| Records |
| Author |
Conte, D.E.; Aboulaich, A.; Robert, F.; Olivier-Fourcade, J.; Jumas, J.C.; Jordy, C.; Willmann, P. |
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Sn-x[BPO4](1-x) composites as negative electrodes for lithium ion cells: Comparison with amorphous SnB0.6P0.4O2.9 and effect of composition |
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Journal Article |
| Year |
2010 |
Publication |
Journal of Solid State Chemistry |
Abbreviated Journal |
J. Solid State Chem. |
Volume  |
183 |
Issue |
1 |
Pages |
65-75 |
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Sn-based composites; Lithium-ion batteries; Negative electrodes; Mossbauer spectroscopy; LixSn alloys |
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A comparative study of two Sn-based composite materials as negative electrode for Li-ion accumulators is presented. The former SnB0.6P0.4O2.9 obtained by in-situ dispersion of SnO in an oxide matrix is shown to be an amorphous tin composite oxide (ATCO). The latter Sn-0.72[BPO4](0.28) obtained by ex-situ dispersion of Sri in a borophosphate matrix consists of Sri particles embedded in a crystalline BPO4 matrix. The electrochemical responses of ATCO and Sn-0.72.[BPO4](0.28) composite in galvanostatic mode show reversible capacities of about 450 and 530 mAhg(-1), respectively, with different irreversible capacities (60% and 29%). Analysis of these composite materials by Sn-119 Mossbauer spectroscopy in transmission (TMS) and emission (CEMS) modes confirms that ATCO is an amorphous Sn-II composite oxide and shows that in the case of Sn-0.72[BPO4](0.28), the Surface of the tin clusters is mainly formed by Sn-II in an amorphous interface whereas the bulk of the clusters is mainly formed by Sn-0. The determination of the recoilless free fractions f (Lamb-Mossbauer factors) leads to the effective fraction of both Sn-0 and Sn-II species in such composites. The influence of chemical composition and especially of the surface-to-bulk tin species ratio oil the electrochemical behaviour has been analysed for several Sn-x[BPO4](1-x) composite materials (0.17 < x < 0.91). The cell using the compound Sn-0.72[BPO4](0.28) as active material exhibits interesting electrochemical performances (reversible capacity of 500 mAh g(-1) at C/5 rate). (C) 2009 Elsevier Inc. All rights reserved. |
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[Conte, Donato Ercole; Aboulaich, Abdelmaula; Robert, Florent; Olivier-Fourcade, Josette; Jumas, Jean-Claude] Univ Montpellier 2, CNRS, UMR 5253,Inst Charles Gerhardt, Equipe Agregats Interfaces & Mat Energie, F-34095 Montpellier, France, Email: iguanasornione@libero.it |
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ACADEMIC PRESS INC ELSEVIER SCIENCE |
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0022-4596 |
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ISI:000273834600010 |
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EcoFoG @ eric.marcon @ |
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83 |
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Leroy, C.; Corbara, B.; Dejean, A.; Cereghino, R. |
| Title |
Ants mediate foliar structure and nitrogen acquisition in a tank-bromeliad |
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Journal Article |
| Year |
2009 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
| Volume |
183 |
Issue |
4 |
Pages |
1124-1133 |
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Aechmea mertensii; antgardens; Camponotus femoratus; foliar structure; delta N-15; Pachycondyla goeldii; phytotelmata contents |
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Aechmea mertensii is a tank-bromeliad that roots on ant-gardens initiated by the ants Camponotus femoratus and Pachycondyla goeldii. Its leaves form compartments acting as phytotelmata that hold rainwater and provide habitats for invertebrates. In this article, we aimed to determine whether the association with either C. femoratus or P. goeldii influenced the vegetative traits of A. mertensii, invertebrate diversity and nutrient assimilation by the leaves. Transmitted light, vegetative traits and phytotelmata contents were compared between the two A. mertensii ant-gardens. Camponotus femoratus colonized partially shaded areas, whereas P. goeldii colonized exposed areas. The bromeliads' rosettes had a large canopy (C. femoratus ant-gardens), or were smaller and amphora shaped (P. goeldii ant-gardens). There were significant differences in leaf anatomy, as shaded leaves were thicker than exposed leaves. The mean volumes of water, fine particulate organic matter and detritus in C. femoratus-associated bromeliads were three to five times higher than in P. goeldii-associated bromeliads. Moreover, the highest invertebrate diversity and leaf delta N-15 values were found in C. femoratus-associated bromeliads. This study enhances our understanding of the dynamics of biodiversity, and shows how ant-plant interactions can have trophic consequences and thus influence the architecture of the interacting plant via a complex feedback loop. |
