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Author Binelli, G.; Montaigne, W.; Sabatier, D.; Scotti-Saintagne, C.; Scotti, I. doi  openurl
  Title Discrepancies between genetic and ecological divergence patterns suggest a complex biogeographic history in a Neotropical genus Type Journal Article
  Year 2020 Publication Ecology and Evolution Abbreviated Journal Ecology and Evolution  
  Volume 10 Issue (down) 11 Pages 4726-4738  
  Keywords allopatric divergence; Amazon; Guiana Shield; interspecific gene flow; Myristicaceae; secondary contact; Virola  
  Abstract Phylogenetic patterns and the underlying speciation processes can be deduced from morphological, functional, and ecological patterns of species similarity and divergence. In some cases, though, species retain multiple similarities and remain almost indistinguishable; in other cases, evolutionary convergence can make such patterns misleading; very often in such cases, the “true” picture only emerges from carefully built molecular phylogenies, which may come with major surprises. In addition, closely related species may experience gene flow after divergence, thus potentially blurring species delimitation. By means of advanced inferential methods, we studied molecular divergence between species of the Virola genus (Myristicaceae): widespread Virola michelii and recently described, endemic V. kwatae, using widespread V. surinamensis as a more distantly related outgroup with different ecology and morphology—although with overlapping range. Contrary to expectations, we found that the latter, and not V. michelii, was sister to V. kwatae. Therefore, V. kwatae probably diverged from V. surinamensis through a recent morphological and ecological shift, which brought it close to distantly related V. michelii. Through the modeling of the divergence process, we inferred that gene flow between V. surinamensis and V. kwatae stopped soon after their divergence and resumed later, in a classical secondary contact event which did not erase their ecological and morphological differences. While we cannot exclude that initial divergence occurred in allopatry, current species distribution and the absence of geographical barriers make complete isolation during speciation unlikely. We tentatively conclude that (a) it is possible that divergence occurred in allopatry/parapatry and (b) secondary contact did not suppress divergence. © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.  
  Address INRAE, URFM, Avignon, France  
  Corporate Author Thesis  
  Publisher John Wiley and Sons Ltd Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 20457758 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 963  
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Author Van Langenhove, L.; Janssens, I.A.; Verryckt, L.; Brechet, L.; Hartley, I.P.; Stahl, C.; Courtois, E.; Urbina, I.; Grau, O.; Sardans, J.; Peguero, G.; Gargallo-Garriga, A.; Peñuelas, J.; Vicca, S. url  doi
openurl 
  Title Rapid root assimilation of added phosphorus in a lowland tropical rainforest of French Guiana Type Journal Article
  Year 2020 Publication Soil Biology and Biochemistry Abbreviated Journal Soil Biol. Biochem.  
  Volume 140 Issue (down) 107646 Pages  
  Keywords Fertilization; Nitrogen; Phosphorus; Plant root simulator probes; Root system; Tropical forest; Nitrogen; Nitrogen fertilizers; Phosphorus; Plants (botany); Soils; Tropics; Fertilization; Mycorrhizal fungus; N and P fertilizer; P availabilities; Plant root simulators; Root system; Tropical forest; Tropical rain forest; Forestry; Fungi  
  Abstract Tree growth on weathered soils in lowland tropical forests is limited by low phosphorous (P) availability. However, nutrient manupulation experiments do not always increase the P content in these trees, which raises the question whether trees are taking up added P. In French Guianese lowland rainforest, we measured changes in nitrogen (N) and P availability before and up to two months after N and P fertilizer addition, in soils with intact root systems and in soils where roots and mycorrhizal fungi were excluded by root exclusion cylinders. When the root system was excluded, P addition increased P availability to a much greater extent and for a longer time than in soils with an intact root system. Soil N dynamics were unaffected by root presence/absence. These results indicate rapid P uptake, but not N uptake, by tree roots, suggesting a very effective P acquisition process in these lowland rainforests.  
