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Author Verryckt, L.T.; Ellsworth, D.S.; Vicca, S.; Van Langenhove, L.; Peñuelas, J.; Ciais, P.; Posada, J.M.; Stahl, C.; Coste, S.; Courtois, E.A.; Obersteiner, M.; Chave, J.; Janssens, I.A.
Title Can light-saturated photosynthesis in lowland tropical forests be estimated by one light level? Type Journal Article
Year 2020 Publication Biotropica Abbreviated Journal Biotropica
Volume 52 Issue 6 Pages 1183-1193
Keywords canopy architecture; interspecific variation; light intensity; lowland environment; parameter estimation; photon flux density; photosynthesis; saturation; tropical forest; French Guiana
Abstract Leaf-level net photosynthesis (An) estimates and associated photosynthetic parameters are crucial for accurately parameterizing photosynthesis models. For tropical forests, such data are poorly available and collected at variable light conditions. To avoid over- or underestimation of modeled photosynthesis, it is critical to know at which photosynthetic photon flux density (PPFD) photosynthesis becomes light-saturated. We studied the dependence of An on PPFD in two tropical forests in French Guiana. We estimated the light saturation range, including the lowest PPFD level at which Asat (An at light saturation) is reached, as well as the PPFD range at which Asat remained unaltered. The light saturation range was derived from photosynthetic light-response curves, and within-canopy and interspecific differences were studied. We observed wide light saturation ranges of An. Light saturation ranges differed among canopy heights, but a PPFD level of 1,000 µmol m−2 s−1 was common across all heights, except for pioneer trees species that did not reach light saturation below 2,000 µmol m−2 s−1. A light intensity of 1,000 µmol m−2 s−1 sufficed for measuring Asat of climax species at our study sites, independent of the species or the canopy height. Because of the wide light saturation ranges, results from studies measuring Asat at higher PPFD levels (for upper canopy leaves up to 1,600 µmol m−2 s−1) are comparable with studies measuring at 1,000 µmol m−2 s−1. © 2020 The Association for Tropical Biology and Conservation
Address (down) UMR 5174, Laboratoire Evolution et Diversité Biologique, CNRS, Université Paul Sabatier, Toulouse, France
Corporate Author Thesis
Publisher Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 00063606 (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 948
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Author Verryckt, L.T.; Van Langenhove, L.; Ciais, P.; Courtois, E.A.; Vicca, S.; Peñuelas, J.; Stahl, C.; Coste, S.; Ellsworth, D.S.; Posada, J.M.; Obersteiner, M.; Chave, J.; Janssens, I.A.
Title Coping with branch excision when measuring leaf net photosynthetic rates in a lowland tropical forest Type Journal Article
Year 2020 Publication Biotropica Abbreviated Journal Biotropica
Volume 52 Issue 4 Pages 608-615
Keywords branch cutting; canopy physiology; French Guiana; gas exchange; photosynthesis; rainforest; stomatal conductance; ecological modeling; environmental conditions; forest canopy; leaf; measurement method; photosynthesis; tree; tropical forest; Gruidae
Abstract Measuring leaf gas exchange from canopy leaves is fundamental for our understanding of photosynthesis and for a realistic representation of carbon uptake in vegetation models. Since canopy leaves are often difficult to reach, especially in tropical forests with emergent trees up to 60 m at remote places, canopy access techniques such as canopy cranes or towers have facilitated photosynthetic measurements. These structures are expensive and therefore not very common. As an alternative, branches are often cut to enable leaf gas exchange measurements. The effect of branch excision on leaf gas exchange rates should be minimized and quantified to evaluate possible bias. We compared light-saturated leaf net photosynthetic rates measured on excised and intact branches. We selected branches positioned at three canopy positions, estimated