Showing papers by "Oliver L. Phillips published in 2015"
University of Leeds1, University of Exeter2, Imperial College London3, James Cook University4, Environmental Change Institute5, University College London6, University of Kent7, Duke University8, National Institute of Amazonian Research9, National Institute for Space Research10, Universidad Autónoma Gabriel René Moreno11, Wageningen University and Research Centre12, University of Amsterdam13, Florida International University14, Institut national de la recherche agronomique15, Universidade Federal do Acre16, Tropenbos International17, Empresa Brasileira de Pesquisa Agropecuária18, National Chung Hsing University19, Paul Sabatier University20, National Park Service21, Amazon.com22, Federal University of Pará23, Universidade do Estado de Mato Grosso24, University of Texas at Austin25, Smithsonian Institution26, World Wide Fund for Nature27, Universidad Mayor28, Field Museum of Natural History29, Universidad Nacional de la Amazonía Peruana30, University of Los Andes31, National University of Colombia32, Museu Paraense Emílio Goeldi33, Naturalis34, Utrecht University35, Northumbria University36, University of Wisconsin–Milwaukee37, Smithsonian Tropical Research Institute38, State University of Campinas39
TL;DR: It is confirmed that Amazon forests have acted as a long-term net biomass sink, but the observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models
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 diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.
767 citations
TL;DR: In this paper, the authors show that severe drought suppresses photosynthetic carbon uptake and plant maintenance respiration, but growth is maintained, suggesting that less carbon is available for tree tissue maintenance and defence, which may cause the subsequent observed increase in tree mortality.
Abstract: Severe drought in a tropical forest ecosystem suppresses photosynthetic carbon uptake and plant maintenance respiration, but growth is maintained, suggesting that, overall, less carbon is available for tree tissue maintenance and defence, which may cause the subsequent observed increase in tree mortality. The underlying mechanisms that determine the response of tropical forest ecosystems to drought remain poorly understood. Based on observations from a network of intensively measured forest plots in the Amazon basin, this study shows that severe drought suppresses photosynthetic carbon uptake and plant maintenance respiration. Plant growth is maintained however, suggesting that less carbon is available for tree tissue maintenance and defence — which may explain the observed increase in tree mortality that follows a drought. In 2005 and 2010 the Amazon basin experienced two strong droughts1, driven by shifts in the tropical hydrological regime2 possibly associated with global climate change3, as predicted by some global models3. Tree mortality increased after the 2005 drought4, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23–0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the absence of growth6. We propose that weakened maintenance and defence investment may, in turn, cause the increase in post-drought tree mortality observed at our plots.
424 citations
Australian National University1, University of Minnesota2, University of Western Sydney3, Carnegie Institution for Science4, Institut national de la recherche agronomique5, Max Planck Society6, Commonwealth Scientific and Industrial Research Organisation7, James Cook University8, Pontifical Catholic University of Peru9, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto10, Purdue University11, National and Kapodistrian University of Athens12, Princeton University13, University of Leeds14, Lamont–Doherty Earth Observatory15, University of Edinburgh16, University of New Hampshire17, University of Western Australia18, Imperial College London19, University of Waikato20, Environmental Change Institute21, Macquarie University22, University of Exeter23, University of Toronto24, National Parks Board25, Estonian University of Life Sciences26, Wageningen University and Research Centre27, Colorado State University28, Smithsonian Tropical Research Institute29, University of Florida30, University of Canterbury31, University of Regina32, Spanish National Research Council33, University of Peradeniya34, Leipzig University35, Chinese Academy of Sciences36
TL;DR: A new global database of Rdark and associated leaf traits is analyzed and values at any given Vcmax or leaf nitrogen concentration were higher in herbs than in woody plants, and variation in Rdark among species and across global gradients in T and aridity is highlighted.
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 siteincreased only twofold from the Arctic to the tropics, despite a 20 degrees C increase in growing T (8-28 degrees C). By contrast, R-dark at a standard T (25 degrees 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).
