| Records |
| Author |
Almeras, T.; Derycke, M.; Jaouen, G.; Beauchene, J.; Fournier, M. |
| Title |
Functional diversity in gravitropic reaction among tropical seedlings in relation to ecological and developmental traits |
Type |
Journal Article |
| Year |
2009 |
Publication |
Journal of Experimental Botany |
Abbreviated Journal |
J. Exp. Bot. |
| Volume |
60 |
Issue |
15 |
Pages |
4397-4410 |
| Keywords |
Biomechanics; French Guiana; functional diversity; gravitropism; reaction wood; tropical rainforest |
| Abstract |
Gravitropism is necessary for plants to control the orientation of their axes while they grow in height. In woody plants, stem re-orientations are costly because they are achieved through diameter growth. The functional diversity of gravitropism was studied to check if the mechanisms involved and their efficiency may contribute to the differentiation of height growth strategies between forest tree species at the seedling stage. Seedlings of eight tropical species were grown tilted in a greenhouse, and their up-righting movement and diameter growth were measured over three months. Morphological, anatomical, and biomechanical traits were measured at the end of the survey. Curvature analysis was used to analyse the up-righting response along the stems. Variations in stem curvature depend on diameter growth, size effects, the increase in self-weight, and the efficiency of the gravitropic reaction. A biomechanical model was used to separate these contributions. Results showed that (i) gravitropic movements were based on a common mechanism associated to similar dynamic patterns, (ii) clear differences in efficiency (defined as the change in curvature achieved during an elementary diameter increment for a given stem diameter) existed between species, (iii) the equilibrium angle of the stem and the anatomical characters associated with the efficiency of the reaction also differed between species, and (iv) the differences in gravitropic reaction were related to the light requirements: heliophilic species, compared to more shade-tolerant species, had a larger efficiency and an equilibrium angle closer to vertical. This suggests that traits determining the gravitropic reaction are related to the strategy of light interception and may contribute to the differentiation of ecological strategies promoting the maintenance of biodiversity in tropical rainforests. |
| Address |
[Almeras, Tancrede; Derycke, Morgane; Jaouen, Gaelle] INRA, UMR Ecol Forets Guyane, F-97310 Kourou, France, Email: t_almeras@hotmail.com |
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OXFORD UNIV PRESS |
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0022-0957 |
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| Notes |
ISI:000271389400017 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
96 |
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| Author |
Chang, S.S.; Clair, B.; Ruelle, J.; Beauchene, J.; Di Renzo, F.; Quignard, F.; Zhao, G.J.; Yamamoto, H.; Gril, J. |
| Title |
Mesoporosity as a new parameter for understanding tension stress generation in trees |
Type |
Journal Article |
| Year |
2009 |
Publication |
Journal of Experimental Botany |
Abbreviated Journal |
J. Exp. Bot. |
| Volume |
60 |
Issue |
11 |
Pages |
3023-3030 |
| Keywords |
Growth stress; hydrogel; mesoporosity; tension wood |
| Abstract |
The mechanism for tree orientation in angiosperms is based on the production of high tensile stress on the upper side of the inclined axis. In many species, the stress level is strongly related to the presence of a peculiar layer, called the G-layer, in the fibre cell wall. The structure of the G-layer has recently been described as a hydrogel thanks to N-2 adsorption-desorption isotherms of supercritically dried samples showing a high mesoporosity (pores size from 2-50 nm). This led us to revisit the concept of the G-layer that had been, until now, only described from anatomical observation. Adsorption isotherms of both normal wood and tension wood have been measured on six tropical species. Measurements show that mesoporosity is high in tension wood with a typical thick G-layer while it is much less with a thinner G-layer, sometimes no more than normal wood. The mesoporosity of tension wood species without a G-layer is as low as in normal wood. Not depending on the amount of pores, the pore size distribution is always centred around 6-12 nm. These results suggest that, among species producing fibres with a G-layer, large structural differences of the G-layer exist between species. |
| Address |
[Chang, Shan-Shan; Clair, Bruno; Gril, Joseph] Univ Montpellier 2, LMGC, CNRS, F-34095 Montpellier 5, France, Email: clair@lmgc.univ-montp2.fr |
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OXFORD UNIV PRESS |
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0022-0957 |
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| Notes |
ISI:000268588300008 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
107 |
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Coste, S.; Roggy, J.C.; Schimann, H.; Epron, D.; Dreyer, E. |