relative to the top of the canopy: upper sunlit foliage, middle canopy foliage, and lower canopy foliage. We studied the variation of the effects of branch excision and transport among branches at these different heights in the canopy. After excision and transport, light-saturated leaf net photosynthetic rates were close to zero for most leaves due to stomatal closure. However, when the branch had acclimated to its new environmental conditions—which took on average 20 min—light-saturated leaf net photosynthetic rates did not significantly differ between the excised and intact branches. We therefore conclude that branch excision does not affect the measurement of light-saturated leaf net photosynthesis, provided that the branch is recut under water and is allowed sufficient time to acclimate to its new environmental conditions. © 2020 The Association for Tropical Biology and Conservation
Address (down) UMR 5174 Laboratoire Evolution et Diversité Biologique, Université Paul Sabatier, CNRS, Toulouse, France
Corporate Author Thesis
Publisher Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 00063606 (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 960
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Author Esquivel-Muelbert, A.; Phillips, O.L.; Brienen, R.J.W.; Fauset, S.; Sullivan, M.J.P.; Baker, T.R.; Chao, K.-J.; Feldpausch, T.R.; Gloor, E.; Higuchi, N.; Houwing-Duistermaat, J.; Lloyd, J.; Liu, H.; Malhi, Y.; Marimon, B.; Marimon Junior, B.H.; Monteagudo-Mendoza, A.; Poorter, L.; Silveira, M.; Torre, E.V.; Dávila, E.A.; del Aguila Pasquel, J.; Almeida, E.; Loayza, P.A.; Andrade, A.; Aragão, L.E.O.C.; Araujo-Murakami, A.; Arets, E.; Arroyo, L.; Aymard C, G.A.; Baisie, M.; Baraloto, C.; Camargo, P.B.; Barroso, J.; Blanc, L.; Bonal, D.; Bongers, F.; Boot, R.; Brown, F.; Burban, B.; Camargo, J.L.; Castro, W.; Moscoso, V.C.; Chave, J.; Comiskey, J.; Valverde, F.C.; da Costa, A.L.; Cardozo, N.D.; Di Fiore, A.; Dourdain, A.; Erwin, T.; Llampazo, G.F.; Vieira, I.C.G.; Herrera, R.; Honorio Coronado, E.; Huamantupa-Chuquimaco, I.; Jimenez-Rojas, E.; Killeen, T.; Laurance, S.; Laurance, W.; Levesley, A.; Lewis, S.L.; Ladvocat, K.L.L.M.; Lopez-Gonzalez, G.; Lovejoy, T.; Meir, P.; Mendoza, C.; Morandi, P.; Neill, D.; Nogueira Lima, A.J.; Vargas, P.N.; de Oliveira, E.A.; Camacho, N.P.; Pardo, G.; Peacock, J.; Peña-Claros, M.; Peñuela-Mora, M.C.; Pickavance, G.; Pipoly, J.; Pitman, N.; Prieto, A.; Pugh, T.A.M.; Quesada, C.; Ramirez-Angulo, H.; de Almeida Reis, S.M.; Rejou-Machain, M.; Correa, Z.R.; Bayona, L.R.; Rudas, A.; Salomão, R.; Serrano, J.; Espejo, J.S.; Silva, N.; Singh, J.; Stahl, C.; Stropp, J.; Swamy, V.; Talbot, J.; ter Steege, H.; Terborgh, J.; Thomas, R.; Toledo, M.; Torres-Lezama, A.; Gamarra, L.V.; van der Heijden, G.; van der Meer, P.; van der Hout, P.; Martinez, R.V.; Vieira, S.A.; Cayo, J.V.; Vos, V.; Zagt, R.; Zuidema, P.; Galbraith, D.
Title Tree mode of death and mortality risk factors across Amazon forests Type Journal Article
Year 2020 Publication Nature Communications Abbreviated Journal Nat. Commun.
Volume 11 Issue 5515 Pages
Keywords bioclimatology; carbon sink; ecological modeling; growth; holistic approach; mortality; mortality risk; risk factor; survival; trade-off; tropical forest; article; climate; controlled study; forest; growth rate; human; mortality rate; mortality risk; survival; biological model; biomass; Brazil; carbon sequestration; ecology; ecosystem; environmental monitoring; growth, development and aging; proportional hazards model; risk factor; tree; tropic climate; Amazonia; carbon dioxide; Biomass; Brazil; Carbon Dioxide; Carbon Sequestration; Ecology; Ecosystem; Environmental Monitoring; Forests; Models, Biological; Proportional Hazards Models; Risk Factors; Trees; Tropical Climate
Abstract The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing > 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted—modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth–survival trade-off in driving tropical tree mortality. © 2020, The Author(s).