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[Leroy, Celine; Dejean, Alain] EcoFoG, CNRS, UMR 8172, F-97379 Kourou, France, Email: Celine.Leroy@ecofog.gf |
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WILEY-BLACKWELL PUBLISHING, INC |
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0028-646X |
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ISI:000268855300020 |
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EcoFoG @ eric.marcon @ |
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106 |
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Salas-Lopez, A.; Mickal, H.; Menzel, F.; Orivel, J. |
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Ant-mediated ecosystem processes are driven by trophic community structure but mainly by the environment |
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Journal Article |
| Year |
2017 |
Publication |
Oecologia |
Abbreviated Journal |
Oecologia |
| Volume |
183 |
Issue |
1 |
Pages |
249-261 |
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The diversity and functional identity of organisms are known to be relevant to the maintenance of ecosystem processes but can be variable in different environments. Particularly, it is uncertain whether ecosystem processes are driven by complementary effects or by dominant groups of species. We investigated how community structure (i.e., the diversity and relative abundance of biological entities) explains the community-level contribution of Neotropical ant communities to different ecosystem processes in different environments. Ants were attracted with food resources representing six ant-mediated ecosystem processes in four environments: ground and vegetation strata in cropland and forest habitats. The exploitation frequencies of the baits were used to calculate the taxonomic and trophic structures of ant communities and their contribution to ecosystem processes considered individually or in combination (i.e., multifunctionality). We then investigated whether community structure variables could predict ecosystem processes and whether such relationships were affected by the environment. We found that forests presented a greater biodiversity and trophic complementarity and lower dominance than croplands, but this did not affect ecosystem processes. In contrast, trophic complementarity was greater on the ground than on vegetation and was followed by greater resource exploitation levels. Although ant participation in ecosystem processes can be predicted by means of trophic-based indices, we found that variations in community structure and performance in ecosystem processes were best explained by environment. We conclude that determining the extent to which the dominance and complementarity of communities affect ecosystem processes in different environments requires a better understanding of resource availability to different species. |
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1432-1939 |
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EcoFoG @ webmaster @ Salas-Lopez2017 |
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715 |
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Medjigbodo, G.; Rozière, E.; Charrier, K.; Izoret, L.; Loukili, A. |
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Hydration, shrinkage, and durability of ternary binders containing Portland cement, limestone filler and metakaolin |
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Journal Article |
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2018 |
Publication |
Construction and Building Materials |
Abbreviated Journal |
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183 |
Issue |
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114-126 |
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Durability; Limestone filler; Metakaolin; Shrinkage; Strength; Ternary binders |
