Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Questions: Several studies have described aggregated spatial patterns in tropical tree species. This study investigates aggregate dynamics of Vouacapoua americana (Aublet), a climax species whose spatial pattern is not simply related to light and soil conditions or to its short seed dispersal range. Location: Two rain forest sites: Nouragues and Paracou, in the Guiana Shield. Methods: We described the spatial pattern of tree locations and spatial autocorrelation of tree diameters, using statistics derived from Ripley's K. We particularly used methods to define analysis subplots according to local density or local mean diameter. We investigated relationships between spatial distributions of adults and saplings. Results: At both sites, populations of Vouacapoua demonstrated several nested levels of aggregation. Tree diameters were spatially autocorrelated, revealing the existence of clusters with similar diameters. In the largest aggregates, tree diameters declined from the centre to the edge. Regeneration was aggregated and occurred mainly at cluster edges and around rare isolated trees, and sapling densities and basal area of adults were negatively correlated. We show that long-distance dispersal events are rare. Conclusions: Environmental factors and seed dispersal only explain part of the observed spatial patterns. We provide two main hypotheses about Vouacapoua population dynamics. First, the lack of regeneration in aggregate centres results in the ageing of existing aggregates. We suggest that this lack of recruitment close to mature trees is due to a Janzen-Connell effect. However, aggregates can continue to grow along colonization fronts. Second, long-distance dispersal events allow the formation of new clusters and play a crucial role in the colonization process. We investigate aggregate dynamics of Vouacapoua americana (Aublet) whose spatial pattern is not simply related to environmental conditions or to its seed dispersal. Regeneration does not occur in centers of aggregate of adults. We suggest that rare long-distance dispersal events and density-dependence predation of seeds and seedlings play a crucial role in formation of new clusters and structuration of larger aggregates.
ISSN: 1100-9233

hal-01502642
https://hal-agroparistech.archives-ouvertes.fr/hal-01502642
DOI : 10.1111/jvs.12080

Éditeur(s) : HAL CCSD Elsevier
Résumé : Siberian cratonic mantle
International audience
The processes that control water distribution in nominally anhydrous minerals from peridotites are twofold. Melt depletion will remove water while metasomatism can potentially add water to these minerals. These processes can lead to a wide range of outcomes in water contents, which in turn could play a role in mantle rheology and long-term cratonic root stability. To examine these complexities, water concentrations in minerals from well-characterized peridotites from the Udachnaya kimberlite in the central Siberian craton were analyzed by FTIR. The peridotites span a complete top to bottom cross-section of typical cratonic lithospheric mantle (2-7 GPa and 700-1400 °C). Diffusion modeling of water content profiles across olivine grains shows that water loss during decompression is limited to the 100 μm rims of olivines; the cores preserved their mantle water contents. Water contents range from 6 to 323 ppm wt H2O in olivine, 28-301 ppm H2O in orthopyroxene (opx), 100-272 ppm H2O in clinopyroxene (cpx) and 0-23 ppm H2O in garnet. Melting modeling cannot reproduce the high water contents of cratonic mantle peridotites and any potential partial melting trend must have been erased by later events. The water contents of minerals, however, are correlated with modal abundances of clinopyroxene and garnet, bulk rock FeO, TiO2 and SiO2 as well as with light and middle rare earth elements in clinopyroxene and garnet. These relationships are best interpreted as interaction of residual, melt-depleted peridotites with silicate melt, which produced modal and cryptic metasomatism. Importantly, the water enrichment in the Siberian cratonic mantle took place prior to kimberlite magmatism and eruption. Water addition by metasomatism occurred from pressures >4 GPa all the way to the base of the cratonic root below central Siberia, but was limited to shallower levels (<5 GPa) in the Kaapvaal cratonic lithosphere. The difference in olivine water contents at the deepest levels of the Kaapvaal (<5 ppm H2O) and Siberian (6-323 ppm H2O) cratonic roots may be linked to oxygen fugacity and resulting fluid speciation or, alternatively, to reaction with different metasomatic agents. Calculated viscosities for the deepest Udachnaya samples are similar to those inferred for the asthenosphere. If these xenoliths are representative of the deep cratonic lithosphere, water is not as important a parameter as previously thought in the strength of cratonic lithosphere, otherwise the cratonic root beneath Udachnaya would have been delaminated. Alternatively, the metasomatic xenoliths may not be representative of the Siberian cratonic root and kimberlites preferentially sample cratonic mantle lithosphere material located near, and metasomatized by, melt conduits, which served as channels for upward migration of water-rich melts and fluids including kimberlites. In that case, the cratonic root overall still may have relatively low water contents, which in addition to its less metasomatized (more refractory) and thereby buoyant nature, still play a role in making it strong enough to resist delamination by the surrounding asthenosphere.
ISSN: 0016-7037

