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Author |
Chanson, Anaïs ; Moreau, Corrie S. ; Duplais, Christophe |
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Title |
Assessing Biosynthetic Gene Cluster Diversity of Specialized Metabolites in the Conserved Gut Symbionts of Herbivorous Turtle Ants |
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Journal Article |
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Year |
2021 |
Publication |
Frontiers in Microbiology |
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Volume |
12 |
Issue |
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Pages |
678100 |
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Keywords  |
insect-microbe mutualism, ants, metagemonic, biosynthetic gene cluster, gut bacteria, Cephalotes |
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Abstract |
Cephalotes are herbivorous ants (>115 species) feeding on low-nitrogen food sources, and they rely on gut symbionts to supplement their diet by recycling nitrogen food waste into amino acids. These conserved gut symbionts, which encompass five bacterial orders, have been studied previously for their primary nitrogen metabolism; however, little is known about their ability to biosynthesize specialized metabolites which can play a role in bacterial interactions between communities living in close proximity in the gut. To evaluate the biosynthetic potential of their gut symbionts, we mine 14 cultured isolate genomes and gut metagenomes across 17 Cephalotes species to explore the biodiversity of biosynthetic gene clusters (BGCs) producing specialized metabolites. The diversity of BGCs across Cephalotes phylogeny was analyzed using sequence similarity networking and BGC phylogenetic reconstruction. Our results reveal that the conserved gut symbionts involved in the nutritional symbiosis possess 80% of all the 233 BGCs retrieved in this work. Furthermore, the phylogenetic analysis of BGCs reveals different patterns of distribution, suggesting different mechanisms of conservation. A siderophore BGC shows high similarity in a single symbiont across different ant host species, whereas a BGC encoding the production of non-ribosomal peptides (NRPs) found different symbionts within a single host species. Additionally, BGCs were abundant in four of the five bacterial orders of conserved symbionts co-occurring in the hindgut. However, one major symbiont localized alone in the midgut lack BGCs. Because the spatial isolation prevents direct interaction with other symbionts, this result supports the idea that BGCs are maintained in bacteria living in close proximity but are dispensable for an alone-living symbiont. These findings together pave the way for studying the mechanisms of BGC conservation and evolution in gut bacterial genomes associated with Cephalotes. This work also provides a genetic background for further study, aiming to characterize bacterial specialized metabolites and to understand their functional role in multipartite mutualisms between conserved gut symbionts and Cephalotes turtle ants. |
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Frontiers Media |
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EcoFoG @ webmaster @ |
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1049 |
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Author |
Barabe, D.; Lacroix, C.; Gibernau, M. |
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Title |
Floral development of Urospatha: merosity and phylogeny in the Lasioideae (Araceae) |
Type |
Journal Article |
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Year |
2011 |
Publication |
Plant Systematics and Evolution |
Abbreviated Journal |
Plant Syst. Evol. |
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Volume |
296 |
Issue |
1-2 |
Pages |
41-50 |
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Keywords |
Inflorescence; Homeosis; Angiosperms; Systematic; Morphogenetic constraints |
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In this paper we study merosity in the genus Urospatha within the framework of a resolved phylogeny of the Araceae. We analyse how a transition from dimerous or tetramerous merosity to pentamerous or hexamerous merosity can occur developmentally in the Lasioideae. In Urospatha, initiation of floral primordia along the inflorescence is acropetal, while development of flowers is basipetal. This indicates the presence of two distinct phases in the development of the Urospatha inflorescence. The first phase corresponds to initiation of flowers and establishment of the phyllotactic pattern, and the second phase to differentiation of floral organs. Urospatha is characterized by the presence of trimerous, tetramerous, pentamerous and rarely hexamerous flowers. In all types of flowers, the stamens are closely associated and opposite to the tepals. Pentamerous flowers are formed by addition of a sector comprising a stamen and tepal. Likewise, in the case of hexamerous flowers, two sectors are added. In the Lasioideae, the increase in the number of tepals and stamens is linked with two developmental processes that have appeared independently in the subfamily: (1) addition of one or two stamen-petal sectors (Anaphyllopsis and Urospatha), and (2) independent increase in the number of tepals and stamens on whorls, more or less organized and inserted in alternate position (Dracontium). Tetramerous whorls as they occur in basal Lasioideae would be homologous to two dimerous whorls from an evolutionary point of view. |