310 citations
University of Leeds1, National University of Saint Anthony the Abbot in Cuzco2, University of Exeter3, Environmental Change Institute4, Utrecht University5, Duke University6, Florida International University7, Centre national de la recherche scientifique8, National Institute of Amazonian Research9, James Cook University10, Paul Sabatier University11, University of Turku12, Universidade Federal do Acre13, Universidad Autónoma Gabriel René Moreno14, Institut national de la recherche agronomique15, University of Los Andes16, Universidade do Estado de Mato Grosso17, Museu Paraense Emílio Goeldi18, National Park Service19, National University of Colombia20, Van Hall Larenstein University of Applied Sciences21, World Wide Fund for Nature22, Wageningen University and Research Centre23, Smithsonian Tropical Research Institute24, Georgetown University25, Federal University of Western Pará26, National Institute for Space Research27, Smithsonian Institution28, Tropenbos International29, Institute of Food and Agricultural Sciences30, Northern Arizona University31, University of Kent32, Central University of Ecuador33, University of Texas at Austin34, University of São Paulo35, University of Michigan36, Venezuelan Institute for Scientific Research37, State University of Campinas38, Conservation International39, National Agrarian University40, University College London41
TL;DR: It is found 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.
Abstract: While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few 'hyperdominant' species. In addition to their diversity, 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.
229 citations
Environmental Change Institute1, Lund University2, National Institute for Space Research3, University of Exeter4, Universidad Autónoma Gabriel René Moreno5, Carnegie Institution for Science6, Federal University of Pará7, University of Leeds8, National Institute of Amazonian Research9, Pontifical Catholic University of Peru10, University of Edinburgh11, Australian National University12
TL;DR: By improving the understanding of poorly understood processes such as CUE, NPP allocation and biomass turnover times, this work can provide more complete and mechanistic approaches to linking climate and tropical forest carbon cycling.
Abstract: Understanding the relationship between photosynthesis, net primary productivity and growth in forest ecosystems is key to understanding how these ecosystems will respond to global anthropogenic change, yet the linkages among these components are rarely explored in detail. We provide the first comprehensive description of the productivity, respiration and carbon allocation of contrasting lowland Amazonian forests spanning gradients in seasonal water deficit and soil fertility. Using the largest data set assembled to date, ten sites in three countries all studied with a standardized methodology, we find that (i) gross primary productivity (GPP) has a simple relationship with seasonal water deficit, but that (ii) site-to-site variations in GPP have little power in explaining site-to-site spatial variations in net primary productivity (NPP) or growth because of concomitant changes in carbon use efficiency (CUE), and conversely, the woody growth rate of a tropical forest is a very poor proxy for its productivity. Moreover, (iii) spatial patterns of biomass are much more driven by patterns of residence times (i.e. tree mortality rates) than by spatial variation in productivity or tree growth. Current theory and models of tropical forest carbon cycling under projected scenarios of global atmospheric change can benefit from advancing beyond a focus on GPP. By improving our understanding of poorly understood processes such as CUE, NPP allocation and biomass turnover times, we can provide more complete and mechanistic approaches to linking climate and tropical forest carbon cycling.
144 citations
Hans ter Steege1, Hans ter Steege2, Nigel C. A. Pitman3, Timothy J. Killeen +160 more•Institutions (57)
TL;DR: A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century.
Abstract: Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century.
140 citations
TL;DR: In this article, the authors extend and expand these analyses to characterize recent climate state and change, as a background for possible ongoing and future changes of these forests, which is consistent with changes in catchment-level peak and minimum river runoff as well as a positive trend of water vapour inflow into the basin.
Abstract: Recent analyses of Amazon runoff and gridded precipitation data suggest an intensification of the hydrological cycle over the past few decades in the following sense: wet-season precipitation and peak river runoff (since ∼ 1980) as well as annual-mean precipitation (since ∼ 1990) have increased while dry-season precipitation and minimum runoff have slightly decreased. There has also been an increase in the frequency of anomalously severe floods and droughts. Here we extend and expand these analyses to characterize recent climate state and change, as a background for possible ongoing and future changes of these forests. The contrasting recent changes in wet and dry season precipitation have continued and are generally consistent with changes in catchment-level peak and minimum river runoff as well as a positive trend of water vapour inflow into the basin. Consistent with the river records the increased vapour inflow is concentrated to the wet season. Temperature has been rising by 0.7∘C since 1980 with more pronounced warming during dry months. Suggestions for the cause of the observed changes of the hydrological cycle come from patterns in tropical sea surface temperatures (SST's). Tropical and North Atlantic SST's have increased rapidly and steadily since 1990, while Pacific SST's have shifted from a negative Pacific Decadal Oscillation (PDO) phase (approximately pre 1990) with warm eastern Pacific temperatures to a positive phase with cold eastern Pacific temperatures. These SST conditions have been shown to be associated with an increase in precipitation over most of the Amazon except the south and south-west. If ongoing changes continue we expect these to be generally beneficial for forests in those regions where there is an increase in precipitation with the exception of floodplain forests. An increase in flood-pulse height and duration could lead to increased mortality at higher levels of the floodplain and, over the long term, to a lateral shift of the zonally stratified floodplain forest communities. Negative effects on forests are mainly expected in the south-west and south, which have become slightly drier and hotter, consistent with tree mortality trends observed at the RAINFOR forest plot census network.
