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Author Denis, T.; Herault, B.; Jaouen, G.; Brunaux, O.; Guitet, S.; Richard-Hansen, C.
Title Black Curassow habitat relationships in terra firme forests of the Guiana Shield: A multiscale approach Type Journal Article
Year 2016 Publication The Condor Abbreviated Journal The Condor
Volume (up) 118 Issue 2 Pages 253-273
Keywords
Abstract ABSTRACT The Black Curassow (Crax alector) is a large game bird with Vulnerable conservation status found in north-central South America. We examined its distributional pattern across French Guiana using a large number of environmental descriptors at 3 scales of analysis: landscape, forest type, and microhabitat. We used a hierarchical model with temporary emigration and imperfect detection for data collected by standard distance sampling methods at 35 study sites. At the landscape scale, Black Curassow density decreased with hunting pressure and increased with steeper slopes in both hunted and unhunted areas. Topography appeared to be a good proxy for Black Curassow ecological requirements and probably reflected habitat quality. At the forest scale, population density was negatively correlated with the abundance of palms and Mimosoideae and positively correlated with the abundance of Lauraceae. Botanical families did not directly influence Black Curassow distribution, but rather determined spatial patterns by being markers of a particular forest type. At the microhabitat scale, Black Curassows used hilltops more frequently than other parts of the local topographical gradient. Our multiscale analysis shows that this species' distribution can be explained by biotic or abiotic conditions, regardless of the scale. For conservation, we recommend maintaining connectivity between Black Curassow populations separated by hunted areas. Our predicted densities could be used to adapt hunting quotas across French Guiana's forests. We show that combining field and remote sensing data helps to understand the ecological processes responsible for Black Curassow habitat relationships.
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Corporate Author Thesis
Publisher American Ornithological Society Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0010-5422 ISBN Medium
Area Expedition Conference
Notes doi: 10.1650/CONDOR-15-28.1 Approved no
Call Number EcoFoG @ webmaster @ Serial 714
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Author Agrawal, Anurag A. ; Boroczky, Katalin ; Haribal, Meena ; Hastings, Amy P. ; White, Ronald, A. ; Jiang, Ren-Wang ; Duplais, Christophe
Title Cardenolides, toxicity, and the costs of sequestration in the coevolutionary interaction between monarchs and milkweeds Type Journal Article
Year 2021 Publication PNAS Abbreviated Journal
Volume (up) 118 Issue 16 Pages e2024463118
Keywords
Abstract For highly specialized insect herbivores, plant chemical defenses are often co-opted as cues for oviposition and sequestration. In such interactions, can plants evolve novel defenses, pushing herbivores to trade off benefits of specialization with costs of coping with toxins? We tested how variation in milkweed toxins (cardenolides) impacted monarch butterfly ( Danaus plexippus ) growth, sequestration, and oviposition when consuming tropical milkweed ( Asclepias curassavica ), one of two critical host plants worldwide. The most abundant leaf toxin, highly apolar and thiazolidine ring–containing voruscharin, accounted for 40% of leaf cardenolides, negatively predicted caterpillar growth, and was not sequestered. Using whole plants and purified voruscharin, we show that monarch caterpillars convert voruscharin to calotropin and calactin in vivo, imposing a burden on growth. As shown by in vitro experiments, this conversion is facilitated by temperature and alkaline pH. We next employed toxin-target site experiments with isolated cardenolides and the monarch’s neural Na + /K + -ATPase, revealing that voruscharin is highly inhibitory compared with several standards and sequestered cardenolides. The monarch’s typical >50-fold enhanced resistance to cardenolides compared with sensitive animals was absent for voruscharin, suggesting highly specific plant defense. Finally, oviposition was greatest on intermediate cardenolide plants, supporting the notion of a trade-off between benefits and costs of sequestration for this highly specialized herbivore. There is apparently ample opportunity for continued coevolution between monarchs and milkweeds, although the diffuse nature of the interaction, due to migration and interaction with multiple milkweeds, may limit the ability of monarchs to counteradapt.
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Corporate Author Thesis
Publisher National Academy of Sciences Place of Publication Editor
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Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 1014
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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.
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 (up) 119 Issue 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 Paine, C.E.T.; Baraloto, C.; Chave, J.; Herault, B.
