Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé :  
1. Despite considerable interest in the application of plant functional traits to questions of community assembly and ecosystem structure and function, there is no consensus on the appropriateness of sampling designs to obtain plot-level estimates in diverse plant communities. 2. We measured 10 plant functional traits describing leaf and stem morphology and ecophysiology for all trees in nine 1-ha plots in terra firme lowland tropical rain forests of French Guiana (N = 4709). 3.We calculated, by simulation, the mean and variance in trait values for each plot and each trait expected under seven sampling methods and a range of sampling intensities. Simulated sampling methods included a variety of spatial designs, as well as the application of existing data base values to all individuals of a given species. 4. For each trait in each plot, we defined a performance index for each sampling design as the proportion of resampling events that resulted in observed means within 5% of the true plot mean, and observed variance within 20%of the true plot variance. 5. The relative performance of sampling designs was consistent for estimations of means and variances. Data base use had consistently poor performance for most traits across all plots, whereas sampling one individual per species per plot resulted in relatively high performance. We found few differences among different spatial sampling strategies; however, for a given strategy, increased intensity of sampling resulted in markedly improved accuracy in estimates of trait mean and variance. 6. We also calculated the financial cost of each sampling design based on data from our 'every individual per plot' strategy and estimated the sampling and botanical effort required. The relative performance of designs was strongly positively correlated with relative financial cost, suggesting that sampling investment returns are relatively constant. 7. Our results suggest that trait sampling for many objectives in species-rich plant communities may require the considerable effort of sampling at least one individual of each species in each plot, and that investment in complete sampling, though great, may be worthwhile for at least some traits.
Functional Ecology

hal-01032175
https://hal.archives-ouvertes.fr/hal-01032175
DOI : 10.1111/j.1365-2435.2009.01600.x

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
In Alpine Corsica (France), deeply subducted metabasalts are well preserved as lawsonite-bearing eclogite (Law-Ecl), occurrence of which is restricted to similar to 10 localities worldwide. The Corsican Law-Ecl, consisting of omphacite + lawsonite + garnet + phengite + titanite, occurs as both single undeformed metabasaltic pillows surrounded by lawsonite blueschist (Law-Bs), and carbonate-bearing eclogitic veins. Law-Bs are found as variably deformed metabasaltic pillows locally cross-cut by eclogitic veins and consist of glaucophane + actinolite + lawsonite + garnet + phengite + titanite. Field evidence and microstructures reveal that both Law-Ecl and Law-Bs are stable at the metamorphic peak in the lawsonite-eclogite stability field. Isochemical phase diagrams (pseudosections) calculated for representative Law-Ecl and Law-Bs samples indicate that both lithologies equilibrated at the same conditions of similar to 520 +/- 20 degrees C and 2.3 +/- 0.1 GPa. Therefore, the coexistence at the same peak metamorphic conditions of Law-Ecl and Law-Bs implies that different portions of deeply subducted oceanic crust may store significantly different H2O contents, depending on bulk-rock chemical composition. In addition, thermodynamic modelling of phase equilibria indicates that the occurring progressive dehydration reactions, which are significantly depending on bulk-rock chemical composition, strongly influence rock densification and eclogite formation in subducting slabs.
ISSN: 0263-4929

hal-00617768
https://hal.archives-ouvertes.fr/hal-00617768
DOI : 10.1111/j.1525-1314.2011.00931.x

Éditeur(s) : HAL CCSD Lamb T. Wiley Blackwell.
Résumé : Le numéro ISSN inscrit dans ce dépôt est en fait le numéro ISBN, nous n'avons pas le numéro ISSN ISBN: 978-0-470-97247-2
Immunity to parasitic infection.

inserm-00838983
http://www.hal.inserm.fr/inserm-00838983
http://www.hal.inserm.fr/inserm-00838983/document
http://www.hal.inserm.fr/inserm-00838983/file/2013_Nacher_-_The_interaction_between_gastrointestinal_nematodes_and_malaria.pdf

Éditeur(s) : Wiley-blackwell Publishing, Inc
Résumé : Oceanic larvae of the European (Anguilla anguilla) and American (A. rostrata) eels have to cross the Atlantic Ocean from the Sargasso Sea to European or North American coasts before entering continental habitats. In some European rivers, eel recruitment is now < 1% of levels in the 1980s. A better understanding of the effects of anthropogenic pressures and environmental fluctuations on eel larvae and subsequent recruitment is a prerequisite to build efficient management plans. The present paper provides insight into the critical oceanic phase of the eel life cycle with a focus on the duration of the larval migration whose estimates varies between 7 months and more than 2 years in both species. Does this range correspond to a natural variability in larval duration or does it stem from methodological artefacts? We first review the different methods used to estimate the duration of larval migration and critically describe their possible sources of misinterpretation. We then evaluate the consistency of these methods with the current knowledge about the ecology and physiology of eel larvae and the physical oceanography. While a moderate discrepancy in migration duration was found between methods for the American eel, the discrepancy was large in the European eel. In this species, otolith microstructure studies indicated migration durations between 7 and 9 months, while other methods pointed to durations of about 2 years. We show that estimates in favour of a long migration duration seem more robust to methodological caveats than methods estimating short durations of migration.
Fish And Fisheries (1467-2960) (Wiley-blackwell Publishing, Inc), 2010-09 , Vol. 11 , N. 3 , P. 289-306