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[Barabe, D; Gibernau, M] CNRS UMR Ecol Forets Guyane 8172, F-97387 Kourou, France, Email: denis.barabe@umontreal.ca |
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Springer Wien |
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0378-2697 |
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WOS:000294201300004 |
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EcoFoG @ webmaster @ |
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338 |
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Laybros, A.; Aubry-Kientz, M.; Féret, J.-B.; Bedeau, C.; Brunaux, O.; Derroire, G.; Vincent, G. |
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Title |
Quantitative airborne inventories in dense tropical forest using imaging spectroscopy |
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Journal Article |
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Year |
2020 |
Publication |
Remote Sensing |
Abbreviated Journal |
Remote Sens. |
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Volume |
12 |
Issue |
10 |
Pages |
1577 |
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Keywords |
Hyperspectral; LiDAR; Species diversity; Tropical forest; Cost effectiveness; Discriminant analysis; Infrared devices; Infrared radiation; Logistic regression; Remote sensing; Tropics; Classification accuracy; Classification performance; Linear discriminant analysis; Operational applications; Regularized discriminant analysis; Remote sensing technology; Short wave infrared bands; Visible and near infrared; Forestry |
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Abstract |
Tropical forests have exceptional floristic diversity, but their characterization remains incomplete, in part due to the resource intensity of in-situ assessments. Remote sensing technologies can provide valuable, cost-effective, large-scale insights. This study investigates the combined use of airborne LiDAR and imaging spectroscopy to map tree species at landscape scale in French Guiana. Binary classifiers were developed for each of 20 species using linear discriminant analysis (LDA), regularized discriminant analysis (RDA) and logistic regression (LR). Complementing visible and near infrared (VNIR) spectral bands with short wave infrared (SWIR) bands improved the mean average classification accuracy of the target species from 56.1% to 79.6%. Increasing the number of non-focal species decreased the success rate of target species identification. Classification performance was not significantly affected by impurity rates (confusion between assigned classes) in the non-focal class (up to 5% of bias), provided that an adequate criterion was used for adjusting threshold probability assignment. A limited number of crowns (30 crowns) in each species class was sufficient to retrieve correct labels effectively. Overall canopy area of target species was strongly correlated to their basal area over 118 ha at 1.5 ha resolution, indicating that operational application of the method is a realistic prospect (R2 = 0.75 for six major commercial tree species). © 2020 by the authors. |
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Address |
Cirad, UMR EcoFoG (AgroParistech, CNRS, INRAE, Université des Antilles, Université de la Guyane), Kourou, French Guiana, 97379, France |
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Mdpi Ag |
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20724292 (Issn) |
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EcoFoG @ webmaster @ |
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969 |
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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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Keywords |
hyperelasticity; woven reinforcements; forming; fabric mechanical behavior; finite element |
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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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no |
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Call Number |
EcoFoG @ eric.marcon @ |
Serial |
84 |
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Author |
Male, P.J.G.; Loiseau, A.; Estoup, A.; Quilichini, A.; Orivel, J. |
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Title |
Characterization of polymorphic microsatellite loci in the neotropical plant-ant Allomerus decemarticulatus (Formicidae: Myrmicinae) and multiplexing with other microsatellites from the ant subfamily Myrmicinae |
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Journal Article |
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Year |
2010 |
Publication |
European Journal of Entomology |
Abbreviated Journal |
Eur. J. Entomol. |
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107 |
Issue |
4 |
Pages |
673-675 |
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Keywords |
Hymenoptera; Formicidae; Myrmicinae; Allomerus; ant-plant mutualism; microsatellites; plant-ant |
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Abstract |
