Éditeur(s) : HAL CCSD
Résumé : International audience
Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, weconducted a meta-analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the totaltrait variation among communities on average. The relative extent of ITV tended to be greater for whole-plant (e.g. plant height) vs. organ-level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait-based community and ecosystem studies.
Ecology Letters

hal-01237101
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237101
DOI : 10.1111/ele.12508
PUBMED : 26415616

Éditeur(s) : HAL CCSD Elsevier
Résumé :  
absent
Ecology management of a neotropical rainforest: lessons drawn from Paracou, a long-term experimental research site in French Guiana

ISBN : 2-84299-455-8
hal-01190858
https://hal.archives-ouvertes.fr/hal-01190858
PRODINRA : 70132

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Rh (Rhesus) is a major blood group system in man, which is clinically significant in transfusion medicine. Rh antigens are carried by an oligomer of two major erythroid specific polypeptides, the Rh (D and CcEe) proteins and the RhAG glycoprotein, that shared a common predicted structure with 12 transmembrane a-helices (M0 to M11). Non erythroid homologues of these proteins have been identified (RhBG and RhCG), notably in diverse organs specialized in ammonia production and excretion, such as kidney, liver and intestine. Phylogenetic studies and experimental evidence have shown that these proteins belong to the Amt/Mep/Rh protein superfamily of ammonium/methylammonium permease, but another view suggests that Rh proteins might function as CO2 gas channels. Until recently no information on the structure of these proteins were available. However, in the last two years, new insight has been gained into the structural features of Rh proteins (through the determination of the crystal structures of bacterial AmtB and archeaebacterial Amt-1. Here, models of the subunit and oligomeric architecture of human Rh proteins are proposed, based on a refined alignment with and crystal structure of the bacterial ammonia transporter AmtB, a member of the Amt/Mep/Rh superfamily. This alignment was performed considering invariant structural features, which were revealed through Hydrophobic Cluster Analysis, and led to propose alternative predictions for the less conserved regions, particularly in the N-terminal sequences. The Rh models, on which an additional Rh-specific, N-terminal helix M0 was tentatively positioned, were further assessed through the consideration of biochemical and immunochemical data, as well as of stereochemical and topological constraints. These models highlighted some Rh specific features that have not yet been reported. Among these, are the prediction of some critical residues, which may play a role in the channel function, but also in the stability of the subunit structure and oligomeric assembly. These results provide a basis to further understand the structure/function relationships of Rh proteins, and the alterations occurring in variant phenotypes.
ISSN: 1246-7820

hal-00112914
https://hal.archives-ouvertes.fr/hal-00112914
DOI : 10.1016/j.tracli.2006.02.001

Éditeur(s) : HAL CCSD Wiley
Résumé : In the Amazon basin and the Guiana Shield, white-sand (WS) forests are recognized as a low-resource habitat often composed by a distinct flora with many edaphic endemic plants. Small patches of nutrient-poor white-sand forests can pose a series of challenges to plants and animals. For plants, these challenges have been shown to function as strong filters that in turn drive taxonomic, functional and phylogenetic plant composition. However, very little is known about animal communities in WS forest and the effect that low-resource availability may have on higher trophic levels. Here, we investigate the diversity of both taxonomic and phylogenetic diversity of three Lepidoptera families' (Nymphalidae, Saturniidae, and Sphingidae) assemblages between low-resource (White-Sand Forest) and two adjacent high-resource habitats, terra firme clay and seasonally flooded forests. We found no clear effect of habitat type on taxonomic composition although butterfly and moth species abundance differed among the three contrasted habitats. The WS forest Lepidoptera community is significantly more phylogenetically overdispersed than expected by chance. We suggest that these low-resource habitats filter the number of plant lineages which, in turn, creates a bottom-up control structuring Lepidoptera phylogenetic structure. We recommend long-term sampling on Lepidoptera community both at larval and adult stages that may complement this study and test hypotheses linking herbivore phylogenetic structure to plant resource availability and trophic cascade theory.
ISSN: 0006-3606

hal-01532550
https://hal.archives-ouvertes.fr/hal-01532550
DOI : 10.1111/btp.12294
PRODINRA : 353400

