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Remy, C. C., Fleury, M., Beauchene, J., Rivier, M., & Goli, T. (2016). Analysis of PAH Residues and Amounts of Phenols in Fish Smoked with Woods Traditionally Used in French Guiana. Journal of Ethnobiology, 36(2), 312–325.
Abstract: Fish smoking with local wood species is a traditional practice in French Guiana. We evaluated the carcinogenic risk and the smoky taste in acoupa weakfish (Cynoscion acoupa) smoked by a small Guianese company specializing in fish smoking using local wood species. The goal of this study is to promote regional economic development by encouraging the establishment of small companies offering fish smoked with local wood species in agreement with the European health norms in terms of polycyclic aromatic hydrocarbon (PAH) content in smoked fish. The fish smoked with three species of wood traditionally used in French Guiana, Parinari campestris, Caesaria grandiflora, and Laetia procera, conformed to European standards for PAH content. Their phenol contents (correlated with the smoky taste) were close to smoked salmon, the reference in Europe. Given the low rate of extractable compounds in these woods, other flavors had little chance of predominating on the smoky taste. These three tropical wood species might be used for the production of cold smoked fish in compliance with European standards for PAH residues. The flavor and consumer's acceptance of the smoked fish should now be investigated to characterize the added typicity of local woods in comparison to the commonly used European woods. © 2016 Society of Ethnobiology.
Keywords: French Guiana; phenols; polycyclic aromatic hydrocarbons; smoked fish; traditional knowledge
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Denis, T., Herault, B., Jaouen, G., Brunaux, O., Guitet, S., & Richard-Hansen, C. (2016). Black Curassow habitat relationships in terra firme forests of the Guiana Shield: A multiscale approach. The Condor, 118(2), 253–273.
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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Goulamoussene, Y., Bedeau, C., Descroix, L., Linguet, L., & Herault, B. (2017). Environmental control of natural gap size distribution in tropical forests. Biogeosciences, 14(2), 353–364.
Abstract: Natural disturbances are the dominant form of forest regeneration and dynamics in unmanaged tropical forests. Monitoring the size distribution of treefall gaps is important to better understand and predict the carbon budget in response to land use and other global changes. In this study, we model the size frequency distribution of natural canopy gaps with a discrete power law distribution. We use a Bayesian framework to introduce and test, using Monte Carlo Markov chain and Kuo-Mallick algorithms, the effect of local physical environment on gap size distribution. We apply our methodological framework to an original light detecting and ranging dataset in which natural forest gaps were delineated over 30 000 ha of unmanaged forest. We highlight strong links between gap size distribution and environment, primarily hydrological conditions and topography, with large gaps being more frequent on floodplains and in wind-exposed areas. In the future, we plan to apply our methodological framework on a larger scale using satellite data. Additionally, although gap size distribution variation is clearly under environmental control, variation in gap size distribution in time should be tested against climate variability. © Author(s) 2017.
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Schimann, H., Bach, C., Lengelle, J., Louisanna, E., Barantal, S., Murat, C., et al. (2017). Diversity and Structure of Fungal Communities in Neotropical Rainforest Soils: The Effect of Host Recurrence. Microbial Ecology, 73(2), 310–320.
Abstract: The patterns of the distribution of fungal species and their potential interactions with trees remain understudied in Neotropical rainforests, which harbor more than 16,000 tree species, mostly dominated by endomycorrhizal trees. Our hypothesis was that tree species shape the non-mycorrhizal fungal assemblages in soil and litter and that the diversity of fungal communities in these two compartments is partly dependent on the coverage of trees in the Neotropical rainforest. In French Guiana, a long-term plantation and a natural forest were selected to test this hypothesis. Fungal ITS1 regions were sequenced from soil and litter samples from within the vicinity of tree species. A broad range of fungal taxa was found, with 42 orders and 14 classes. Significant spatial heterogeneity in the fungal communities was found without strong variation in the species richness and evenness among the tree plots. However, tree species shaped the fungal assemblages in the soil and litter, explaining up to 18 % of the variation among the communities in the natural forest. These results demonstrate that vegetation cover has an important effect on the structure of fungal assemblages inhabiting the soil and litter in Amazonian forests, illustrating the relative impact of deterministic processes on fungal community structures in these highly diverse ecosystems. © 2016, Springer Science+Business Media New York.
Keywords: Amazonian forest; Fungal communities; Host recurrence; Litter; Second-generation sequencing; Soil
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Duval, R., & Duplais, C. (2017). Fluorescent natural products as probes and tracers in biology. Natural Product Reports, 34(2), 161–193.
Abstract: Covering: 1985 up to the end of 2016 Fluorescence is a remarkable property of many natural products in addition to their medicinal and biological values. Herein, we provide a review on these peculiar secondary metabolites to stimulate prospecting of them as original fluorescent tracers, endowed with unique photophysical properties and with applications in most fields of biology. The compounds are spectrally categorized (i.e. fluorescing from violet to the near infra-red) and further structurally classified within each category. Natural products selected for their high impact in modern fluorescence-based biological studies are highlighted throughout the article. Finally, we discuss aspects of chemical ecology where fluorescent natural products might have key evolutionary roles and thus open new research directions in the field. © 2017 The Royal Society of Chemistry.
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Touré, S., Nirma, C., Falkowski, M., Dusfour, I., Boulogne, I., Jahn-Oyac, A., et al. (2017). Aedes aegypti Larvicidal Sesquiterpene Alkaloids from Maytenus oblongata. Journal of Natural Products, 80(2), 384–390.