hal-01053920
https://hal.archives-ouvertes.fr/hal-01053920
DOI : 10.1016/j.gca.2014.04.011

Éditeur(s) : Gauthier-Villars
Résumé : Several models for the evolution of complex life histories have assumed a carrying capacity for both larval and postlarval stages. In addition, the densities of larvae in laboratory experiments are often so high that there is competition for food. Published values for maximal clearance rates and estimated abundances of larvae suggest that these assumptions and experimental conditions are unrealistic for most marine larvae. For most ciliated larvae, maximum clearance rates are at most a few mi of water daily, and their estimated larval concentrations are at most one to several larvae per liter. Therefore these larvae appear to be too scarce for their grazing to affect their food supply. Larvae of most species are also scarce relative to co-occurring planktonic animals that feed on particles in the same size range. Larvae of many species are scarce relative to co-occurring larvae with a similar feeding apparatus. These observations suggest that larvae of most species have a negligible effect on their food supply. Exceptions could occur when a single species of larva dominates the zooplankton; such circumstances appear to be rare, although extreme aggregations of larvae dominated by a single species could be missed by pump or net samples. Analogous but more conjectural arguments can be made for density-dependent attraction of predators to larval prey. These inferences apply to single species, not to meroplanktonic larvae as a whole: in some coastal waters, larvae of benthic invertebrates comprise a large portion of the multicellular planktonic animals. Also, a species' larval growth may be food-limited in many waters, even when the abundance of food is independent of the abundance of its larvae.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1996 , Vol. 19 , N. 3-4 , P. 399-407

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00094/20495/18164.pdf
http://archimer.ifremer.fr/doc/00094/20495/

Éditeur(s) : Elsevier
Résumé : The multi-component aspect of species diversity of groundfish assemblages was examined on the basis of a set of experimental trawl surveys conducted on the east coast of Corsica. We analysed and compared the structuration of diversity within three different bathymetric strata: the continental shelf (60-120 m depth), the upper slope (250-400 m) and the lower slope (450-570 m). For each of these three bathymetric strata, we simultaneously analysed 12 indices that are theoretically complementary and relate to 4 diversity components: (1) the number of species, (2) rarity, (3) evenness and (4) taxonomic diversity. Principal component analysis based on Spearman's correlation coefficients was carried out to investigate empirical relationships between the selected indices. Our results showed not only that a single diversity index cannot provide a complete view of the groundfish diversity along the east coast of Corsica, but also that-in some cases-one index cannot even encapsulate a complete description of a specific diversity component. We also found that the nature and the number of independent diversity components slightly varied from one bathymetric stratum to another. The main differences-which mainly occurred in the deepest bathymetric stratum-might be associated with lower density of individuals and lower dominance of some species at deeper depths. Finally, this study is the first dealing with groundfish diversity in this area, which is currently characterized by one of the lowest fishing intensity rates in the northern Mediterranean Sea. It might be considered as a first '' reference state '' with a view to monitoring the spatio-temporal changes in species diversity patterns along the east coast of Corsica in the future. (C) 2007 Elsevier B.V. All rights reserved.
Fisheries Research (0165-7836) (Elsevier), 2007-12 , Vol. 88 , N. 1-3 , P. 120-132

Droits : 2007 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2007/publication-3512.pdf
DOI:10.1016/j.fishres.2007.08.003
http://archimer.ifremer.fr/doc/00000/3512/