Éditeur(s) : HAL CCSD SPRINGER
Résumé : International audience
A key question in evolutionary biology is the reproducibility of adaptation. This question can now be quantitatively analyzed using experimental evolution coupled to whole genome sequencing (WGS). With complete sequence data, one can assess convergence among replicate populations. In turn, convergence reflects the action of natural selection and also the breadth of the field of possible adaptive solutions. That is, it provides insight into how many genetic solutions or adaptive paths may lead to adaptation in a given environment. Convergence is both a property of an adaptive landscape and, reciprocally, a tool to study that landscape. In this chapter we present the links between convergence and the properties of adaptive landscapes with respect to two types of microbial experimental evolution. The first tries to reconstruct a full adaptive landscape using a handful of carefully identified mutations (the reductionist approach), while the second uses WGS of replicate experiments to infer properties of the adaptive landscape. Reductionist approaches have highlighted the importance of epistasis in shaping the adaptive landscape, but have also uncovered a wide diversity of landscape architectures. The WGS approach has uncovered a very high diversity of beneficial mutations that affect a limited set of genes or functions and also suggests some shortcomings of the reductionist approach. We conclude that convergence may be better defined at an integrated level, such as the genic level or even at a phenotypic level, and that integrated mechanistic models derived from systems biology may offer an interesting perspective for the analysis of convergence at all levels.
ECOLOGICAL GENOMICS: ECOLOGY AND THE EVOLUTION OF GENES AND GENOMES

ISBN : 978-94-007-7347-9; 978-94-007-7346-2
hal-01544757
https://hal.archives-ouvertes.fr/hal-01544757
DOI : 10.1007/978-94-007-7347-9__11

Éditeur(s) : HAL CCSD
Résumé : International audience
Cytogenetics provides a unique platform to study in situ structural, functional, and evolutionary aspects of the genome. As such it holds powerful promise in decoding mechanisms and processes of genome architectural changes and their role in organism's diversification and evolution. Since the early 80s, such an approach has been applied to the study of the Antarctic notothenioid fishes. In almost three decades, the cytogenetic information has expanded to cover half of the known species inhabiting the high Antarctic waters. Although started 10 years later, cytogenetic studies of species from the Ross sea region have provided valuable contributions to this bulk of knowledge. Here, we synthesize the currently available cytogenetic information on Antarctic notothenioid fishes from the Ross Sea Region, inclusive of both conventional karyotyping and gene mapping. In addition, new karyotypic data on four species (Lepidonotothen squamifrons, Trematomus scotti, T. loennbergii, and T. lepidorhinus) are provided. In discussing these data, specific focus is made on the patterns and subtleties of cytogenetic diversity at inter- and intra-specific levels aiming at contributing to the refinement of the knowledge of fish diversity in a region, the Ross Sea area, whose primary ecological value is widely recognized.
Hydrobiologia

hal-01544905
https://hal.archives-ouvertes.fr/hal-01544905
DOI : 10.1007/s10750-015-2355-5

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : Nucleotide diversity was assessed within nine candidate genes (in total 4.6 kb) for the time of bud burst in nine sessile oak (Quercus petraea) populations distributed in central and northern Europe. The sampled populations were selected on the basis of their contrasting time of bud burst observed in common garden experiments (provenance tests). The candidate genes were selected according to their expression profiles during the transition from quiescent to developing buds and/or their functional role in model plants. The overall nucleotide diversity was large (pi(tot) - 6.15 x 10(-3); pi(silent) - 11.2 x 10(-3)), but population differentiation was not larger than for microsatellites. No outlier single-nucleotide polymorphism (SNP), departing from neutral expectation, was found among the total of 125 SNPs. These results contrasted markedly with the significant associations that were observed between the candidate genes and bud burst in segregating populations. Quantitative trait loci (QTLs) for bud burst were identified for 13 year*site seasonal observations in a cloned mapping pedigree. Nineteen QTLs were detected, and QTLs located on linkage groups 2, 5 and 9 contributed repeatedly to more than 12% of the phenotypic variation of the trait. Eight genes were polymorphic in the two parents of the pedigree and could be mapped on the existing genetic map. Five of them located within the confidence intervals of QTLs for bud burst. Interestingly, four of them located within the three QTLs exhibiting the largest contributions to bud burst.
ISSN: 0018-067X

hal-01032156
https://hal.archives-ouvertes.fr/hal-01032156
DOI : 10.1038/hdy.2009.170