  Address Global Change Research Institute, Czech Academy of Sciences, Czech Republic  
  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 00380717 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 19 November 2019; Coden: Sbioa; Correspondence Address: Van Langenhove, L.; Centre of Excellence PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, Wilrijk, Belgium; email: leandro.vanlangenhove@uantwerpen.be Approved no  
  Call Number EcoFoG @ webmaster @ Serial 897  
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Author Céréghino, R.; Françoise, L.; Bonhomme, C.; Carrias, J.-F.; Compin, A.; Corbara, B.; Jassey, V.; Leflaive, J.; Rota, T.; Farjalla, V.; Leroy, C. doi  openurl
  Title Desiccation resistance traits predict freshwater invertebrate survival and community response to drought scenarios in a Neotropical ecosystem Type Journal Article
  Year 2020 Publication Ecological Indicators Abbreviated Journal Ecol. Indic.  
  Volume 119 Issue (down) 106839 Pages  
  Keywords Climate change; Functional traits; Lt50; Macroinvertebrates; Rainforests; Biodiversity; Climate change; Driers (materials); Drought; Environmental management; Population statistics; Tanks (containers); Water; Aquatic invertebrates; Climate change adaptation; Controlled conditions; Environmental managers; Freshwater biodiversity; Freshwater invertebrates; Future climate scenarios; Laboratory conditions; Aquatic organisms; aquatic community; biodiversity; climate change; cuticle; desiccation; drought stress; invertebrate; Neotropical Region; population size; survival; French Guiana; Invertebrata  
  Abstract The intensification of dry seasons is a major threat to freshwater biodiversity in Neotropical regions. Little is known about resistance to drying stress and the underpinning traits in Neotropical freshwater species, so we don't know whether desiccation resistance allows to anticipate shifts in biological diversity under future climate scenarios. Here, we used the aquatic invertebrates that live in the rainwater-filled leaves of tank bromeliads, to examine the extent to which desiccation resistance of species measured in the laboratory predicts community response to drought intensification in nature. We measured desiccation resistance in 17 invertebrate species (>90% of the biomass usually found in bromeliads of French Guiana) by recording the median lethal time (LT50) of experimental populations exposed to controlled conditions of residual moisture. In the field, we placed rainshelters above tank bromeliads to emulate drought scenarios ranging from the ambient norm to IPCC scenarios and extreme events, and we recorded the response of functional community structure. LT50 ranged from 4.18 to 19.06 days, and was related to cuticle content and dry body mass. Among other functional indicators that represent strategies to optimize resource use under stressful conditions (e.g., habitat use, trophic specialization), LT50 was the best predictor of community structure responses along a gradient of emulated drought intensities. Therefore, species’ LT50s measured under laboratory conditions can be used to forecast aquatic community response to drying stress in nature. Anticipating how species will cope with drought has never been more important for environmental managers to support climate change adaptation. We show that desiccation resistance in freshwater invertebrates is a key indicator of potential population size and local–global range shifts, and this could be especially true in the Neotropics where species have narrow physiological tolerances for climatic variation. © 2020 Elsevier Ltd  
  Address ECOFOG, AgroParisTech, CIRAD, CNRS, INRA, Université de Guyane, Université des Antilles, Campus Agronomique, Kourou, 97379, France  
  Corporate Author Thesis  
  Publisher Elsevier B.V. Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1470160x (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 941  
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Author Falkowski, M.; Jahn-Oyac, A.; Odonne, G.; Flora, C.; Estevez, Y.; Touré, S.; Boulogne, I.; Robinson, J.-C.; Béreau, D.; Petit, P.; Azam, D.; Coke, M.; Issaly, J.; Gaborit, P.; Stien, D.; Eparvier, V.; Dusfour, I.; Houël, E. url  doi
openurl 
  Title Towards the optimization of botanical insecticides research: Aedes aegypti larvicidal natural products in French Guiana Type Journal Article
  Year 2020 Publication Acta Tropica Abbreviated Journal  
  Volume 201 Issue (down) 105179 Pages  
  Keywords Amazonian chemodiversity; Chemical defense; Culicidae; Mosquito larvicides; Quasi-Poisson generalized linear model; Screening optimization  
  Abstract Natural products have proven to be an immeasurable source of bioactive compounds. The exceptional biodiversity encountered in Amazonia, alongside a rich entomofauna and frequent interactions with various herbivores is the crucible of a promising chemodiversity. This prompted us to search for novel botanical insecticides in French Guiana. As this French overseas department faces severe issues linked to insects, notably the strong incidence of vector-borne infectious diseases, we decided to focus our research on products able to control the mosquito Aedes aegypti. We tested 452 extracts obtained from 85 species originating from 36 botanical families and collected in contrasted environments against an Ae. aegypti laboratory strain susceptible to all insecticides, and a natural population resistant to both pyrethroid and organophosphate insecticides collected in Cayenne for the most active of them. Eight species (Maytenus oblongata Reissek, Celastraceae; Costus erythrothyrsus Loes., Costaceae; Humiria balsamifera Aubl., Humiriaceae; Sextonia rubra (Mez) van der Werff, Lauraceae; Piper hispidum Sw., Piperaceae; Laetia procera (Poepp.) Eichl., Salicaceae; Matayba arborescens (Aubl.) Radlk., Sapindaceae; and Cupania scrobitulata Rich., Sapindaceae) led to extracts exhibiting more than 50% larval mortality after 48 h of exposition at 100 µg/mL against the natural population and were considered active. Selectivity and phytochemistry of these extracts were therefore investigated and discussed, and some active compounds highlighted. Multivariate analysis highlighted that solvents, plant tissues, plant family and location had a significant effect on mortality while light, available resources and vegetation type did not. Through this case study we highlighted that plant defensive chemistry mechanisms are crucial while searching for novel insecticidal products.  
