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Grangier, J.; Orivel, J.; Negrini, M.; Dejean, A. |
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Title |
Low intraspecific aggressiveness in two obligate plant-ant species |
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Journal Article |
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2008 |
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Insectes Sociaux |
Abbreviated Journal |
Insect. Soc. |
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55 |
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3 |
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238-240 |
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aggressiveness; Allomerus; myrmecophytes; plant-ants; recognition ability |
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Little is known about the aggressiveness of plant-ants typically living in isolated trees nor about how that aggressiveness varies based on this isolation. Here, we examine intra- and interspecific aggressiveness between workers of two Allomerus species associated with two different myrmecophytes. In both cases, the level of intraspecific aggressiveness is very low whatever the distance separating the tested nests, while interspecific conflicts are always violent. Similar patterns of aggressiveness have been reported in various ant species, but the strictly arboreal life of Allomerus ants associated with the isolation of their adult colonies highlight different ecological conditions that might explain the lack of aggressiveness between conspecifics. |
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[Grangier, J.; Orivel, J.; Negrini, M.; Dejean, A.] Univ Toulouse 3, CNRS, UMR 5174, Lab Evolut & Diversite Biol, F-31062 Toulouse 9, France, Email: grangier@cict.fr |
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BIRKHAUSER VERLAG AG |
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0020-1812 |
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ISI:000258959300004 |
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EcoFoG @ eric.marcon @ |
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208 |
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Lebrini, M.; Mbomekallé, I.M.; Dolbecq, A.; Marrot, J.; Berthet, P.; Ntienoue, J.; Sécheresse, F.; Vigneron, J.; Etcheberry, A. |
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Title |
Manganese(III)-containing wells-dawson sandwich-type polyoxometalates: Comparison with their manganese(II) counterparts |
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Journal Article |
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Year |
2011 |
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Inorganic Chemistry |
Abbreviated Journal |
Inorg. Chem. |
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50 |
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14 |
Pages |
6437-6448 |
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We present the synthesis and structural characterization, assessed by various techniques (FTIR, TGA, UV-vis, elemental analysis, single-crystal X-ray diffraction for three compounds, magnetic susceptibility, and electrochemistry) of five manganese-containing Wells-Dawson sandwich-type (WDST) complexes. The dimanganese(II)-containing complex, [Na2(H2O) 2MnII2(As2W15O 56)2]18- (1), was obtained by reaction of MnCl2 with 1 equiv of [As2W15O 56]12- in acetate medium (pH 4.7). Oxidation of 1 by Na2S2O8 in aqueous solution led to the dimanganese(III) complex [Na2(H2O)2Mn III2(As2W15O56) 2]16- (2), while its trimanganese(II) homologue, [Na(H2O)2MnII(H2O)Mn II2(As2W15O56) 2]17- (3), was obtained by addition of ca. 1 equiv of MnCl2 to a solution of 1 in 1 M NaCl. The trimanganese(III) and tetramanganese(III) counterparts, [MnIII(H2O)Mn III2(As2W15O56) 2]15- (4) and [MnIII2(H 2O)2MnIII2(As2W 15O56)2]12- (6), are, respectively, obtained by oxidation of aqueous solutions of 3 and [MnII2(H2O)2MnII2(As 2W15O56)2]16- (5) by Na2S2O8. Single-crystal X-ray analyses were carried out on 2, 3, and 4. BVS calculations and XPS confirmed that the oxidation state of Mn centers is +II for complexes 1, 3, and 5 and +III for 2, 4, and 6. A complete comparative electrochemical study was carried out on the six compounds cited above, and it was possible to observe the distinct redox steps MnIV/III and MnIII/II. Magnetization measurements, as a function of temperature, confirm the presence of antiferromagnetic interactions between the Mn ions in these compounds in all cases with the exception of compound 2. © 2011 American Chemical Society. |
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Laboratoire de Physico-Chimie de L'Etat Solide, ICMMO, Université Paris-Sud, Bâtiment 410, 91405 Orsay Cedex, France |
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00201669 (Issn) |
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Export Date: 21 October 2011; Source: Scopus; Coden: Inoca; doi: 10.1021/ic102237x; Language of Original Document: English; Correspondence Address: Mbomekallé, I.M.; Institut Lavoisier de Versailles, UMR 8180, CNRS Université de Versailles Saint-Quentin, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France; email: israel.mbomekalle@chimie.uvsq.fr |