Éditeur(s) : HAL CCSD Elsevier
Résumé : Understanding the pattern in spatial distribution of soil microbial processes is critical to understand the environmental factors that regulate them as well as to scale up these processes to ecosystem. Soil samples from a I ha tropical rainforest plot (Paracou, French Guiana) were analyzed according a nested sampling approach using different separation distances ranging from 0.4 to 40 m. The variability of substrate induced respiration (SIR) and of denitrification enzyme activity (DEA) was characterized in relation to various soil properties (total C and N contents, NIRS related index of soil organic matter quality, SOMQ and index of tree influence potential, IP). The variability of SIR and DEA was higher than that of environmental properties. The patterns of accumulated variance as a function of distance varied among the soil properties. The variability of SIR and DEA mainly occurred at small (1 m) scale (and at the 10-40 m-scales for SIR), probably reflecting the quality of litter input that results of the influence of local assemblage of different tree species, though changes in the soil N and C contents. Indeed, total soil C and N contents explained the microbial properties at every scale. Coefficients of codispersion showed that neither SOMQ nor IP did correlate with SIR and DEA, and confirmed that total C and N contents explained microbial properties in a scale dependent and complex manner. Such spatial dependency underlines the importance of soil heterogeneity in this tropical forest with implications for sampling strategies when studying the microbial processes and their response to disturbances. (C) 2012 Elsevier B.V. All rights reserved.
ISSN: 0016-7061

hal-01032409
https://hal.archives-ouvertes.fr/hal-01032409
DOI : 10.1016/j.geoderma.2012.12.009

Éditeur(s) : HAL CCSD
Résumé : Neotropical forests shelter an astonishing and underrated biodiversity. The integrity and stability of these natural ecosystems are threatened by human-induced environmental changes. Therefore, highlighting the determinants of ecosystem functioning, be they natural or anthropogenic, is a daunting but paramount scientific challenge. The intrinsic complexity of highly diversified ecosystems arouses both conceptual and logistical difficulties, which we handle, by manipulating tiny ecosystems, the tank bromeliads. The leaves of tank bromeliads form wells that hold rainwater and intercept leaf litter, allowing for a simple invertebrate aquatic community to thrive. These plants can be exhaustively sampled, are naturally replicated, and widely distributed.From local to biogeographic scales, this thesis aims at understanding how these communities respond to the natural heterogeneity of Amazonian forests, and at predicting the impacts of human-induced disturbances on the structure and functioning of these communities, using in situ and lab experiments. Particular focus is attributed to the influence of some aspects of climate changes (e.g., warming, and various precipitations scenarios) on individual physiology, behavior, and trophic interactions.
Les forêts néotropicales accueillent une importante biodiversité encore méconnue. L’intégrité des écosystèmes naturels est menacée par les changements environnementaux (e.g., réchauffement climatique, destruction des habitats), par conséquent, identifier les facteurs structurants, naturels et anthropiques, du fonctionnement des écosystèmes, représente un défi scientifique crucial. L’inhérente complexité de ces milieux diversifiés pose de nombreux problèmes conceptuels et logistiques comme un échantillonnage exhaustif et/ou l’identification des espèces. Les broméliacées à réservoirs sont des écosystèmes miniatures adéquats pour pallier ces difficultés, car elles retiennent de l’eau de pluie et accumulent de la matière organique au creux de leurs feuilles, permettant ainsi de supporter des réseaux trophiques simples d’invertébrés aquatiques. Elles peuvent être échantillonnées exhaustivement, ont une forte abondance locale, et une large aire de répartition. De l’échelle locale à biogéographique, les travaux de cette thèse visent d’abord à comprendre comment ces communautés se structurent en réponse à l’hétérogénéité naturelle des forêts amazoniennes (e.g., ouverture de la canopée, fluctuations climatiques saisonnières), puis tente de prédire, par le biais d’expérimentations in situ et au laboratoire les réponses structurelles et fonctionnelles de ces communautés à divers scénarios de changement climatique. Une attention particulière a été portée sur l’impact de la température et des précipitations sur la physiologie et le comportement d’espèces clefs, et sur les interactions trophiques au sein des communautés.
https://tel.archives-ouvertes.fr/tel-01405025

NNT : 2015YANE0003
tel-01405025
https://tel.archives-ouvertes.fr/tel-01405025
https://tel.archives-ouvertes.fr/tel-01405025/document
https://tel.archives-ouvertes.fr/tel-01405025/file/These-DEZERALD-Diffusion.pdf