Title Functional traits of individual trees reveal ecological constraints on community assembly in tropical rain forests Type Journal Article
Year 2011 Publication Oikos Abbreviated Journal Oikos
Volume (up) 120 Issue 5 Pages 720-727
Keywords
Abstract Niche differentiation and ecological filtering are primary ecological processes that shape community assembly, but their relative importance remains poorly understood. Analyses of the distributions of functional traits can provide insight into the community structure generated by these processes. We predicted the trait distributions expected under the ecological processes of niche differentiation and environmental filtering, then tested these predictions with a dataset of 4672 trees located in nine 1-ha plots of tropical rain forest in French Guiana. Five traits related to leaf function (foliar N concentration, chlorophyll content, toughness, tissue density and specific leaf area), and three traits related to stem function (trunk sapwood density, branch sapwood density, and trunk bark thickness), as well as laminar surface area, were measured on every individual tree. There was far more evidence for environmental filtering than for niche differentiation in these forests. Furthermore, we contrasted results from species-mean and individual-level trait values. Analyses that took within-species trait variation into account were far more sensitive indicators of niche differentiation and ecological filtering. Species-mean analyses, by contrast, may underestimate the effects of ecological processes on community assembly. Environmental filtering appeared somewhat more intense on leaf traits than on stem traits, whereas niche differentiation affected neither strongly. By accounting for within-species trait variation, we were able to more properly consider the ecological interactions among individual trees and between individual trees and their environment. In so doing, our results suggest that the ecological processes of niche differentiation and environmental filtering may be more pervasive than previously believed.
Address [Paine, C. E. Timothy] ENGREF, UMR Ecol Forets Guyane, Kourou 97387, French Guiana, Email: timothy.paine@ieu.uzh.ch
Corporate Author Thesis
Publisher Wiley-Blackwell Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0030-1299 ISBN Medium
Area Expedition Conference
Notes ISI:000289740200008 Approved no
Call Number EcoFoG @ webmaster @ Serial 313
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Author Salvin, P.; Roos, C.; Robert, F.
Title Tropical mangrove sediments as a natural inoculum for efficient electroactive biofilms Type Journal Article
Year 2012 Publication Bioresource Technology Abbreviated Journal Bioresour. Technol.
Volume (up) 120 Issue Pages 45-51
Keywords Chronoamperometry; Cyclic voltammetry; Electroactive biofilms; Microbial fuel cells; Three-electrode systems
Abstract Chronoamperometry is known to be an efficient way to form electroactive biofilms (EAB) on conductive electrodes. For the first time, tropical mangrove sediments are analyzed as a potential inoculum to form MFC anodes with the use of acetate as substrate. The performance of the EAB-coated carbon cloth electrodes are evaluated according to the maximal current density, the coulombic efficiency and the cyclic voltammogramms. Working electrodes (WE) polarized at -0.2V/SCE gave better results compared to -0.4V/SCE and 0.0V/SCE. The maximal current density attained was 12A/m 2 with a CE of 24%. Contributions of the EAB in the generation of current were discussed and mechanisms of electronic transfer by the bacteria were discussed. Epifluorescence and SEM images showed the evolution of the biofilms on the electrode surface and the heterogeneity of the structure. © 2012 Elsevier Ltd.
Address Laboratoire des Matériaux et des Molécules en Milieu Amazonien, Université des Antilles et de la Guyane, UAG-UMR ECOFOG, F-97337 Cayenne, French Guiana
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 09608524 (Issn) ISBN Medium
Area Expedition Conference
Notes Export Date: 16 August 2012; Source: Scopus; Coden: Birte; doi: 10.1016/j.biortech.2012.05.131; Language of Original Document: English; Correspondence Address: Robert, F.; Laboratoire des Matériaux et des Molécules en Milieu Amazonien, Université des Antilles et de la Guyane, UAG-UMR ECOFOG, F-97337 Cayenne, French Guiana; email: florent.robert@guyane.univ-ag.fr Approved no
Call Number EcoFoG @ webmaster @ Serial 421
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Author Ezanno, P.; Aubry-Kientz, M.; Arnoux, S.; Cailly, P.; L'Ambert, G.; Toty, C.; Balenghien, T.; Tran, A.
