz, de Andrade Lima Filho, Diogenes, Salomão, Rafael P., Leão Amaral, Iêda, deAlmeida Matos, Francisca Dionízia, Castilho, CarolinaV., Phillips, Oliver L., Guevara, Juan Ernesto, Veiga Carim, Marcelo de Jesus, Cárdenas López, Dairon, Magnusson, William E., Wittmann, Florian, Irume, Mariana Victória, Pires Martins, Maria, Sabatier, Daniel, da Silva Guimarães, José Renan, Molino, Jean François, Monteagudo Mendoza, Abel, and Peñuela Mora, María Cristina
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Amazónicos ,Tropical forest ,Ecology ,Entropy ,Amazon tree - Abstract
Drivers of species distributions and their predictions have been a long-standing search in ecology, with approaches varying from deterministic to neutral (i.e. stochastic) and almost everything in between (e.g. near neutral, continuum or emergent-neutral1,2 ). Most models are based on prior assumptions of processes that drive community dynamics. Te Maximum Entropy Formalism (hereafer called MEF) makes no such, potentially unjustifed, a-priori assumptions in generating predictions of species abundance distributions, as such it is a use ful construct to infer processes driving community dynamics given the constraints imposed by prior knowledge (e.g. functional traits or summed regional abundances)3 . Quantifying the relative importance of these distinct constraints can thus provide additional answers to understand the complexity of community dynamics (see Supporting Materials SM: boxes S1–S3). Tis is especially so because, although many diferent tests are available that link variation in taxon abundances to (1) trait variation, (2) taxon turnover between habitats or environ ments and (3) the distance decay of similarities between samples, none quantify the importance of these relative to each other. Te MEF as applied here, however, is capable of and designed to do exactly this by decomposing variation to separate information explained by each of these aspects in a four-step model (Fig. 1 and Box S2). Its application to an unprecedented large tree inventory database on genus level taxonomy consisting of>2,000 1-ha plots distributed over Amazonia4 and a genus trait database of 13 key functional traits representing global axes of plant strategies5 allows us to advance the study of Amazonian tree community dynamics from a new cross-disciplinary perspective.
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- 2023
5. Forest Fire History in Amazonia Inferred From Intensive Soil Charcoal Sampling and Radiocarbon Dating
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Feldpausch, Ted R., Carvalho, Lidiany, Macario, Kita D., Ascough, Philippa L., Flores, César F., Honorio Coronado, Eurídice N., Kalamandeen, Michelle, Phillips, Oliver L., Staff, Richard A., and University of St Andrews. School of Geography & Sustainable Development
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Global and Planetary Change ,GB ,Ecology ,Holocene ,NDAS ,Pre-Columbian ,Forestry ,Environmental Science (miscellaneous) ,Terra firme ,Radiocarbon ,Tropical forest ,GB Physical geography ,SDG 13 - Climate Action ,Charcoal samples ,Fire soil ,Nature and Landscape Conservation ,SDG 15 - Life on Land - Abstract
This study was supported by funding from the UK Natural Environment Research Council (NERC, NE/N011570/1 and NE/R017980/1) and a radiocarbon dating allocation (allocation 2122.0818) from the NERC-funded NEIF Radiocarbon Laboratory. Fire has a historical role in tropical forests related to past climate and ancient land use spanning the Holocene; however, it is unclear from charcoal records how fire varied at different spatiotemporal scales and what sampling strategies are required to determine fire history and their effects. We evaluated fire variation in structurally intact, terra-firme Amazon forests, by intensive soil charcoal sampling from three replicate soil pits in sites in Guyana and northern and southern Peru. We used radiocarbon (14C) measurement to assess (1) locally, how the timing of fires represented in our sample varied across the surface of forest plots and with soil depth, (2) basin-wide, how the age of fires varies across climate and environmental gradients, and (3) how many samples are appropriate when applying the 14C approach to assess the date of last fire. Considering all 14C dates (n = 33), the most recent fires occurred at a similar time at each of the three sites (median ages: 728–851 cal years BP), indicating that in terms of fire disturbance at least, these forests could be considered old-growth. The number of unique fire events ranged from 1 to 4 per pit and from 4 to 6 per site. Based upon our sampling strategy, the N-Peru site—with the highest annual precipitation—had the most fire events. Median fire return intervals varied from 455 to 2,950 cal years BP among sites. Based on available dates, at least three samples (1 from the top of each of 3 pits) are required for the sampling to have a reasonable likelihood of capturing the most recent fire for forests with no history of a recent fire. The maximum fire return interval for two sites was shorter than the time since the last fire, suggesting that over the past ∼800 years these forests have undergone a longer fire-free period than the past 2,000–3,500 years. Our analysis from terra-firme forest soils helps to improve understanding of changes in fire regime, information necessary to evaluate post-fire legacies on modern vegetation and soil and to calibrate models to predict forest response to fire under climate change. Publisher PDF
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- 2022
6. Contrasting Patterns of Diameter and Biomass Increment across Tree Functional Groups in Amazonian Forests
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Keeling, Helen C., Baker, Timothy R., Martinez, Rodolfo Vasquez, Monteagudo, Abel, and Phillips, Oliver L.