Droits : 2010 Blackwell Publishing Ltd.
http://archimer.ifremer.fr/doc/00011/12208/9033.pdf
DOI:10.1111/j.1467-2979.2010.00362.x
http://archimer.ifremer.fr/doc/00011/12208/

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
Six morphotypes of small mussels (Bivalvia: Mytilidae) were found attached to naturally sunken wood collected in the Bohol Sea (Philippines). These specimens are related to the large Bathymodiolus mussels that are found worldwide at cold seeps and hydrothermal vents. In these habitats, the mytilids harbour sulphur- and methane-oxidizing endosymbionts in their gills and depend on the energy and carbon provided by the symbionts. In this study, bacteria associated with the gills of wood-associated mussels are characterized using molecular and microscopic techniques. The existence of bacteria in the lateral zone of gill filaments in all specimens is demonstrated. Comparative analyses of 16S rRNA gene and adenosine 5′-phosphosulphate (APS) reductase gene sequences indicate that the bacteria are closely related to sulphur-oxidizing endosymbionts of Bathymodiolus. FISHs using specific probes confirm that sulphur oxidizers are by far the most abundant, if not the only bacteria present. Electron micrographs displayed mostly extracellular bacteria located between microvilli at the apical surface of host gill epithelial cells all along the lateral zone of each gill filament. In some specimens, occasional occurrence of intracellular bacteria with similar morphology was noted. This study provides the first molecular evidence for the presence of possible thiotrophic symbiosis in sunken wood ecosystems. With their epibiotic bacteria, wood-associated mussels display a less integrated type of interaction than described in their seep, vent and whale fall relatives.
ISSN: 0168-6496

hal-00715244
https://hal.univ-antilles.fr/hal-00715244
DOI : 10.1111/j.1574-6941.2008.00438.x

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
In the Pyrenees, the lherzolites nowhere occur as continuous units. Rather, they always outcrop as restricted bodies, never more than 3 km wide, scattered across Mesozoic sedimentary units along the North Pyrenean Fault. We report the results of a detailed analysis of the geological setting of the Lherz massif (central Pyrenees), the type-locality of lherzolites and one of the most studied occurrences of mantle rocks worldwide. The Lherz body is only 1.5 km long and belongs to a series of ultramafic bodies of restricted size (a few metres to some hundreds of metres), occurring within sedimentary formations composed mostly of carbonate breccias originating from the reworking of Mesozoic platform limestones and dolomites. The clastic formations also include numerous layers of polymictic breccias reworking lherzolitic clasts. These layers are found far from any lherzolitic body, implying that lherzolitic clasts cannot derive from the in situ fragmentation of an ultramafic body alone, but might also have been transported far away from their sources by sedimentary processes. A detailed analysis of the contacts between the Lherz ultramafic body and the surrounding limestones confirms that there is no fault contact and that sediments composed of ultramafic material have been emplaced into fissures within the brecciated carapace of the peridotites. These observations bear important constraints for the mode of emplacement of the lherzolite bodies. We infer that mantle exhumation may have occurred during Albian strike-slip deformation linked to the rotation of Iberia along the proto-North Pyrenean Fault.
ISSN: 0954-4879

hal-00412602
https://hal.archives-ouvertes.fr/hal-00412602

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
ISSN: 0954-4879

hal-00708866
https://hal.archives-ouvertes.fr/hal-00708866
DOI : 10.1111/j.1365-3121-2011-014-x

Éditeur(s) : HAL CCSD Wiley-Blackwell Wiley
Résumé : A new record from the heart of the Moroccan Middle Atlas cedar forests spans the last 18 000 years and provides valuable insight into our understanding of the natural vegetation and environmental changes. The approach is based on the study of pollen content, geochemical elements and grain size analysis. The pollen data indicate that the vegetation was dominated by herbaceous plants until 9000 BP. Such open landscape allowed greater soil erosion and an input of chemical elements from the watershed. After 9000 BP, tree cover, mainly oak, increased slightly and was accompanied by a higher taxonomic diversity. However, several steppe elements remain well represented in the area until 5000 BP, which suggests that the climate was rather dry during the first part of the Holocene. After 6000 BP, the climate became more favourable to expansion of the forest ecosystems, including Cedrus atlantica, thereby reducing erosion. A strong reduction of the tree pollen percentages is recorded after 2000 BP, which may be related to increasing human activities during the Roman period. These forest changes are concomitant with an increase of lead and copper concentrations in the record, probably related to Roman metalworking activities.
ISSN: 0267-8179

hal-01122848
https://hal.archives-ouvertes.fr/hal-01122848
DOI : 10.1002/jqs.2708

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
P>Most fault-related pseudotachylytes in the Val Sesia area, Ivrea zone, NW Italian Alps, occur in two areas: near the Canavese Line in the Kinzigite Formation paragneisses and in an elongate belt in the Mafic Complex gabbros away from the Canavese Line. Ar-40/Ar-39 dating indicates that pseudotachylytes from the Kinzigite Formation were formed in the late Eocene, likely during the early stages of the collision between the NW corner of the Adriatic indenter and the European margin. Pseudotachylytes from the Mafic Complex were formed under a transpressive strain regime, as suggested by kinematic indicators, and yield Early Cretaceous (Albian) Ar-40/Ar-39 ages. Their formation is possibly related to shortening during the inception of the tectonic inversion of the Adriatic passive margin.
ISSN: 0954-4879

hal-00617518
https://hal.archives-ouvertes.fr/hal-00617518
DOI : 10.1111/j.1365-3121.2011.00994.x