  Address INRS-Institut Armand Frappier, Groupe recherche en écologie microbienne, 531 boulevard des prairies, Laval, QC H7V 1B7, Canada  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 888  
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Author Sardans, J.; Urbina, I.; Grau, O.; Asensio, D.; Ogaya, R.; Peñuelas, J. doi  openurl
  Title Long-term drought decreases ecosystem C and nutrient storage in a Mediterranean holm oak forest Type Journal Article
  Year 2020 Publication Environmental and Experimental Botany Abbreviated Journal Environ. Exp. Bot.  
  Volume 177 Issue (down) 104135 Pages  
  Keywords Aridity; Carbon stocks; Climate change; Nitrogen; Phosphorus; Potassium; Stoichiometry; carbon sequestration; deciduous forest; drought; experimental study; forest soil; long-term change; Mediterranean environment; net ecosystem exchange; nutrient cycling; shrub; stoichiometry; Mediterranean Sea; Phillyrea latifolia  
  Abstract Aridity has increased in recent decades in the Mediterranean Basin and is projected to continue to increase in the coming decades. We studied the consequences of drought on the concentrations, stoichiometries and stocks of carbon (C), nitrogen (N), phosphorus (P) and potassium (K) in leaves, foliar litter of a three dominant woody species and soil of a Mediterranean montane holm oak forest where soil-water content was experimentally reduced (15 % lower than the control plots) for 15 years. Nitrogen stocks were lower in the drought plots than in the control plots (8.81 ± 1.01 kg ha−1 in the forest canopy and 856 ± 120 kg ha−1 in the 0−15 cm soil layer), thus representing 7 and 18 % lower N stocks in the canopy and soil respectively. δ15N was consistently higher under drought conditions in all samples, indicating a general loss of N. Foliar C and K stocks were also lower but to a lesser extent than N. Decreases in biomass and C and N stocks due to drought were smallest for the most dominant tall shrub, Phillyrea latifolia, so our results suggest a lower capacity of this forest to store C and nutrients but also substantial resulting changes in forest structure with increasing drought. © 2020 Elsevier B.V.  