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A partial replacement of the clinker by latent hydraulic or pozzolanic materials is encouraged due to environmental and specific technical requirements. Such substitution remains limited to a relatively low level (less than 30% by mass of cementitious materials). An experimental research work was carried out on mortars made with binary and ternary binders (Portland cement; metakaolin; limestone filler) to reach 45% total replacement. In order to investigate the activating effect of reduced water-to-cement ratio, two series of mixtures were designed with W/C0 of 0.42 and 0.5. Their heat of hydration, portlandite content, shrinkage, porosity, and carbonation were monitored. The tests were performed to understand the evolution of their relative strength (activity index) and durability parameters. The strength development of mortars with ternary binders was found to depend on metakaolin properties, including manufacturing process and particle size distribution. Reducing W/C0 ratio accelerated pozzolanic reaction and allowed improving early-age strength and durability parameters. © 2018 Elsevier Ltd |
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Association Technique de l'Industrie des Liants Hydrauliques (ATILH), 7 place de la Défense, Paris La Défense, 92974, France |
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Export Date: 1 September 2018 |
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EcoFoG @ webmaster @ |
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814 |
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Perrin, A.-S.; Fujisaki, K.; Petitjean, C.; Sarrazin, M.; Godet, M.; Garric, B.; Horth, J.-C.; Balbino, L.C.; Filho, A.S.; de Almeida Machado, P.L.O.; Brossard, M. |
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Conversion of forest to agriculture in Amazonia with the chop-and-mulch method: Does it improve the soil carbon stock? |
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Journal Article |
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2014 |
Publication |
Agriculture, Ecosystems and Environment |
Abbreviated Journal |
Agric. Ecosyst. Environ. |
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184 |
Issue |
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101-114 |
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Annual crops; Brachiaria; Deforestation; Fire-free; French Guiana; No-tillage |
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Fire-free forest conversion with organic inputs as an alternative to slash-and-burn could improve agro-ecosystem sustainability. We assessed soil carbon mass changes in a sandy-clayey and well-drained soil in French Guiana after forest clearing by the chop-and-mulch method and crop establishment. At the experimental site of Combi, native forest was cut down in October 2008; woody biomass was chopped and incorporated into the top 20cm of soil. After about one year of legume and grass cover, three forms of land management were compared: grassland (Urochloa ruziziensis), maize/soybean crop rotation with disk tillage and in direct seeding without tillage. There were four replicates. We measured 14.16kgm-2 of carbon in 2mm-sieved soil down to 2m depth for the initial forest. Forest clearing did not induce significant soil compaction; neither did any specific agricultural practice. In converted soils, C stocks were measured in the 0-30cm layer after each crop for three years. Carbon mass changes for soil fractions <2mm (soil C stock) and >2mm (soil C pool) in the 0-5, 5-10, 10-20 and 20-30cm soil layers were assessed on an equivalent soil mass basis. One year and 1.5 years after deforestation, higher C stocks (+0.64 to 1.16kgCm-2yr-1) and C pools (+0.52 to 0.90kgCm-2yr-1) were measured in converted soils, compared to those of the forest into the top 30cm of soil. However, the masses of carbon in these converted soils declined later. The highest rates of carbon decrease were measured between 1.5 and 2 years after forest conversion in the <2mm soil fraction, from 0.46kgCm-2yr-1 (in grassland soils) to 0.71kgCm-2yr-1 (in cropland under no tillage). The carbon pool declined during the third year at rates of 0.41kgCm-2yr-1 (cropland under disk tillage) to 0.76kgCm-2yr-1 (grassland soils). Three years after forest conversion, C masses in the top 30cm of soils for grassland showed similar values than for forest. In comparison, the carbon stock in cropped soils managed under no tillage in direct seeding (without mulch) was significantly 17% and 16% lower than in forest and grassland soils, respectively. None of the studied agricultural practices succeeded in accumulating carbon from the chopped forest biomass. © 2013 Elsevier B.V. |
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EMBRAPA Arroz e Feijao, Cx Postal 179, CEP 75375-000 Santo Antonio de Goias, GO, Brazil |
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01678809 (Issn) |
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Export Date: 2 January 2014; Source: Scopus; Coden: Aeend; doi: 10.1016/j.agee.2013.11.009 |
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EcoFoG @ webmaster @ |
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521 |