Éditeur(s) : HAL CCSD Wiley
Résumé :  
The forests in Cat Tien National Park, appear as a mosaic of different communities, distinct from each other with respect to their floristic and structural parameters. The objectives of this study are (1) to characterize the different formations occurring in the lowland part and (2) to identify the main successional trends in the area. Understanding forest succession is important for silviculture and restoration of forests and land rehabilitation, as adequate information on the ecological role of local species in the functioning of the forests is not available in Vietnam. Five plots (1 ha each) were established in the lowland part of Cat Tien National Park, where all the trees ≥ 10 cm d.b.h. (diameter at breast height) were located, measured and identified. A systematic sampling was made to assess the regeneration. Three plots (A, C and D) can be considered as secondary forests on the basis of their structural parameters. Plots A and C are dominated by Lagerstrmia calyculata and plot D by Dipterocarpus alatus. The other two plots can be regarded as mature forests. Plot B corresponds to a semideciduous formation dominated by Lagerstrmia calyculata and Fabaceae species, and plot E to an evergreen one dominated by dipterocarp species. The floristic composition of plots A and C will change in the future because dominant canopy species are rare or absent in regeneration. A correspondence analysis performed on the number of trees per species shows two kinds of successional trends: one from A to B on shallow and drier soils, and another from C to E on deeper and wetter soils.
ISSN: 0305-0270

hal-01032094
https://hal.archives-ouvertes.fr/hal-01032094
DOI : 10.1046/j.1365-2699.2000.00347.x

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : En Amérique centrale, l’élevage des abeilles sans dard est une pratique vieille d’au moins deux millénaires, qui a connu son apogée à la fin de l’ère maya. Les Méliponinés, sous-famille à laquelle appartiennent ces abeilles, rassemblent près de 500 espèces distribuées pour l’essentiel en zone intertropicale. La plupart d’entre elles nichent dans des cavités d’arbres secs ou sous terre, et affectionnent les forêts ombrophiles où elles assurent un rôle actif dans la pollinisation des plantes sauvages. Sur l’île de Cuba, une seule espèce de méliponinés (Melipona beecheii) est présente, elle a probablement été introduite durant l’époque précolombienne à partir de souches génétiques originaires de la péninsule du Yucatán. Dans les campagnes autour de La Havane, les abeilles mélipones continuent d’être un vecteur de socialisation, car leur domestication correspond souvent à une tradition familiale et parce que les bénéficiaires des produits de la ruche sont des familiers du méliponiculteur. En forêt, en revanche, le miel donne davantage lieu à des pratiques de cueillette. Depuis une vingtaine d’années, la prise de conscience du rôle de l’abeille dans le fonctionnement des écosystèmes et la valeur des services qu’elles seraient susceptibles de rendre à l’agriculture sont à l’origine d’une évolution rapide des représentations sociales associées à l’insecte. Cette évolution contribue à diversifier les profils des éleveurs, à détacher les pratiques du poids des traditions d’élevage ou de cueillette, et à concevoir la méliponiculture comme une activité de loisir voire à envisager son intégration dans une logique marchande.
In central America, stingless beekeeping is a practice older than two thousand years which reached its peak at the end of the Maya era. The melipona sub-family which these bees belong to gather more than 500 species mainly in the intertropical area. Most of them nest in cavities, in dead wood or underground, and have a liking for ombrophile forests where they provide the pollinisation of wild plantes in Cuba. There is only are single species (Melipona beecheii) probably introduced during the pre-colombian era, from genetic strains deriving from the Yucatan peninsula. In the countryside surrounding Havana, the melipona bees are still a vector of socialization, knowing their domestication often results from a familial tradition and is profitable to the beekeeper’s relatives. On the other hand, in the forest, honey is the fruit of gathering. For twenty years now people have been aware of the essential function of bees in the ecosystem and of the valuable services they are able to provide agriculture. This awareness has launched a quick evolution in the social representation of the insect. Thanks to this evolution the beekeepers’ profiles are becoming more diverse, traditions in beekeeping or gathering, weigh less heavily on practices, and the meliponiculture can be regarded as a space-time activity or even a trade one.
Cuba

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.6967
http://journals.openedition.org/etudescaribeennes/6967