105 citations
TL;DR: In this paper, the authors assess the ability of repeated LiDAR acquisitions to map AGB stocks and changes in an old-growth Neotropical forest of French Guiana.
104 citations
TL;DR: In this paper, the authors quantify the impacts of biomass burning aerosol on diffuse radiation and plant photosynthesis across Amazonia during 1998-2007, with quoted ranges driven by uncertainty in BBA emissions.
Abstract: Atmospheric aerosol scatters solar radiation increasing the fraction of diffuse radiation and the efficiency of photosynthesis. We quantify the impacts of biomass burning aerosol (BBA) on diffuse radiation and plant photosynthesis across Amazonia during 1998–2007. Evaluation against observed aerosol optical depth allows us to provide lower and upper BBA emissions estimates. BBA increases Amazon basin annual mean diffuse radiation by 3.4–6.8% and net primary production (NPP) by 1.4–2.8%, with quoted ranges driven by uncertainty in BBA emissions. The enhancement of Amazon basin NPP by 78–156 Tg C a−1 is equivalent to 33–65% of the annual regional carbon emissions from biomass burning. This NPP increase occurs during the dry season and acts to counteract some of the observed effect of drought on tropical production. We estimate that 30–60 Tg C a−1 of this NPP enhancement is within woody tissue, accounting for 8–16% of the observed carbon sink across mature Amazonian forests.
81 citations
James Cook University1, University of Leeds2, University of Edinburgh3, Karlsruhe Institute of Technology4, National Institute of Amazonian Research5, Forest Research Institute6, Commonwealth Scientific and Industrial Research Organisation7, Tropical Forest Research Institute8, Universidade do Estado de Mato Grosso9, Royal Botanic Garden Edinburgh10, University of Yaoundé11, University of Brasília12, Forestry Commission13, École Normale Supérieure14, World Wide Fund for Nature15, Conservation International16, University College London17, Imperial College London18
TL;DR: In this article, the authors present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia.
Abstract: Through interpretations of remote-sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia Woody plant leaf area index variation was related to tree canopy cover in a similar way for both savanna and forest with substantial overlap between the two vegetation types As total woody plant canopy cover increased, so did the relative contribution of middle and lower strata of woody vegetation Herbaceous layer cover declined as woody cover increased This pattern of understorey grasses and herbs progressively replaced by shrubs as the canopy closes over was found for both savanna and forests and on all continents Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna–forest-species discontinuum is observed compared to that inferred when trees of a basal diameter > 01 m are considered in isolation This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs Despite similarities in canopy-cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater amount of above-ground biomass than in South America Up to three times as much above-ground biomass is stored in forests compared to savannas under equivalent climatic conditions Savanna–forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa Nevertheless, consistent across all three continents coexistence was found to be confined to a well-defined edaphic–climate envelope with soil and climate the key determinants of the relative location of forest and savanna stands Moreover, when considered in conjunction with the appropriate water availability metrics, it emerges that soil exchangeable cations exert considerable control on woody canopy-cover extent as measured in our pan-continental (forest + savanna) data set Taken together these observations do not lend support to the notion of alternate stable states mediated through fire feedbacks as the prime force shaping the distribution of the two dominant vegetation types of the tropical lands
76 citations
University of Leeds1, Amazon.com2, University of Edinburgh3, Royal Botanic Garden Edinburgh4, Paul Sabatier University5, University College London6, University of Kent7, National Institute of Amazonian Research8, Universidad Autónoma Gabriel René Moreno9, Wageningen University and Research Centre10, Institut national de la recherche agronomique11, Florida International University12, Central University of Ecuador13, University of Texas at Austin14, Wake Forest University15, University of Exeter16, James Cook University17, Universidade do Estado de Mato Grosso18, Duke University19, National University of Colombia20, University of Los Andes21, Empresa Brasileira de Pesquisa Agropecuária22, University of Oxford23, Museu Paraense Emílio Goeldi24, Naturalis25, Utrecht University26
TL;DR: It is suggested that high s.PDss and ses.MNTD in western Amazonia results from its favourable, easy-to-colonize environment, whereas high values in the Brazilian and Guianan Shields may be due to accumulation of lineages over a longer period of time, which may reflect greater lineage diversity in communities.