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) : Société des sciences naturelles de la Charente-Maritime
Résumé : During 1975, a number of rare fishes or caught out of their distr:ibution area were observed in La Rochelle, especially Chlamycloselachus anguineus Garman, 1884 (one specimen) Mitsukurina sp. (three specimens), Pseudotriakis microdon Capello, 1868 (five specimens), Somniosus sp. (one specimen), probably a new species, Zenopsis cO/1chîfer (Lowe, 1852) (one specimen) recorded for the first time from the French Atlantic coast, Puntazzo puntazzo (Gmelin, 1789) (one specimen), Hyperoglyphe percifonnîs (Mitchill, 1818) (one specimen), Glyptocephalus cynoglossus (Linné, 1758) (one specimen) caught off the coast of Vendée and Lima11da limanda (Linné, 1758) (one specimen) caught off the coast of Landes. On the other hand, the authors found two albino fishes and five specimens remarkable for their large size. They also observed nine species of fishes from the Bay of Biscay belonging to a colder fauna and eight species of fishes from the Bay of Biscay belonging to a hotter fauna. Not controlled OCR
En 1975, les auteurs ont observé à la Rochelle un certain nombre de poissons «rares» ou capturés en dehors de leur aire de répartition et plus particulièrement un exemplaire de Chlamycloselachus anguineus Garman, 1884, trois exemplaires de Mitsukurina sp., cinq exemplaires de Pseuclotriakis microdon Capello, 1868, un exemplaire de Somniosus sp., cette espèce étant probablement nouvelle, un exemplaire de Zenopsis conchifer (Lowe, 1852) signalé pour la première fois au large des côtes françaises de l'Atlantique, un exemplaire de Puntazzo plmtazzo (Gmelin, 1789), un exemplaire d'Hyperoglyphe percîformis (Mitchill, 1818), un exemplaire de Glyptocephalus cynoglossus (Linné, 1758) pêché au large de la Vendée et un exemplaire de Limanda limanda (Linné, 1758) pris au large de la côte des Landes. D'autre part, ils ont observé deux cas d'albinisme ainsi que cinq exemplaires remarquables par leur grande taille. Ils ont aussi noté la présence dans le golfe de Gascogne de neuf espèces de poissons appartenant à une faune plus froide et de huit à une faune plus chaude. OCR non contrôlé
Annales de la Société des Sciences Naturelles de la Charente-Maritime (Société des sciences naturelles de la Charente-Maritime), 1976 , Vol. 6 , N. 3 , P. 177-190

Droits : 1976 Société des sciences naturelles de la Charente-Maritime
http://archimer.ifremer.fr/doc/1976/publication-3645.pdf
http://archimer.ifremer.fr/doc/00000/3645/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The tropical to warm-temperate marine brown macroalgal genus Lobophora (Dictyotales, Phaeophyceae) recently drew attention because of its striking regional diversity. In this study we reassess Lobophora global species diversity, and species distributions, and explore how historical factors have shaped current diversity patterns. We applied a series of algorithmic species delineation techniques on a global mitochondrial cox3 dataset of 598 specimens, resulting in an estimation of 98–121 species. This diversity by far exceeds traditional diversity estimates based on morphological data. A multi-locus time-calibrated species phylogeny using a relaxed molecular clock, along with DNA-confirmed species distribution data was used to analyse ancestral area distributions, dispersal-vicariance-founder events, and temporal patterns of diversification under different biogeographical models. The origin of Lobophora was estimated in the Upper Cretaceous (−75 to −60 MY), followed by gradual diversification until present. While most speciation events were inferred within marine realms, founder events also played a non-negligible role in Lobophora diversification. The Central Indo-Pacific showed the highest species diversity as a result of higher speciation events in this region. Most Lobophora species have small ranges limited to marine realms. Lobophora probably originated in the Tethys Sea and dispersed repeatedly in the Atlantic (including the Gulf of Mexico) and Pacific Oceans. The formation of the major historical marine barriers (Terminal Tethyan event, Isthmus of Panama, Benguela upwelling) did not act as important vicariance events. Long-distance dispersal presumably represented an important mode of speciation over evolutionary time-scales. The limited geographical ranges of most Lobophora species, however, vouch for the rarity of such events.
ISSN: 1055-7903

hal-01535635
http://hal.upmc.fr/hal-01535635
http://hal.upmc.fr/hal-01535635/document
http://hal.upmc.fr/hal-01535635/file/Vieira_2017_Historical.pdf
DOI : 10.1016/j.ympev.2017.03.007