Five polymorphic microsatellite loci of the arboreal ant Allomerus decemarticulatus (Myrmicinae) were isolated and characterized. The amplification and polymorphism of seven additional microsatellite loci, previously developed for the ant species A. octoarticulatus and Wasmannia auropunctata, were also tested and the amplification conditions necessary for genotyping the complete set of 12 multiplexed markers in A. decemarticulatus determined. The number of alleles per locus ranged from three to 15 and observed heterozygosity varied front 0.09 to 0.95. Cross-species amplification of these loci was also successfully achieved in additional species of the same ant subfamily, Myrmicinae. This set of microsatellite markers will be used in studies on the mating system and population genetic structure of Myrmicinae in general and A. decemarticulatus in particular. |
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[Male, Pierre-Jean G.; Orivel, Jerome] Univ Toulouse, Lab Evolut & Divers Biol EDB, UMR 5174, F-31062 Toulouse 9, France, Email: pjmale@cict.fr |
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CZECH ACAD SCI, INST ENTOMOLOGY |
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1210-5759 |
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ISI:000284434300020 |
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EcoFoG @ eric.marcon @ |
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19 |
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Author |
Christensen-Dalsgaard, K.K.; Fournier, M.; Ennos, A.R.; Barfod, A.S. |
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Title |
Changes in vessel anatomy in response to mechanical loading in six species of tropical trees |
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Journal Article |
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Year |
2007 |
Publication |
New Phytologist |
Abbreviated Journal |
New Phytol. |
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176 |
Issue |
3 |
Pages |
610-622 |
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Keywords |
hydraulic architecture; hydraulic-mechanical trade-off; mechanical adaptation; rooting morphology; tropical trees; vascular anatomy |
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Abstract |
It is well known that trees adapt their supportive tissues to changes in loading conditions, yet little is known about how the vascular anatomy is modified in this process. We investigated this by comparing more and less mechanically loaded sections in six species of tropical trees with two different rooting morphologies. We measured the strain, vessel size, frequency and area fraction and from this calculated the specific conductivity, then measured the conductivity, modulus of elasticity and yield stress. The smallest vessels and the lowest vessel frequency were found in the parts of the trees subjected to the greatest stresses or strains. The specific conductivity varied up to two orders of magnitude between mechanically loaded and mechanically unimportant parts of the root system. A trade-off between conductivity and stiffness or strength was revealed, which suggests that anatomical alterations occur in response to mechanical strain. By contrast, between-tree comparisons showed that average anatomical features for the whole tree seemed more closely related to their ecological strategy. |
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Univ Manchester, Fac Life Sci, Manchester M60 1QD, Lancs, England, Email: karen@cd-mail.dk |
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BLACKWELL PUBLISHING |
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0028-646X |
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ISI:000250275000013 |
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no |
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EcoFoG @ eric.marcon @ |
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156 |
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Author |
Dejean, A.; Lachaud, J.P. |
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Title |
The hunting behavior of the African ponerine ant Pachycondyla pachyderma |
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Journal Article |
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Year |
2011 |
Publication |
Behavioural Processes |
Abbreviated Journal |
Behav. Processes |
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Volume |
86 |
Issue |
2 |
Pages |
169-173 |
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Keywords |
Hunting behavior; Feeding specialization; Behavioral flexibility; Ponerine ants; Pachycondyla; Myriapoda |
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Abstract |
The hunting behavior of the African ponerine ant Pachycondyla pachyderma, a semi-specialized centipede predator, appears well adapted to this kind of prey and shows a graded complexity according to the difficulty it has in overwhelming prey. Small prey (5-to-8-mm-long termites) were detected by contact and seized by the thorax while larger prey (>= 30-mm-long centipedes) were frequently detected from a distance and seized by the anterior-most part of their body. Termites and 30-mm-long lithobiomorph centipedes were not always stung, whereas stinging and even repeated stinging was needed for 50-mm-long geophilomorphs and scolopendromorphs. Moreover, overwhelming wide and heavy scolopendromorphs, which have better defensive abilities, involved the use of additional behaviors allowing the workers to capture them safely: venom spreading, and a peculiar stinging posture, the “fatal embrace”. Here the workers seize scolopendromorphs by an antenna or by one of their first legs, wrap themselves around the prey while maintaining their grip with their mandibles and legs, and slowly inject venom into the prey's ventral surface. Workers retrieve small prey solitarily while, for large geophilomorphs and scolopendromorphs, nestmates can be recruited at short range or even at long range through tandem running. (C) 2010 Elsevier B.V. All rights reserved. |