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Martos, F.; Dulormne, M.; Pailler, T.; Bonfante, P.; Faccio, A.; Fournel, J.; Dubois, M.-P.; Selosse, M.-A. |
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Independent recruitment of saprotrophic fungi as mycorrhizal partners by tropical achlorophyllous orchids |
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Journal Article |
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2009 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytologist |
| Volume |
184 |
Issue |
3 |
Pages |
668-681 |
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Mycoheterotrophy; Mycorrhizas; Orchids; Rainforests; Saprotrophic fungi; Stable isotopes |
| Abstract |
Mycoheterotrophic orchids have adapted to shaded forest understory by shifting to achlorophylly and receiving carbon from their mycorrhizal fungi. In temperate forests, they associate in a highly specific way with fungi forming ectomycorrhizas on nearby trees, and exploiting tree photosynthates. However, many rainforests lack ectomycorrhizal fungi, and there is evidence that some tropical Asiatic species associate with saprotrophic fungi. To investigate this in different geographic and phylogenetic contexts, we identified the mycorrhizal fungi supporting two tropical mycoheterotrophic orchids from Mascarene (Indian Ocean) and Caribbean islands. We tested their possible carbon sources by measuring natural nitrogen (15N) and carbon (13C) abundances. Saprotrophic basidiomycetes were found: Gastrodia similis associates with a wood-decaying Resinicium (Hymenochaetales); Wullschlaegelia aphylla associates with both litter-decaying Gymnopus and Mycena species, whose rhizomorphs link orchid roots to leaf litter. The 15N and 13C abundances make plausible food chains from dead wood to G. similis and from dead leaves to W. aphylla. We propose that temperature and moisture in rainforests, but not in most temperate forests, may favour sufficient saprotrophic activity to support development of mycoheterotrophs. By enlarging the spectrum of mycorrhizal fungi and the level of specificity in mycoheterotrophic orchids, this study provides new insights on orchid and mycorrhizal biology in the tropics. © 2009 New Phytologist. |
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Dipartimento di Biologia Vegetale dell'Università, Istituto per la Protezione Delle Piante – CNR, Viale Mattioli 25, I-10125 Torino, Italy |
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Cited By :65; Export Date: 7 February 2017 |
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EcoFoG @ webmaster @ |
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728 |
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Phillips, O.L.; van der Heijden, G.; Lewis, S.L.; Lopez-Gonzalez, G.; Aragao, L.E.O.C.; Lloyd, J.; Malhi, Y.; Monteagudo, A.; Almeida, S.; Davila, E.A.; Amaral, I.; Andelman, S.; Andrade, A.; Arroyo, L.; Aymard, G.; Baker, T.R.; Blanc, L.; Bonal, D.; de Oliveira, A.C.A.; Chao, K.J.; Cardozo, N.D.; da Costa, L.; Feldpausch, T.R.; Fisher, J.B.; Fyllas, N.M.; Freitas, M.A.; Galbraith, D.; Gloor, E.; Higuchi, N.; Honorio, E.; Jimenez, E.; Keeling, H.; Killeen, T.J.; Lovett, J.C.; Meir, P.; Mendoza, C.; Morel, A.; Vargas, P.N.; Patino, S.; Peh, K.S.H.; Cruz, A.P.; Prieto, A.; Quesada, C.A.; Ramirez, F.; Ramirez, H.; Rudas, A.; Salamao, R.; Schwarz, M.; Silva, J.; Silveira, M.; Slik, J.W.F.; Sonke, B.; Thomas, A.S.; Stropp, J.; Taplin, J.R.D.; Vasquez, R.; Vilanova, E. |
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Drought-mortality relationships for tropical forests |
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Journal Article |
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2010 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
| Volume |
187 |
Issue |
3 |
Pages |
631-646 |
| Keywords |
Amazon; Borneo; drought; lags mortality; RAINFOR; trees; tropics |
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The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality. |
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[Phillips, Oliver L.; van der Heijden, Geertje; Lewis, Simon L.; Lopez-Gonzalez, Gabriela; Lloyd, Jon; Baker, Tim R.; Chao, Kuo-Jung; Feldpausch, Ted R.; Fyllas, Nikolaos M.; Gloor, Emanuel; Honorio, Euridice; Keeling, Helen; Quesada, Carlos A.; Schwarz, Michael] Univ Leeds, Sch Geog, Leeds LS2 9JT, W Yorkshire, England, Email: o.phillips@leeds.ac.uk |
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WILEY-BLACKWELL PUBLISHING, INC |
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0028-646X |
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ISI:000280122500028 |
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EcoFoG @ eric.marcon @ |