Éditeur(s) : Museum National d'Histoire Naturelle
Résumé : During the " Jean Charcot " cruise Polymed II, 18 species of the 5 classes of Echinodermata have been collected in 15 samples from the bathyal zone of the Alboran sea. Most species are already known from the Mediterranean and the North East Atlantic. Some rare species (Odontaster mediterranea, Ophiactis balli) have been collected, and two others (Neocomatella europaea. Henricia abyssalis) are recorded for the first time in the Mediterranean. Endemic distributions of Ceramaster hystricis and Ophiocten abyssicolum are discussed. The Echinoderms population of the Alboran sea is noteworthy for its Atlantic characteristic, which is besides, dominating in the North part of this area. The atlantic biogeographical relationships of the Echinoderm fauna of the Alboran sea is especially perceptible in the northern part of the basin. [NOT CONTROLLED OCR]
Lors de la campagne Polymède II du " Jean Charcot ", 18 espèces appartenant aux cinq classes d'Échinodermes ont été récoltées dans 15 prélèvements effectués dans l'étage bathyal de la mer d'Alboran. La plupart des espèces sont connues à la fois de la Méditerranée et des côtes européennes et africaines de l'Atlantique. On peut signaler la récolte d'espèces considérées comme rares en Méditerranée (Odontaster mediterranea, Ophiactis balli) et d'autres nouvelles pour cette mer (Neocomatella europaea, Henricia abyssalis). L'endémisme de deux espèces Ceramaster hystricis et Ophiocten abyssicolum est rediscuté. La faune échinologique de la mer d'Alboran se caractérise par sa dominance atlantique par ailleurs plus sensible au nord qu'au sud. [OCR NON CONTRÔLE]
Bulletin du Museum National d'Histoire Naturelle (Museum National d'Histoire Naturelle), 1974-08 , Vol. 3 , N. 231 , P. 25-34

Droits : Museum National d'Histoire Naturelle
http://archimer.ifremer.fr/doc/1974/publication-4975.pdf
http://archimer.ifremer.fr/doc/00000/4975/

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The life-history traits and population dynamics of species are increasingly being attributed to the characteristics of their preferred habitats. While coral reef fish are often strongly associated with particular habitats, long-term studies establishing the demographic and life-history consequences of occupying different reef substrata are rare and no studies have monitored individuals in situ over their lifetime and determined the fate of their offspring. Here, we documented a quasi-turnover and local reproductive success for an entire population of orange clownfish (Amphiprion percula) from Kimbe Island, Papua New Guinea, by taking bi-annual samples of DNA over a 10-yr period (2003–2013). We compared demographic and life-history traits of individuals living on two host anemone species, Heteractis magnifica and Stichodactyla gigantea, including female size, adult continued presence (a proxy for relative longevity range), early post-settlement growth, the number of eggs per clutch and ‘local’ reproductive success (defined for each adult as the number of offspring returning to the natal population). Our results indicate that while the relative longevity of adults was similar on both host anemone species, females living in H. magnifica were larger than females in S. gigantea. However, despite females growing larger and producing more eggs on H. magnifica, we found that local reproductive success was significantly higher for clownfish living in S. gigantea. Life-history traits also exhibited local spatial variation, with higher local reproductive success recorded for adults living on S. gigantea on the eastern side of the island. Our findings support a ‘silver-spoon’ hypothesis that predicts individuals that are fortunate enough to recruit into good habitat and location will be rewarded with higher long-term reproductive success and will make a disproportionate contribution to population renewal.
ISSN: 0722-4028

hal-01357939
https://hal-univ-perp.archives-ouvertes.fr/hal-01357939
DOI : 10.1007/s00338-016-1485-1

