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Latouche-Halle, C.; Ramboer, A.; Bandou, E.; Caron, H.; Kremer, A. |
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Title |
Long-distance pollen flow and tolerance to selfing in a neotropical tree species |
Type |
Journal Article |
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Year |
2004 |
Publication |
Molecular Ecology |
Abbreviated Journal |
Mol. Ecol. |
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Volume |
13 |
Issue  |
5 |
Pages |
1055-1064 |
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Keywords |
Dicorynia guianensis; microsatellites; outcrossing rate; pollen flow; reproductive success; tropical tree |
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Abstract |
Outcrossing rates, pollen dispersal and male mating success were assessed in Dicorynia guianensis Amshoff, a neotropical tree endemic to the Guiana shield. All adult trees within a continuous area of 40 ha (n = 157) were mapped, and were genotyped with six microsatellite loci. In addition, progenies were genotyped from 22 mature trees. At the population level, the species was mostly outcrossing (t(m) = 0.89) but there was marked variation among individuals. One tree exhibited mixed mating, confirming earlier results obtained with isozymes that D. guianensis can tolerate selfing. A Bayesian extension of the fractional paternity method was used for paternity analysis, and was compared with the neighbourhood method used widely for forest trees. Both methods indicated that pollen dispersal was only weakly related to distance between trees within the study area, and that the majority (62%) of pollen came from outside the study stand. Using maximum likelihood, male potential population size was estimated to be 1119, corresponding to a neighbourhood size of 560 hectares. Male mating success was, however, related to the diameter of the stem and to flowering intensity assessed visually. The mating behaviour of D. guianensis is a combination of long-distance pollen flow and occasional selfing. The species can still reproduce when it is extremely rare, either by selfing or by dispersing pollen at long distances. These results, together with the observation that male mating success was correlated with the size of the trees, could be implemented in management procedures aiming at regenerating the species. |
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INRA, UMR Ecol Forets Guyane, F-97387 Kourou, France, Email: caron@pierroton.mra.fr |
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BLACKWELL PUBLISHING LTD |
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0962-1083 |
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ISI:000221016300007 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
237 |
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Author |
Gond, V.; Bartholome, E.; Ouattara, F.; Nonguierma, A.; Bado, L. |
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Title |
Monitoring and mapping of waters and wetlands in arid regions using the SPOT-4 VEGETATION imaging system |
Type |
Journal Article |
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Year |
2004 |
Publication |
International Journal of Remote Sensing |
Abbreviated Journal |
Int. J. Remote Sens. |
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Volume |
25 |
Issue |
5 |
Pages |
987-1004 |
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Abstract |
Monitoring the state of small waterbodies and wetlands is very useful in dry regions, because their existence is entirely controlled by the rhythm of local rainfall. On VEGETATION image colour composites, waterbodies and marshy vegetation show up clearly. Yet simple image classification does not yield sufficiently good results because 'spectral signatures' vary significantly together with the ecological conditions of these surfaces. A robust contextual procedure taking into account local contrast was successfully developed and tested. A systematic validation was carried out and a map of waterbodies and wetlands was produced for Burkina Faso and neighbouring regions. |
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Ctr Commun Rech, I-21020 Ispra, VA, Italy, Email: valery.gond@cirad.fr |
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TAYLOR & FRANCIS LTD |
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0143-1161 |
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ISI:000187996500007 |
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EcoFoG @ eric.marcon @ |
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266 |
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Author |
Sobotnik, J.; Sillam-Dusses, D.; Weyda, F.; Dejean, A.; Roisin, Y.; Hanus, R.; Bourguignon, T. |
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Title |
The frontal gland in workers of Neotropical soldierless termites |
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Journal Article |
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Year |
2010 |
Publication |
Naturwissenschaften |
Abbreviated Journal |
Naturwissenschaften |
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Volume |
97 |
Issue |
5 |
Pages |
495-503 |
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Keywords |
Frontal gland; Workers; Soldierless termites; Apicotermitinae; Anoplotermes; Aparatermes |
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Abstract |
The presence of the frontal gland is well established in termite soldiers of Rhinotermitidae, Serritermitidae, and Termitidae. It is one of their main defensive adaptations or even an exclusive weapon. The gland was also occasionally reported in alate imagoes, but never in the worker caste. Here, we report the first observation of a frontal gland in workers of several Neotropical and one African species of Apicotermitinae. The ultrastructure of Aparatermes cingulatus and Anoplotermes nr. subterraneus is described in detail. In these two species, the gland is well-developed, functional and consists of class 1 secretory cells. The presence of envelope cells, wrapping the gland, is an unusual feature, as well as the presence of several zonulae adherens, connecting neighbouring glandular cells. The frontal gland of workers is homologous to this organ in soldiers and imagoes, as evidenced by the same position in the head and its connection to the same muscle. However, the defensive role of the frontal gland in workers remains to be confirmed. |