  Address Cirad, UMR EcoFoG (AgroParisTech, CNRS, Inra, Univ Antilles, Univ Guyane), Campus Agronomique, Kourou, 97310, French Guiana  
  Corporate Author Thesis  
  Publisher Elsevier B.V. Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 00988472 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 954  
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Author ter Steege, H.; Prado, P.I.; Lima, R.A.F.; Pos, E.; de Souza Coelho, L.; de Andrade Lima Filho, D.; Salomão, R.P.; Amaral, I.L.; de Almeida Matos, F.D.; Castilho, C.V.; Phillips, O.L.; Guevara, J.E.; de Jesus Veiga Carim, M.; Cárdenas López, D.; Magnusson, W.E.; Wittmann, F.; Martins, M.P.; Sabatier, D.; Irume, M.V.; da Silva Guimarães, J.R.; Molino, J.-F.; Bánki, O.S.; Piedade, M.T.F.; Pitman, N.C.A.; Ramos, J.F.; Monteagudo Mendoza, A.; Venticinque, E.M.; Luize, B.G.; Núñez Vargas, P.; Silva, T.S.F.; de Leão Novo, E.M.M.; Reis, N.F.C.; Terborgh, J.; Manzatto, A.G.; Casula, K.R.; Honorio Coronado, E.N.; Montero, J.C.; Duque, A.; Costa, F.R.C.; Castaño Arboleda, N.; Schöngart, J.; Zartman, C.E.; Killeen, T.J.; Marimon, B.S.; Marimon-Junior, B.H.; Vasquez, R.; Mostacedo, B.; Demarchi, L.O.; Feldpausch, T.R.; Engel, J.; Petronelli, P.; Baraloto, C.; Assis, R.L.; Castellanos, H.; Simon, M.F.; de Medeiros, M.B.; Quaresma, A.; Laurance, S.G.W.; Rincón, L.M.; Andrade, A.; Sousa, T.R.; Camargo, J.L.; Schietti, J.; Laurance, W.F.; de Queiroz, H.L.; Nascimento, H.E.M.; Lopes, M.A.; de Sousa Farias, E.; Magalhães, J.L.L.; Brienen, R.; Aymard C, G.A.; Revilla, J.D.C.; Vieira, I.C.G.; Cintra, B.B.L.; Stevenson, P.R.; Feitosa, Y.O.; Duivenvoorden, J.F.; Mogollón, H.F.; Araujo-Murakami, A.; Ferreira, L.V.; Lozada, J.R.; Comiskey, J.A.; de Toledo, J.J.; Damasco, G.; Dávila, N.; Lopes, A.; García-Villacorta, R.; Draper, F.; Vicentini, A.; Cornejo Valverde, F.; Lloyd, J.; Gomes, V.H.F.; Neill, D.; Alonso, A.; Dallmeier, F.; de Souza, F.C.; Gribel, R.; Arroyo, L.; Carvalho, F.A.; de Aguiar, D.P.P.; do Amaral, D.D.; Pansonato, M.P.; Feeley, K.J.; Berenguer, E.; Fine, P.V.A.; Guedes, M.C.; Barlow, J.; Ferreira, J.; Villa, B.; Peñuela Mora, M.C.; Jimenez, E.M.; Licona, J.C.; Cerón, C.; Thomas, R.; Maas, P.; Silveira, M.; Henkel, T.W.; Stropp, J.; Paredes, M.R.; Dexter, K.G.; Daly, D.; Baker, T.R.; Huamantupa-Chuquimaco, I.; Milliken, W.; Pennington, T.; Tello, J.S.; Pena, J.L.M.; Peres, C.A.; Klitgaard, B.; Fuentes, A.; Silman, M.R.; Di Fiore, A.; von Hildebrand, P.; Chave, J.; van Andel, T.R.; Hilário, R.R.; Phillips, J.F.; Rivas-Torres, G.; Noronha, J.C.; Prieto, A.; Gonzales, T.; de Sá Carpanedo, R.; Gonzales, G.P.G.; Gómez, R.Z.; de Jesus Rodrigues, D.; Zent, E.L.; Ruschel, A.R.; Vos, V.A.; Fonty, É.; Junqueira, A.B.; Doza, H.P.D.; Hoffman, B.; Zent, S.; Barbosa, E.M.; Malhi, Y.; de Matos Bonates, L.C.; de Andrade Miranda, I.P.; Silva, N.; Barbosa, F.R.; Vela, C.I.A.; Pinto, L.F.M.; Rudas, A.; Albuquerque, B.W.; Umaña, M.N.; Carrero Márquez, Y.A.; van der Heijden, G.; Young, K.R.; Tirado, M.; Correa, D.F.; Sierra, R.; Costa, J.B.P.; Rocha, M.; Vilanova Torre, E.; Wang, O.; Oliveira, A.A.; Kalamandeen, M.; Vriesendorp, C.; Ramirez-Angulo, H.; Holmgren, M.; Nascimento, M.T.; Galbraith, D.; Flores, B.M.; Scudeller, V.V.; Cano, A.; Ahuite Reategui, M.A.; Mesones, I.; Baider, C.; Mendoza, C.; Zagt, R.; Urrego Giraldo, L.E.; Ferreira, C.; Villarroel, D.; Linares-Palomino, R.; Farfan-Rios, W.; Farfan-Rios, W.; Casas, L.F.; Cárdenas, S.; Balslev, H.; Torres-Lezama, A.; Alexiades, M.N.; Garcia-Cabrera, K.; Valenzuela Gamarra, L.; Valderrama Sandoval, E.H.; Ramirez Arevalo, F.; Hernandez, L.; Sampaio, A.F.; Pansini, S.; Palacios Cuenca, W.; de Oliveira, E.A.; Pauletto, D.; Levesley, A.; Melgaço, K.; Pickavance, G. doi  openurl
  Title Biased-corrected richness estimates for the Amazonian tree flora Type Journal Article
  Year 2020 Publication Scientific Reports Abbreviated Journal Sci. Rep.  