Éditeur(s) : Museum National d'Histoire Naturelle
Résumé : -A new species was found among the Asteroids collected near the Açores at a depth of 350 m.This species is described and attributed to the genus Ophidiaster according to the presence of 8 series of pore areas. Some characters can be related to the genus Hacelia and Tamaria mainly the massive shape of the triangular arms and the series of subrectangular actinal plates Besides, the valvula-pedicellarian are few and are situated dorsally, further the pore areas contains more than 40 pores each, these characters are specific to Ophidiaster reyssi n. sp. [NOT CONTROLLED OCR]
Parmi les Astérides récoltées au large des Açores par 350 m de profondeur, une espèce nouvelle est décrite.La présence de huit rangées d'aires papulaires a contribué à attribuer la nouvelle espèce au genre Ophidiaster, mais il est à remarquer quelques caractères qui la rapprochent des genres Hacelia et Tamaria, notamment la forme massive des bras à section triangulaire, et les séries de plaques actinales subrectangulaires. D'autre part, la présence rare de pédicellaires valvulaires dorsaux et de plus de 40 pores par aire papulaire sont des caractères propres à Ophidiaster reyssi n. sp. [OCR NON CONTRÔLE]
Bulletin du Museum National d'Histoire Naturelle (Museum National d'Histoire Naturelle), 1977 , Vol. 3 , N. 494 , P. 1085-1090

Droits : Museum National d'Histoire Naturelle
http://archimer.ifremer.fr/doc/1977/publication-5199.pdf
http://archimer.ifremer.fr/doc/00000/5199/

Éditeur(s) : HAL CCSD Mineralogical Society
Résumé : International audience
Almost all magmas contain sulfide- or sulfate-bearing phases. In most natural samples the sulfur-bearing phase is a sulfide, which typically is pyrrhotite (Fe1−xS) or pyrite (FeS2) although chalcopyrite (CuFeS2), pentlandite ((Fe,Ni)9S8), sphalerite (ZnS) or molybdenite (MoS2) may be present as well. Sulfate minerals are rare at magmatic conditions, and anhydrite (CaSO4) is the most common. Other magmatic SO4-bearing minerals include the sodalite group minerals (haüyne simplified formula: (Na,Ca)4-8(Al6Si6(O,S)24)(SO4,Cl)1-2), scapolite minerals (silvialite: (Ca,Na)4Al6Si6O24(SO4,CO3)), and S-bearing apatite (Ca5(PO4)3(F, Cl, OH)). Barite (BaSO4) has been mentioned in rare cases (Marchev 1991). Sulfur-bearing minerals usually constitute a negligible fraction of the mineral assemblage in magmatic rocks and thus can be classified as accessory minerals. The crystallization of sulfide, sulfate, and S-bearing minerals strongly depends on melt composition, temperature and pressure, and the S speciation in melt which, in turn, is strongly dependent on the prevailing oxygen fugacity (Baker and Moretti 2011, this volume; Wilke et al. 2011, this volume). Irrespectively of the low abundance of S-bearing minerals, the evolution of sulfur in magmas may be evaluated from the occurrence of sulfides and sulfates. These minerals are critical for estimating the activity of various sulfur-bearing species in magmas and can be used to constrain the oxygen fugacity and the S concentration in the melt (e.g., pre-eruptive sulfur concentration in melts). The presence of either sulfide or sulfate in silicate melt indicates that the predominant dissolved sulfur species in the melt are S2− or S6+, respectively. Typically one of these species is dominant, but there are conditions where S2− ...
ISSN: 1529-6466

hal-00644580
https://hal.archives-ouvertes.fr/hal-00644580
DOI : 10.2138/rmg.2011.73.10