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[Sobotnik, Jan; Sillam-Dusses, David; Hanus, Robert] Acad Sci Czech Republic, Inst Organ Chem & Biochem, Res Team Infochem, CR-16610 Prague 6, Czech Republic, Email: robert@uochb.cas.cz |
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SPRINGER |
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ISSN |
0028-1042 |
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Notes |
ISI:000277318800007 |
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no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
285 |
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Author |
Fanin, N.; Hattenschwiler, S.; Barantal, S.; Schimann, H.; Fromin, N. |
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Title |
Does variability in litter quality determine soil microbial respiration in an Amazonian rainforest? |
Type |
Journal Article |
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Year |
2011 |
Publication |
Soil Biology & Biochemistry |
Abbreviated Journal |
Soil Biol. Biochem. |
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Volume |
43 |
Issue |
5 |
Pages |
1014-1022 |
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Keywords |
Carbon forms; French Guiana; Litter quality; Microbial respiration process; Nitrogen; Phosphorus; Stoichiometry |
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Abstract |
Tree species-rich tropical rainforests are characterized by a highly variable quality of leaf litter input to the soil at small spatial scales. This diverse plant litter is a major source of energy and nutrients for soil microorganisms, particularly in rainforests developed on old and nutrient-impoverished soils. Here we tested the hypothesis that the variability in leaf litter quality produced by a highly diverse tree community determines the spatial variability of the microbial respiration process in the underlying soil. We analyzed a total of 225 litter-soil pairs from an undisturbed Amazonian rainforest in French Guiana using a hierarchical sampling design. The microbial respiration process was assessed using substrate-induced respiration (SIR) and compared to a wide range of quality parameters of the associated litter layer (litter nutrients, carbon forms, stoichiometry, litter mass and pH). The results show that the variability of both litter quality and SIR rates was more important at large than at small scales. SIR rates varied between 1.1 and 4.0 μg h(-1) and were significantly correlated with litter layer quality (up to 50% of the variability explained by the best mixed linear model). Total litter P content was the individual most important factor explaining the observed spatial variation in soil SIR, with higher rates associated to high litter P. SIR rates also correlated positively with total litter N content and with increasing proportions of labile C compounds. However, contrary to our expectation, SIR rates were not related to litter stoichiometry. These data suggest that in the studied Amazonian rainforest, tree canopy composition is an important driver of the microbial respiration process via leaf litter fall, resulting in potentially strong plant-soil feedbacks. (C) 2011 Elsevier Ltd. All rights reserved. |
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Address |
[Fanin, Nicolas; Haettenschwiler, Stephan; Barantal, Sandra; Fromin, Nathalie] CNRS, CEFE, UMR 5175, F-34293 Montpellier 5, France, Email: nicolas.fanin@cefe.cnrs.fr |
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Pergamon-Elsevier Science Ltd |
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ISSN |
0038-0717 |
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Notes |
ISI:000289219500019 |
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no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
304 |
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Author |
Paine, C.E.T.; Baraloto, C.; Chave, J.; Herault, B. |
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Title |
Functional traits of individual trees reveal ecological constraints on community assembly in tropical rain forests |
Type |
Journal Article |
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Year |
2011 |
Publication |
Oikos |
Abbreviated Journal |
Oikos |
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Volume |
120 |
Issue |
5 |
Pages |
720-727 |
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Abstract |
Niche differentiation and ecological filtering are primary ecological processes that shape community assembly, but their relative importance remains poorly understood. Analyses of the distributions of functional traits can provide insight into the community structure generated by these processes. We predicted the trait distributions expected under the ecological processes of niche differentiation and environmental filtering, then tested these predictions with a dataset of 4672 trees located in nine 1-ha plots of tropical rain forest in French Guiana. Five traits related to leaf function (foliar N concentration, chlorophyll content, toughness, tissue density and specific leaf area), and three traits related to stem function (trunk sapwood density, branch sapwood density, and trunk bark thickness), as well as laminar surface area, were measured on every individual tree. There was far more evidence for environmental filtering than for niche differentiation in these forests. Furthermore, we contrasted results from species-mean and individual-level trait values. Analyses that took within-species trait variation into account were far more sensitive indicators of niche differentiation and ecological filtering. Species-mean analyses, by contrast, may underestimate the effects of ecological processes on community assembly. Environmental filtering appeared somewhat more intense on leaf traits than on stem traits, whereas niche differentiation affected neither strongly. By accounting for within-species trait variation, we were able to more properly consider the ecological interactions among individual trees and between individual trees and their environment. In so doing, our results suggest that the ecological processes of niche differentiation and environmental filtering may be more pervasive than previously believed. |