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EcoFoG @ webmaster @ |
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346 |
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Tindo, M.; Mbenoun Masse, P.S.; Kenne, M.; Mony, R.; Orivel, J.; Doumtsop Fotio, A.; Fotso Kuaté, A.; Djiéto-Lordon, C.; Fomena, A.; Estoup, A.; Dejean, A.; Foucaud, J. |
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Title |
Current distribution and population dynamics of the little fire ant supercolony in cameroon |
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Journal Article |
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Year |
2012 |
Publication |
Insectes Sociaux |
Abbreviated Journal |
Insectes Sociaux |
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Volume |
59 |
Issue |
2 |
Pages |
175-182 |
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Keywords |
Auropunctata; Dispersion; Invasive ants; Reproduction strategy; Unicoloniality; Wasmannia |
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The little fire ant, Wasmannia auropunctata, is native to Central America, but has been introduced into many parts of the world. We examined the current distribution of W. auropunctata in Cameroon, tested for aggression between workers from different parts of the country, and examined the genotypes of workers, queens, and males to evaluate the mating system. We found W. auropunctata at 36 sites in three provinces (Centre, East, and South). We found W. auropunctata only in human-disturbed habitats. Its spread appears to be primarily human mediated. Aggressive behaviour was almost non-existent between workers from different sites, indicating that there is only one supercolony in Cameroon. Our genetic analysis found that only one male/female pair of clones was introduced into Cameroon, probably from Gabon. No new male clonal lineage was identified, whereas new sexually derived female clonal lineages were noted. Apart from the genotype of the founding queen, which was well distributed but generally not dominant, a new clonal queen genotype emerged and was both omnipresent and dominant at most sites. These results may be useful in the development of management strategies. © International Union for the Study of Social Insects (IUSSI) 2011. |
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Laboratoire Evolution Genome Speciation, Centre National de la Recherche Scientifique, Avenue de la Terrasse, F 91198 Gif sur Yvette, France |
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00201812 (Issn) |
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Export Date: 24 April 2012; Source: Scopus; Coden: Insoa; doi: 10.1007/s00040-011-0202-x; Language of Original Document: English; Correspondence Address: Tindo, M.; Département de Biologie des Organismes Animaux, Faculté des Sciences, Université de Douala, BP 24157 Douala, Cameroon; email: tindodouala@yahoo.com |
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EcoFoG @ webmaster @ |
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392 |
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Herault, B.; Ouallet, J.; Blanc, L.; Wagner, F.; Baraloto, C. |
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Title |
Growth responses of neotropical trees to logging gaps |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of Applied Ecology |
Abbreviated Journal |
J. Appl. Ecol. |
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Volume |
47 |
Issue |
4 |
Pages |
821-831 |
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Keywords |
canopy openings; functional traits; incidence function model; light partitioning; selective logging; tree growth rates; tropical rain forest |
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P>1. Modelling growth strategies among tropical trees is an important objective in predicting the response of tree dynamics to selective logging and in gaining insights into the ecological processes that structure tree communities in managed tropical forests. 2. We developed a disturbance index to model the effects of distance to and area of logging gaps on stem radial growth rates. This index was tested using census data of 43 neotropical tree species, representing a variety of life-history strategies and developmental stages, from a selectively logged forest at Paracou, French Guiana. Growth strategies were analyzed in light of two indicators: the inherent species growth rate (when disturbance index is null) and the species reaction (change in growth rate) to logging gaps. 3. Across species, the predicted inherent growth rates in unlogged forest ranged from 0 center dot 25 to 6 center dot 47 mm year-1, with an average growth of 2 center dot 29 mm year-1. Ontogenetic shifts in inherent growth rate were found in 26 of the 43 species. 4. Species growth response to logging gaps varied widely among species but was significantly positive for 27 species. The effect of ontogeny on growth response to logging was retained for 14 species, and species with inherent fast growth rate (5 mm year-1) responded less to logging gap disturbances than did species with slow inherent growth (1 mm year-1). 5. Functional traits explained 19-42% of the variation in the inherent growth rate and in species' response across all developmental stages. Whereas maximum diameters and seed mass were strong predictors of inherent growth rate, maximum height, wood density, mode of germination and stem architecture were additionally involved in tree growth response. 6. Synthesis and applications: This study provides a necessary framework for developing predictive post-logging growth models for the thousands of species comprising tropical forests and is sufficiently general to apply to a broad range of managed tropical forests. |