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- 2008
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7. Low Stocks of Coarse Woody Debris in a Southwest Amazonian Forest
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Baker, Timothy R., Coronado, Eurídice N. Honorio, Phillips, Oliver L., Martin, Jim, van der Heijden, Geertje M. F., Garcia, Michael, and Espejo, Javier Silva
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- 2007
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8. Leaf traits from stomata to morphology are associated with climatic and edaphic variables for dominant tropical forest evergreen oaks.
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Lin, Yutong, Kuang, Luhui, Tang, Songbo, Mou, Zhijian, Phillips, Oliver L, Lambers, Hans, Liu, Zhanfeng, Sardans, Jordi, Peñuelas, Josep, Lai, Yuan, Lin, Mingxian, Chen, Dexiang, and Kuang, Yuanwen
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TROPICAL forests ,STOMATA ,LEAF area ,OAK ,EVERGREENS ,MORPHOLOGY - Abstract
Aims Understanding variation and coordination of leaf traits at multiscales along elevational gradients can help predict the likely responses of dominant species to climate change. We seek to determine the extent to which variation in leaf stomatal, anatomical and morphological traits is associated with environmental factors, and whether ecological strategies of Cyclobalanopsis species shift with elevations. Methods In a tropical forest landscape in Jianfengling, South China, we determined leaf traits related to stomata, anatomy and morphology of six evergreen oak species (Cyclobalanopsis bambusaefolia , C. hui , C. patelliformis , C. fleuryi , C. tiaoloshanica and C. phanera) along a long elevational gradient (400–1400 m above sea level). Important Findings We found that stomatal density and stomatal pore index increased, whereas spongy mesophyll thickness to leaf thickness ratios decreased, significantly with elevation. The leaf area and leaf dry matter content increased and decreased, respectively, with elevation. Variations in stomatal, anatomical and morphological traits were mainly correlated to the mean annual temperature, mean annual sum precipitation and soil pH. At low and high elevations, the oak species exhibited strong stress tolerance combined with competition strategy, while they shifted toward more clearly the competitive strategy at intermediate elevations. And the changes in soil phosphorus concentration and soil pH along the elevation may drive the shift of ecological strategy. The results showed that the dominant oak species in tropical forests respond to environmental change by modulating traits at multiple levels, from that of the individual cell, through tissue and up to the whole leaf scale. [ABSTRACT FROM AUTHOR]
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- 2021
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9. From plots to policy: How to ensure long‐term forest plot data supports environmental management in intact tropical forest landscapes.
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Baker, Timothy R., Vicuña Miñano, Edgar, Banda‐R, Karina, Castillo Torres, Dennis, Farfan‐Rios, William, Lawson, Ian T., Loja Alemán, Eva, Pallqui Camacho, Nadir, Silman, Miles R., Roucoux, Katherine H., Phillips, Oliver L., Honorio Coronado, Euridice N., Monteagudo Mendoza, Abel, and Rojas Gonzáles, Rocío
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ENVIRONMENTAL management ,FOREST landscape design ,SUSTAINABLE development ,FOREST surveys ,DATA analysis - Abstract
Societal Impact Statement: The approach that we take to our science is as important as the questions that we address if we would like our research to inform management. Here, we discuss our experience of using networks of permanent forest inventory plots to support sustainable management and conservation of intact tropical forests. A key conclusion is that to maximize the use of data from such large international networks within policymaking, it is crucial that leadership is widely shared among participants. Such an approach helps to address ethical concerns surrounding international collaborations and also achieves greater policy impact. Summary: Long‐term data from permanent forest inventory plots have much to offer the management and conservation of intact tropical forest landscapes. Knowledge of the growth and mortality rates of economically important species, forest carbon balance, and the impact of climate change on forest composition are all central to effective management. However, this information is rarely integrated within the policymaking process. The problem reflects broader issues in using evidence to influence environmental management, and in particular, the need to engage with potential users beyond the collection and publication of high‐quality data. To ensure permanent plot data are used, (a) key "policy windows"—opportunities to integrate data within policy making—need to be identified; (b) long‐term relationships need to be developed between scientists and policy makers and policymaking organizations; and (c) leadership of plot networks needs to be shared among all participants, and particularly between institutions in the global north and those in tropical countries. Addressing these issues will allow permanent plot networks to make tangible contributions to ensuring that intact tropical forest persists over coming decades. [ABSTRACT FROM AUTHOR]
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- 2021
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10. Differences in leaf thermoregulation and water use strategies between three co-occurring Atlantic forest tree species
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Fauset, Sophie, Freitas, Helber C., Galbraith, David R., Sullivan, Martin J.P., Aidar, Marcos P.M., Joly, Carlos A., Phillips, Oliver L., Vieira, Simone A., and Gloor, Manuel U.