Abstract: Aim: To examine variation in the phylogenetic diversity (PD) of tree communities across geographical and environmental gradients in Amazonia. Location: Two hundred and eighty-three c. 1 ha forest inventory plots from across Amazonia. Methods: We evaluated PD as the total phylogenetic branch length across species in each plot (PDss), the mean pairwise phylogenetic distance between species (MPD), the mean nearest taxon distance (MNTD) and their equivalents standardized for species richness (ses.PDss, ses.MPD, ses.MNTD). We compared PD of tree communities growing (1) on substrates of varying geological age; and (2) in environments with varying ecophysiological barriers to growth and survival. Results: PDss is strongly positively correlated with species richness (SR), whereas MNTD has a negative correlation. Communities on geologically young- and intermediate-aged substrates (western and central Amazonia respectively) have the highest SR, and therefore the highest PDss and the lowest MNTD. We find that the youngest and oldest substrates (the latter on the Brazilian and Guiana Shields) have the highest ses.PDss and ses.MNTD. MPD and ses.MPD are strongly correlated with how evenly taxa are distributed among the three principal angiosperm clades and are both highest in western Amazonia. Meanwhile, seasonally dry tropical forest (SDTF) and forests on white sands have low PD, as evaluated by any metric. Main conclusions: High ses.PDss and ses.MNTD reflect greater lineage diversity in communities. We suggest that high ses.PDss and ses.MNTD in western Amazonia results from its favourable, easy-to-colonize environment, whereas high values in the Brazilian and Guianan Shields may be due to accumulation of lineages over a longer period of time. White-sand forests and SDTF are dominated by close relatives from fewer lineages, perhaps reflecting ecophysiological barriers that are difficult to surmount evolutionarily. Because MPD and ses.MPD do not reflect lineage diversity per se, we suggest that PDss, ses.PDss and ses.MNTD may be the most useful diversity metrics for setting large-scale conservation priorities.
01 Jan 2015
TL;DR: A field manual for intensive census plots (v3.0) as mentioned in this paper describes the field methods used across the RAINFOR-GEM network of forest census plots, including initial plot set up and ongoing measurement of ecosystem carbon components including above-ground live biomass, litter, roots, woody debris and various forms of CO2 efflux.
Abstract: A RAINFOR-GEM field manual for intensive census plots (v3.0) A complete description of the field methods used across the RAINFOR-GEM network of forest census plots, including initial plot set-up and ongoing measurement of ecosystem carbon components including above-ground live biomass, litter, roots, woody debris and various forms of CO2 efflux. See http://gem.tropicalforests.ox.ac.uk/page/resources/ and http://www.tobymarthews.com/rainfor-gem-manual-v30.html for further information. Data was collected 2011 to 2014
James Cook University1, Imperial College London2, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto3, Max Planck Society4, University of Exeter5, Karlsruhe Institute of Technology6, National Institute of Amazonian Research7, University of Leeds8, Universidade do Estado de Mato Grosso9, Royal Botanic Garden Edinburgh10, University of Edinburgh11, Universidad Autónoma Gabriel René Moreno12, Conservation International13
TL;DR: In this paper, the authors investigated the role of potassium as a modulator of tropical vegetation structure and function in the Amazon Basin, and found that it is an excellent predictor of 13C isotope discrimination.