  Volume 10 Issue (down) 10130 Pages  
  Keywords adult; article; averaging; flora; forest; population abundance  
  Abstract Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come. © 2020, The Author(s).  
  Address Instituto de Biodiversidade e Floresta, Universidade Federal do Oeste do Pará, Rua Vera Paz, Campus Tapajós, Santarém, PA 68015-110, Brazil  
  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 20452322 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 946  
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Author Do, N.A.; Dias, D.; Zhang, Z.; Huang, X.; Nguyen, T.T.; Pham, V.V.; Nait-Rabah, O. url  doi
openurl 
  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 (down) 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 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 Schmitt, S.; Hérault, B.; Ducouret, É.; Baranger, A.; Tysklind, N.; Heuertz, M.; Marcon, É.; Cazal, S.O.; Derroire, G. doi  openurl
  Title Topography consistently drives intra- and inter-specific leaf trait variation within tree species complexes in a Neotropical forest Type Journal Article
  Year 2020 Publication Oikos Abbreviated Journal Oikos  
  Volume 129 Issue (down) 10 Pages 1521-1530  
  Keywords intraspecific variability; leaf traits; Paracou; species complex; syngameon; tropical forests; Bayesian analysis; coexistence; divergence; genetic variation; hierarchical system; leaf area; local adaptation; niche overlap; species diversity; topography; tropical forest; Guyana Shield  
  Abstract Tropical forests shelter the highest species diversity worldwide, although genus diversity is lower than expected. In the species-rich genera, species complexes are composed of closely-related species that share large amounts of genetic variation. Despite the key role of species complexes in diversification, evolution and functioning of ecological communities, little is known on why species complexes arise and how they are maintained in Neotropical forests. Examining how individual phenotypes vary along environmental gradients, within and among closely-related species within species complexes, can reveal processes allowing species coexistence within species complexes. We examined leaf functional trait variation with topography in a hyperdiverse tropical forest of the Guiana Shield. We collected leaf functional traits from 766 trees belonging to five species in two species complexes in permanent plots encompassing a diversity of topographic positions. We tested the role of topography on leaf functional trait variation with a hierarchical Bayesian model, controlling for individual tree diameter effect. We show that, mirroring what has been previously observed among species and communities, individual leaf traits covary from acquisitive to conservative strategy within species. Moreover, decreasing wetness from bottomlands to plateaus was associated with a shift of leaf traits from an acquisitive to a conservative strategy both across and within closely-related species. Our results suggest that intraspecific trait variability widens species’ niches and converges at species’ margins where niches overlap, potentially implying local neutral processes. Intraspecific trait variability favors local adaptation and divergence of closely-related species within species complexes. It is potentially maintained through interspecific sharing of genetic variation through hybridization. © 2020 Nordic Society Oikos. Published by John Wiley & Sons Ltd  
  Address INRAE, UMR EcoFoG (Agroparistech, CNRS, Cirad, Université des Antilles, Univ. de la Guyane), Kourou, French Guiana  
  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 00301299 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 950  
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Author Laybros, A.; Aubry-Kientz, M.; Féret, J.-B.; Bedeau, C.; Brunaux, O.; Derroire, G.; Vincent, G. doi  openurl
  Title Quantitative airborne inventories in dense tropical forest using imaging spectroscopy Type Journal Article
  Year 2020 Publication Remote Sensing Abbreviated Journal Remote Sens.  