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montane ,tropical forest ,Euphorbiaceae ,Temperature ,Water ,Original Articles ,boundary layer ,leaf temperature ,energy balance ,transpiration ,Trees ,leaf width ,radiation ,Plant Leaves ,stomatal conductance ,Melastomataceae ,Original Article ,functional traits ,Energy Metabolism ,Brazil ,Nyctaginaceae ,Body Temperature Regulation - Abstract
In the first study of leaf energy balance in tropical montane forests, we observed current leaf temperature patterns in the Atlantic forest, Brazil, and assessed whether and why patterns may vary among species. We found large leaf‐to‐air temperature differences that were influenced strongly by radiation and differences in leaf temperature between 2 species due to variation in leaf width and stomatal conductance. We highlight the importance of leaf functional traits for leaf thermoregulation and also note that the high radiation levels that occur in montane forests may exacerbate the threat from increasing air temperatures., Given anticipated climate changes, it is crucial to understand controls on leaf temperatures including variation between species in diverse ecosystems. In the first study of leaf energy balance in tropical montane forests, we observed current leaf temperature patterns on 3 tree species in the Atlantic forest, Brazil, over a 10‐day period and assessed whether and why patterns may vary among species. We found large leaf‐to‐air temperature differences (maximum 18.3 °C) and high leaf temperatures (over 35 °C) despite much lower air temperatures (maximum 22 °C). Leaf‐to‐air temperature differences were influenced strongly by radiation, whereas leaf temperatures were also influenced by air temperature. Leaf energy balance modelling informed by our measurements showed that observed differences in leaf temperature between 2 species were due to variation in leaf width and stomatal conductance. The results suggest a trade‐off between water use and leaf thermoregulation; Miconia cabussu has more conservative water use compared with Alchornea triplinervia due to lower transpiration under high vapour pressure deficit, with the consequence of higher leaf temperatures under thermal stress conditions. We highlight the importance of leaf functional traits for leaf thermoregulation and also note that the high radiation levels that occur in montane forests may exacerbate the threat from increasing air temperatures.
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- 2018
11. Limited biomass recovery from gold mining in Amazonian forests.
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Kalamandeen, Michelle, Gloor, Emanuel, Johnson, Isaac, Agard, Shenelle, Katow, Martin, Vanbrooke, Ashmore, Ashley, David, Batterman, Sarah A., Ziv, Guy, Holder‐Collins, Kaslyn, Phillips, Oliver L., Brondizio, Eduardo S., Vieira, Ima, Galbraith, David, and Magrach, Ainhoa
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GOLD mining ,SECONDARY forests ,FOREST biomass ,ABANDONED mines ,TROPICAL forests - Abstract
Copyright of Journal of Applied Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2020
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12. Competition influences tree growth, but not mortality, across environmental gradients in Amazonia and tropical Africa.
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Rozendaal, Danaë M. A., Phillips, Oliver L., Lewis, Simon L., Affum‐Baffoe, Kofi, Alvarez-Davila, Esteban, Andrade, Ana, Aragão, Luiz E. O. C., Araujo‐Murakami, Alejandro, Baker, Timothy R., Bánki, Olaf, Brienen, Roel J. W., Camargo, José Luis C., Comiskey, James A., Djuikouo Kamdem, Marie Noël, Fauset, Sophie, Feldpausch, Ted R., Killeen, Timothy J., Laurance, William F., Laurance, Susan G. W., and Lovejoy, Thomas
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TREE growth , *TROPICAL forests , *FOREST dynamics , *WATER supply , *SOIL fertility ,WOOD density - Abstract
Competition among trees is an important driver of community structure and dynamics in tropical forests. Neighboring trees may impact an individual 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 individual 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 individual tree growth rather than mortality and that the strength of competition largely depends on environment‐mediated variation in basal area. [ABSTRACT FROM AUTHOR]
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- 2020
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13. Reconciling the contribution of environmental and stochastic structuring of tropical forest diversity through the lens of imaging spectroscopy.
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Bongalov, Boris, Burslem, David F. R. P., Jucker, Tommaso, Thompson, Samuel E. D., Rosindell, James, Swinfield, Tom, Nilus, Reuben, Clewley, Daniel, Phillips, Oliver L., Coomes, David A., and Comita, Liza
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SPECTRAL imaging ,TROPICAL forests ,FOREST biodiversity ,PLANT diversity ,STOCHASTIC processes ,AIRBORNE lasers - Abstract
Both niche and stochastic dispersal processes structure the extraordinary diversity of tropical plants, but determining their relative contributions has proven challenging. We address this question using airborne imaging spectroscopy to estimate canopy β‐diversity for an extensive region of a Bornean rainforest and challenge these data with models incorporating niches and dispersal. We show that remotely sensed and field‐derived estimates of pairwise dissimilarity in community composition are closely matched, proving the applicability of imaging spectroscopy to provide β‐diversity data for entire landscapes of over 1000 ha containing contrasting forest types. Our model reproduces the empirical data well and shows that the ecological processes maintaining tropical forest diversity are scale dependent. Patterns of β‐diversity are shaped by stochastic dispersal processes acting locally whilst environmental processes act over a wider range of scales. [ABSTRACT FROM AUTHOR]
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- 2019
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14. Carbon concentration declines with decay class in tropical forest woody debris.