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Address |
[Dejean, Alain] CNRS, Ecol Forets Guyane UMR CNRS 8172, F-97379 Kourou, France, Email: alain.dejean@wanadoo.fr |
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Elsevier Science Bv |
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ISSN |
0376-6357 |
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Notes |
ISI:000287984900001 |
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no |
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EcoFoG @ webmaster @ |
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301 |
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Author |
Freycon, V.; Krencker, M.; Schwartz, D.; Nasi, R.; Bonal, D. |
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Title |
The impact of climate changes during the Holocene on vegetation in northern French Guiana |
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Journal Article |
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Year |
2010 |
Publication |
Quaternary Research |
Abbreviated Journal |
Quat. Res. |
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Volume |
73 |
Issue |
2 |
Pages |
220-225 |
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Keywords |
Holocene; Vegetation change; French Guiana; Carbon isotope composition; Soil organic matter |
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Abstract |
The impact of climatic changes that occurred during the last glacial maximum and the Holocene on vegetation changes in the Amazon Basin and the Guiana Shield are still widely debated. The aim of our study was to investigate whether major changes in vegetation (i.e. transitions between rainforests and C-4 savannas) occurred in northern French Guiana during the Holocene. We measured variations in the delta C-13 of soil organic matter at eight sites now occupied by forest or savannah. The forest sites were selected to cover two regions (forest refugia and peneplains) which are thought to have experienced different intensities of disturbance during the latest Pleistocene and the Holocene. We found that none of the forest sites underwent major disturbances during the Holocene, i.e. they were not replaced by C-4 savannahs or C-4 forest savannahs for long periods. Our results thus suggest that tropical rainforests in northern French Guiana were resilient to drier climatic conditions during the Holocene. Nevertheless, geographical and vertical variations in the C-13 of SOM were compatible with minor changes in vegetation, variations in soil processes or in soil physical properties. (C) 2009 University of Washington. Published by Elsevier Inc. All rights reserved. |
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[Freycon, Vincent] CIRAD, UR Dynam Forestiere, F-34398 Montpellier 5, France, Email: vincent.freycon@cirad.fr |
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ACADEMIC PRESS INC ELSEVIER SCIENCE |
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0033-5894 |
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ISI:000275246700007 |
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EcoFoG @ eric.marcon @ |
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66 |
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Author |
Groc, S.; Delabie, J.H.C.; Longino, J.T.; Orivel, J.; Majer, J.D.; Vasconcelos, H.L.; Dejean, A. |
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Title |
A new method based on taxonomic sufficiency to simplify studies on Neotropical ant assemblages |
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Journal Article |
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Year |
2010 |
Publication |
Biological Conservation |
Abbreviated Journal |
Biol. Conserv. |
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Volume |
143 |
Issue |
11 |
Pages |
2832-2839 |
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Keywords |
Higher-taxon surrogacy; “Indicator taxa” surrogacy; Multi-taxonomic assemblages; Mixed-level method; Terrestrial arthropod assemblages; Biodiversity indicators |
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Abstract |