  Volume 12 Issue (down) 10 Pages 1577  
  Keywords Hyperspectral; LiDAR; Species diversity; Tropical forest; Cost effectiveness; Discriminant analysis; Infrared devices; Infrared radiation; Logistic regression; Remote sensing; Tropics; Classification accuracy; Classification performance; Linear discriminant analysis; Operational applications; Regularized discriminant analysis; Remote sensing technology; Short wave infrared bands; Visible and near infrared; Forestry  
  Abstract Tropical forests have exceptional floristic diversity, but their characterization remains incomplete, in part due to the resource intensity of in-situ assessments. Remote sensing technologies can provide valuable, cost-effective, large-scale insights. This study investigates the combined use of airborne LiDAR and imaging spectroscopy to map tree species at landscape scale in French Guiana. Binary classifiers were developed for each of 20 species using linear discriminant analysis (LDA), regularized discriminant analysis (RDA) and logistic regression (LR). Complementing visible and near infrared (VNIR) spectral bands with short wave infrared (SWIR) bands improved the mean average classification accuracy of the target species from 56.1% to 79.6%. Increasing the number of non-focal species decreased the success rate of target species identification. Classification performance was not significantly affected by impurity rates (confusion between assigned classes) in the non-focal class (up to 5% of bias), provided that an adequate criterion was used for adjusting threshold probability assignment. A limited number of crowns (30 crowns) in each species class was sufficient to retrieve correct labels effectively. Overall canopy area of target species was strongly correlated to their basal area over 118 ha at 1.5 ha resolution, indicating that operational application of the method is a realistic prospect (R2 = 0.75 for six major commercial tree species). © 2020 by the authors.  
  Address Cirad, UMR EcoFoG (AgroParistech, CNRS, INRAE, Université des Antilles, Université de la Guyane), Kourou, French Guiana, 97379, France  
  Corporate Author Thesis  
  Publisher Mdpi Ag Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 20724292 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 969  
Permanent link to this record
 

 
Author Van Langenhove, L.; Depaepe, T.; Vicca, S.; van den Berge, J.; Stahl, C.; Courtois, E.; Weedon, J.; Urbina, I.; Grau, O.; Asensio, D.; Peñuelas, J.; Boeckx, P.; Richter, A.; Van Der Straeten, D.; Janssens, I.A. doi  openurl
  Title Regulation of nitrogen fixation from free-living organisms in soil and leaf litter of two tropical forests of the Guiana shield Type Journal Article
  Year 2020 Publication Plant and Soil Abbreviated Journal Plant Soil  
  Volume 450 Issue (down) 1-2 Pages 93-110  
  Keywords Free-living nitrogen fixation; French Guiana; Molybdenum; Nutrients; Phosphorus; Tropical forest; acetylene; leaf litter; molybdenum; nitrogen fixation; nutrient cycling; phosphorus; rainforest; reduction; soil biota; soil carbon; soil nitrogen; soil water; topographic effect; tropical forest; French Guiana  
  Abstract Background and aims: Biological fixation of atmospheric nitrogen (N2) is the main pathway for introducing N into unmanaged ecosystems. While recent estimates suggest that free-living N fixation (FLNF) accounts for the majority of N fixed in mature tropical forests, the controls governing this process are not completely understood. The aim of this study was to quantify FLNF rates and determine its drivers in two tropical pristine forests of French Guiana. Methods: We used the acetylene reduction assay to measure FLNF rates at two sites, in two seasons and along three topographical positions, and used regression analyses to identify which edaphic explanatory variables, including carbon (C), nitrogen (N), phosphorus (P) and molybdenum (Mo) content, pH, water and available N and P, explained most of the variation in FLNF rates. Results: Overall, FLNF rates were lower than measured in tropical systems elsewhere. In soils seasonal variability was small and FLNF rates differed among topographies at only one site. Water, P and pH explained 24% of the variation. In leaf litter, FLNF rates differed seasonally, without site or topographical differences. Water, C, N and P explained 46% of the observed variation. We found no regulatory role of Mo at our sites. Conclusions: Rates of FLNF were low in primary rainforest on poor soils on the Guiana shield. Water was the most important rate-regulating factor and FLNF increased with increasing P, but decreased with increasing N. Our results support the general assumption that N fixation in tropical lowland forests is limited by P availability. © 2019, The Author(s).  
  Address Department of Microbiology and Ecosystem Science, University of Vienna, Althanstr. 14, Vienna, 1090, Austria  
  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 0032079x (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 971  
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