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Chao, Kuo-Jung, Chen, Yi-Sheng, Song, Guo-Zhang Michael, Chang, Yuan-Mou, Sheue, Chiou-Rong, Phillips, Oliver L., and Hsieh, Chang-Fu
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PHYSIOLOGICAL effects of carbon ,FOREST ecology ,CARBON in soils ,BIODEGRADATION ,COARSE woody debris - Abstract
Carbon stored in woody debris is a key carbon pool in forest ecosystems. The most widely-used method to convert woody debris volume to carbon is by first multiplying field-measured volume with wood density to obtain necromass, and then assuming that a fixed proportion (often 50%) of the necromass is carbon. However, this crucial assumption is rarely tested directly, especially in the tropics. The aim of this study is to verify the field carbon concentration values of living trees and woody debris in two distinct tropical forests in Taiwan. Wood from living trees and woody debris across five decay classes was sampled to measure density and carbon concentrations. We found that both wood density and carbon concentration (carbon mass/total mass) declined significantly with the decay class of the wood. Mean (±SE) carbon concentration values for living trees were 44.6 ± 0.1%, while for decay classes one to five they were respectively 41.1 ± 1.4%, 41.4 ± 1.0%, 37.7 ± 1.3%, 30.5 ± 2.0%, and 19.6 ± 2.2%. Total necromass carbon stock was low, only 3.33 ± 0.55 Mg C ha −1 in the windward forest (Lanjenchi) and 4.65 ± 1.63 Mg C ha −1 in the lowland forest (Nanjenshan). Applying the conventional 50% necromass carbon fraction value would cause a substantial overestimate of the carbon stocks in woody debris of between 17% and 36%, or about 1 Mg of carbon per hectare. The decline in carbon concentration and the increase of variances in the heavily decayed class suggest that in high-diversity tropical forests there are diverse decomposition trajectories and that assuming a fixed carbon fraction across woody pieces is not justified. Our work reveals the need to consider site-specific and decay class-specific carbon concentrations in order to accurately estimate carbon stocks and fluxes in forest ecosystems. If the marked decline in carbon content with necromass decay is typical of tropical forests, the dead wood carbon pool in the biome needs revision and is likely to be overestimated. [ABSTRACT FROM AUTHOR]
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- 2017
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15. Scaling leaf respiration with nitrogen and phosphorus in tropical forests across two continents.
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Rowland, Lucy, Zaragoza‐Castells, Joana, Bloomfield, Keith J., Turnbull, Matthew H., Bonal, Damien, Burban, Benoit, Salinas, Norma, Cosio, Eric, Metcalfe, Daniel J., Ford, Andrew, Phillips, Oliver L., Atkin, Owen K., and Meir, Patrick
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TROPICAL forests ,SOIL fertility ,PLANT indicators ,BIOFORTIFICATION ,RESPIRATION in plants - 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 Rdark and its relationship with photosynthesis using three widely separated tropical forests which differ in soil fertility., Rdark was measured on 431 rainforest canopy trees, from 182 species, in French Guiana, Peru and Australia. The variation in Rdark was examined in relation to leaf N and P content, leaf structure and maximum photosynthetic rates at ambient and saturating atmospheric CO2 concentration., We found that the site with the lowest fertility (French Guiana) exhibited greater rates of Rdark per unit leaf N, P and photosynthesis. The data from Australia, for which there were no phylogenetic overlaps with the samples from the South American sites, yielded the most distinct relationships of Rdark with the measured leaf traits., Our data indicate that no single universal scaling relationship accounts for variation in Rdark across this large biogeographical space. Variability between sites in the absolute rates of Rdark and the Rdark : photosynthesis ratio were driven by variations in N- and P-use efficiency, which were related to both taxonomic and environmental variability. [ABSTRACT FROM AUTHOR]- Published
- 2017
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16. Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models.
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Johnson, Michelle O., Galbraith, David, Gloor, Manuel, De Deurwaerder, Hannes, Guimberteau, Matthieu, Rammig, Anja, Thonicke, Kirsten, Verbeeck, Hans, Randow, Celso, Monteagudo, Abel, Phillips, Oliver L., Brienen, Roel J. W., Feldpausch, Ted R., Lopez Gonzalez, Gabriela, Fauset, Sophie, Quesada, Carlos A., Christoffersen, Bradley, Ciais, Philippe, Sampaio, Gilvan, and Kruijt, Bart
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ALLOMETRY ,TREE growth ,CARBON sequestration in forests ,GROUND vegetation cover ,TROPICAL forests - Abstract
Understanding the processes that determine above-ground biomass ( AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models ( DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity ( NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs. [ABSTRACT FROM AUTHOR]
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- 2016
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17. An integrated pan-tropical biomass map using multiple reference datasets.
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Avitabile, Valerio, Herold, Martin, Heuvelink, Gerard B. M., Lewis, Simon L., Phillips, Oliver L., Asner, Gregory P., Armston, John, Ashton, Peter S., Banin, Lindsay, Bayol, Nicolas, Berry, Nicholas J., Boeckx, Pascal, Jong, Bernardus H. J., DeVries, Ben, Girardin, Cecile A. J., Kearsley, Elizabeth, Lindsell, Jeremy A., Lopez ‐ Gonzalez, Gabriela, Lucas, Richard, and Malhi, Yadvinder
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BIOMASS ,TROPICAL forests ,CARBON cycle ,REMOTE sensing ,FOREST surveys - Abstract
We combined two existing datasets of vegetation aboveground biomass ( AGB) ( Proceedings of the National Academy of Sciences of the United States of America, 108, 2011, 9899; Nature Climate Change, 2, 2012, 182) into a pan-tropical AGB map at 1-km resolution using an independent reference dataset of field observations and locally calibrated high-resolution biomass maps, harmonized and upscaled to 14 477 1-km AGB estimates. Our data fusion approach uses bias removal and weighted linear averaging that incorporates and spatializes the biomass patterns indicated by the reference data. The method was applied independently in areas (strata) with homogeneous error patterns of the input (Saatchi and Baccini) maps, which were estimated from the reference data and additional covariates. Based on the fused map, we estimated AGB stock for the tropics (23.4 N-23.4 S) of 375 Pg dry mass, 9-18% lower than the Saatchi and Baccini estimates. The fused map also showed differing spatial patterns of AGB over large areas, with higher AGB density in the dense forest areas in the Congo basin, Eastern Amazon and South-East Asia, and lower values in Central America and in most dry vegetation areas of Africa than either of the input maps. The validation exercise, based on 2118 estimates from the reference dataset not used in the fusion process, showed that the fused map had a RMSE 15-21% lower than that of the input maps and, most importantly, nearly unbiased estimates (mean bias 5 Mg dry mass ha
−1 vs. 21 and 28 Mg ha−1 for the input maps). The fusion method can be applied at any scale including the policy-relevant national level, where it can provide improved biomass estimates by integrating existing regional biomass maps as input maps and additional, country-specific reference datasets. [ABSTRACT FROM AUTHOR]- Published
- 2016
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18. Consistent, small effects of treefall disturbances on the composition and diversity of four Amazonian forests.