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
We studied the diversity within the former genus Gymnangium in the South West IndianOcean by using an integrative approach of both traditional (morphology-based) and modernmolecular taxonomy. Nine species were recorded in the material collected. A total of 97 16Smitochondrial DNA sequences and 54 Calmodulin nuclear sequences from eight Gymnangium/Taxella species were analyzed. We found both morphological and molecular differencesin the studied Gymnangium species that make it necessary to split the genus. It isproposed to revalidate the genus Taxella which is currently regarded as a synonym ofGymnangium. Two species of the genus Taxella (T. eximia and T. gracilicaulis), until nowregarded as distinct species based on morphological characteristics, cluster together in onephylogenetic clade. Possible explanations are discussed. Two species from Madagascarnew to science are herein described and rare species from the Indian Ocean islands are redescribed.
ISSN: 1932-6203

hal-01564043
https://hal-univ-perp.archives-ouvertes.fr/hal-01564043
DOI : 10.1371/journal.pone.0174244

Éditeur(s) : Gauthier-Villars
Résumé : Relatively little is known of the fauna found on rock substrates in the deep ocean. As a result of the Franco-British deep diving cruise Cyaporc in 1986 using the submersible Cyana we present observations of a highly diverse sponge, cnidarian and echinoderm fauna occurring between 1 800 and 3 000 m on the steep slopes to the west of the Porcupine Bank and Goban Spur. This fauna is dominated. by suspension feeders and appears to show a vertical zonation corresponding to water mass structure. The highest biomass and variety of echinoderms are found between 2 100 and 2 600 m bathed in northward flowing North East Atlantic Deep Water. We present also additional observations of species known from previous sampling programmes but rarely photographed in their natural environment.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1992 , Vol. 15 , N. 2 , P. 211-226

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00100/21154/18773.pdf
http://archimer.ifremer.fr/doc/00100/21154/

Éditeur(s) : HAL CCSD Wiley
Résumé :  
Drier periods from the late Pleistocene and early Holocene have been hypothesized to have caused the disappearance of various rainforest species over large geographical areas in South America and restricted the extant populations to mesic sites. Subsequent improvement in climatic conditions has been associated with recolonization. Changes in population size associated with these extinction-recolonization events should have affected genetic diversity within species. However, these historical hypotheses and their genetic consequences have rarely been tested in South America. Here, we examine the diversity of the chloroplast and nuclear genomes in a Neotropical rainforest tree species, Vouacapoua americana (Leguminosae, Caesalpinioideae) in French Guiana. The chloroplast diversity was analyzed using a polymerase chain reaction-restriction fragment length polymorphism method (six pairs of primers) in 29 populations distributed over most of French Guiana, and a subset of 17 populations was also analyzed at nine polymorphic microsatellite loci. To determine whether this species has experienced extinction-recolonization, we sampled populations in areas supposedly not or only slightly affected by climatic changes, where the populations would not have experienced frequent extinction, and in areas that appear to have been recently recolonized. In the putatively recolonized areas, we found patches of several thousands of hectares homogeneous for chloroplast variation that can be interpreted as the effect of recolonization processes from several geographical origins. In addition, we observed that, for both chloroplast and nuclear genomes, the populations in newly recolonized areas exhibited a significantly smaller allelic richness than others. Controlling for geographic distance, we also detected a significant correlation between chloroplast and nuclear population differentiation. This result indicates a cytonuclear disequilibrium that can be interpreted as a historical signal of a genetic divergence between fragmented populations. In conclusion, the spatial genetic structure of contemporary V. americana populations shows evidence that this species has experienced large extinction-recolonization events, which were possibly caused by past climatic change.
ISSN: 0014-3820

hal-01032194
https://hal.archives-ouvertes.fr/hal-01032194
DOI : 10.1111/j.0014-3820.2003.tb01517.x