Address (down) Tropenbos International, Wageningen, Netherlands
Corporate Author Thesis
Publisher Nature Research Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 20411723 (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 945
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Author Nixon, S.; Agwa, A.; Robinson, S.; Walker, A.; Touchard, A.; Schroeder, C.; Vetter, I.; Kotze, A.C.; Herzig, V.; King, G.F.
Title Discovery and characterisation of novel peptides from Amazonian stinging ant venoms with antiparasitic activity Type Journal Article
Year 2020 Publication Toxicon Abbreviated Journal Toxicon
Volume 177 Issue 1 Pages S60
Keywords
Abstract
Address (down) The Institute for Molecular Bioscience, The University of Queensland, Australia; CSIRO Agriculture and Food, Australia; CNRS, UMR Ecologie des forêts de Guyane, France
Corporate Author Thesis
Publisher NLM (Medline) Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 18793150 (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 973
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Author Sayer, E.J.; Rodtassana, C.; Sheldrake, M.; Bréchet, L.M.; Ashford, O.S.; Lopez-Sangil, L.; Kerdraon-Byrne, D.; Castro, B.; Turner, B.L.; Wright, S.J.; Tanner, E.V.J.
Title Revisiting nutrient cycling by litterfall—Insights from 15 years of litter manipulation in old-growth lowland tropical forest Type Journal Article
Year 2020 Publication Advances in Ecological Researc Abbreviated Journal Adv. Ecol. Res.
Volume 62 Issue Pages 173-223
Keywords Forest floor; Litter addition; Litter removal; Litterfall; Nutrient cycling; Nutrient use efficiency; Soil fertility; Trace elements; Tropical lowland forest
Abstract The crucial role of tropical forests in the global carbon balance is underpinned by their extraordinarily high biomass and productivity, even though the majority of tropical forests grow on nutrient-poor soils. Nutrient cycling by litterfall has long been considered essential for maintaining high primary productivity in lowland tropical forests but few studies have tested this assumption experimentally. We review and synthesise findings from the Gigante Litter Manipulation Project (GLiMP), a long-term experiment in lowland tropical forest in Panama, Central America, in which litter has been removed from or added to large-scale plots for 15 years. We assessed changes in soil and litter nutrient concentrations in response to the experimental treatments and estimated nutrient return and nutrient use efficiency to indicate changes in nutrient cycling. The soil concentrations of most nutrients increased with litter addition and declined with litter removal. Litter removal altered nitrogen, potassium, manganese and zinc cycling, demonstrating the importance of litter inputs for maintaining the availability of these elements to plants. By contrast, litter addition only altered nitrogen cycling and, despite low concentrations of available soil phosphorus, the effects of litter manipulation on phosphorus cycling were inconsistent. We discuss potential mechanisms underlying the observed changes, and we emphasise the importance of decomposition processes in the forest floor for retaining nutrient elements, which partially decouples nutrient cycling from the mineral soil. Finally, by synthesising GLiMP studies conducted during 15 years of litter manipulation, we highlight key knowledge gaps and avenues for future research into tropical forest nutrient cycling. © 2020 Elsevier Ltd
Address (down) Teagasc, Johnstown Castle, Wexford, Ireland
Corporate Author Thesis
Publisher Academic Press Inc. Place of Publication Editor Dumbrell A.J.; Turner E.C.; Fayle T.M.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title Advances in Ecological Research
Series Volume 62 Series Issue Edition
ISSN 00652504 (Issn); 9780128211342 (Isbn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 1001
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Author Van Langenhove, L.; Verryckt, L.T.; Bréchet, L.; Courtois, E.A.; Stahl, C.; Hofhansl, F.; Bauters, M.; Sardans, J.; Boeckx, P.; Fransen, E.; Peñuelas, J.; Janssens, I.A.