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[Herault, Bruno] Univ Antilles Guyane, UMR Ecol Forets Guyane, F-97387 Kourou, France, Email: bruno.herault@ecofog.gf |
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WILEY-BLACKWELL PUBLISHING, INC |
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0021-8901 |
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ISI:000279405100012 |
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EcoFoG @ eric.marcon @ |
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53 |
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Aimene, Y.; Vidal-Salle, E.; Hagege, B.; Sidoroff, F.; Boisse, P. |
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Title |
A Hyperelastic Approach for Composite Reinforcement Large Deformation Analysis |
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Journal Article |
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Year |
2010 |
Publication |
Journal of Composite Materials |
Abbreviated Journal |
J. Compos Mater. |
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Volume |
44 |
Issue |
1 |
Pages |
5-26 |
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hyperelasticity; woven reinforcements; forming; fabric mechanical behavior; finite element |
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A hyperelastic constitutive model is developed for textile composite reinforcement at large strain. A potential is proposed, which is the addition of two tension and one shear energies. The proposed potential is a function of the right Cauchy Green and structural tensor invariants whose choice corresponds to textile composite reinforcement mechanical behavior which exhibits weak elongations in the fiber directions and large angular variations in the fabric plane. The model is implemented in a Vumat user routine of ABAQUS/Explicit. Some elementary tests are performed in order to identify the model and verify its validity. It is then used to simulate the hemispherical punch forming of balanced and unbalanced fabrics. A correct agreement is obtained with experimental forming processes. |
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[Aimene, Y.; Vidal-Salle, E.; Boisse, P.] Univ Lyon, INSA Lyon, LaMCoS, F-69621 Villeurbanne, France, Email: philippe.boisse@insa-lyon.fr |
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SAGE PUBLICATIONS LTD |
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0021-9983 |
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ISI:000273509100001 |
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EcoFoG @ eric.marcon @ |
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84 |
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Baraloto, C.; Herault, B.; Paine, C.E.T.; Massot, H.; Blanc, L.; Bonal, D.; Molino, J.-F.; Nicolini, E.A.; Sabatier, D. |
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Contrasting taxonomic and functional responses of a tropical tree community to selective logging |
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Journal Article |
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Year |
2012 |
Publication |
Journal of Applied Ecology |
Abbreviated Journal |
J. Appl. Ecol. |
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Volume |
49 |
Issue |
4 |
Pages |
861-870 |
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Canopy gap dynamics; Disturbance; French Guiana; Functional diversity; Functional evenness; Functional traits; Light partitioning; Species richness; Tropical rain forest |
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1.Considerable debate surrounds the extent to which tropical forests can be managed for resource extraction while conserving biodiversity and ecosystem properties, which depend on functional composition. Here we evaluate the compatibility of these aims by examining the effects of logging on taxonomic and functional diversity and composition in a tropical forest. 2.Twenty years after selective logging, we inventoried 4140 stems regenerating in logging gaps and adjacent undisturbed areas, and we integrated a database of 13 functional traits describing leaf and wood economics of tropical trees. 3.We found no differences in taxonomic and functional richness among habitats, but logging gaps had significantly higher taxonomic and functional evenness. 4.Logging also effected striking, long-term changes in both species and functional composition. In particular, the xylem density of recruits in logging gaps was 6% less than in unlogged forests, leaves were 11% less tough and had 6-13% greater mineral nutrient concentrations. 5.Synthesis and applications. Our results suggest that managers of tropical forests should limit overall surface area converted to logging gaps by creating fewer, larger gaps during selective logging, to reduce impacts on the taxonomic and functional composition of the regenerating stand. Our results suggest that managers of tropical forests should limit overall surface area converted to logging gaps by creating fewer, larger gaps during selective logging, to reduce impacts on the taxonomic and functional composition of the regenerating stand. © 2012 The Authors. Journal of Applied Ecology © 2012 British Ecological Society. |
