Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
BACKGROUND: Phthalic acid esters are widely used in the manufacture of plastics. Numerous studies have shown that these phthalates impair testicular testosterone production in the rat. However, the scarce and contradictory data concerning humans have cast doubt over whether these compounds are also anti-androgenic in man. We therefore investigated the direct effects of di-(2-ethylhexyl) phthalate (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) on organo-cultured adult human testis and a human cell line. METHODS: Adult human testis explants or NCI-H295R adrenocortical human cells were cultured with DEHP or MEHP. The effects of ketoconazole, used as a reference molecule, were also assessed. RESULTS: In both models, DEHP and MEHP significantly inhibited testosterone production. The effects of both phthalates appeared to be specific for steroidogenesis, as INSL3 production by Leydig cells was not altered. Furthermore, the phthalates of interest had no effect on inhibin B production by Sertoli cells or on germ cell apoptosis. As only a small fraction of the phthalates added was found in the testis explants, and as these compounds were found to be metabolized, we estimate that the anti-androgenic effects observed occurred at concentrations of phthalates that are of the same order of magnitude as exposures reported in the literature for men. CONCLUSIONS: We provide the first evidence that DEHP and MEHP can inhibit testosterone production in the adult human testis. This is consistent with recent epidemiological findings of an inverse correlation between exposure to MEHP and testosterone concentrations.
ISSN: 0268-1161

hal-00876965
https://hal.archives-ouvertes.fr/hal-00876965
DOI : 10.1093/humrep/des069
PUBMED : 22402212

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
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. fenaoratus-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.
Functional Ecology

hal-01096909
https://hal-agroparistech.archives-ouvertes.fr/hal-01096909
DOI : 10.1111/j.1365-2435-2011.01863.x

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BackgroundTo date, all studies conducted on breast cancer diagnosis have focused on the expression of the full-length 66-kDa estrogen receptor alpha (ERα66). However, much less attention has been paid to a shorter 46-kDa isoform (ERα46), devoid of the N-terminal region containing the transactivation function AF-1. Here, we investigated the expression levels of ERα46 in breast tumors in relation to tumor grade and size, and examined the mechanism of its generation and its specificities of coregulatory binding and its functional activities.MethodsUsing approaches combining immunohistochemistry, Western blotting, and proteomics, antibodies allowing ERα46 detection were identified and the expression levels of ERα46 were quantified in 116 ERα-positive human breast tumors. ERα46 expression upon cellular stress was studied, and coregulator bindings, transcriptional, and proliferative response were determined to both ERα isoforms.ResultsERα46 was expressed in over 70% of breast tumors at variable levels which sometimes were more abundant than ERα66, especially in differentiated, lower-grade, and smaller-sized tumors. We also found that ERα46 can be generated via internal ribosome entry site-mediated translation in the context of endoplasmic reticulum stress. The binding affinities of both unliganded and fully-activated receptors towards co-regulator peptides revealed that the respective potencies of ERα46 and ERα66 differ significantly, contributing to the differential transcriptional activity of target genes to 17β estradiol (E2). Finally, increasing amounts of ERα46 decrease the proliferation rate of MCF7 tumor cells in response to E2.ConclusionsWe found that, besides the full-length ERα66, the overlooked ERα46 isoform is also expressed in a majority of breast tumors. This finding highlights the importance of the choice of antibodies used for the diagnosis of breast cancer, which are able or not to detect the ERα46 isoform. In addition, since the function of both ERα isoforms differs, this work underlines the need to develop new technologies in order to discriminate ERα66 and ERα46 expression in breast cancer diagnosis which could have potential clinical relevance.
ISSN: 1465-5411

inserm-01412032
http://www.hal.inserm.fr/inserm-01412032
http://www.hal.inserm.fr/inserm-01412032/document
http://www.hal.inserm.fr/inserm-01412032/file/13058_2016_Article_780.pdf
DOI : 10.1186/s13058-016-0780-7