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Baker, Timothy R., Vela Díaz, Dilys M., Chama Moscoso, Victor, Navarro, Gilberto, Monteagudo, Abel, Pinto, Ruy, Cangani, Katia, Fyllas, Nikolaos M., Lopez Gonzalez, Gabriela, Laurance, William F., Lewis, Simon L., Lloyd, Jonathan, ter Steege, Hans, Terborgh, John W., Phillips, Oliver L., and Zotz, Gerhard
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TROPICAL forests ,FOREST biodiversity ,PLANT communities ,PLANT diversity ,ECOSYSTEMS - Abstract
Understanding the resilience of moist tropical forests to treefall disturbance events is important for understanding the mechanisms that underlie species coexistence and for predicting the future composition of these ecosystems. Here, we test whether variation in the functional composition of Amazonian forests determines their resilience to disturbance., We studied the legacy of natural treefall disturbance events in four forests across Amazonia that differ substantially in functional composition. We compared the composition and diversity of all free-standing woody stems 2-10 cm diameter in previously disturbed and undisturbed 20 × 20 m subplots within 55, one-hectare, long-term forest inventory plots., Overall, stem number increased following disturbance, and species and functional composition shifted to favour light-wooded, small-seeded taxa. Alpha-diversity increased, but beta-diversity was unaffected by disturbance, in all four forests., Changes in response to disturbance in both functional composition and alpha-diversity were, however, small (2 - 4% depending on the parameter) and similar among forests., Synthesis. This study demonstrates that variation in the functional composition of Amazonian forests does not lead to large differences in the response of these forests to treefall disturbances, and overall, these events have a minor role in maintaining the diversity of these ecosystems. [ABSTRACT FROM AUTHOR]
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- 2016
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19. Soil-induced impacts on forest structure drive coarse woody debris stocks across central Amazonia.
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Martins, Demétrius L., Schietti, Juliana, Feldpausch, Ted R., Luizão, Flávio J., Phillips, Oliver L., Andrade, Ana, Castilho, Carolina V., Laurance, Susan G., Oliveira, Átila, Amaral, Ieda L., Toledo, José J., Lugli, Laynara F., Veiga Pinto, José Luiz Purri, Oblitas Mendoza, Erick M., and Quesada, Carlos A.
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COARSE woody debris ,FOREST ecology ,SOIL classification ,SOIL depth ,FOREST biomass ,FOREST dynamics - Abstract
Background:Coarse woody debris (CWD) is an essential component in tropical forest ecosystems and its quantity varies widely with forest types. Aims:Relationships among CWD, soil, forest structure and other environmental factors were analysed to understand the drivers of variation in CWD in forests on different soil types across central Amazonia. Methods:To estimate CWD stocks and density of dead wood debris, 75 permanent forest plots of 0.5 ha in size were assessed along a transect that spanned ca. 700 km in undisturbed forests from north of the Rio Negro to south of the Rio Amazonas. Soil physical properties were evaluated by digging 2-m-deep pits and by taking auger samples. Results:Soil physical properties were the best predictors of CWD stocks; 37% of its variation was explained by effective soil depth. CWD stocks had a two-fold variation across a gradient of physical soil constraints (i.e. effective soil depth, anoxia and soil structure). Average biomass per tree was related to physical soil constraints, which, in turn, had a strong relationship with local CWD stocks. Conclusions:Soil physical properties appear to control average biomass per tree (and through this affect forest structure and dynamics), which, in turn, is correlated with CWD production and stocks. [ABSTRACT FROM AUTHOR]
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- 2015
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20. Tropical forest wood production: a cross-continental comparison.