Title Atmospheric deposition of elements and its relevance for nutrient budgets of tropical forests Type Journal Article
Year 2020 Publication Biogeochemistry Abbreviated Journal Biogeochemistry
Volume 149 Issue 2 Pages 175-193
Keywords Litterfall; Nitrogen; Nutrient cycling; Phosphorus; Potassium; Throughfall; atmospheric deposition; canopy exchange; field method; forest floor; leaching; litterfall; nutrient cycling; phosphorus; potassium; precipitation (climatology); rainforest; tropical forest; French Guiana
Abstract Atmospheric deposition is an important component of the nutrient cycles of terrestrial ecosystems, but field measurements are especially scarce in tropical regions. In this study we analysed 15 months of precipitation chemistry collected in an old growth tropical forest located in French Guiana. We measured nutrient inputs via bulk precipitation and throughfall and used the canopy budget model to estimate nutrient fluxes via canopy exchange and dry deposition. Based on this method we quantified net fluxes of macronutrients and compared their contribution to internal cycling rates via litterfall. Our results suggest that while atmospheric deposition of nitrogen was relatively high (13 kg ha−1 year−1), and mainly in organic forms, the N inputs via litterfall were an order of magnitude higher. In contrast to nitrogen, we found that atmospheric deposition of phosphorus (0.5 kg ha−1 year−1) supplied up to one third of the annual litterfall input to the forest floor. Most strikingly, combined annual inputs of potassium via atmospheric deposition (14 kg ha−1 year−1) and canopy leaching (22 kg ha−1 year−1) were three times larger than internal nutrient recycling via litterfall (11 kg ha−1 year−1). We conclude that atmospheric deposition of phosphorus and especially potassium may play an important role in sustaining the productivity of this old-growth tropical rainforest. © 2020, Springer Nature Switzerland AG.
Address (down) StatUa Center for Statistics, University of Antwerp, Prinsstraat 13, Antwerp, 2000, Belgium
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 01682563 (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 964
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Author Do, N.A.; Dias, D.; Zhang, Z.; Huang, X.; Nguyen, T.T.; Pham, V.V.; Nait-Rabah, O.
Title Study on the behavior of squared and sub-rectangular tunnels using the Hyperstatic Reaction Method Type Journal Article
Year 2020 Publication Transportation Geotechnics Abbreviated Journal Transp. Geotech.
Volume 22 Issue 100321 Pages
Keywords Finite element method; Lining; Squared shape; Sub-rectangular shape; Tunnel; efficiency measurement; finite element method; numerical model; transportation development; transportation planning; tunnel design; tunnel lining
Abstract
Address (down) Saint-Petersburg Mining University, Russian Federation
Corporate Author Thesis
Publisher Elsevier Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 22143912 (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 915
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Author Ntawuhiganayo, E.B.; Uwizeye, F.K.; Zibera, E.; Dusenge, M.E.; Ziegler, C.; Ntirugulirwa, B.; Nsabimana, D.; Wallin, G.; Uddling, J.
Title Traits controlling shade tolerance in tropical montane trees Type Journal Article
Year 2020 Publication Tree physiology Abbreviated Journal Tree Physiol.
Volume 40 Issue 2 Pages 183-197
Keywords biomass allocation; leaf temperature; plant traits; Rwanda; shade intolerance; shade tolerance; tropical montane forest; article; biomass allocation; breathing; canopy; carbon balance; compensation; photosynthesis; plant leaf; plant stem; rain forest; Rwanda; shade tolerance; species difference; sweating
Abstract Tropical canopies are complex, with multiple canopy layers and pronounced gap dynamics contributing to their high species diversity and productivity. An important reason for this complexity is the large variation in shade tolerance among different tree species. At present, we lack a clear understanding of which plant traits control this variation, e.g., regarding the relative contributions of whole-plant versus leaf traits or structural versus physiological traits. We investigated a broad range of traits in six tropical montane rainforest tree species with different degrees of shade tolerance, grown under three different radiation regimes (under the open sky or beneath sparse or dense canopies). The two distinct shade-tolerant species had higher fractional biomass in leaves and branches while shade-intolerant species invested more into stems, and these differences were greater under low radiation. Leaf respiration and photosynthetic light compensation point did not vary with species shade tolerance, regardless of radiation regime. Leaf temperatures in open plots were markedly higher in shade-tolerant species due to their low transpiration rates and large leaf sizes. Our results suggest that interspecific variation in shade tolerance of tropical montane trees is controlled by species differences in whole-plant biomass allocation strategy rather than by difference in physiological leaf traits determining leaf carbon balance at low radiation. © The Author(s) 2019. Published by Oxford University Press.