Abstract: Four new sesquiterpene alkaloids (1-4) with a β-dihydroagrofuran skeleton and a new triterpenoid (5) were isolated from an ethyl acetate extract of Maytenus oblongata stems. Their structures were elucidated using 1D and 2D NMR spectroscopy as well as MS and ECD experiments. The M. oblongata stem EtOAc extract and the pure compounds isolated were tested for larvicidal activity against Aedes aegypti under laboratory conditions, and compounds 2 and 3 were found to be active. © 2017 The American Chemical Society and American Society of Pharmacognosy.
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Bastias, C. C., Fortunel, C., Valladares, F., Baraloto, C., Benavides, R., Cornwell, W., et al. (2017). Intraspecific leaf trait variability along a boreal-to-tropical community diversity gradient. PLoS ONE, 12(2), e0172495.
Abstract: Disentangling the mechanisms that shape community assembly across diversity gradients is a central matter in ecology. While many studies have explored community assembly through species average trait values, there is a growing understanding that intraspecific trait variation (ITV) can also play a critical role in species coexistence. Classic biodiversity theory hypothesizes that higher diversity at species-rich sites can arise from narrower niches relative to species-poor sites, which would be reflected in reduced ITV as species richness increases. To explore how ITV in woody plant communities changes with species richness, we compiled leaf trait data (leaf size and specific leaf area) in a total of 521 woody plant species from 21 forest communities that differed dramatically in species richness, ranging from boreal to tropical rainforests. At each forest, we assessed ITV as an estimate of species niche breadth and we quantified the degree of trait overlap among co-occurring species as a measure of species functional similarity. We found ITV was relatively invariant across the species richness gradient. In addition, we found that species functional similarity increased with diversity. Contrary to the expectation from classic biodiversity theory, our results rather suggest that neutral processes or equalizing mechanisms can be acting as potential drivers shaping community assembly in hyperdiverse forests. © This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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Ghislain, B., & Clair, B. (2017). Diversity in the organisation and lignification of tension wood fibre walls – A review. IAWA Journal, 38(2), 245–265.
Abstract: Tension wood, a tissue developed by angiosperm trees to actively recover their verticality, has long been defined by the presence of an unlignified cellulosic inner layer in the cell wall of fibres, called the G-layer. Although it was known that some species have no G-layer, the definition was appropriate since it enabled easy detection of tension wood zones using various staining techniques for either cellulose or lignin. For several years now, irrespective of its anatomical structure, tension wood has been defined by its high mechanical internal tensile stress. This definition enables screening of the diversity of cell walls in tension wood fibres. Recent results obtained in tropical species with tension wood with a delay in the lignification of the G-layer opened our eyes to the effective presence of large amounts of lignin in the G-layer of some species. This led us to review older literature mentioning the presence of lignin deposits in the G-layer and give them credit. Advances in the knowledge of tension wood fibres allow us to reconsider some previous classifications of the diversity in the organisation of the fibre walls of the tension wood. © 2017 International Association of Wood Anatomists.
Keywords: diversity; fibres; G-layer; lignification; multilayered tension wood fibre walls; S1 + S2 + S3 + G; Tension wood
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Lebrini, M., Suedile, F., & Roos, C. (2018). Corrosion inhibitory action of ethanol extract from Bagassa guianensis on the corrosion of zinc in ASTM medium. Journal of Materials and Environmental Sciences, 9(2), 414–423.
Abstract: Ethanol extract of Bagassa guianensis was tested as corrosion inhibitor for zinc in ASTM medium using polarization and electrochemical impedance spectroscopy (EIS). The results obtained show that this plant extract could serve as an effective inhibitor for the corrosion of zinc in sodium chloride media. The extract obtained give inhibition around 85%. Polarization curves show that Bagassa guianensis extract affects the anodic and cathodic reactions and the corrosion potential values were shifted to the positive potentials in the presence of the crude extract in the ASTM medium. The experimental data obtained from EIS method show a frequency distribution and therefore a modelling element with frequency dispersion behavior, a constant phase element (CPE alpha,Q ) has been used. Graphical methods are illustrated by synthetic data to determine the parameter of CPE (alpha, Q). Studies on the phytochemical constituents of thetotal extract were also established. Electrochemical studies, on the chemical families present in the crude extract, were also carried out to find the main constituents responsible for corrosion inhibition properties of the plant extract.
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Pétillon, J., Leroy, B., Djoudi, E. A., & Vedel, V. (2018). Small and large spatial scale coexistence of ctenid spiders in a neotropical forest (French Guiana). Tropical Zoology, 31(2), 85–98.
Abstract: While spiders constitute the most abundant and diverse arthropods in many habitats, they remained under-studied, especially in tropical rainforests. The goal of this study is to assess the spatial distribution of the spider family Ctenidae by assessing associations of species diversity and population traits among different habitat conditions. Fieldwork was carried out during 2013 in habitats varying in flooding frequency (plateau vs. flooded forest) and elevation (inselberg vs. lowland) in the Nouragues National Natural Reserve, French Guiana. Assemblage composition, population structure, and trait measurements of one dominant species were assessed using hand collection in replicated quadrats. We found strong effects on ctenid assemblages attributable to both elevation and flooding, with changes in relative abundance of species among habitats, but few correlated densities between species. At the population level, main differences in species distribution between and within habitats were detected only when juveniles were taken into account. No effect of elevation was found on the measurements of traits of the dominant species, but legs were proportionally shorter in flooded habitats, suggesting reduced active dispersal in these habitats. Our study highlights the value of complementary of measures of diversity and traits at different biological scales in Ctenidae.
Keywords: Araneae; flooding; Guianese shield; inselberg; juveniles
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