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Banin, Lindsay, Lewis, Simon L., Lopez‐Gonzalez, Gabriela, Baker, Timothy R., Quesada, Carlos A., Chao, Kuo‐Jung, Burslem, David F. R. P., Nilus, Reuben, Abu Salim, Kamariah, Keeling, Helen C., Tan, Sylvester, Davies, Stuart J., Monteagudo Mendoza, Abel, Vásquez, Rodolfo, Lloyd, Jon, Neill, David A., Pitman, Nigel, Phillips, Oliver L., and Wurzburger, Nina
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TROPICAL forests ,WOOD products ,EFFECT of environment on plants ,CARBON cycle ,SOIL fertility ,DIPTEROCARPACEAE - Abstract
1. Tropical forest above-ground wood production (AGWP) varies substantially along environmental gradients. Some evidence suggests that AGWP may vary between regions and specifically that Asian forests have particularly high AGWP. However, comparisons across biogeographic regions using standardized methods are lacking, limiting our assessment of pan-tropical variation in AGWP and potential causes. 2. We sampled AGWP in NW Amazon (17 long-term forest plots) and N Borneo (11 plots), both with abundant year-round precipitation. Within each region, forests growing on a broad range of edaphic conditions were sampled using standardized soil and forest measurement techniques. 3. Plot-level AGWP was 49% greater in Borneo than in Amazonia (9.73 ± 0.56 vs. 6.53 ± 0.34 Mg dry mass ha
-1 a-1 , respectively; regional mean ± 1 SE). AGWP was positively associated with soil fertility (PCA axes, sum of bases and total P). After controlling for the edaphic environment,AGWP remained significantly higher in Bornean plots. Differences in AGWP were largely attributable to differing height-diameter allometry in the two regions and the abundance of large trees in Borneo. This may be explained, in part, by the greater solar radiation in Borneo compared with NWAmazonia. 4. Trees belonging to the dominant SE Asian family, Dipterocarpaceae, gained woody biomass faster than otherwise equivalent, neighbouring non-dipterocarps, implying that the exceptional production of Bornean forests may be driven by floristic elements. This dominant SE Asian family may partition biomass differently or be more efficient at harvesting resources and in converting themto woody biomass. 5. Synthesis. N Bornean forests have much greater AGWP rates than those in NW Amazon when soil conditions and rainfall are controlled for. Greater resource availability and the highly productive dipterocarps may, in combination, explain why Asian forests produce wood half as fast again as comparable forests in the Amazon. Our results also suggest that taxonomic groups differ in their fundamental ability to capture carbon and that different tropical regions may therefore have different carbon uptake capacities due to biogeographic history. [ABSTRACT FROM AUTHOR]- Published
- 2014
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21. Basin-wide variations in Amazon forest nitrogen-cycling characteristics as inferred from plant and soil N: N measurements.
- Author
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Nardoto, Gabriela B., Quesada, Carlos A., Patiño, Sandra, Saiz, Gustavo, Baker, Tim R., Schwarz, Michael, Schrodt, Franziska, Feldpausch, Ted R., Domingues, Tomas F., Marimon, Beatriz S., Marimon Junior, Ben-Hur, Vieira, Ima C.G., Silveira, Marcos, Bird, Michael I., Phillips, Oliver L., Lloyd, Jon, and Martinelli, Luiz A.
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NITROGEN cycle ,CLIMATE change ,LEGUMES ,FOREST canopies ,EFFECT of phosphorus on plants ,NITROGEN fixation ,FOREST soils - Abstract
Background:Patterns in tropical forest nitrogen cycling are poorly understood. In particular, the extent to which leguminous trees in these forests fix nitrogen is unclear. Aims:We aimed to determine factors that explain variation in foliar δ15N (δ15NF) for Amazon forest trees, and to evaluate the extent to which putatively N2-fixing Fabaceae acquire nitrogen from the atmosphere. Methods:Upper-canopy δ15NFvalues were determined for 1255 trees sampled across 65 Amazon forest plots. Along with plot inventory data, differences in δ15NFbetween nodule-forming Fabaceae and other trees were used to estimate the extent of N2fixation. Results:δ15NFranged from −12.1‰ to +9.3‰. Most of this variation was attributable to site-specific conditions, with extractable soil phosphorus and dry-season precipitation having strong influences, suggesting a restricted availability of nitrogen on both young and old soils and/or at low precipitation. Fabaceae constituted fewer than 10% of the sampled trees, and only 36% were expressed fixers. We estimated an average Amazon forest symbiotic fixation rate of 3 kg N ha−1year−1. Conclusion:Plant δ15N indicate that low levels of nitrogen availability are only likely to influence Amazon forest function on immature or old weathered soils and/or where dry-season precipitation is low. Most Fabaceae species that are capable of nodulating do not fix nitrogen in Amazonia. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
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22. Shifting dynamics of climate-functional groups in old-growth Amazonian forests.
- Author
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Butt, Nathalie, Malhi, Yadvinder, New, Mark, Macía, Manuel J., Lewis, Simon L., Lopez-Gonzalez, Gabriela, Laurance, William F., Laurance, Susan, Luizão, Regina, Andrade, Ana, Baker, Timothy R., Almeida, Samuel, and Phillips, Oliver L.