Éditeur(s) : HAL CCSD Wiley
Résumé : 1. Niche theory proposes that species differences underlie both coexistence within communities and the differentiation in species composition among communities via limiting similarity and environmental filtering. However, it has been difficult to extend niche theory to species-rich communities because of the empirical challenge of quantifying niches for many species. This has motivated the development of functional and phylogeny-based approaches in community ecology, which represent two different means of approximating niche attributes. 2. Here, we assess the utility of plant functional traits and phylogenetic relationships in predicting community assembly processes using the largest trait and phylogenetic data base to date for any set of species-rich communities. 3. We measured 17 functional traits for all 4672 individuals of 668 tree species co-occurring in nine tropical rain forest plots in French Guiana. Trait variation was summarized into two ordination axes that reflect species niche overlap. 4. We also generated a dated molecular phylogenetic tree based on DNA sequencing of two plastid loci (rbcL and matK) comprising 97% of the individuals and 91% of the species in the plots. 5. We found that, on average, co-occurring species had greater functional and, to a lesser extent, phylogenetic similarity than expected by chance. 6. We also found that functional traits and their ordination loadings showed significant, albeit weak, phylogenetic signal, suggesting that phylogenetic distance provides pertinent information on niche overlap in tropical tree communities. 7. Synthesis. We provide the most comprehensive examination to date of the relative importance of environmental filtering and limiting similarity in structuring tropical tree communities. Our results confirm that environmental filtering is the overriding influence on community assembly in these species-rich systems.
ISSN: 0141-6707

hal-01032423
https://hal.archives-ouvertes.fr/hal-01032423
DOI : 10.1111/j.1365-2745.2012.01966.x

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : National audience
Late Triassic submarine alkali basalts and hawaiites were collected from two superimposed tectonic slices belonging to the Kara Dere – Sayrun unit of the Middle Antalya nappes, southwestern Turkey. New determinations on conodont faunas allow to date this sequence to the Lower Carnian (Julian). The volcanic rocks show rather homogeneous compositions, with high TiO2 and relatively low MgO and Ni contents which suggest olivine fractionation. Their primitive mantle-normalised multi-elements plots show Nb and Ta enrichments relative to La, Pb negative anomalies and heavy rare earth element and Y depletions typical of intraplate ocean island basalts. These characteristics are consistent with the major and trace element compositions of their primary clinopyroxene phenocrysts, which do not show any feature ascribable to crustal contamination. The studied lavas display a restricted range of {varepsilon}Nd (+4.6 to +5.2) which falls within the range of ocean island basalts. Their initial (143Nd/144Nd)i ratios are too low to be explained by a simple mixing line between depleted MORB mantle (DMM) and HIMU components. Their Pb and Nd isotopic compositions plot along a mixing line between HIMU component and an enriched mantle, the composition of which could be the result of the addition of about 5 to 8% of an EM2 component (recycled marine sediments) to DMM. The lack of evidence for any continental crustal component in their genesis could be consistent with their emplacement in an intra-oceanic setting.
EISSN: 1777-5817

insu-00338829
https://hal-insu.archives-ouvertes.fr/insu-00338829
DOI : 10.2113/gssgfbull.179.4.397

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
ISSN: 0006-3606

hal-01093932
https://hal-agroparistech.archives-ouvertes.fr/hal-01093932
DOI : 10.1111/j.1744-7429.2009.00614.x

Éditeur(s) : HAL CCSD Wiley
Résumé : 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 613% 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.
ISSN: 0021-8901

hal-01032420
https://hal.archives-ouvertes.fr/hal-01032420
DOI : 10.1111/j.1365-2664.2012.02164.x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Although ants may induce community-wide effects via changes in physical habitats in terrestrial environments, their influence on aquatic communities living in plant-held waters remains largely underexplored. The neotropical tank-bromeliad Aechmea mertensii (Bromeliaceae) occurs along forest edges in ant-gardens initiated by Camponotus femoratus or by Pachycondyla goeldii. Its leaves form wells that hold rainwater and provide suitable habitats for many aquatic organisms. We postulated that these ant-plant mutualisms indirectly affect the microbial community structure via changes in the environmental conditions experienced by the plants. To test this hypothesis, we analyzed the protist communities from 63 tank-bromeliads associated with either C. femoratus or P. goeldii (hereafter Cf-Aechmea and Pg-Aechmea) along a forest edge in French Guiana. For each plant, a large number of environmental variables (including habitat structure, food resources, incident radiation and the presence of aquatic invertebrates) were quantified to determine their relative importance in driving any observed differences across ant-associated plants. Pg-Aechmea are located in sun-exposed areas and hold low volumes of water and low amounts of detritus, whereas Cf-Aechmea are located in partially shaded areas and accumulate higher amounts of water and detritus. Protists (i.e., protozoa and algae) inhabiting Cf-Aechmea exhibit greater richness and abundances than those in Pg-Aechmea. Variations in detritus content, number of leaves, incident radiation, and the epiphyte richness of the ant-garden were the main factors explaining the variation in protist richness. A shift in the functional group composition of protists between bromeliads tended by different ant species suggested that mutualistic ants indirectly mediate changes in the microbial food web.
Basic and Applied Ecology

hal-00913126
https://hal.archives-ouvertes.fr/hal-00913126
https://hal.archives-ouvertes.fr/hal-00913126/document
DOI : 10.1016/j.baae.2012.10.002
OATAO : 10190