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Address |
[Paine, C. E. Timothy] ENGREF, UMR Ecol Forets Guyane, Kourou 97387, French Guiana, Email: timothy.paine@ieu.uzh.ch |
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Wiley-Blackwell |
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ISSN |
0030-1299 |
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Notes |
ISI:000289740200008 |
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no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
313 |
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Author |
Dejean, A. |
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Title |
Prey Capture Behavior in an Arboreal African Ponerine Ant |
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Journal Article |
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Year |
2011 |
Publication |
PLoS One |
Abbreviated Journal |
PLoS One |
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Volume |
6 |
Issue |
5 |
Pages |
e19837 |
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Abstract |
I studied the predatory behavior of Platythyrea conradti, an arboreal ponerine ant, whereas most species in this subfamily are ground-dwelling. The workers, which hunt solitarily only around dusk, are able to capture a wide range of prey, including termites and agile, nocturnal insects as well as diurnal insects that are inactive at that moment of the Nyctemeron, resting on tree branches or under leaves. Prey are captured very rapidly, and the antennal palpation used by ground-dwelling ponerine species is reduced to a simple contact; stinging occurs immediately thereafter. The venom has an instant, violent effect as even large prey (up to 30 times the weight of a worker) never struggled after being stung. Only small prey are not stung. Workers retrieve their prey, even large items, singly. To capture termite workers and soldiers defending their nest entrances, ant workers crouch and fold their antennae backward. In their role as guards, the termites face the crouching ants and end up by rolling onto their backs, their legs batting the air. This is likely due to volatile secretions produced by the ants' mandibular gland. The same behavior is used against competing ants, including territorially-dominant arboreal species that retreat further and further away, so that the P. conradti finally drive them from large, sugary food sources. |
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Address |
[Dejean, Alain] CNRS, Ecol Forets Guyane UMR 8172, Kourou, France, Email: alain.dejean@wanadoo.fr |
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Public Library Science |
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ISSN |
1932-6203 |
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Notes |
ISI:000290483600033 |
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no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
316 |
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Author |
Brouard, O.; Le Jeune, A.H.; Leroy, C.; Cereghino, R.; Roux, O.; Pelozuelo, L.; Dejean, A.; Corbara, B.; Carrias, J.F. |
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Title |
Are Algae Relevant to the Detritus-Based Food Web in Tank-Bromeliads? |
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Journal Article |
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Year |
2011 |
Publication |
PLoS One |
Abbreviated Journal |
PLoS One |
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Volume |
6 |
Issue |
5 |
Pages |
e20129 |
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Abstract |
We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from similar to 10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web. |
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Address |
[Brouard, Olivier; Le Jeune, Anne-Helene; Corbara, Bruno; Carrias, Jean-Francois] Univ Clermont Ferrand, CNRS, Lab Microorganismes Genome & Environm, LMGE,UMR 6023, Aubiere, France, Email: j-francois.carrias@univ-bpclermont.fr |
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Public Library Science |
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1932-6203 |
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Notes |
ISI:000290720200066 |
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no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
319 |
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Author |
Roux, O.; Cereghino, R.; Solano, P.J.; Dejean, A. |
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Title |
Caterpillars and Fungal Pathogens: Two Co-Occurring Parasites of an Ant-Plant Mutualism |
Type |
Journal Article |
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Year |
2011 |
Publication |
PLoS One |
Abbreviated Journal |
PLoS One |
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Volume |
6 |
Issue |
5 |
Pages |
e20538 |
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Abstract |
In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia) and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae) as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae) can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs) whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes), that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth. |
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Address |
[Roux, Olivier; Dejean, Alain] CNRS, Ecol Forets Guyane UMR 8172, Kourou, France, Email: olivier.roux@ird.fr |
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Public Library Science |
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1932-6203 |
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Notes |
ISI:000291097600091 |
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no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
322 |
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Author |
Cereghino, R.; Leroy, C.; Carrias, J.F.; Pelozuelo, L.; Segura, C.; Bosc, C.; Dejean, A.; Corbara, B. |
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Title |
Ant-plant mutualisms promote functional diversity in phytotelm communities |
Type |