Abstract: . Sampling along a precipitation gradient in tropical South America extending from ca. 0.8 to 2.0 m a−1, savanna soils had consistently lower exchangeable cation concentrations and higher C / N ratios than nearby forest plots. These soil differences were also reflected in canopy averaged leaf traits with savanna trees typically having higher leaf mass per unit area but lower mass-based nitrogen (Nm) and potassium (Km). Both Nm and Km also increased with declining mean annual precipitation (PA), but most area-based leaf traits such as leaf photosynthetic capacity showed no systematic variation with PA or vegetation type. Despite this invariance, when taken in conjunction with other measures such as mean canopy height, area-based soil exchangeable potassium content, [K]sa , proved to be an excellent predictor of several photosynthetic properties (including 13C isotope discrimination). Moreover, when considered in a multivariate context with PA and soil plant available water storage capacity (θP) as covariates, [K]sa also proved to be an excellent predictor of stand-level canopy area, providing drastically improved fits as compared to models considering just PA and/or θP. Neither calcium, nor magnesium, nor soil pH could substitute for potassium when tested as alternative model predictors (ΔAIC > 10). Nor for any model could simple soil texture metrics such as sand or clay content substitute for either [K]sa or θP. Taken in conjunction with recent work in Africa and the forests of the Amazon Basin, this suggests – in combination with some newly conceptualised interacting effects of PA and θP also presented here – a critical role for potassium as a modulator of tropical vegetation structure and function.
Universidad Técnica Particular de Loja1, National University of Tucumán2, National Agrarian University3, National University of Colombia4, Wake Forest University5, National Scientific and Technical Research Council6, University of Göttingen7, National University of Jujuy8, Universidad del Tolima9, University of Leeds10, Florida International University11
TL;DR: The results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes.
Abstract: General patterns of forest dynamics and productivity in the Andes Mountains are poorly characterized. Here we present the first large-scale study of Andean forest dynamics using a set of 63 permanent forest plots assembled over the past two decades. In the North-Central Andes tree turnover (mortality and recruitment) and tree growth declined with increasing elevation and decreasing temperature. In addition, basal area increased in Lower Montane Moist Forests but did not change in Higher Montane Humid Forests. However, at higher elevations the lack of net basal area change and excess of mortality over recruitment suggests negative environmental impacts. In North-Western Argentina, forest dynamics appear to be influenced by land use history in addition to environmental variation. Taken together, our results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes. More extensive and longer-term monitoring and analyses of forest dynamics in permanent plots will be necessary to understand how demographic processes and woody biomass are responding to changing environmental conditions along elevation gradients through this century.
TL;DR: In this article, the relationship among CWD, soil, forest structure and other environmental factors was analyzed to understand the drivers of variation in CWD in forests on different soil types across central Amazonia.
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 constra...
TL;DR: The murundus function as critical bases for the maintenance of species diversity in this extensive floodplain, thereby deserving recognition among ecosystems with high conservation priorities.
Abstract: Premise of research. This represents one of the first studies of the ecology, diversity, and structure of campos de murundus termite savannas in the vast seasonal wetlands of southern Amazonia. We aimed to improve understanding of this threatened system by assessing species richness, abundance, and co-occurrence among trees and herbs of murundus (earth mounds), investigating the environmental and biological mechanisms underlying these patterns, and discussing implications for biodiversity conservation.Methodology. We identified every tree, shrub, subshrub, and herb on 373 murundus across 11 ha at Araguaia State Park, southern Amazonia. We constructed species abundance distributions of trees and herbs, assessed best-fit models, and tested for nonrandom patterns of species co-occurrence using checkerboard scores. Using detrended correspondence analysis (DCA), we assessed the affinities among tree species and their positions in murundus.Pivotal results. A total of 166 species, 123 genera, and 49 families occ...
TL;DR: In this paper, a list of 527 species of woody trees in five plots of 1.0 ha recorded along an altitudinal gradient from 250 to 2230 m in the Communal Reserve Sira, located between the regions of Ucayali, Huanuco and Pasco in Peru central jungle region.
Abstract: Resumen Se presenta una lista anotada de 527 especies de plantas lenosas arboreas en cinco parcelas permanentes de 1.0 ha a traves de la gradiente altitudinal desde los 250 a 2230 m en la Reserva Comunal El Sira, ubicada entre las regiones de Ucayali, Huanuco y Pasco, en la Selva Central del Peru. Palabras clave: parcelas permanentes de arboles, Reserva Comunal El Sira, Peru. Abstract We present an annotated list of 527 species of woody trees in five plots of 1.0 ha recorded along an altitudinal gradient from 250 to 2230 m in the Communal Reserve Sira, located between the regions of Ucayali, Huanuco and Pasco in Peru central jungle region. Keywords : tree plots, Sira Communal Reserve, Peru.