Éditeur(s) : HAL CCSD Ecological Society of America
Résumé : We investigated the relationship between habitat association and physiological performance in four congeneric species pairs exhibiting contrasting distributions between seasonally flooded and terra firme habitats in lowland tropical rain forests of French Guiana, including Virola and Iryanthera (Myristicaceae), Symphonia (Clusiaceae), and Eperua (Caesalpiniaceae). We analyzed 10-year data sets of mapped and measured saplings (stems 150 cm in height and <10 cm diameter at breast height [dbh]) and trees (stems 10 cm dbh) across 37.5 ha of permanent plots covering a 300-ha zone, within which seasonally flooded areas (where the water table never descends below 1 m) have been mapped. Additionally, we tested the response of growth, survival, and leaf functional traits of these species to drought and flood stress in a controlled experiment. We tested for habitat preference using a modification of the torus translation method. Strong contrasting associations of the species pairs of Iryanthera, Virola, and Symphonia were observed at the sapling stage, and these associations strengthened for the tree stage. Neither species of Eperua was significantly associated with flooded habitats at the sapling stage, but E. falcata was significantly and positively associated with flooded forests at the tree stage, and trees of E. grandiflora were found almost exclusively in nonflooded habitats. Differential performance provided limited explanatory support for the observed habitat associations, with only congeners of Iryanthera exhibiting divergent sapling survival and tree growth. Seedlings of species associated with flooded forest tended to have higher photosynthetic capacity than their congeners at field capacity. In addition, they tended to have the largest reductions in leaf gas exchange and growth rate in response to experimental drought stress and the least reductions in response to experimental inundation. The corroboration of habitat association with differences in functional traits and, to a lesser extent, measures of performance provides an explanation for the regional coexistence of these species pairs. We suggest that specialization to seasonally flooded habitats may explain patterns of adaptive radiation in many tropical tree genera and thereby provide a substantial contribution to regional tree diversity.
ISSN: 0012-9658

hal-01031746
https://hal.archives-ouvertes.fr/hal-01031746

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : National audience
The immune system contributes to maintaining the integrity of the organism. It can be the target of many xenobiotics, and immunotoxicology attempts to analyze the immunological alterations caused by exposure to these xenobiotics. Several environmental pollutants are strongly suspected of acting on the immune system to cause a decrease in the organism protective functions. Thus, polycyclic aromatic hydrocarbons, well known for their carcinogenic effects, have also been shown to induce immunosuppressive effects, pro-inflammatory actions and some hypersensitivity reactions, involved in the development of various pathologies. These different immunotoxic effects have mainly been identified by experimental studies on animals and our knowledge of the effects on humans remains incomplete. To better understand the immunotoxic effects of exposure to environmental pollutants and their consequences for human health, it is appropriate to strengthen immunotoxicology studies on humans.
Le système immunitaire contribue à la surveillance et au maintien de l’intégrité de l’organisme. Il peut être la cible de nombreux xénobiotiques, et l’immunotoxicologie s’attache à étudier les différentes atteintes immunologiques induites par l’exposition à ces xénobiotiques. De nombreux polluants environnementaux sont fortement suspectés d’agir sur le système immunitaire pour entraîner une diminution des fonctions de protection de l’organisme. Ainsi, les hydrocarbures aromatiques polycycliques, bien connus pour leurs effets cancérogènes, se sont révélés également capables d’induire des effets immunosuppresseurs, d’entraîner des actions pro-inflammatoires et de majorer certaines réactions d’hypersensibilité, impliqués dans le développement de diverses pathologies. Ces différents effets immunotoxiques ont surtout été identifiés par des études expérimentales chez l’animal et la transposition de ces effets à l’homme reste incomplète. Pour mieux appréhender les effets immunotoxiques de l’exposition aux polluants environnementaux et leurs conséquences sur la santé humaine, il convient donc de renforcer les études en immunotoxicologie chez l’homme.
ISSN: 1775-8785

hal-01467562
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01467562
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01467562/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01467562/file/Effets%20immunotoxiques%20des%20polluants%20environnementaux_accepted.pdf
DOI : 10.1016/j.admp.2016.09.003