Éditeur(s) : HAL CCSD
Résumé : International audience
European Geosciences Union General Assembly April-2013
Vienne, Austria

hal-01134025
https://hal.archives-ouvertes.fr/hal-01134025

Éditeur(s) : HAL CCSD Wiley/Blackwell
Résumé : International audience
This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.
ISSN: 1755-098X

hal-01094222
https://hal-agroparistech.archives-ouvertes.fr/hal-01094222
DOI : 10.1111/j.1755-0998.2010.02916.x

Éditeur(s) : HAL CCSD CRC Press
Résumé : Among the ecosystem services provided by forests, wood provisioning takes a central position. Wood and derived products have played a critical role in the evolution of human kind and demand for raw material is increasing in a foreseeable future. Wood is used for energy production, construction and a wide variety of products for which different properties are required. Anatomical, chemical and physical properties of wood are determined through a complex process called xylogenesis controlled by internal and external signals and occurring during the life of the tree. In this chapter we describe i/how wood is formed and ii/the different factors controlling this developmental process with emphasis on the molecular machinery involved, iii/the functions of wood and iv/the biotechnology approaches developed to improve wood biomass production and properties genetically.
Tree Biotechnology

ISBN : 978-1466597143
hal-01032436
https://hal.archives-ouvertes.fr/hal-01032436

Éditeur(s) : HAL CCSD
Résumé : International audience
o abstract
Journées Nationales Génie Côtier – Génie Civil, Dunkerque, 2-4 Juillet 2014

hal-01426583
https://hal.archives-ouvertes.fr/hal-01426583

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Middle to Late Triassic lavas were sampled within three tectonostratigraphic groups of the Hawasina Nappes in the Oman Mountains. They are predominantly alkali basalts and trachybasalts, associated with minor sub-alkaline basalts, trachyandesites, trachytes and rhyolites. Their major, trace elements and Nd-Pb isotopic compositions are very similar to those of the Permian plume-related high-Ti basalts which also occur in the Hawasina Nappes. The Triassic lavas derive from low-degree melting of an enriched OIB-type mantle source, characterized by εNdi = 0.3-5.3 and (206Pb/204Pb)i = 16.96-19.31 (for t = 230 My). With time, melting depths decreased from the garnet + spinel to the spinel lherzolite facies and the degree of melting increased. The oldest are distinguished from the others by unradiogenic Nd and Pb signatures, with εNdi = − 4.5 to − 1.2 and (206Pb/204Pb)i = 16.35-17.08, which we attribute to their contamination by Arabo-Nubian lower crust. The lavas likely derived from the Oman lithospheric mantle, the original DMM-HIMU signature of which was overprinted during its pervasive metasomatism by the Permian plume-related melts. We suggest that these lavas were emplaced during post-breakup decompression-triggered melting in the Middle Triassic during global kinematic reorganization of the Tethyan realm.
ISSN: 0024-4937

insu-00559080
https://hal-insu.archives-ouvertes.fr/insu-00559080
https://hal-insu.archives-ouvertes.fr/insu-00559080/document
https://hal-insu.archives-ouvertes.fr/insu-00559080/file/FC_TriasOman.pdf
DOI : 10.1016/j.lithos.2010.12.006

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : Le lido de Villeneuve-lès-Maguelone (Languedoc-Roussillon) est un archétype de littoral microtidal, dominé par la houle, en érosion, et largement affecté par la submersion marine lors des tempêtes. Les observations réalisées dans le cadre du Système d'Observation Littoral - Trait de Côte (SO LTC) concernent l'hydrodynamique et le transport sédimentaire dans l'avant-côte et la lagune. La tache d'observation MAGOBS (Observatoire Aresquiers-Maguelone-Palavas) de cet observatoire regroupe un dispositif instrumental automatisé composé de 30 points d'acquisition en temps réel entre 6 mètres de profondeur et le haut de plage (à terre) ainsi que dans la lagune. Le dispositif est opérationnel depuis mai 2011. Son déploiement a permis de déverrouiller les difficultés techniques liées à la mesure temps réel en zone littorale : choix du type des appareils de mesure, de la technologie embarquée, des cadences d'acquisition, résolution des questions du transfert de la donnée. Le dispositif produit 2 Tera-octets de données par an. Les données sont stockées sur un ensemble de serveurs dédiés. Les données sont mises en ligne sur le site du SO-LTC (www.soltc.org), immédiatement après premiers traitements et qualification. Elles commencent à être utilisées pour des calculs de niveau d'eau à la côte, et dansdes outils de prédiction des vagues et des niveaux à la côte associant mesure et modélisation.
ISSN: 1760-8716

hal-00854410
https://hal.archives-ouvertes.fr/hal-00854410
DOI : 10.5150/jngcgc.2012.064-G