| Title |
A cost-benefit analysis of acclimation to low irradiance in tropical rainforest tree seedlings: leaf life span and payback time for leaf deployment |
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of Experimental Botany |
Abbreviated Journal |
J. Exp. Bot. |
| Volume |
62 |
Issue |
11 |
Pages |
3941-3955 |
| Keywords |
Carbon balance; construction cost; functional diversity; leaf life span; payback time; photosynthesis; tropical rainforest |
| Abstract |
The maintenance in the long run of a positive carbon balance under very low irradiance is a prerequisite for survival of tree seedlings below the canopy or in small gaps in a tropical rainforest. To provide a quantitative basis for this assumption, experiments were carried out to determine whether construction cost (CC) and payback time for leaves and support structures, as well as leaf life span (i) differ among species and (ii) display an irradiance-elicited plasticity. Experiments were also conducted to determine whether leaf life span correlates to CC and payback time and is close to the optimal longevity derived from an optimization model. Saplings from 13 tropical tree species were grown under three levels of irradiance. Specific-CC was computed, as well as CC scaled to leaf area at the metamer level. Photosynthesis was recorded over the leaf life span. Payback time was derived from CC and a simple photosynthesis model. Specific-CC displayed only little interspecific variability and irradiance-elicited plasticity, in contrast to CC scaled to leaf area. Leaf life span ranged from 4 months to > 26 months among species, and was longest in seedlings grown under lowest irradiance. It was always much longer than payback time, even under the lowest irradiance. Leaves were shed when their photosynthesis had reached very low values, in contrast to what was predicted by an optimality model. The species ranking for the different traits was stable across irradiance treatments. The two pioneer species always displayed the smallest CC, leaf life span, and payback time. All species displayed a similar large irradiance-elicited plasticity. |
| Address |
[Coste, S; Epron, D; Dreyer, E] INRA, UMR1137, Ctr INRA Nancy, F-54280 Champenoux, France, Email: dreyer@nancy.inra.fr |
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Oxford Univ Press |
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0022-0957 |
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| Notes |
WOS:000292838700021 |
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no |
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EcoFoG @ webmaster @ |
Serial |
331 |
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| Author |
Seymour, R.S.; White, C.R.; Gibernau, M. |
| Title |
Endothermy of dynastine scarab beetles (Cyclocephala colasi) associated with pollination biology of a thermogenic arum lily (Philodendron solimoesense) |
Type |
Journal Article |
| Year |
2009 |
Publication |
Journal of Experimental Biology |
Abbreviated Journal |
J. Exp. Biol. |
| Volume |
212 |
Issue |
18 |
Pages |
2960-2968 |
| Keywords |
beetle; endothermy; pollination biology; Cyclocephala; Philodendron |
| Abstract |
Cyclocephala colasi beetles are facultative endotherms that spend most of their adult lives inside the inflorescences of Philodendron solimoesense, where ambient temperature (T-a) averages about 28 degrees C due to floral thermogenesis. Measurements of respiration within a range of T-a showed that active beetles became spontaneously endothermic at T-a below 28 degrees C but were rarely endothermic above it. There was no evidence of endothermy within the inflorescences, indicating that activities in the floral chamber can occur without the high energy expense of endothermy. Bouts of endothermy occurred at lower T-a in respirometer chambers mainly in the evening, when the insects normally fly from one inflorescence to another, and during the night, when they normally eat and mate within the inflorescence. Patterns of endothermy in individual episodes were studied in non-flying beetles with respirometry and infrared thermal imaging. Heat was generated in the thorax by oscillatory waves of respiration that were coupled with thoracic temperature (T-th) increases. Stationary beetles could regulate T-th at about 33 degrees C independently of T-a between 16 and 29 degrees C. At T-a=20 degrees C, this represents a 116-fold increase in metabolic rate over resting, ectothermic values. Endothermy was clearly a requirement for flight, and beetles departing inflorescences warmed to about 30 degrees C before take-off. During flight, T-th was dependent on T-a, decreasing from 37 to 28 degrees C at T-a of 37 to 20 degrees C, respectively. The lowest T-a at which flight could occur was about 20 degrees C. Thermal conductance of stationary, endothermic beetles increased at higher metabolic rates, probably because of increased ventilatory heat loss. |
| Address |
[Seymour, Roger S.] Univ Adelaide, Sch Earth & Environm Sci, Adelaide, SA 5005, Australia, Email: roger.seymour@adelaide.edu.au |