Journal Article |
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Year |
2011 |
Publication |
Functional Ecology |
Abbreviated Journal |
Funct. Ecol. |
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Volume |
25 |
Issue |
5 |
Pages |
954-963 |
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Keywords |
ant gardens; biodiversity; bromeliads; community functions; forest; French Guiana; invertebrates; phytotelmata; two-species mutualism |
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Abstract |
1. Our understanding of the contribution of interspecific interactions to functional diversity in nature lags behind our knowledge of spatial and temporal patterns. Although two-species mutualisms are found in all types of ecosystems, the study of their ecological influences on other community members has mostly been limited to third species, while their influence on entire communities remains largely unexplored. 2. We hypothesized that mutualistic interactions between two respective ant species and an epiphyte mediate the biological traits composition of entire invertebrate communities that use the same host plant, thereby affecting food webs and functional diversity at the community level. 3. Aechmea mertensii (Bromeliaceae) is both a phytotelm ('plant-held water') and an ant-garden epiphyte. We sampled 111 bromeliads (111 aquatic invertebrate communities) associated with either the ant Pachycondyla goeldii or Camponotus femoratus. The relationships between ants, bromeliads and invertebrate abundance data were examined using a redundancy analysis. Biological traits information for invertebrates was structured using a fuzzy-coding technique, and a co-inertia analysis between traits and abundance data was used to interpret functional differences in bromeliad ecosystems. 4. The vegetative traits of A. mertensii depended on seed dispersion by C. femoratus and P. goeldii along a gradient of local conditions. The ant partner selected sets of invertebrates with traits that were best adapted to the bromeliads' morphology, and so the composition of the biological traits of invertebrate phytotelm communities depends on the identity of the ant partner. Biological traits suggest a bottom-up control of community structure in C. femoratus-associated phytotelmata and a greater structuring role for predatory invertebrates in P. goeldii-associated plants. 5. This study presents new information showing that two-species mutualisms affect the functional diversity of a much wider range of organisms. Most biological systems form complex networks where nodes (e. g. species) are more or less closely linked to each other, either directly or indirectly, through intermediate nodes. Our observations provide community-level information about biological interactions and functional diversity, and perspectives for further observations intended to examine whether large-scale changes in interacting species/community structure over broad geographical and anthropogenic gradients affect ecosystem functions. |
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Address |
[Cereghino, R; Pelozuelo, L; Segura, C; Bosc, C] Univ Toulouse, EcoLab, Lab Ecol Fonct & Environm, UMR 5245, F-31062 Toulouse, France, Email: cereghin@cict.fr |
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Wiley-Blackwell |
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ISSN |
0269-8463 |
ISBN |
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Notes |
WOS:000295132100003 |
Approved |
no |
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Call Number |
EcoFoG @ webmaster @ |
Serial |
341 |
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Author |
Zhang, T.; Bai, S.-L.; Bardet, S.; Almeras, T.; Thibaut, B.; Beauchene, J. |
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Title |
Radial variations of vibrational properties of three tropical woods |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Wood Science |
Abbreviated Journal |
J. Wood Sci. |
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Volume |
57 |
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5 |
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377-386 |
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Damping coefficient; Dynamic modulus; Extractives; Microfibril angle; Tropical woods |
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Abstract |
The radial trends of vibrational properties, represented by the specific dynamic modulus (E′/ρ) and damping coefficient (tan δ), were investigated for three tropical rainforest hardwood species (Simarouba amara, Carapa procera, and Symphonia globulifera) using free-free flexural vibration tests. The microfibril angle (MFA) was estimated using X-ray diffraction. Consistent patterns of radial variations were observed for all studied properties. E′/ρ was found to decrease from pith to bark, which was strongly related to the increasing pith-bark trend of MFA. The variation of tan δ along the radius could be partly explained by MFA and partly by the gradient of extractives due to heartwood formation. The coupling effect of MFA and extractives could be separated through analysis of the log(tan δ) versus log(E′/ρ) diagram. For the species studied, the extractive content putatively associated with heartwood formation generally tends to decrease the wood damping coefficient. However, this weakening effect of extractives was not observed for the inner part of the heartwood, suggesting that the mechanical action of extractives was reduced during their chemical ageing. © 2011 The Japan Wood Research Society. |
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CIRAD, UMR Ecofog, BP 701, 97387 Kourou Cedex, Guyane Française, France |
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14350211 (Issn) |
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Notes |
Export Date: 26 October 2011; Source: Scopus; Coden: Jwscf; doi: 10.1007/s10086-011-1189-7; Language of Original Document: English; Correspondence Address: Bai, S.-L.; Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871, China; email: slbai@pku.edu.cn |
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EcoFoG @ webmaster @ |
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363 |
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