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FORESTS & forestry ,CLIMATE change ,FOREST microclimatology ,PLANT growth ,MOISTURE content of plants - Abstract
Background:Climate change is driving ecosystem shifts, which has implications for tropical forest system function and productivity. Aim:To investigate Amazon forest dynamics and test for compositional changes between 1985 and 2005 across different plant groups. Methods:Tree census data from 46 long-term RAINFOR forest plots in Amazonia for three climate-functional groups were used: dry-affiliate, climate-generalist and wet affiliate. Membership of each group was ascribed at genus level from the distribution of individuals across a wet–dry gradient in Amazonia, and then used to determine whether the proportions of these functional groups have changed over time, and the direction of any change. Results:In total, 91 genera, representing 59% of the stems and 18% of genera in the plots, were analysed. Wet-affiliates tended to move from a state of net basal area gain towards dynamic equilibrium, defined as where gain ≈ loss, governed by an increase in loss rather than a decrease in growth and mainly driven by plots in north-west Amazonia, the wettest part of the region. Dry-affiliates remained in a state of strong net basal area gain across western Amazonia and showed a strong increase in stem recruitment. Wet-affiliates and climate-generalists showed increases in stem mortality, and climate-generalists showed increased stem recruitment, resulting in overall equilibrium of stem numbers. Conclusions:While there were no significant shifts in most genera, the results suggest an overall shift in climate-functional forest composition in western Amazonia away from wet-affiliates, and potential for increased forest persistence under projected drier conditions in the future. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
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23. Residence times of woody biomass in tropical forests.
- Author
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Galbraith, David, Malhi, Yadvinder, Affum-Baffoe, Kofi, Castanho, Andrea D.A., Doughty, Christopher E., Fisher, Rosie A., Lewis, Simon L., Peh, Kelvin S.-H., Phillips, Oliver L., Quesada, Carlos A., Sonké, Bonaventure, and Lloyd, Jon
- Subjects
FOREST biomass ,VEGETATION greenness ,SOIL physical chemistry ,ATMOSPHERIC carbon dioxide ,GLOBAL environmental change - Abstract
Background:The woody biomass residence time (τw) of an ecosystem is an important variable for accurately simulating its biomass stocks. Methods and results:We reviewed published data from 177 forest plots across the tropics and found a six-fold variation (23–129 years) in τwacross our dataset, with a median τwof ca. 50 years. This value is similar to the median default value across 21 vegetation models for tropical forests, although the range of values used in models is large (20 to 200 years). Conclusions:The notion of a constant τwacross all tropical forests may be of limited utility, given the large observed variation in τw. We found that while there was little relationship between climate variables and τw, there was evidence that edaphic factors exerted a strong influence on τw. In both the Neotropics and the Paleotropics, τwwas highest in heavily weathered soils, suggesting that low soil fertility and/or non-limiting soil physical conditions exert a critical influence on τw. There is considerable uncertainty in how τwwill be affected by global environmental change, especially by increased atmospheric CO2. Even small changes in τwcould significantly reduce the future tropical forest carbon sink predicted by many vegetation models. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
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24. Reconciling the contribution of environmental and stochastic structuring of tropical forest diversity through the lens of imaging spectroscopy
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Bongalov, Boris, Burslem, David FRP, Jucker, Tommaso, Thompson, Samuel ED, Rosindell, James, Swinfield, Tom, Nilus, Reuben, Clewley, Daniel, Phillips, Oliver L, and Coomes, David A
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Beta diversity ,tropical forest ,Tropical Climate ,LiDAR ,neutral theory ,Rainforest ,Spectrum Analysis ,Biodiversity ,15. Life on land ,niche ,hyperspectral ,Borneo ,Remote Sensing Technology ,dispersal ,Ecosystem - Abstract
Both niche and stochastic dispersal processes structure the extraordinary diversity of tropical plants, but determining their relative contributions has proven challenging. We address this question using airborne imaging spectroscopy to estimate canopy β-diversity for an extensive region of a Bornean rainforest and challenge these data with models incorporating niches and dispersal. We show that remotely sensed and field-derived estimates of pairwise dissimilarity in community composition are closely matched, proving the applicability of imaging spectroscopy to provide β-diversity data for entire landscapes of over 1000 ha containing contrasting forest types. Our model reproduces the empirical data well and shows that the ecological processes maintaining tropical forest diversity are scale dependent. Patterns of β-diversity are shaped by stochastic dispersal processes acting locally whilst environmental processes act over a wider range of scales.
25. Necromasa de los bosques de Madre de Dios, Perú; una comparación entre bosques de tierra firme y de bajíos
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Araujo-Murakami, Alejandro, Parada, Alexander G., Teran, Jeremy J., Baker, Tim R., Ted R. Feldpausch, Phillips, Oliver L., and Brienen, Roel J. W.