Title A generic weather-driven model to predict mosquito population dynamics applied to species of Anopheles, Culex and Aedes genera of southern France Type Journal Article
Year 2015 Publication Preventive Veterinary Medicine Abbreviated Journal Preventive Veterinary Medicine
Volume (up) 120 Issue 1 Pages 39-50
Keywords Mathematical modelling; Mosquito; Population dynamics; Seasonality; Sensitivity analysis; Surveillance
Abstract An accurate understanding and prediction of mosquito population dynamics are needed to identify areas where there is a high risk of mosquito-borne disease spread and persistence. Simulation tools are relevant for supporting decision-makers in the surveillance of vector populations, as models of vector population dynamics provide predictions of the greatest risk periods for vector abundance, which can be particularly helpful in areas with a highly variable environment. We present a generic weather-driven model of mosquito population dynamics, which was applied to one species of each of the genera Anopheles, Culex, and Aedes, located in the same area and thus affected by similar weather conditions. The predicted population dynamics of Anopheles hyrcanus, Culex pipiens, and Aedes caspius were not similar. An. hyrcanus was abundant in late summer. Cx. pipiens was less abundant but throughout the summer. The abundance of both species showed a single large peak with few variations between years. The population dynamics of Ae. caspius showed large intra- and inter-annual variations due to pulsed egg hatching. Predictions of the model were compared to longitudinal data on host-seeking adult females. Data were previously obtained using CDC-light traps baited with carbon dioxide dry ice in 2005 at two sites (. Marais du Viguerat and Tour Carbonnière) in a favourable temperate wetland of southern France (Camargue). The observed and predicted periods of maximal abundance for An. hyrcanus and Cx. pipiens tallied very well. Pearson's coefficients for these two species were over 75% for both species. The model also reproduced the major trends in the intra-annual fluctuations of Ae. caspius population dynamics, with peaks occurring in early summer and following the autumn rainfall events. Few individuals of this species were trapped so the comparison of predicted and observed dynamics was not relevant. A global sensitivity analysis of the species-specific models enabled us to identify the parameters most influencing the maximal abundance of mosquitoes. These key parameters were almost similar between species, but not with the same contributions. The emergence of adult mosquitoes was identified as a key process in the population dynamics of all of the three species considered here. Parameters associated with adult emergence therefore need to be precisely known to achieve accurate predictions. Our model is a flexible and efficient tool that predicts mosquito abundance based on local environmental factors. It is useful to and already used by a mosquito surveillance manager in France. © 2015 Elsevier B.V.
Address Université des Antilles et de la Guyane, UMR 'Ecologie des Forêts de Guyane'Kourou, France
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Notes Cited By :1; Export Date: 18 May 2015 Approved no
Call Number EcoFoG @ webmaster @ Serial 603
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Author Leroy, C.; Jauneau, A.; Martinez, Y.; Cabin-Flaman, A.; Gibouin, D.; Orivel, J.; Séjalon-Delmas, N.
Title Exploring fungus-plant N transfer in a tripartite ant-plant-fungus mutualism Type Journal Article
Year 2017 Publication Annals of Botany Abbreviated Journal Annals of Botany
Volume (up) 120 Issue 3 Pages 417-426
Keywords Ascomycetes; endophytic fungi; Hirtella physophora; microscopy; mutualism; myrmecophyte; NanoSIMS; stable isotope
Abstract Background and Aims The plant Hirtella physophora, the ant Allomerus decemarticulatus and a fungus, Trimmatostroma sp., form a tripartite association. The ants manipulate both the plant trichomes and the fungus to build galleries under the stems of their host plant used to capture prey. In addition to its structural role, the fungus also improves nutrient uptake by the host plant. But it still remains unclear whether the fungus plays an indirect or a direct role in transferring nutrients to the plant. This study aimed to trace the transfer of N from the fungus to the plant's stem tissue. • Methods Optical microscopy and transmission electron microscopy (TEM) were used to investigate the presence of fungal hyphae in the stem tissues. Then, a 15N-labelling experiment was combined with a nanoscale secondary-ion mass spectrometry (NanoSIMS 50) isotopic imaging approach to trace the movement of added 15N from the fungus to plant tissues. • Key Results The TEM images clearly showed hyphae inside the stem tissue in the cellular compartment. Also, fungal hyphae were seen perforating the wall of the parenchyma cell. The 15N provisioning of the fungus in the galleries resulted in significant enrichment of the 15N signature of the plant's leaves 1 d after the 15N-labelling solution was deposited on the fungus-bearing trap. Finally, NanoSIMS imaging proved that nitrogen was transferred biotrophically from the fungus to the stem tissue. • Conclusions This study provides evidence that the fungi are connected endophytically to an ant-plant system and actively transfer nitrogen from 15N-labelling solution to the plant's stem tissues. Overall, this study underlines how complex the trophic structure of ant-plant interactions is due to the presence of the fungus and provides insight into the possibly important nutritional aspects and tradeoffs involved in myrmecophyte-ant mutualisms. © The Author 2017.
Address Laboratoire de Recherches en Sciences Végétales, Université de Toulouse, CNRS, UPS, France
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Notes Export Date: 2 October 2017 Approved no
Call Number EcoFoG @ webmaster @ Serial 767
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Author Marcon, E.; Herault, B.; Baraloto, C.; Lang, G.