Address (down) Rwanda Agriculture and Animal Resources Development, PO Box 5016Kigali, Rwanda
Corporate Author Thesis
Publisher NLM (Medline) Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 17584469 (Issn) ISBN Medium
Area Expedition Conference
Notes Export Date: 16 March 2020 Approved no
Call Number EcoFoG @ webmaster @ Serial 922
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Author Lang, G.; Marcon, E.; Puech, F.
Title Distance-based measures of spatial concentration: introducing a relative density function Type Journal Article
Year 2020 Publication Annals of Regional Science Abbreviated Journal Ann. Reg. Sci.
Volume 64 Issue 2 Pages 243-265
Keywords Agglomeration; Aggregation; Economic geography; Point patterns; Spatial concentration; accuracy assessment; econometrics; economic activity; economic geography; industrial agglomeration; industrial location; location decision; spatial analysis; spatial distribution
Abstract For more than a decade, distance-based methods have been widely employed and constantly improved in spatial economics. These methods are a very useful tool for accurately evaluating the spatial distribution of economic activity. We introduce a new distance-based statistical measure for evaluating the spatial concentration of industries. The m function is the first relative density function to be proposed in economics. This tool supplements the typology of distance-based methods recently drawn up by Marcon and Puech (J Econ Geogr 3(4):409–428, 2003). By considering several simulated and real examples, we show the advantages and the limits of the m function for detecting spatial structures in economics. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Address (down) RITM, Univ. Paris-Sud, Université Paris-Saclay and CREST, Sceaux, France
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 05701864 (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 976
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Author Svensk, M.; Coste, S.; Gérard, B.; Gril, E.; Julien, F.; Maillard, P.; Stahl, C.; Leroy, C.
Title Drought effects on resource partition and conservation among leaf ontogenetic stages in epiphytic tank bromeliads Type Journal Article
Year 2020 Publication Physiologia Plantarum Abbreviated Journal Physiol. Plant.
Volume 170 Issue 4 Pages 488-507
Keywords chlorophyll; nitrogen; water; Bromeliaceae; drought; metabolism; photosynthesis; plant leaf; Bromeliaceae; Chlorophyll; Droughts; Nitrogen; Photosynthesis; Plant Leaves; Water
Abstract Studying the response to drought stress of keystone epiphytes such as tank bromeliads is essential to better understand their resistance capacity to future climate change. The objective was to test whether there is any variation in the carbon, water and nutrient status among different leaf ontogenetic stages in a bromeliad rosette subjected to a gradient of drought stress. We used a semi-controlled experiment consisting in a gradient of water shortage in Aechmea aquilega and Lutheria splendens. For each bromeliad and drought treatment, three leaves were collected based on their position in the rosette and several functional traits related to water and nutrient status, and carbon metabolism were measured. We found that water status traits (relative water content, leaf succulence, osmotic and midday water potentials) and carbon metabolism traits (carbon assimilation, maximum quantum yield of photosystem II, chlorophyll and starch contents) decreased with increasing drought stress, while leaf soluble sugars and carbon, nitrogen and phosphorus contents remained unchanged. The different leaf ontogenetic stages showed only marginal variations when subjected to a gradient of drought. Resources were not reallocated between different leaf ontogenetic stages but we found a reallocation of soluble sugars from leaf starch reserves to the root system. Both species were capable of metabolic and physiological adjustments in response to drought. Overall, this study advances our understanding of the resistance of bromeliads faced with increasing drought stress and paves the way for in-depth reflection on their strategies to cope with water shortage. © 2020 Scandinavian Plant Physiology Society
Address (down) Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, 31062, France
Corporate Author Thesis
Publisher Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 00319317 (Issn) ISBN Medium
Area Expedition Conference
Notes PDF trop gros voir la documentaliste – merci Approved no
Call Number EcoFoG @ webmaster @ Serial 943
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