Éditeur(s) : Elsevier
Résumé : Changes in biodiversity may disrupt the ecological functions performed by species assemblages. Hence, we urgently need to examine the implications of biodiversity loss not only in terms of species conservation but also in terms of sustainability of ecosystem services. The ability of protected areas to maintain local species richness has been clearly demonstrated. However, preserving goods and services provided by ecosystems requires not only the conservation of species richness but also the conservation of the most 'original' species, i.e. the ones with the highest average rarity of their attributes which are likely to perform some unique functions in ecosystems. We proposed a new conservation of biological originality (CBO) index as well as associated randomization tests to quantify the ability of piotected areas to maintain viable populations for the most original species. As an application, we used long-term fisheries data collected in the Bonifacio Strait Natural Reserve (BSNR) to determine the species which benefited from the protection reinforcement in 1999. We also estimated a set of 14 ecomorphological functional traits on the 37 fish species caught in the BSNR and we obtained a functional originality value for each species. As a result, we found that functional originality was significantly protected in the fish assemblage of the BSNR: species with the most original functional trait combinations became more abundant after 1999. Our finding suggests that protecting most original species is an insurance against functional diversity erosion in the BSNR. More generally, our new index can be used to test whether protected areas may protect preferentially the most original species and whether restorative management promotes the reestablishment of the most original species with particular habitat requirements. (c) 2008 Elsevier Ltd. All rights reserved.
Biological Conservation (0006-3207) (Elsevier), 2008-06 , Vol. 141 , N. 6 , P. 1569-1580

Droits : 2008 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4480.pdf
DOI:10.1016/j.biocon.2008.04.002
http://archimer.ifremer.fr/doc/00000/4480/

Éditeur(s) : Magnolia Press
Résumé : Twenty-two species of the genus Munidopsis from the Atlantic Ocean are studied. Five new species are described (M. anemia, M. exuta, M. hirtella, M. laurentae and M. truculenta), and diagnoses and illustrations of some relatively rare species (M. acuminata, M. bairdii, M. livida, M. parfaiti and M. thieli) are provided. None of the species discussed here is restricted to a particular habitat, including species collected from hydrothermal vent (M. acutispina, M. exuta) and cold seep areas (M. acutispina, M. geyeri, M. hirtella, M. livida, M. marionis). The new records of some species greatly extend the previously known distribution range of the species (i.e., M. abyssicola, M. aries, M. bairdii, M. geyeri, M. livida, M. parfaiti, M. thieli). Finally, some biological and biogeographical data for the different species are discussed.
Zootaxa (1175-5326) (Magnolia Press), 2005-12-13 , Vol. 1095 , N. 0 , P. 3-60

Droits : 2006 Magnolia Press
http://archimer.ifremer.fr/doc/2005/publication-1812.pdf
http://archimer.ifremer.fr/doc/00000/1812/

Éditeur(s) : Gauthier-Villars
Résumé : Holothuria atra is the most common aspidochirotid holothurian on tropical Indo-Pacific reefs, Asexual reproduction by transverse fission, followed by regeneration, has been studied at Reunion Island (Indian Ocean) and compared with different populations of the Indo-Pacific zone, thus permitting a better identification of the most significant parameters and a better understanding of this reproductive strategy. At Reunion Island, the species is studied at two stations on the same fringing reef: 1) on the back-reef where the fission rate is high (20 % of the population), the individuals small (generally weighting less than 150 g) and the population density high (4/m(2)); and 2) on the reef front, where fission is extremely rare, the mean size of the individuals larger (up to 300 g) and the density low (0.01/m(2)), Different categories of individuals, fissioning (F), after fission, anterior and posterior parts (A and P), and regenerating (Ap and Pa) have been identified from external observations. Dissection has demonstrated the unequal allocation of organs during fission and the variability of the regenerative states, mostly in the anterior part. Concerning fission, the position of the split in an individual is in the anterior half (at 44 % of the total length). The monthly incidence of fission is higher from October to January and in June-July. Fission does not result in an increase in the density of the population. The monthly rates of regenerating individuals originating from anterior (3.7 %) and posterior (5.1 %) parts suggest that survival is higher in the latter instance. The occurrence of asexual reproduction in various populations of this species is discussed in relation to the ecology and the parameters of the populations considered. On the back-reef studied at Reunion Island, the population is subtidal and emersion cannot explain fission. Anthropogenic disturbances are possible triggers of this phenomenon.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1996 , Vol. 19 , N. 3-4 , P. 209-216

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00094/20479/18149.pdf
http://archimer.ifremer.fr/doc/00094/20479/