Insects, particularly ants, are good bioindicators of the state of ecosystems. Nevertheless, incorporating them into conservation surveys is expensive due to problems associated with their identification, which is exacerbated by the fact that there are fewer and fewer taxonomists working today. “Taxonomic sufficiency” (TS), which identifies organisms to a level of taxonomic resolution sufficient enough to satisfy the objectives of a study, has never been applied to Neotropical ant communities. We analysed five Neotropical datasets representing ant assemblages collected with different sampling methods in various habitats. We first treated them using two complementary and cumulative TS methods, higher-taxon and “indicator taxa” surrogacies, before testing a new approach called “mixed-level method” that combines the two previous approaches. For the higher-taxon surrogacy, we showed that, above species, genus is the most informative taxonomic level. Then, mixed-level method provided more information on ant assemblages than did the two others, even though the “indicator taxa” surrogacy was based on relevant indicator genera. Although habitat type has no effect on its efficiency, this new method is influenced by the dataset structure and the type of sampling method used to collect data. We have thus developed a new method for analyzing Neotropical ant faunas that enables the taxonomic work linked to the identification of problematic species to be significantly reduced, while conserving most of the information on the ant assemblage. This method should enhance the work of Neotropical entomologists not specialised in taxonomy, particularly those concerned with biological conservation and indication. (C) 2010 Elsevier Ltd. All rights reserved. |
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Address |
[Groc, Sarah; Dejean, Alain] CNRS, Ecol Forets Guyane UMR 8172, F-97379 Kourou, France, Email: sarah.groc@laposte.net |
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ELSEVIER SCI LTD |
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0006-3207 |
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Notes |
ISI:000283412300048 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
22 |
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Author |
Flores, O.; Rossi, V.; Mortier, F. |
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Title |
Autocorrelation offsets zero-inflation in models of tropical saplings density |
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Journal Article |
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Year |
2009 |
Publication |
Ecological Modelling |
Abbreviated Journal |
Ecol. Model. |
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Volume |
220 |
Issue |
15 |
Pages |
1797-1809 |
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Keywords |
Hierarchical Bayesian Modelling; Conditional Auto-Regressive model; Variable selection; Zero-Inflated Poisson; Posterior predictive; Paracou; French Guiana |
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Abstract |
Modelling the local density of tropical saplings can provide insights into the ecological processes that drive species regeneration and thereby help predict population recovery after disturbance. Yet, few studies have addressed the challenging issues in autocorrelation and zero-inflation of local density. This paper presents Hierarchical Bayesian Modelling (HBM) of sapling density that includes these two features. Special attention is devoted to variable selection, model estimation and comparison. We developed a Zero-Inflated Poisson (ZIP) model with a latent correlated spatial structure and compared it with non-spatial ZIP and Poisson models that were either autocorrelated (Spatial Generalized Linear Mixed, SGLM) or not (generalized linear models, GLM). In our spatial models, local density autocorrelation was modeled by a Conditional Auto-Regressive (CAR) process. 13 explicative variables described ecological conditions with respect to topography, disturbance, stand structure and intraspecific processes. Models were applied to six tropical tree species with differing biological attributes: Oxandra asbeckii, Eperua falcata, Eperua grandiflora, Dicorynia guianensis, Qualea rosea, and Tachigali melinonii. We built species-specific models using a simple method of variable selection based on a latent binary indicator. Our spatial models showed a close correlation between observed and estimated densities with site spatial structure being correctly reproduced. By contrast, the non-spatial models showed poor fits. Variable selection highlighted species-specific requirements and susceptibility to local conditions. Model comparison overall showed that the SGLM was the most accurate explanatory and predictive model. Surprisingly, zero-inflated models performed less well. Although the SZIP model was relevant with respect to data distribution, and more flexible with respect to response curves, its model complexity caused marked variability in parameter estimates. In the SUM, the spatial process alone accounted for zero-inflation in the data. A refinement of the hypotheses employed at the process level could compensate for distribution flaws at the data level. This study emphasized the importance of the HBM framework in improving the modelling of density-environment relationships. (C) 2008 Elsevier B.V. All rights reserved. |
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[Flores, O.] CNRS, Ctr Ecol Fonct & Evolut, UMR 5175, F-34293 Montpellier 5, France, Email: olivierflores@free.fr |
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ELSEVIER SCIENCE BV |
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0304-3800 |
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ISI:000267585400007 |
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EcoFoG @ eric.marcon @ |
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201 |
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