Sebbenn, A. M., Blanc-Jolivet, C., Mader, M., Meyer-Sand, B. R. V., Paredes-Villanueva, K., Honorio Coronado, E. N., et al. (2019). Nuclear and plastidial SNP and INDEL markers for genetic tracking studies of Jacaranda copaia. Conserv. Gen. Res., 11(3), 341–343.
Abstract: Nuclear and plastidial single nucleotide polymorphism (SNP) and INDEL markers were developed using restriction associated DNA sequencing (RADSeq) and low coverage MiSeq genome sequencing for population genetics and timber tracking purposes in the Neotropical timber species Jacaranda copaia. We used 407 nuclear SNPs, 29 chloroplast, and 31 mitochondrial loci to genotype 92 individuals from Brazil, Bolivia, French Guiana, and Peru. Based on high amplification rates and genetic differentiation among populations, 113 nuclear SNPs, 11 chloroplast, and 4 mitochondrial loci were selected, and their use validated for genetic tracking of timber origin.
Keywords: DNA fingerprints; Geographical origin; Jacaranda copaia; MassARRAY; MiSeq; RADSeq; Tropical timber
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Schepaschenko, D., Chave, J., Phillips, O. L., Lewis, S. L., Davies, S. J., Réjou-Méchain, M., et al. (2019). The Forest Observation System, building a global reference dataset for remote sensing of forest biomass. Scientific data, 6(198).
Abstract: Forest biomass is an essential indicator for monitoring the Earth's ecosystems and climate. It is a critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies such as REDD+, among others. Wall-to-wall mapping of aboveground biomass (AGB) is now possible with satellite remote sensing (RS). However, RS methods require extant, up-to-date, reliable, representative and comparable in situ data for calibration and validation. Here, we present the Forest Observation System (FOS) initiative, an international cooperation to establish and maintain a global in situ forest biomass database. AGB and canopy height estimates with their associated uncertainties are derived at a 0.25 ha scale from field measurements made in permanent research plots across the world's forests. All plot estimates are geolocated and have a size that allows for direct comparison with many RS measurements. The FOS offers the potential to improve the accuracy of RS-based biomass products while developing new synergies between the RS and ground-based ecosystem research communities.
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Ruiz-González, M. X., Leroy, C., Dejean, A., Gryta, H., Jargeat, P., Carrión, A. D. A., et al. (2019). Do host plant and associated ant species affect microbial communities in myrmecophytes? Insects, 10(11), 391.
Abstract: Ant-associated microorganisms can play crucial and often overlooked roles, and given the diversity of interactions that ants have developed, the study of the associated microbiomes is of interest. We focused here on specialist plant-ant species of the genus Allomerus that grow a fungus to build galleries on their host-plant stems. Allomerus-inhabited domatia, thus, might be a rich arena for microbes associated with the ants, the plant, and the fungus. We investigated the microbial communities present in domatia colonised by four arboreal ants: Allomerus decemarticulatus, A. octoarticulatus, A. octoarticulatus var. demerarae, and the non-fungus growing plant-ant Azteca sp. cf. depilis, inhabiting Hirtella physophora or Cordia nodosa in French Guiana. We hypothesized that the microbial community will differ among these species. We isolated microorganisms from five colonies of each species, sequenced the 16S rRNA or Internal TranscribedSpacer (ITS) regions, and described both the alpha and beta diversities. We identified 69 microbial taxa, which belong to five bacterial and two fungal phyla. The most diverse phyla were Proteobacteria and Actinobacteria. The microbial community of Azteca cf. depilis and Allomerus spp. differed in composition and richness. Geographical distance affected microbial communities and richness but plant species did not. Actinobacteria were only associated with Allomerus spp.
Keywords: Allomerus decemarticulatus; Allomerus octoarticulatus; Azteca sp; Cf; Cordia nodosa; Depilis; Domatia; Hirtella physophora; Microbial diversity
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Rodrigues, A. M. S., Eparvier, V., Odonne, G., Amusant, N., Stien, D., & Houël, E. (2019). The antifungal potential of (Z)-ligustilide and the protective effect of eugenol demonstrated by a chemometric approach. Sci. Rep., 9, 8729.
Abstract: Mankind is on the verge of a postantibiotic era. New concepts are needed in our battle to attenuate infectious diseases around the world and broad spectrum plant-inspired synergistic pharmaceutical preparations should find their place in the global fight against pathogenic microorganisms. To progress towards the discovery of potent antifungal agents against human pathologies, we embarked upon developing chemometric approach coupled with statistical design to unravel the origin of the anticandidal potential of a set of 66 essential oils (EOs). EOs were analyzed by GC-MS and tested against Candida albicans and C. parapsilosis (Minimal Inhibitory Concentration, MIC). An Orthogonal Partial Least Square (OPLS) analysis allowed us to identify six molecules presumably responsible for the anticandidal activity of the oils: (Z)-ligustilide, eugenol, eugenyl acetate, citral, thymol, and β-citronellol. These compounds were combined following a full factorial experimental design approach in order to optimize the anticandidal activity and selectivity index (SI = IC50(MRC5 cells)/MIC) through reconstituted mixtures. (Z)-Ligustilide and citral were the most active compounds, while (Z)-ligustilide and eugenol were the two main factors that most contributed to the increase of the SI. These two terpenes can, therefore, be used to construct bioinspired synergistic anticandidal mixtures. © 2019, The Author(s).