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COMPANY OF BIOLOGISTS LTD |
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0022-0949 |
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ISI:000269383500014 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
198 |
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| Author |
Ferry, B.; Morneau, F.; Bontemps, J.D.; Blanc, L.; Freycon, V. |
| Title |
Higher treefall rates on slopes and waterlogged soils result in lower stand biomass and productivity in a tropical rain forest |
Type |
Journal Article |
| Year |
2010 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
| Volume |
98 |
Issue |
1 |
Pages |
106-116 |
| Keywords |
biomass; community ecology; growth; mortality; productivity; soil waterlogging; topography; treefall; tropical moist forest; wood density |
| Abstract |
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. |
| Address |
[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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| Notes |
ISI:000272657400012 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
87 |
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| Author |
Gonzalez, M.A.; Roger, A.; Courtois, E.A.; Jabot, F.; Norden, N.; Paine, C.E.T.; Baraloto, C.; Thebaud, C.; Chave, J. |
| Title |
Shifts in species and phylogenetic diversity between sapling and tree communities indicate negative density dependence in a lowland rain forest |
Type |
Journal Article |
| Year |
2010 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
| Volume |
98 |
Issue |
1 |
Pages |
137-146 |
| Keywords |
APG II plus rbcL megatree; density dependence; DNA barcoding; French Guiana; phylogenetic diversity; species diversity; tropical plant communities |
| Abstract |
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. |
| Address |
[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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| Notes |
ISI:000272657400015 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
88 |
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Baraloto, C.; Forget, P.M.; Goldberg, D.E. |
| Title |
Seed mass, seedling size and neotropical tree seedling establishment |
Type |
Journal Article |
| Year |
2005 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
| Volume |
93 |
Issue |
6 |
Pages |
1156-1166 |
| Keywords |
French Guiana; life-history trade-offs; microhabitat; path analysis; regeneration strategy; relative growth rate; seedling survival; shade tolerance |
| Abstract |
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. |
| Address |
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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no |
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EcoFoG @ eric.marcon @ |
Serial |
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. |
| Title |
Trophic mediation by a fungus in an ant-plant mutualism |
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
| Volume |
99 |
Issue |
2 |
Pages |
583-590 |
| Keywords |
delta N-15; Allomerus decemarticulatus; ant-plant-fungus interactions; Ascomycete; fungal mediation; Hirtella physophora; mutualisms; myrmecophytes; nutrient provisioning; stable isotopes |
| Abstract |
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. |
| Address |
[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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no |
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EcoFoG @ webmaster @ |
Serial |
297 |
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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. |
| Title |
Contrasting taxonomic and functional responses of a tropical tree community to selective logging |
Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Applied Ecology |
Abbreviated Journal |
J. Appl. Ecol. |
| Volume |
49 |
Issue |
4 |
Pages |
861-870 |
| Keywords |
Canopy gap dynamics; Disturbance; French Guiana; Functional diversity; Functional evenness; Functional traits; Light partitioning; Species richness; Tropical rain forest |
| Abstract |
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. |
| Address |
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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| Notes |
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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no |
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EcoFoG @ webmaster @ |
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410 |
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| Author |
Aimene, Y.; Vidal-Salle, E.; Hagege, B.; Sidoroff, F.; Boisse, P. |
| Title |
A Hyperelastic Approach for Composite Reinforcement Large Deformation Analysis |
Type |
Journal Article |
| Year |
2010 |
Publication |
Journal of Composite Materials |
Abbreviated Journal |
J. Compos Mater. |
| Volume |
44 |
Issue |
1 |
Pages |
5-26 |
| Keywords |
hyperelasticity; woven reinforcements; forming; fabric mechanical behavior; finite element |
| Abstract |
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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