Éditeur(s) : HAL CCSD PeerJ
Résumé : International audience
The tiger shark Galeocerdo cuvier (Carcharhinidae) is a large elasmobranch suspected to have, as other apex predators, a keystone function in marine ecosystems and is currently considered Near Threatened (Red list IUCN). Knowledge on its ecology, which is crucial to design proper conservation and management plans, is very scarce. Here we describe the isolation of eight polymorphic microsatellite loci using 454 GS-FLX Titanium pyrosequencing of enriched DNA libraries. Their characteristics were tested on a population of tiger shark (n = 101) from Reunion Island (SouthWestern Indian Ocean). All loci were polymorphic with a number of alleles ranging from two to eight. No null alleles were detected and no linkage disequilibrium was detected after Bonferroni correction. Observed and expected heterozygosities ranged from 0.03 to 0.76 and from 0.03 to 0.77, respectively. No locus deviated from Hardy-Weinberg equilibrium and the global F IS of the population was of 0.04 NS. Some of the eight loci developed here successfully cross-amplified in the bull shark Carcharhinus leucas (one locus), the spinner shark Carcharhinus brevipinna (four loci), the sandbar shark Carcharhinus plumbeus (five loci) and the scalloped hammerhead shark Sphyrna lewini (two loci). We also designed primers to amplify and sequence a mitochondrial marker, the control region. We sequenced 862 bp and found a low genetic diversity, with four polymorphic sites, a haplotype diversity of 0.15 and a nucleotide diversity of 2 × 10 −4 .
ISSN: 2167-8359

hal-01317961
https://hal.archives-ouvertes.fr/hal-01317961
https://hal.archives-ouvertes.fr/hal-01317961/document
https://hal.archives-ouvertes.fr/hal-01317961/file/Pirog_2016PeerJ_microsat_tiger_shark.pdf
DOI : 10.7717/peerj.2041

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Clin Microbiol Infect 2012; 18 (Suppl. 4): 4043 Abstract In order to study complex microbial communities and their associated mobile genetic elements, such as the human gut microbiome, evolutionists could explore their genetic diversity with shared sequence networks. In particular, the detection of remarkable structures in gene networks of the gut microbiome could serve to identify important functions within the community, and would ease comparison of data sets from microbiomes of various sources (human, ape, mouse etc.) in a single analysis.
ISSN: 1198-743X

hal-01544804
https://hal.archives-ouvertes.fr/hal-01544804
DOI : 10.1111/j.1469-0691.2012.03856.x

Éditeur(s) : HAL CCSD
Résumé : Juin 2003
Dans le contexte actuel de mondialisation, de changement climatique et de forte anthropisation de la biosphère, les Petites Antilles s'érigent en monde marginal ou encore en anti-monde. Fracturées du point de vue politique, économique, linguistique et à certains égards culturel, ces territoires insulaires du Bassin caraïbe recèlent de richesses environnementales (physiques, écosystèmiques et paysagères). Comme partout ailleurs dans le monde humanisé, la survie de ces sociétés implique le rétablissement des grands équilibres écologiques consubstantiels à une articulation efficiente entre le naturel, l'urbain et l'agricole. Compte tenu de la pression démographique, variable d'une île à l'autre, la pérennité des écosystèmes en covariance avec un développement économique profitant au plus grand nombre ne peut se concevoir à l'échelle insulaire. Il semble judicieux d'imaginer un développement à l'échelle de l'archipel basé sur la complémentarité, puisque au sein de chaque composante les diverses ressources biologiques terrestres et marines sont insuffisantes pour assurer une autosuffisance en termes de produits de premières nécessités et d'énergie. Le développement des Petites Antilles s'il doit être durable et prendre comme ossature les directives de Rio (Brésil, 1992) et de Johannesburg (Afrique du Sud, 2002), il devra s'inscrire dans une gestion administrative, scientifique, technique et agricole commune dans le cadre d'une Caraïbe fonctionnellement unifiée. A l'unité floristique, faunistique et biocénotique doivent correspondre des stratégies et donc des politiques, similaires mais diversifiées, d'utilisation des ressources abiotiques (énergie éolienne, hydroélectrique et photovoltaïque) et biotiques (écosystèmes terrestres et marins, flore, faune, sols). Malheureusement dans le présent, la compartimentation économique et politique de la Caraïbe rend ces propos profondément utopiques. Néanmoins dans le futur la survie des peuples des Petites Antilles, impliquera un développement durable signifié par des rapports équilibrés entre hommes et milieux.
–––––
In the nowadays context of "globalization", climatic variation and great anthropization of the biosphere, the Lesser Antilles appear as a marginal world. In a political point of view, those islands offer a greatly distinct and fractured image. The same fact can also be observed in an economic, linguistic and, in a certain measure, cultural perspective. Despite of such a statement, those territories of the Caribbean basin keep economic and landscape resources whom survival depends on the re-establishment of the great ecologic structures implying a productive articulation between the natural, the urban and the agricultural. It seems pertinent to imagine a development on the level of the archipelago based upon complementarity since each constituent presents a limited number of earth and marine biologic reserves which do not guarantee an autosubsistance in energy and first nessecity productivity. A lasting development of the Lesser Antilles supposes a necessary and commun administrative, scientific, technical and agricultural management within the setting of a Caribbean functionally unified. Facing the biocenotic unity, a useful strategy, based on a similar and diversified organization in the exploitation of biophisic resources, must be erected. Such statements could be considered as utopic, regarding the situation of politic and economic division in the Caribbean nowadays. However, in the future, the survival of those insular societies will imply a lasting development lying upon an efficient relationship between Man and environment.
https://halshs.archives-ouvertes.fr/halshs-00003054