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Richard-Hansen, C., Davy, D., Longin, G., Gaillard, L., Renoux, F., Grenand, P., et al. (2019). Hunting in French Guiana Across Time, Space and Livelihoods. Frontiers in Ecology and Evolution, 7, 289.
Abstract: Hunting sustainability in Amazonian ecosystems is a key challenge for modern stakeholders. Predictive models have evolved from first mostly biological data-based to more recent modelling including human behavior. We analyze here the hunting data collected in French Guiana through a panel of indices aiming at drawing the puzzle of parameters influencing hunting activity and impact in various socio ecological conditions across the country. Data were collected from five different study sites differing in cultural origins and remoteness from market economy, and over a ten years period. Most indices show an impact on wildlife populations, and using a full set of indicators allowed us to better understand some underlying mechanisms that lead to a community’s hunting profile. The results showed that there are noticeable differences between the study sites in the practices and the ways hunters face the changes in environment and resources availability
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Prunier, J., Maurice, L., Perez, E., Gigault, J., Pierson Wickmann, A. - C., Davranche, M., et al. (2019). Trace metals in polyethylene debris from the North Atlantic subtropical gyre. Environ. Pollut., 245, 371–379.
Abstract: Plastic pollution in the marine environment poses threats to wildlife and habitats through varied mechanisms, among which are the transport and transfer to the food web of hazardous substances. Still, very little is known about the metal content of plastic debris and about sorption/desorption processes, especially with respect to weathering. In this study, plastic debris collected from the North Atlantic subtropical gyre was analyzed for trace metals; as a comparison, new packaging materials were also analyzed. Both the new items and plastic debris showed very scattered concentrations. The new items contained significant amounts of trace metals introduced as additives, but globally, metal concentrations were higher in the plastic debris. The results provide evidence that enhanced metal concentrations increase with the plastic state of oxidation for some elements, such as As, Ti, Ni, and Cd. Transmission electron microscopy showed the presence of mineral particles on the surface of the plastic debris. This work demonstrates that marine plastic debris carries complex mixtures of heavy metals. Such materials not only behave as a source of metals resulting from intrinsic plastic additives but also are able to concentrate metals from ocean water as mineral nanoparticles or adsorbed species. Plastic debris collected from the North Atlantic subtropical gyre was analyzed for trace metals. Marine plastic debris carry complex mixtures of heavy metals but it is evidence that plastic oxidation favors their adsorption.
Keywords: metals'accumulation; Microplastic; Plastic debris; Polyethylene; Polymer
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Piponiot, C., Rutishauser, E., Derroire, G., Putz, F. E., Sist, P., West, T. A. P., et al. (2019). Optimal strategies for ecosystem services provision in Amazonian production forests. Environmental Research Letters, 14(12), 124090.
Abstract: Although tropical forests harbour most of the terrestrial carbon and biological diversity on Earth they continue to be deforested or degraded at high rates. In Amazonia, the largest tropical forest on Earth, a sixth of the remaining natural forests is formally dedicated to timber extraction through selective logging. Reconciling timber extraction with the provision of other ecosystem services (ES) remains a major challenge for forest managers and policy-makers. This study applies a spatial optimisation of logging in Amazonian production forests to analyse potential trade-offs between timber extraction and recovery, carbon storage, and biodiversity conservation. Current logging regulations with unique cutting cycles result in sub-optimal ES-use efficiency. Long-term timber provision would require the adoption of a land-sharing strategy that involves extensive low-intensity logging, although high transport and road-building costs might make this approach economically unattractive. By contrast, retention of carbon and biodiversity would be enhanced by a land-sparing strategy restricting high-intensive logging to designated areas such as the outer fringes of the region. Depending on management goals and societal demands, either choice will substantially influence the future of Amazonian forests. Overall, our results highlight the need for revaluation of current logging regulations and regional cooperation among Amazonian countries to enhance coherent and trans-boundary forest management.
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Piponiot, C., Rödig, E., Putz, F. E., Rutishauser, E., Sist, P., Ascarrunz, N., et al. (2019). Can timber provision from Amazonian production forests be sustainable? Environmental Research Letters, 14(6), 064014.
