Abstract: Background and aims – The evolutionary history of Amazonia’s hyperabundant tropical tree species, also known as “hyperdominant” species, remains poorly investigated. We assessed whether the hyperdominant Eschweilera coriacea (DC.) S.A.Mori (Lecythidaceae) represents a single genetically cohesive species, and how its genetic constitution relates to other species from the same clade with which it occurs sympatrically in French Guiana. Methods – We sampled 152 individuals in nine forest sites in French Guiana, representing 11 species of the genus Eschweilera all belonging to the Parvifolia clade, with emphasis on E. coriacea. Samples were genotyped at four simple sequence repeat (SSR) markers. We delimited gene pools, i.e., genetically coherent putative taxa, using STRUCTURE software and principal component analysis. We compared the genetic assignment of individuals with their morphological species determination and estimated genetic diversity and differentiation for gene pools and species. We also estimated genome size using flow cytometry. Key results – SSR profiles commonly displayed up to four alleles per genotype, suggesting that the investigated Eschweilera species bear a paleopolyploid signature. Flow cytometry suggested that the studied species are diploid with haploid genome sizes of 871–1046 Mbp. We detected five gene pools and observed a good correspondence between morphological and genetic delimitation for Eschweilera sagotiana Miers and the undescribed morphospecies E. sp. 3 (which resembles E. grandiflora (Aubl.) Sandwith), and to a lesser extent for E. decolorans Sandwith and E. micrantha (O.Berg) Miers. Eschweilera coriacea was the most genetically diverse species and included individuals assigned to each gene pool. Conclusions – We found no conclusive evidence for cryptic species within E. coriacea in French Guiana. SSRs detected fewer gene pools than expected based on morphology in the Parvifolia clade but discriminated evolutionary relationships better than available plastid markers. A positive trend between demographic abundance of species and allelic richness illustrates that hyperdominants may have a high evolutionary potential. This hypothesis can be tested using more powerful genomic data in combination with tree phenotypic trait variation and characterization of niche breadth, to enhance our understanding of the causes of hyperdominance in Amazonian trees.

Abstract: The components of ecosystem evapotranspiration of a Norway spruce forest (Picea abies L.) as well as the vertical structure of canopy evapotranspiration were analyzed with a combination of measurements and models for a case study of 5 days in September 2007. Eddy-covariance and sap flux measurements were performed at several heights within the canopy at the FLUXNET site Waldstein-Weidenbrunnen (DE-Bay) in the Fichtelgebirge mountains in Germany. Within and above canopy fluxes were simulated with two stand-scale models, the 1D multilayer model ACASA that includes a third-order turbulence closure and the 3D model STANDFLUX. The soil and understory evapotranspiration captured with the eddy-covariance system in the trunk space constituted 10% of ecosystem evapotranspiration measured with the eddy-covariance system above the canopy. A comparison of transpiration measured with the sap flux technique and inferred from below and above canopy eddy-covariance systems revealed higher estimates from eddy-covariance measurements than for sap flux measurements. The relative influences of possible sources of this mismatch, such as the assumption of negligible contribution of evaporation from intercepted water, and differences between the eddy-covariance flux footprint and the area used for scaling sap flux measurements, were discussed. Ecosystem evapotranspiration as well as canopy transpiration simulated with the two models captured the dynamics of the measurements well, but slightly underestimated eddy-covariance values. Profile measurements and models also gave us the chance to assess in-canopy profiles of canopy evapotranspiration and the contributions of in-canopy layers. For daytime and a coupled or partly coupled canopy, mean simulated profiles of both models agreed well with eddy-covariance measurements, with a similar performance of the ACASA and the STANDFLUX model. Both models underestimated profiles for nighttime and decoupled conditions. During daytime, the upper half of the canopy contributed approximately 80% to canopy evapotranspiration, whereas during nighttime the contribution shifted to lower parts of the canopy. © 2010 Elsevier B.V.

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.

Abstract: Ethnopharmacological relevance: Up until now, the plant pharmacopoeia of the Chayahuita, an ethnic group from the Peruvian Amazon, has been poorly defined. This paper details the uses of medicinal plants within this community, as recorded in two villages of the Paranapura basin, Soledad and Atahualpa de Conchiyacu. This study aimed to describe the basis of the Chayahuita traditional medical system, to document part of the medicinal plant corpus, and to compare it with data from other Amazonian ethnic groups. Material and methods: Methodology was based (i) on field prospection with 26 informants (ethnobotanical walks methodology), (ii) semi-structured interviews including 93 people (49 men and 44 women) focused on the most recent health problem experienced and on the therapeutic options chosen, (iii) individual or group thematic discussions relating to disease and treatments, (iv) 6-months of participants' observations between May 2007 and May 2008. At the end of the project in May 2008 a workshop was organized to cross-check the data with the help of 12 of the most interested informants. Results: Six hundred and seventeen voucher specimens were collected, corresponding to 303 different species, from which 274 (belonging to 83 families) are documented here. Altogether 492 recipes were recorded, corresponding to a global figure of 541 therapeutic uses and a total of 664 use reports. The main therapeutic uses are related to dermatological problems (103 uses; 19%), gastro-intestinal complaints (69 uses; 13%) and malaria/fevers (52 uses; 10%). Diseases are analysed according to Chayahuita concepts, and for each disease the species having a high frequency of citation are listed, and the most frequently used remedies are described. Whenever possible, comparisons with other Amazonian groups have been drawn. Conclusion: Chayahuita nosology and medical ethnobotany appear to draw their inspiration from a common panamazonian root. Despite the fact that a certain number of medicinal plants are shared with other nearby groups, there seem to be specific uses for some species, thus highlighting the originality of the Chayahuita pharmacopoeia. Presently there is a certain disinterest in the most traditional area of the Chayahuita medical ways, and the role of the penutu (shaman) seems to be less highly-valued than in the past. Nonetheless, the use of medicinal plants in phytotherapeutic treatment is very much a living, shared knowledge. © 2012 Elsevier Ireland Ltd. All rights reserved.

Abstract: Insects, particularly ants, are good bioindicators of the state of ecosystems. Nevertheless, incorporating them into conservation surveys is expensive due to problems associated with their identification, which is exacerbated by the fact that there are fewer and fewer taxonomists working today. “Taxonomic sufficiency” (TS), which identifies organisms to a level of taxonomic resolution sufficient enough to satisfy the objectives of a study, has never been applied to Neotropical ant communities. We analysed five Neotropical datasets representing ant assemblages collected with different sampling methods in various habitats. We first treated them using two complementary and cumulative TS methods, higher-taxon and “indicator taxa” surrogacies, before testing a new approach called “mixed-level method” that combines the two previous approaches. For the higher-taxon surrogacy, we showed that, above species, genus is the most informative taxonomic level. Then, mixed-level method provided more information on ant assemblages than did the two others, even though the “indicator taxa” surrogacy was based on relevant indicator genera. Although habitat type has no effect on its efficiency, this new method is influenced by the dataset structure and the type of sampling method used to collect data. We have thus developed a new method for analyzing Neotropical ant faunas that enables the taxonomic work linked to the identification of problematic species to be significantly reduced, while conserving most of the information on the ant assemblage. This method should enhance the work of Neotropical entomologists not specialised in taxonomy, particularly those concerned with biological conservation and indication. (C) 2010 Elsevier Ltd. All rights reserved.