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dead wood ,madera muerta ,Carbon storage ,lcsh:Biology (General) ,Bosque tropical ,ciclo de carbono ,Tropical forest ,Amazonía ,almacén de carbono ,Carbon cycle ,lcsh:Q ,lcsh:Science ,lcsh:QH301-705.5 ,Amazon - Abstract
Stocks of dead wood or necromass represent an important portion of biomass and nutrients in tropical forests. The objectives of this study were: 1) to evaluate and compare the necromass of “terra firme” and lowlands forests, (2) to study the relationship between necromass, above-ground biomass and wood density, and (3) to estimate the necromass of the department of Madre de Dios, Peru. Stocks of necromass and above-ground biomass were estimated at three different locations using permanent plots and line intercept transects. The average volume of necromass for the three sites was 72.9 m3 ha-1 with an average weight varying between 24.8 and 30.7 Mg ha-1, depending on the estimations of dead wood density used for the calculations. Terra firme forests had significantly higher stocks of necromass than lowland forests. The amount of necromass was 11% of the total above-ground biomass in Madre de Dios forests. The total stock of carbon stored in dead wood for the entire department of Madre de Dios was estimated to be approximately 100 mega tonnes of carbon. This is ten times more than the annual fossil fuel emissions of Peru between 2000 and 2008. The substantial stocks of necromass emphasize the importance of these types of field studies, considering that this component of tropical forest carbon cannot be detected using other methods such as satellite remote sensing. La cantidad de madera muerta o necromasa representa una importante porción de la biomasa y de los nutrientes en los bosques tropicales. Los objetivos de este estudio son: 1) hacer una evaluación y comparación entre la necromasa de los bosques de altura o tierra firme y los bosques inundables o bajíos, (2) estudiar las relaciones entre la necromasa, la biomasa aérea y la densidad de madera del bosque, y (3) proporcionar una primera estimación de la necromasa para todo el departamento de Madre de Dios. La necromasa gruesa y la masa aérea vegetativa fueron estudiados en tres diferentes lugares utilizando parcelas permanentes y líneas de intersección. El promedio del volumen de madera muerta gruesa fue de 72,9 m3 ha-1, con un peso entre 24,8 y 30,7 Mg ha-1 dependiendo de la densidad de madera muerta usada en los cálculos. Los bosques de tierra firme contienen significativamente más madera muerta que los bosques inundables. La necromasa constituye 11% de la masa aérea vegetativa almacenada en los bosques de Madre de Dios. Finalmente, se estima que el departamento de Madre de Dios contiene alrededor de 100 mega toneladas de carbono en su madera muerta. Este valor es bastante alto, siendo diez veces más que la emisión anual de combustibles fósiles de Perú entre 2000 – 2008. Esta substancial porción de la necromasa enfatiza la importancia de estos tipos de estudios de campo, considerando que este componente de carbono en el bosque tropical no se logra detectar con otros métodos como la detección remota por satélites.
26. Maximising Synergy among Tropical Plant Systematists, Ecologists, and Evolutionary Biologists.
- Author
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Baker, Timothy R., Pennington, R. Toby, Dexter, Kyle G., Fine, Paul V.A., Fortune-Hopkins, Helen, Honorio, Euridice N., Huamantupa-Chuquimaco, Isau, Klitgård, Bente B., Lewis, Gwilym P., de Lima, Haroldo C., Ashton, Peter, Baraloto, Christopher, Davies, Stuart, Donoghue, Michael J., Kaye, Maria, Kress, W. John, Lehmann, Caroline E.R., Monteagudo, Abel, Phillips, Oliver L., and Vasquez, Rodolfo
- Subjects
- *
TROPICAL plants , *SPECIES diversity , *BIODIVERSITY , *SPECIES distribution , *ENVIRONMENTAL protection , *GENETICS - Abstract
Closer collaboration among ecologists, systematists, and evolutionary biologists working in tropical forests, centred on studies within long-term permanent plots, would be highly beneficial for their respective fields. With a key unifying theme of the importance of vouchered collection and precise identification of species, especially rare ones, we identify four priority areas where improving links between these communities could achieve significant progress in biodiversity and conservation science: (i) increasing the pace of species discovery; (ii) documenting species turnover across space and time; (iii) improving models of ecosystem change; and (iv) understanding the evolutionary assembly of communities and biomes. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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27. Using repeated small-footprint LiDAR acquisitions to infer spatial and temporal variations of a high-biomass Neotropical forest.
- Author
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Réjou-Méchain, Maxime, Tymen, Blaise, Blanc, Lilian, Fauset, Sophie, Feldpausch, Ted R., Monteagudo, Abel, Phillips, Oliver L., Richard, Hélène, and Chave, Jérôme
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- *
TROPICAL forests , *LIDAR , *SPATIOTEMPORAL processes , *BIOMASS , *FOREST ecology , *FOREST regeneration - Abstract
In recent years, LiDAR technology has provided accurate forest aboveground biomass (AGB) maps in several forest ecosystems, including tropical forests. However, its ability to accurately map forest AGB changes in high-biomass tropical forests has seldom been investigated. Here, we assess the ability of repeated LiDAR acquisitions to map AGB stocks and changes in an old-growth Neotropical forest of French Guiana. Using two similar aerial small-footprint LiDAR campaigns over a four year interval, spanning ca. 20 km 2 , and concomitant ground sampling, we constructed a model relating median canopy height and AGB at a 0.25-ha and 1-ha resolution. This model had an error of 14% at a 1-ha resolution (RSE = 54.7 Mg ha − 1 ) and of 23% at a 0.25-ha resolution (RSE = 86.5 Mg ha − 1 ). This uncertainty is comparable with values previously reported in other tropical forests and confirms that aerial LiDAR is an efficient technology for AGB mapping in high-biomass tropical forests. Our map predicts a mean AGB of 340 Mg ha − 1 within the landscape. We also created an AGB change map, and compared it with ground-based AGB change estimates. The correlation was weak but significant only at the 0.25-ha resolution. One interpretation is that large natural tree-fall gaps that drive AGB changes in a naturally regenerating forest can be picked up at fine spatial scale but are veiled at coarser spatial resolution. Overall, both field-based and LiDAR-based estimates did not reveal a detectable increase in AGB stock over the study period, a trend observed in almost all forest types of our study area. Small footprint LiDAR is a powerful tool to dissect the fine-scale variability of AGB and to detect the main ecological controls underpinning forest biomass variability both in space and time. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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