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50 |
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Dejean, A.; Céréghino, R.; Leponce, M.; Rossi, V.; Roux, O.; Compin, A.; Delabie, J.H.C.; Corbara, B. |
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The fire ant Solenopsis saevissima and habitat disturbance alter ant communities |
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Journal Article |
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2015 |
Publication |
Biological Conservation |
Abbreviated Journal |
Biological Conservation |
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187 |
Issue |
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145-153 |
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Ant community; Fire ants; Invasive species; Species coexistence; Supercoloniality |
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The fire ant Solenopsis saevissima is a major pest frequent in human-disturbed areas of its native range where it forms 'supercolonies'. We determined that its natural habitat in French Guiana is likely the sporadically flooded riparian forest and aimed to evaluate this ant's impact on the abundance and diversity of other ants by comparing different habitats at two sites. We noted a significant decrease in ant species richness between the rainforest and human-disturbed habitats (but not between the former and the naturally disturbed riparian forest), and between extreme habitats and all others. The number of ant nests per surface unit (i.e., quadrats of equal surface area), a proxy of ant abundance, globally followed this pattern. S. saevissima was absent from pristine rainforest (as expected) and from extreme habitats, showing the limits of its adaptability, whereas some other native ants can develop in these habitats. Ant species richness was significantly lower in the presence of S. saevissima in the riparian forest, forest edges and meadows, illustrating that this ant species has a negative impact on the ant communities in addition to the impact of natural- and man-made disturbances. Only some ant species can develop in its presence, and certain of these can even thrive. Because it has been recorded in Africa, Guadeloupe and the Galápagos Islands, we concluded that, due to the increasing volume of global trade and forest destruction, S. saevissima could become a pantropical invasive species. © 2015 Elsevier Ltd. |
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Université Clermont Auvergne, Université Blaise Pascal (LMGE), Clermont-Ferrand, France |
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Export Date: 11 June 2015 |
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EcoFoG @ webmaster @ |
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605 |
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Houel, E.; Nardella, F.; Jullian, V.; Valentin, A.; Vonthron-Sénécheau, C.; Villa, P.; Obrecht, A.; Kaiser, M.; Bourreau, E.; Odonne, G.; Fleury, M.; Bourdy, G.; Eparvier, V.; Deharo, E.; Stien, D. |
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Wayanin and guaijaverin, two active metabolites found in a Psidium acutangulum Mart. ex DC (syn. P. persoonii McVaugh) (Myrtaceae) antimalarial decoction from the Wayana Amerindians |
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Journal Article |
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2016 |
Publication |
Journal of Ethnopharmacology |
Abbreviated Journal |
Journal of Ethnopharmacology |
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187 |
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241-248 |
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Antimalarial; Cytokines; French guiana; Glycosylated flavonols; Psidium acutangulum; Traditional remedy |
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Ethnopharmacological relevance Psidium acutangulum Mart. ex DC is a small tree used by the Wayana Amerindians from the Upper-Maroni in French Guiana for the treatment of malaria. Aim of the study In a previous study, we highlighted the in vitro antiplasmodial, antioxidant and anti-inflammatory potential of the traditional decoction of P. acutangulum aerial parts. Our goal was then to investigate on the origin of the biological activity of the traditional remedy, and eventually characterize active constituents. Materials and methods Liquid-liquid extractions were performed on the decoction, and the antiplasmodial activity evaluated against chloroquine-resistant FcB1 ([3H]-hypoxanthine bioassay) and 7G8 (pLDH bioassay) P. falciparum strains, and on a chloroquine sensitive NF54 ([3H]-hypoxanthine bioassay) P. falciparum strain. The ethyl acetate fraction (D) was