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CIRAD-ES, Research Unit 'Biens et Services des Ecosystémes Forestiers tropicaux', Embrapa Amazonia Oriental, Caixa Postal, 48, Belem, Para – CEP 66095-100, Brazil |
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00218901 (Issn) |
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Export Date: 30 July 2012; Source: Scopus; Coden: Japea; doi: 10.1111/j.1365-2664.2012.02164.x; Language of Original Document: English; Correspondence Address: Baraloto, C.; INRA, UMR 'Ecologie des Forêts de Guyane', 97387 Kourou Cedex, French Guiana; email: chris.baraloto@ecofog.gf |
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EcoFoG @ webmaster @ |
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410 |
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Ferry, B.; Morneau, F.; Bontemps, J.D.; Blanc, L.; Freycon, V. |
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Title |
Higher treefall rates on slopes and waterlogged soils result in lower stand biomass and productivity in a tropical rain forest |
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Journal Article |
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Year |
2010 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
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Volume |
98 |
Issue |
1 |
Pages |
106-116 |
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biomass; community ecology; growth; mortality; productivity; soil waterlogging; topography; treefall; tropical moist forest; wood density |
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P>1. Relationships between tropical rain forest biomass and environmental factors have been determined at regional scales, e.g. the Amazon Basin, but the reasons for the high variability in forest biomass at local scales are poorly understood. Interactions between topography, soil properties, tree growth and mortality rates, and treefalls are a likely reason for this variability. 2. We used repeated measurements of permanent plots in lowland rain forest in French Guiana to evaluate these relationships. The plots sampled topographic gradients from hilltops to slopes to bottomlands, with accompanying variation in soil waterlogging along these gradients. Biomass was calculated for > 175 tree species in the plots, along with biomass productivity and recruitment rates. Mortality was determined as standing dead and treefalls. 3. Treefall rates were twice as high in bottomlands as on hilltops, and tree recruitment rates, radial growth rates and the abundance of light-demanding tree species were also higher. 4. In the bottomlands, the mean wood density was 10% lower than on hilltops, the basal area 29% lower and the height:diameter ratio of trees was lower, collectively resulting in a total woody biomass that was 43% lower in bottomlands than on hilltops. 5. Biomass productivity was 9% lower in bottomlands than on hilltops, even though soil Olsen P concentrations were higher in bottomlands. 6. Synthesis. Along a topographic gradient from hilltops to bottomlands there were higher rates of treefall, which decreased the stand basal area and favoured lower allocation to height growth and recruitment of light-demanding species with low wood density. The resultant large variation in tree biomass along the gradient shows the importance of determining site characteristics and including these characteristics when scaling up biomass estimates from stand to local or regional scales. |
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[Ferry, Bruno; Morneau, Francois; Bontemps, Jean-Daniel] AgroParisTech, ENGREF Nancy, UMR 1092, CS 14216, F-54000 Nancy, France, Email: bruno.ferry@engref.agroparistech.fr |
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WILEY-BLACKWELL PUBLISHING, INC |
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0022-0477 |
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ISI:000272657400012 |
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EcoFoG @ eric.marcon @ |
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87 |
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Gonzalez, M.A.; Roger, A.; Courtois, E.A.; Jabot, F.; Norden, N.; Paine, C.E.T.; Baraloto, C.; Thebaud, C.; Chave, J. |
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Title |
Shifts in species and phylogenetic diversity between sapling and tree communities indicate negative density dependence in a lowland rain forest |
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Journal Article |
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Year |
2010 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