Droits : info:eu-repo/semantics/OpenAccess
halshs-00003054
https://halshs.archives-ouvertes.fr/halshs-00003054
https://halshs.archives-ouvertes.fr/halshs-00003054/document
https://halshs.archives-ouvertes.fr/halshs-00003054/file/Devpt-durable_JOSEPH-PHILIPPE.pdf

Éditeur(s) : HAL CCSD Wiley
Résumé : The evolutionary potential of long-lived species, such as forest trees, is fundamental for their local persistence under climate change (CC). Genome–environment association (GEA) analyses reveal if species in heterogeneous environments at the regional scale are under differential selection resulting in populations with potential preadaptation to CC within this area. In 79 natural [i]Fagus sylvatica[/i] populations, neutral genetic patterns were characterized using 12 simple sequence repeat (SSR) markers, and genomic variation (144 single nucleotide polymorphisms (SNPs) out of 52 candidate genes) was related to 87 environmental predictors in the latent factor mixed model, logistic regressions and isolation by distance/environmental (IBD/IBE) tests. SSR diversity revealed relatedness at up to 150m intertree distance but an absence of large-scale spatial genetic structure and IBE. In the GEA analyses, 16 SNPs in 10 genes responded to one or several environmental predictors and IBE, corrected for IBD, was confirmed. The GEA often reflected the proposed gene functions, including indications for adaptation to water availability and temperature. Genomic divergence and the lack of large-scale neutral genetic patterns suggest that gene flow allows the spread of advantageous alleles in adaptive genes. Thereby, adaptation processes are likely to take place in species occurring in heterogeneous environments, which might reduce their regional extinction risk under CC
ISSN: 0028-646X

hal-01309135
https://hal.archives-ouvertes.fr/hal-01309135
PRODINRA : 343710
DOI : 10.1111/nph.13809

Éditeur(s) : HAL CCSD PeerJ
Résumé : International audience
Understanding the role of predators in food webs can be challenging in highly diverse predator/prey systems composed of small cryptic species. DNA based dietary analysis can supplement predator removal experiments and provide high resolution for prey identification. Here we use a metabarcoding approach to provide initial insights into the diet and functional role of coral-dwelling predatory fish feeding on small invertebrates. Fish were collected in Moorea (French Polynesia) where the BIOCODE project has generated DNA barcodes for numerous coral associated invertebrate species. Pyrosequencing data revealed a total of 292 Operational Taxonomic Units (OTU) in the gut contents of the arc-eye hawkfish (Paracirrhites arcatus), the flame hawkfish (Neocirrhites armatus) and the coral croucher (Caracanthus maculatus). One hundred forty-nine (51%) of them had species-level matches in reference libraries (>98% similarity) while 76 additional OTUs (26%) could be identified to higher taxonomic levels. Decapods that have a mutualistic relationship with Pocillopora and are typically dominant among coral branches, represent a minor contribution of the predators' diets. Instead, predators mainly consumed transient species including pelagic taxa such as copepods, chaetognaths and siphonophores suggesting non random feeding behavior. We also identified prey species known to have direct negative interactions with stony corals, such as Hapalocarcinus sp, a gall crab considered a coral parasite, as well as species of vermetid snails known for their deleterious effects on coral growth. Pocillopora DNA accounted for 20.8% and 20.1% of total number of sequences in the guts of the flame hawkfish and coral croucher but it was not detected in the guts of the arc-eye hawkfish. Comparison of diets among the three fishes demonstrates remarkable partitioning with nearly 80% of prey items consumed by only one predator. Overall, the taxonomic resolution provided by the metabarcoding approach highlights a highly complex interaction web and demonstrates that levels of trophic partitioning among coral reef fishes have likely been underestimated. Therefore, we strongly encourage further empirical approaches to dietary studies prior to making assumptions of trophic equivalency in food web reconstruction. How to cite this article Leray et al. (2015), Metabarcoding dietary analysis of coral dwelling predatory fish demonstrates the minor contribution of coral mutualists to their highly partitioned, generalist diet. PeerJ 3:e1047
ISSN: 2167-8359