Éditeur(s) : HAL CCSD
Résumé : International audience
This communication reports on a field experiment carried out on a microtidal beach in Camargue, France. The analysis is built on the initial work presented by Sous et al. (2016) on swash-groundwater dynamics. The analysis of a cross-shore network of buried pressure sensors allows to monitor the watertable dynamics over the full 2013-2014 winter season. The pressure head gradients are observed to be primarily seaward, forced by a higher level at the landward boundary. The groundwater flux is driven by the relative fluctuations of Still Water Level and inland elevations. Rain and tides have a little effect. A nearly isolated groundwater circulation is driven by wave activity below the swash zone whatever the overall watertable gradient. Estimations of beach groundwater discharge over the Gulf of Beauduc reveal the importance of beach groundwater in the exchanges between coastal aquifer and open sea.
Coastal Dynamics 2017
Helsingor, Denmark

hal-01562908
https://hal.archives-ouvertes.fr/hal-01562908

Éditeur(s) : HAL CCSD
Résumé :   Diffusion du document : INRA Antilles-Guyane, SDAR/ERIST, Domaine Duclos, F97170 Petitt-Bourg (Guadeloupe) Diplôme : DEA
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
ln French Guiana, the mangrove covers almost ail the coastline. It results original because of a dynamic influenced by the system of the amazon muds' dispersion. The coastline's variations are important and the mangrove growing there constitutes various facies. To understand the structure and dynamic of this forest, a test-site has been selected at the Kaw river's estuary. Field measurements of structure parameters permited to identify 3 major types of mangrove forests with different developement stages. Relations between the measured parameters show the facies'dynamic with a self-thinning phnomenon then a gap regeneration. Correlations between structure parameters and corresponding spectral parameters extracted from an IKONOS image have been tested. The use of texture indexes are discussed. Then, a classification of the image reveals the spatial distribution of the facies Parallely, the constitution of a temporal series from 1950 to 2001, base on various remote sensed datas, shows the evolution of the coastline and the associated mangrove. During this period, succeed accretion phases (1950-1981; 1991-2001) and erosion phase (1981-1991). A theorical ages map of the forest stands are also established. Relating with the facies map, it explains the complex evolution of limited Rhizophora zones. A comparison with Sinnamary test-site is made and futurs researches considered.
En Guyane française, la mangrove couvre l'essentiel du littoral. Elle tire son originalité d'une dynamique influencée par le système de dispersion des boues amazoniennes. Les variations de la ligne de côte sont alors importantes et les mangroves s'y développant constituent des faciès variés. Pour mieux comprendre la structure et la dynamique de ces mangroves, un site atelier a été choisi au niveau de l'estuaire de la rivière de Kaw. Les mesures sur le terrain de paramètres de structure des peuplements permettent d'identifier 3 grands types de forêt avec différents stades de développement. Des relations entre les différents paramètres mesurés mettent en évidence la dynamique de ces faciès, basée sur un phénomène d'auto-éclaircie puis une régénération par chablis. Un essai de corrélation entre paramètres de structure et paramètres spectraux correspondant sur une image IKONOS a été faite. L'apport des indices de texture est discuté. Une classification de l'image montre la distribution spatiale des faciès. Parallèlement, la reconstitution d'une série temporelle de 1950 à 2001 à partir de données de télédétection variées permet de suivre l'évolution de la côte et de la mangrove associée. Pendant cette période se succèdent phases d'accrétion (1950-1981 ; 1991-2001) et phase d'érosion (1981-1991). Une carte des âges théoriques des peuplements est également établie. Mise en relation avec la carte des faciès, elle explique notamment l'évolution complexe des zones limitées de mangrove à Rhizophora. Une comparaison avec le site de Sinnamary est faite et de futures recherches envisagées.
https://hal.archives-ouvertes.fr/hal-01189238