Title The decomposition of Shannon's entropy and a confidence interval for beta diversity Type Journal Article
Year 2012 Publication Oikos Abbreviated Journal Oikos
Volume (up) 121 Issue 4 Pages 516-522
Keywords
Abstract Beta diversity is among the most employed theoretical concepts in ecology and biodiversity conservation. Up to date, a self-contained definition of it, with no reference to alpha and gamma diversity, has never been proposed. Using Kullback-Leibler divergence, we present the explicit formula of Shannon's β entropy, a bias correction for its estimator and a confidence interval. We also provide the mathematical framework to decompose Shannon diversity into several hierarchical nested levels. From botanical inventories of tropical forest plots in French Guiana, we estimate Shannon diversity at the plot, forest and regional level. We believe this is a complete and usefulness toolbox for ecologists interested in partitioning biodiversity. © 2011 The Authors. Oikos © 2012 Nordic Society Oikos.
Address AgroParisTech, UMR 518 Math. Info. Appli., 16 rue Claude Bernard, FR-75005 Paris, France
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ISSN 00301299 (Issn) ISBN Medium
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Notes Export Date: 28 March 2012; Source: Scopus; Coden: Oiksa; doi: 10.1111/j.1600-0706.2011.19267.x; Language of Original Document: English; Correspondence Address: Marcon, E.; AgroParisTech, UMR EcoFoG, BP 709, FR-97310 Kourou, France; email: eric.marcon@ecofog.gf Approved no
Call Number EcoFoG @ webmaster @ Serial 386
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Author Lehnebach, R.; Beyer, R.; Letort, V.; Heuret, P.
Title The pipe model theory half a century on: a review Type Journal Article
Year 2018 Publication Annals of Botany Abbreviated Journal
Volume (up) 121 Issue 5 Pages 773-795
Keywords
Abstract BackgroundMore than a half century ago, Shinozaki et al. (Shinozaki K, Yoda K, Hozumi K, Kira T. 1964a. A quantitative analysis of plant form – the pipe model theory. I. Basic analyses. Japanese Journal of Ecology B: 97–105) proposed an elegant conceptual framework, the pipe model theory (PMT), to interpret the observed linear relationship between the amount of stem tissue and corresponding supported leaves. The PMT brought a satisfactory answer to two vividly debated problems that were unresolved at the moment of its publication: (1) What determines tree form and which rules drive biomass allocation to the foliar versus stem compartments in plants? (2) How can foliar area or mass in an individual plant, in a stand or at even larger scales be estimated? Since its initial formulation, the PMT has been reinterpreted and used in applications, and has undoubtedly become an important milestone in the mathematical interpretation of plant form and functioning.ScopeThis article aims to review the PMT by going back to its initial formulation, stating its explicit and implicit properties and discussing them in the light of current biological knowledge and experimental evidence in order to identify the validity and range of applicability of the theory. We also discuss the use of the theory in tree biomechanics and hydraulics as well as in functional–structural plant modelling.ConclusionsScrutinizing the PMT in the light of modern biological knowledge revealed that most of its properties are not valid as a general rule. The hydraulic framework derived from the PMT has attracted much more attention than its mechanical counterpart and implies that only the conductive portion of a stem cross-section should be proportional to the supported foliage amount rather than the whole of it. The facts that this conductive portion is experimentally difficult to measure and varies with environmental conditions and tree ontogeny might cause the commonly reported non-linear relationships between foliage and stem metrics. Nevertheless, the PMT can still be considered as a portfolio of properties providing a unified framework to integrate and analyse functional–structural relationships.
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ISSN 0305-7364 ISBN Medium
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Notes 10.1093/aob/mcx194 Approved no
Call Number EcoFoG @ webmaster @ Serial 801
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Author Lehnebach, R.; Beyer, R.; Letort, V.; Heuret, P.
Title Corrigendum: The pipe model theory half a century on: A review (Annals of Botany DOI: 10.1093/aob/mcx194) Type Journal Article
Year 2018 Publication Annals of Botany Abbreviated Journal Annals of Botany
Volume (up) 121 Issue 7 Pages 1427
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Abstract There was an error in the affiliations of Véronique Letort. The correct affiliation is Laboratory of Mathematics in Interaction with Computer Science (MICS), CentraleSupélec, France The online paper has been corrected.
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Notes Export Date: 16 July 2018 Approved no
Call Number EcoFoG @ webmaster @ Serial 810
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