Éditeur(s) : Springer
Résumé : The distribution of summer phytoplankton across the Straits of Magellan (SOM) was studied with the aims of tracing differences among the distinct subregions of the area and contributing to the knowledge of its biodiversity. Samples collected at 25 stations were observed and counted in light microscopy. Selected samples were observed with transmission electron microscopy. The main unifying feature of the phytoplankton in the SOM was the high abundance and numerical dominance of small-sized (<10 μm) eukaryotic species, among which coccoid cells of <3 μm size were predominant (56.2 ± 30.6 of the total phytoplankton abundance). They mostly belonged to the prasinophyte Pycnococcus provasolii, which was abundant (0.8–6,834 cells × 103 ml−1) at all stations with the exception of those in proximity to the Atlantic entrances, where it was not recorded. Small-sized (<3 and 3–5 μm) diatoms (Minidiscus trioculatus, Lennoxia faveolata and other undetermined centric species) attained high densities (<3,757 cells 103 ml−1) especially at stations of the Patagonian sectors, whereas microplanktonic diatoms were only found at the two entrances of the Straits. Dinoflagellates were constituted mainly by >10 μm forms in the Andean subregion and <10 μm naked species in the Patagonian subregion, contributing up to 75.9 and 41.8% of the total carbon in these two areas, respectively. In the Patagonian subregion, flagellates mainly constituted by <5 μm forms and by cryptomonads <10 μm comprised up to 53.9% of the total biomass. Several species identified in this study have never been reported in other investigations in the SOM, while others, including Pycnococcus provasolii and Lennoxia faveolata, have rarely been recorded elsewhere. Overall, the summer phytoplankton of the Straits does not resemble that of any other region of the world’s seas. Although some of the predominant species might have been overlooked elsewhere, their abundance and relative importance apparently constitute a distinctive feature of the SOM.
Polar Biology (0722-4060) (Springer), 2011 , Vol. 34 , N. 9 , P. 1269-1284

Droits : The Author(s) 2010. This article is published with open access at Springerlink.com
http://archimer.ifremer.fr/doc/00026/13722/10828.pdf
DOI:10.1007/s00300-010-0937-2
http://archimer.ifremer.fr/doc/00026/13722/

Éditeur(s) : HAL CCSD
Résumé : Modern measures of diversity satisfy reasonable axioms, are parameterized to produce diversity profiles, come with an effective number of species to simplify their interpretation, and estimators to apply them to real data. Generalized Simpson's entropy has all of these features and can be used as a measure of biodiversity. Moreover, unlike most commonly used diversity indices, it has unbiased estimator, which allows for robust estimation of the diversity of poorly sampled, rich communities.
https://hal-agroparistech.archives-ouvertes.fr/hal-01276738

hal-01276738
https://hal-agroparistech.archives-ouvertes.fr/hal-01276738
https://hal-agroparistech.archives-ouvertes.fr/hal-01276738/document
https://hal-agroparistech.archives-ouvertes.fr/hal-01276738/file/GSimpson.pdf

Éditeur(s) : Gauthier-Villars
Résumé : The paper summarizes the biostratigraphic results of eighteen dives of the French submersible Cyana at the Mazagan Escarpment (CYAMAZ cruise), based on calcareous nannoplankton and foraminifera. This paper is restricted to the study of the Early Cretaceous to Quaternary post-platform series. Most of the stratigraphical data are based on the determination of calcareous nannofossils (P. Cepek) which, however, are mostly poorly preserved and of rare occurrence. From the 170 studied subsamples 49 are barren of calcareous samples are listed according to the species epithets, separated for the Cretaceous and Tertiary. The biostratigraphy based on foraminifera and the microfacies was studied in thin-section (H. hagn). Foraminiferal microfaunas of Late Cretaceous, Paleocene, Eocene-Oligocene and Quaternary age are described and shown in Plates.
Oceanologica Acta, Special issue (0399-1784) (Gauthier-Villars), 1985

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00247/35827/34337.pdf
http://archimer.ifremer.fr/doc/00247/35827/