hal-01189238
https://hal.archives-ouvertes.fr/hal-01189238
PRODINRA : 18075

Éditeur(s) : HAL CCSD Royal Society, The
Résumé :  
Plant phenology is concerned with the timing of recurring biological events. Though phenology has traditionally been studied using intensive surveys of a local flora, results from such surveys are difficult to generalize to broader spatial scales. In this study, contrastingly, we assembled a continental-scale dataset of herbarium specimens for the emblematic genus of Neotropical pioneer trees, Cecropia, and applied Fourier spectral and cospectral analyses to investigate the reproductive phenology of 35 species. We detected significant annual, sub-annual and continuous patterns, and discuss the variation in patterns within and among climatic regions. Although previous studies have suggested that pioneer species generally produce flowers continually throughout the year, we found that at least one third of Cecropia species are characterized by clear annual flowering behaviour. We further investigated the relationships between phenology and climate seasonality, showing strong associations between phenology and seasonal variations in precipitation and temperature. We also verified our results against field survey data gathered from the literature. Our findings indicate that herbarium material is a reliable resource for use in the investigation of large-scale patterns in plant phenology, offering a promising complement to local intensive field studies
ISSN: 0962-8452

hal-01032193
https://hal.archives-ouvertes.fr/hal-01032193
DOI : 10.1098/rspb.2010.2259

Éditeur(s) : HAL CCSD Kluwer Academic Publishers
Résumé : International audience
The interlocking leaves of tank-forming bromeliads (Bromeliaceae) collect rainwater and detritus, thus creating a freshwater habitat for specialized organisms. Their abundance and the possibility of quantifying communities with accuracy give us unparalleled insight into how changes in local to regional environments influence community diversity in small water bodies. We sampled 365 bromeliads (365 invertebrate communities) along a southeastern to northwestern range in French Guiana. Geographic locality determined the species pool for bromeliad invertebrates, and local environments determined the abundance patterns through the selection of traits that are best adapted to the bromeliad habitats. Patterns in community structure mostly emerged from patterns of predator species occurrence and abundance across local-regional environments, while the set of detritivores remained constant. Water volume had a strong positive correlation with invertebrate diversity, making it a biologically relevant measure of the pools' carrying capacity. The significant effects of incoming detritus and incident light show that changes in local environments (e.g., the conversion of forest to cropping systems) strongly influence freshwater communities. Because changes in local environments do not affect detritivores and predators equally, one may expect functional shifts as sets of invertebrates with particular traits are replaced or complemented by other sets with different traits.
Hydrobiologia

hal-00845572
https://hal.archives-ouvertes.fr/hal-00845572

Éditeur(s) : HAL CCSD American Association for the Advancement of Science
Résumé : International audience
Most eukaryotic organisms are arthropods. Yet, their diversity in rich terrestrial ecosystems is still unknown. Here we produce tangible estimates of the total species richness of arthropods in a tropical rainforest. Using a comprehensive range of structured protocols, we sampled the phylogenetic breadth of arthropod taxa from the soil to the forest canopy in the San Lorenzo forest, Panama. We collected 6144 arthropod species from 0.48 hectare and extrapolated total species richness to larger areas on the basis of competing models. The whole 6000-hectare forest reserve most likely sustains 25,000 arthropod species. Notably, just 1 hectare of rainforest yields >60% of the arthropod biodiversity held in the wider landscape. Models based on plant diversity fitted the accumulated species richness of both herbivore and nonherbivore taxa exceptionally well. This lends credence to global estimates of arthropod biodiversity developed from plant models.
ISSN: 0036-8075

hal-00817285
https://hal.archives-ouvertes.fr/hal-00817285
https://hal.archives-ouvertes.fr/hal-00817285/document
https://hal.archives-ouvertes.fr/hal-00817285/file/1226727Revisedtext.pdf
DOI : 10.1126/science.1226727

Éditeur(s) : HAL CCSD
Résumé : International audience
Island barriers are common features along the world coastlines. They have a crucial role in protecting inland and rich lagoonal ecosystems. Erosion and sand transfers on these island barriers during extreme events such as tropical storms or typhoons remain poorly investigated. This work focuses on a multi-scales nalysis (season to decade) of the morphodynamics of Wan-Tzu-Liao sand barrier subjected to extreme waves and sea surges. We combine topographic measurements of the emerged beach at seasonal scale between 2011 to 2012 and long-term (1993-2009) shoreline changes using aerial photographs and satellite images. At the seasonal scale, during Monsoon, the sand was taken from the beach-front and transported seaward outside the study area. During typhoons season, 12 typhoons drove a beach recovery process resulting in a seaward shoreline shift. This annual behavior is discussed in term of roll-over process of the barrier. At the decadal scale, the shoreline changes evidence cross-shore processes in the north part of the barrier and longshore processes in the south. Although the chronic landward migration displays several stages, the strong losses of the barrier area occurs only since 2004 and call into question the general concept of conservation of mass during the roll-over of a barrier.
Revue Paralia, XIIIème Journées Nationales Génie CIvil Génie Côtier
Dunkerque, France

hal-01018203
https://hal.archives-ouvertes.fr/hal-01018203