Droits : http://creativecommons.org/licenses/by/
hal-01174184
https://hal-univ-perp.archives-ouvertes.fr/hal-01174184
https://hal-univ-perp.archives-ouvertes.fr/hal-01174184/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01174184/file/peerj-1047.pdf
DOI : 10.7717/peerj.1047

Éditeur(s) : HAL CCSD Springer Verlag/EDP Sciences
Résumé : We characterised the among species variability in leaf gas exchange and morphological traits under controlled conditions of seedlings of 22 tropical rainforest canopy species to understand the origin of the variability in leaf carbon isotope discrimination (Delta) among species with different growth and dynamic characteristics (successional gradient). Our results first suggest that these species pursue a consistent strategy in terms of (Delta) throughout their ontogeny (juveniles grown here versus canopy adult trees from the natural forest). Second, leaf (Delta) was negatively correlated with WUE and N, and positively correlated with gs, but among species differences in (Delta) were mainly explained by differences in WUE. Finally, species belonging to different successional groups display distinct leaf functional and morphological traits. We confirmed that fast growing early successional species maximise carbon assimilation with high stomatal conductance. In contrast, fast and slow growing late successional species are both characterised by low carbon assimilation values, but by distinct stomatal conductance and leaf morphological features. Along the successional gradient, these differences result in much lower (Delta) for the intermediate species (i.e. fast growing late successional) as compared to the two other groups.
ISSN: 1286-4560

hal-01032038
https://hal.archives-ouvertes.fr/hal-01032038
DOI : 10.1051/forest:2006101

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Background : Biological communities are normally composed of a few abundant and many rare species. This pattern is particularly prominent in microbial communities, in which most constituent taxa are usually extremely rare. Although abundant and rare subcommunities may present intrinsic characteristics that could be crucial for understanding community dynamics and ecosystem functioning, microbiologists normally do not differentiate between them. Here, we investigate abundant and rare subcommunities of marine microbial eukaryotes, a crucial group of organisms that remains among the least-explored biodiversity components of the biosphere. We surveyed surface waters of six separate coastal locations in Europe, independently considering the picoplankton, nanoplankton, and microplankton/mesoplankton organismal size fractions.Results : Deep Illumina sequencing of the 18S rRNA indicated that the abundant regional community was mostly structured by organismal size fraction, whereas the rare regional community was mainly structured by geographic origin. However, some abundant and rare taxa presented similar biogeography, pointing to spatiotemporal structure in the rare microeukaryote biosphere. Abundant and rare subcommunities presented regular proportions across samples, indicating similar species-abundance distributions despite taxonomic compositional variation. Several taxa were abundant in one location and rare in other locations, suggesting large oscillations in abundance. The substantial amount of metabolically active lineages found in the rare biosphere suggests that this subcommunity constitutes a diversity reservoir that can respond rapidly to environmental change.Conclusions : We propose that marine planktonic microeukaryote assemblages incorporate dynamic and metabolically active abundant and rare subcommunities, with contrasting structuring patterns but fairly regular proportions, across space and time.
ISSN: 0960-9822

hal-01149637
http://hal.upmc.fr/hal-01149637
http://hal.upmc.fr/hal-01149637/document
http://hal.upmc.fr/hal-01149637/file/Logares_et_al_CurrentBiol_accepted.pdf
DOI : 10.1016/j.cub.2014.02.050