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Volume |
98 |
Issue |
1 |
Pages |
137-146 |
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Keywords |
APG II plus rbcL megatree; density dependence; DNA barcoding; French Guiana; phylogenetic diversity; species diversity; tropical plant communities |
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P>1. As trees in a given cohort progress through ontogeny, many individuals die. This risk of mortality is unevenly distributed across species because of many processes such as habitat filtering, interspecific competition and negative density dependence. Here, we predict and test the patterns that such ecological processes should inscribe on both species and phylogenetic diversity as plants recruit from saplings to the canopy. 2. We compared species and phylogenetic diversity of sapling and tree communities at two sites in French Guiana. We surveyed 2084 adult trees in four 1-ha tree plots and 943 saplings in sixteen 16-m2 subplots nested within the tree plots. Species diversity was measured using Fisher's alpha (species richness) and Simpson's index (species evenness). Phylogenetic diversity was measured using Faith's phylogenetic diversity (phylogenetic richness) and Rao's quadratic entropy index (phylogenetic evenness). The phylogenetic diversity indices were inferred using four phylogenetic hypotheses: two based on rbcLa plastid DNA sequences obtained from the inventoried individuals with different branch lengths, a global phylogeny available from the Angiosperm Phylogeny Group, and a combination of both. 3. Taxonomic identification of the saplings was performed by combining morphological and DNA barcoding techniques using three plant DNA barcodes (psbA-trnH, rpoC1 and rbcLa). DNA barcoding enabled us to increase species assignment and to assign unidentified saplings to molecular operational taxonomic units. 4. Species richness was similar between saplings and trees, but in about half of our comparisons, species evenness was higher in trees than in saplings. This suggests that negative density dependence plays an important role during the sapling-to-tree transition. 5. Phylogenetic richness increased between saplings and trees in about half of the comparisons. Phylogenetic evenness increased significantly between saplings and trees in a few cases (4 out of 16) and only with the most resolved phylogeny. These results suggest that negative density dependence operates largely independently of the phylogenetic structure of communities. 6. Synthesis. By contrasting species richness and evenness across size classes, we suggest that negative density dependence drives shifts in composition during the sapling-to-tree transition. In addition, we found little evidence for a change in phylogenetic diversity across age classes, suggesting that the observed patterns are not phylogenetically constrained. |
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[Gonzalez, Mailyn A.; Roger, Aurelien; Courtois, Elodie A.; Jabot, Franck; Norden, Natalia; Thebaud, Christophe; Chave, Jerome] Univ Toulouse 3, Lab Evolut & Diversite Biol, UMR 5174, CNRS, F-31062 Toulouse, France, Email: gonzalez.mailyn@gmail.com |
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WILEY-BLACKWELL PUBLISHING, INC |
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0022-0477 |
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ISI:000272657400015 |
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EcoFoG @ eric.marcon @ |
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88 |
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Baraloto, C.; Forget, P.M.; Goldberg, D.E. |
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Title |
Seed mass, seedling size and neotropical tree seedling establishment |
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Journal Article |
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Year |
2005 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
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Volume |
93 |
Issue |
6 |
Pages |
1156-1166 |
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Keywords |
French Guiana; life-history trade-offs; microhabitat; path analysis; regeneration strategy; relative growth rate; seedling survival; shade tolerance |
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1 We examined among- and within-species effects of seed mass for seedling establishment from seed to 5 years of age in a field experiment at Paracou, French Guiana. 2 Six seeds of each of eight species were weighed and planted into each of 120 plots (1 m(2)) throughout closed-canopy forest along 12 100-m transects in 1998. 3 We described the microhabitat of each planting site using principal components derived from measurements of light availability, soil moisture, carbon and nitrogen content, and soil phosphorus availability. Although both survival and relative growth rate (RGR) increased with increasing light availability, no other microhabitat variable significantly affected seedling performance. Nor did the magnitude of microhabitat effects on survival or RGR differ among species. 