active and underwent bioguided fractionation. All the isolated compounds were tested on P. falciparum FcB1 strain. In vitro anti-inflammatory activity (IL-1β, IL-6, IL-8, TNFα) of the ethyl acetate fraction and of an anti-Plasmodium active compound, was concurrently assessed on LPS-stimulated human PBMC and NO secretion inhibition was measured on LPS stimulated RAW murine macrophages. Cytotoxicity of the fractions and pure compounds was measured on VERO cells, L6 mammalian cells, PBMCs, and RAW cells. Results Fractionation of the ethyl acetate soluble fraction (IC50 ranging from 3.4 to <1 μg/mL depending on the parasite strain) led to the isolation of six pure compounds: catechin and five glycosylated quercetin derivatives. These compounds have never been isolated from this plant species. Two of these compounds (wayanin and guaijaverin) were found to be moderately active against P. falciparum FcB1 in vitro (IC50 5.5 and 6.9 μM respectively). We proposed the name wayanin during public meetings organized in June 2015 in the Upper-Maroni villages, in homage to the medicinal knowledge of the Wayana population. At 50 μg/mL, the ethyl acetate fraction (D) significantly inhibited IL-1β secretion (-46%) and NO production (-21%), as previously observed for the decoction. The effects of D and guiajaverin (4) on the secretion of other cytokines or NO production were not significant. Conclusions The confirmed antiplasmodial activity of the ethyl acetate soluble fraction of the decoction and of the isolated compounds support the previous results obtained on the P. acutangulum decoction. The antiplasmodial activity might be due to a mixture of moderately active non-toxic flavonoids. The anti-inflammatory activities were less marked for ethyl acetate fraction (D) than for the decoction. © 2016 Elsevier Ireland Ltd. All rights reserved. |
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Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM), Observatoire Océanologique, Banyuls/Mer, France |
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Export Date: 20 May 2016 |
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EcoFoG @ webmaster @ |
Serial |
679 |
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| Author |
Rodríguez Pérez, H.; Borrel, G.; Leroy, C.; Carrias, J.-F.; Corbara, B.; Srivastava, D.S.; Céréghino, R. |
| Title |
Simulated drought regimes reveal community resilience and hydrological thresholds for altered decomposition |
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Journal Article |
| Year |
2018 |
Publication |
Oecologia |
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| Volume |
187 |
Issue |
1 |
Pages |
267-279 |
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| Abstract |
Future climate scenarios forecast a 10–50% decline in rainfall in Eastern Amazonia. Altered precipitation patterns may change important ecosystem functions like decomposition through either changes in physical and chemical processes or shifts in the activity and/or composition of species. We experimentally manipulated hydroperiods (length of wet:dry cycles) in a tank bromeliad ecosystem to examine impacts on leaf litter decomposition. Gross loss of litter mass over 112 days was greatest in continuously submersed litter, lowest in continuously dry litter, and intermediate over a range of hydroperiods ranging from eight cycles of 7 wet:7 dry days to one cycle of 56 wet:56 dry days. The resilience of litter mass loss to hydroperiod length is due to a shift from biologically assisted decomposition (mostly microbial) at short wet:dry hydroperiods to physicochemical release of dissolved organic matter at longer wet:dry hydroperiods. Biologically assisted decomposition was maximized at wet:dry hydroperiods falling within the range of ambient conditions (12–22 consecutive dry days) but then declined under prolonged wet:dry hydroperiods (28 and 56 dry days. Fungal:bacterial ratios showed a similar pattern as biologically assisted decomposition to hydroperiod length. Our results suggest that microbial communities confer functional resilience to altered hydroperiod in tank bromeliad ecosystems. We predict a substantial decrease in biological activity relevant to decomposition under climate scenarios that increase consecutive dry days by 1.6- to 3.2-fold in our study area, whereas decreased frequency of dry periods will tend to increase the physicochemical component of decomposition. |
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1432-1939 |
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no |
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EcoFoG @ webmaster @ Rodríguez Pérez2018 |
Serial |
850 |
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