Abstract: Around 30 Mm3 of sawlogs are extracted annually by selective logging of natural production forests in Amazonia, Earth’s most extensive tropical forest. Decisions concerning the management of these production forests will be of major importance for Amazonian forests’ fate. To date, no regional assessment of selective logging sustainability supports decision-making. Based on data from 3500 ha of forest inventory plots, our modelling results show that the average periodic harvests of 20 m3 ha−1 will not recover by the end of a standard 30 year cutting cycle. Timber recovery within a cutting cycle is enhanced by commercial acceptance of more species and with the adoption of longer cutting cycles and lower logging intensities. Recovery rates are faster in Western Amazonia than on the Guiana Shield. Our simulations suggest that regardless of cutting cycle duration and logging intensities, selectively logged forests are unlikely to meet timber demands over the long term as timber stocks are predicted to steadily decline. There is thus an urgent need to develop an integrated forest resource management policy that combines active management of production forests with the restoration of degraded and secondary forests for timber production. Without better management, reduced timber harvests and continued timber production declines are unavoidable.
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Peguero, G., Sardans, J., Asensio, D., Fernández-Martínez, M., Gargallo-Garriga, A., Grau, O., et al. (2019). Nutrient scarcity strengthens soil fauna control over leaf litter decomposition in tropical rainforests. Proc. Biol. Sci., 286(1910), 20191300.
Abstract: Soil fauna is a key control of the decomposition rate of leaf litter, yet its interactions with litter quality and the soil environment remain elusive. We conducted a litter decomposition experiment across different topographic levels within the landscape replicated in two rainforest sites providing natural gradients in soil fertility to test the hypothesis that low nutrient availability in litter and soil increases the strength of fauna control over litter decomposition. We crossed these data with a large dataset of 44 variables characterizing the biotic and abiotic microenvironment of each sampling point and found that microbe-driven carbon (C) and nitrogen (N) losses from leaf litter were 10.1 and 17.9% lower, respectively, in the nutrient-poorest site, but this among-site difference was equalized when meso- and macrofauna had access to the litterbags. Further, on average, soil fauna enhanced the rate of litter decomposition by 22.6%, and this contribution consistently increased as nutrient availability in the microenvironment declined. Our results indicate that nutrient scarcity increases the importance of soil fauna on C and N cycling in tropical rainforests. Further, soil fauna is able to equalize differences in microbial decomposition potential, thus buffering to a remarkable extent nutrient shortages at an ecosystem level.
Keywords: biogeochemistry; extracellular enzyme activity; litter decomposition; nutrients; soil fauna
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Odonne, G., van den Bel, M., Burst, M., Brunaux, O., Bruno, M., Dambrine, E., et al. (2019). Long-term influence of early human occupations on current forests of the Guiana Shield. Ecology, 100(10), e02806.
Abstract: To decipher the long-term influences of pre-Columbian land occupations on contemporary forest structure, diversity, and functioning in Amazonia, most of the previous research focused on the alluvial plains of the major rivers of the Amazon basin. Terra firme, that is, nonflooded forests, particularly from the Guiana Shield, are yet to be explored. In this study, we aim to give new insights into the subtle traces of pre-Columbian influences on present-day forests given the archaeological context of terra firme forests of the Guiana Shield. Following archaeological prospects on 13 sites in French Guiana, we carried out forest inventories inside and outside archaeological sites and assessed the potential pre-Columbian use of the sampled tree species using an original ethnobotanical database of the Guiana Shield region. Aboveground biomass (320 and 380 T/ha, respectively), basal area (25–30 and 30–35 m2/ha, respectively), and tree density (550 and 700 stem/ha, respectively) were all significantly lower on anthropized plots (As) than on nonanthropized plots (NAs). Ancient human presence shaped the species composition of the sampled forests with Arecaceae, Burseraceae, and Lauraceae significantly more frequent in As and Annonaceae and Lecythidaceae more frequent in NAs. Although alpha diversity was not different between As and NAs, the presence of pre-Columbian sites enhances significantly the forest beta diversity at the landscape level. Finally, trees with edible fruits are positively associated with pre-Columbian sites, whereas trees used for construction or for their bark are negatively associated with pre-Columbian sites. Half a millennium after their abandonment, former occupied places from the inner Guiana Shield still bear noticeable differences with nonanthropized places. Considering the lack of data concerning archaeology of terra firme Amazonian forests, our results suggest that pre-Columbian influences on the structure (lower current biomass), diversity (higher beta diversity), and composition (linked to the past human tree uses) of current Amazonian forests might be more important than previously thought. © 2019 by the Ecological Society of America
Keywords: Amazonian forest; archaeology; ethnobotany; Guiana Shield; historical ecology; pre-Columbian settlements; ring-ditched hills; alluvial plain; anthropogenic effect; archaeology; basal area; database; ethnobotany; forest ecosystem; historical ecology; occupation; paleoecology; species diversity; Amazonia; French Guiana; Guyana Shield; Annonaceae; Arecaceae; Burseraceae; Lauraceae; Lecythidaceae; Brazil; forest; French Guiana; human; occupation; tree; Brazil; Forests; French Guiana; Humans; Occupations; Trees
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