4 Larger-seeded species were more likely to survive from germination to 1 year as well as from 1 to 5 years of age. RGR for seedling height during the first year post-germination was not related to seed mass, but smaller-seeded species did grow slightly faster thereafter. Path analyses revealed that correlations between seed mass and performance were explained in part because larger seeds produced larger initial seedlings, which tended to survive better but grow more slowly. 5 We also analysed within-species effects of seed mass for the larger-seeded Eperua grandiflora and Vouacapoua americana (both Caesalpiniaceae). Larger seeds produced larger seedlings in both species, but larger seeds survived better only for Eperua. Larger seedlings grew more slowly in both species, but did not offset the early (Eperua) and later (Vouacapoua) positive direct effects of seed mass on RGR that may represent contrasting strategies for reserve deployment. 6 Our results demonstrate that seed size influences performance within and among species in part because of indirect effects of initial seedling size. However, we suggest that traits tightly correlated with seed mass at the species level, such as specific leaf area, leaf longevity and photosynthetic capacity, may also contribute to interspecific performance differences. |
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Museum Natl Hist Nat, Dept Ecol & Gest Biodivers, UMR 5176, CNRS, Brunoy, France, Email: baraloto.c@kourou.cirad.fr |
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BLACKWELL PUBLISHING |
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0022-0477 |
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ISI:000233287500012 |
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EcoFoG @ eric.marcon @ |
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250 |
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Leroy, C.; Sejalon-Delmas, N.; Jauneau, A.; Ruiz-Gonzalez, M.X.; Gryta, H.; Jargeat, P.; Corbara, B.; Dejean, A.; Orivel, J. |
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Trophic mediation by a fungus in an ant-plant mutualism |
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2011 |
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Journal of Ecology |
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J. Ecol. |
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99 |
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2 |
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583-590 |
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delta N-15; Allomerus decemarticulatus; ant-plant-fungus interactions; Ascomycete; fungal mediation; Hirtella physophora; mutualisms; myrmecophytes; nutrient provisioning; stable isotopes |
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1. Plants often rely on external, mutualistic partners to survive and reproduce in resource-limited environments or for protection from enemies. Such interactions, including mycorrhizal symbioses and ant plant associations, are widespread and play an important role at the ecosystem and community levels. In ant-plant mutualisms, the plants may benefit from both the protection provided by the presence of ants and from the nutrients absorbed from insect debris. However, the role of third partners in plant nutrition, particularly ant-associated fungi, has never before been demonstrated. 2. We investigate this issue in the ant-plant Hirtella physophora. In this model system, Allomerus decemarticulatus ants are involved in two, highly specific interactions: first, with their host plant, and, secondly, with a fungus that they actively manipulate. Moreover, the ants combine both plant trichomes and fungal hyphae to make a trap to capture prey. 3. We empirically demonstrate the existence of a third type of interaction between the fungus and the plant through the use of both experimental enrichments with stable isotopes (N-15) and histological approaches. The fungus growing in the galleries plays a role in providing nutrients to the host plant, in addition to the structural role it plays for the ants. Fungus-facilitated nitrogen uptake occurs mainly in old domatia, where abundant hyphae are in close contact with the plant cells. Whether the fungi inside the domatia and those in the galleries are the same is still uncertain. 4. Synthesis. Together, our results show that a fungal partner in an ant-plant mutualism can benefit the plant by improving its nutrient uptake, and they demonstrate the existence of a true tripartite mutualism in this system. Our results add further evidence to the notion that interpretations of some ant plant symbioses as purely protective mutualisms have overlooked these nutritional aspects. |
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[Leroy, Celine; Dejean, Alain; Orivel, Jerome] CNRS, UMR Ecol Forets Guyane, F-97379 Kourou, France, Email: jerome.orivel@ecofog.gf |
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Wiley-Blackwell |
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0022-0477 |
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ISI:000287785300024 |
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EcoFoG @ webmaster @ |
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297 |
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