TL;DR: Agarwal et al. as mentioned in this paper report a 729 especies agrupadas en 120 familias with 398 generos entre arboles, lianas, arbustos, hierbas, hemiepifitos, and epifito.
Abstract: Registramos a 729 especies agrupadas en 120 familias con 398 generos entre arboles, lianas, arbustos, hierbas, hemiepifitos y epifitos. Caracterizamos la vegetacion del area en cinco tipos de bosque: Llanura amazonica, Transicional pre-Montano, pre-Montano, Nublado o Montano alto y el Esclerofilo; sobre ellos establecimos, 6 parcelas permanentes con la finalidad de implementar un sistema de monitoreo de la dinamica de los bosques. El mayor contenido de biomasa aerea se halla sobre el bosque transicional pre-Montano con 264 T/ha. La vegetacion sobre el llano amazonico aparentemente presenta una dinamica mas estable, donde las tasas de reclutamiento y mortalidad fluctuan entre los 2.4 y 2%. La mayor diversidad vegetal ocurre sobre los bosques de Llanura amazonica. El mayor area basal ocupado por los individuos de la parcela III, con 31.7 m², un area menor es ocupado por los arboles de la parcela IV con solo 3 m². La estructura horizontal, esta dado mayormente por arboles cuyos diametros fluctuan entre los 10 y 30 cm de diametro, en las parcelas I, II, III, y V. En cambio la parcela IV, sigue el mismo patron de distribucion, pero el mayor numero de individuos se encuentran agrupados entre 5 a 15 cm de diametro. La estructura vertical esta dada por arboles de 5 a 10 m de alto, que forman el sotobosque, seguido de aquellos que tienen alturas >10-15 m, que forman el dosel y el grupo de los arboles emergentes conformados por individuos cuyas alturas fluctuan entre los 15 y 25 m de alto
TL;DR: In this paper, the size and frequency of natural forest disturbances and the Amazon forest carbon balance were investigated in the context of the Amazon Forest Carbon Balance System (CARS) project.
Abstract: Corrigendum: Size and frequency of natural forest disturbances and the Amazon forest carbon balance
02 Apr 2015
TL;DR: The size and frequency of natural forest disturbances and the Amazon forest carbon balance are studied to assess the impact of disturbances on the carbon balance in the Amazon basin.
Abstract: The original version of this Article contained an error in the computation of the total basin-wide mass loss per year. Following publication of the paper, it was brought to our attention by Mr Silva and Dr Kellner of Brown University that losses from both small and intermediate disturbances had been wrongly calculated, resulting in an overestimate of total disturbance loss. For small disturbances, losses from the pan-Amazon RAINFOR permanent plot network and large plots in the Tapajos National Forest were summed, when instead a weighted mean should have been used, while for intermediate disturbances all LiDAR-detected losses >4 m2 were summed, whereas only disturbances >0.1 ha should have been included. For example, values for the aboveground biomass losses attributed to small-, intermediate- and large-scale disturbances, detailed in the Abstract (and the associated percentages in the Results section), required revision from ~1.7 to ~1.28 (88.3 to 98.6%), 0.2 to 0.01 (12.7 to 1.1%) and 0.004 to 0.003 (0.02 to 0.3%) Pg C y−1, respectively. In the Results, the estimated total carbon released as a result of these natural disturbances has been revised from 1.88 to 1.30 Pg C y−1. The conversion of the mortality to Amazon forest areas, also detailed in the Results, has also been modified to reflect the corrected disturbance losses. The modified values reflect that natural mortality affects only 7.80 × 106 ha y−1 (1.15% of the total forest area of ~6.8 × 108 ha) rather than c. 2.0 × 107 ha y−1, with contributions of 98.7%, ~1.1% and 0.3%, rather than 80.0%, 19.9% and 0.1% from small-, intermediate- and large-scale disturbances, respectively. These changes have now been applied throughout the PDF and HTML versions of the Article.