Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Despite the importance of invertebrate resources for Pacific coral reef islands, few studies have specifically addressed the effects of harvesting on invertebrate assemblages including targeted and non-targeted species. The impacts of recreational harvesting on reef and seagrass invertebrate assemblages in New Caledonia (South Pacific) are investigated by comparing communities in non-MPA and MPA areas. Sampling was done using a standard core method on seagrasses and by visual survey along belt transects on reefs. A total of 371 species were recorded, 174 on seagrasses and 254 on reefs, with 57 common species. Reef and seagrass invertebrate communities were very different in MPA and non-MPA areas. On both habitats, MPAs were identified as undisturbed areas while non-MPAs were defined as moderately disturbed with a predominance of small-sized and opportunistic species. Fishing not only affects target species but also non-target species through secondary effects. These results highlight the necessity of a community based approach for the conservation of resources in tropical poorly known environments.
ISSN: 0165-7836

hal-01311486
http://hal.univ-reunion.fr/hal-01311486
http://hal.univ-reunion.fr/hal-01311486/document
http://hal.univ-reunion.fr/hal-01311486/file/Harvesting%20effects%20on%20tropical%20invertebrate%20assemblages%20in%20New_hal.pdf
DOI : 10.1016/j.fishres.2015.02.001

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
With the development of genetics methods, it becomes possible to study the population structure and some aspects of the reproductive behaviour of endangered sharks. Here we describe the isolation of 20 polymorphic microsatellite markers in the bull shark Carcharhinus leucas (Carcharhinidae) and their characteristics. Two to 10 alleles per locus were detected. Observed and expected heterozygosities ranged from 0.00 to 0.78 and from 0.05 to0.80, respectively. Four markers showed deviations from Hardy–Weinberg equilibrium; among them, three showed presence of null alleles. No linkage disequilibrium was detected among any of the loci. Moreover, four, 11 and 19 of these 20 markers successfully cross-amplified in the tiger shark Galeocerdo cuvier, the sandbar shark Carcharhinus plumbeus and the dusky shark Carcharhinus obscurus, respectively.
ISSN: 1877-7252

hal-01253773
https://hal.archives-ouvertes.fr/hal-01253773
https://hal.archives-ouvertes.fr/hal-01253773/document
https://hal.archives-ouvertes.fr/hal-01253773/file/Pirog%20et%20al.%20-%202015%20-%20Isolation%20and%20characterization%20of%2020%20microsatellit_hal.pdf
DOI : 10.1007/s12686-014-0308-3

Éditeur(s) : HAL CCSD
Résumé : Master
La biodiversité peut être mesurée de nombreuses façons. La dualité entropie-diversité fournit un cadre clair et rigoureux pour le faire. L’entropie est la surprise moyenne fournie par les individus d’une communauté. Le choix de la fonction d’information qui mesure cette surprise à partir des probabilités d’occurence des espèces (ou d’autres catégories) permet de définir les mesures de diversités neutres, fonctionnelles ou phylogénétique présentées ici. L’entropie est transformée en diversité au sens strict par une fonction croissante (l’exponentielle déformée), ce qui simplifie son interprétation en tant que nombre équivalent d’espèces.L’entropie phylogénétique généralise les indices de diversité classique, intègre si nécessaire la distance entre espèces, peut être écomposée et corrigée des biais d’estimation. Sa transformation en diversité au sens strict permet d’interpréter les valeurs sous une forme unique : un nombre équivalent d’espèces et un nombre équivalent de communautés. La diversité de Leinster et Cobbold généralise à son tour la diversité phylogénétique et permet d’autres définitions de la distance entre espèces. Le paramétrage des mesures (l’ordre de la diversité) permet de donner plus ou moins d’importance aux espèces rares et de tracer des profils de diversité.La construction de ce cadre méthodologique est présentée en détail ainsi que plusieurs approches différentes, qui constituent l'état de l'art de la mesure de la biodiversité.
https://hal-agroparistech.archives-ouvertes.fr/cel-01205813
Kourou, France

cel-01205813
https://hal-agroparistech.archives-ouvertes.fr/cel-01205813
https://hal-agroparistech.archives-ouvertes.fr/cel-01205813v4/document
https://hal-agroparistech.archives-ouvertes.fr/cel-01205813/file/Mesures_de_la_Biodiversite.pdf

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The scleractinian coral Pocillopora damicornis type β is known to present a mixed reproduction mode: through sexual reproduction, new genotypes are created, while asexual reproduction insures their propagation. In order to investigate the relative proportion of each reproduction mode in P. damicornis type β populations from Reunion Island, Indian Ocean, clonal propagation along the west coast was assessed through four sampling sites with increasing geographical distance between sites. Coral colonies were sampled either exhaustively, randomly or haphazardly within each site, and genotypic diversity was assessed using 13 microsatellite loci over a total of 510 P. damicornis type β determined a posteriori from their mtDNA haplotype (a 840 bp sequenced fragment of the Open Reading Frame). Overall, 47% of all the sampled colonies presented the same multi-locus genotype (MLG), a superclone, suggesting that asexual propagation is extremely important in Reunion Island. Within each site, numerous MLGs were shared by several colonies, suggesting local clonal propagation through fragmentation. Moreover, some of these MLGs were found to be shared among several sites located 40 km apart. While asexual reproduction by fragmentation seems unlikely over long distances, our results suggest a production of parthenogenetic larvae. Despite shared MLGs, two differentiated clusters were enclosed among populations of the west coast of Reunion Island, revealing the necessity to set up appropriate managing strategies at a local scale.
ISSN: 1932-6203

hal-01450078
http://hal.univ-reunion.fr/hal-01450078
DOI : 10.1371/journal.pone.0169692

Éditeur(s) : HAL CCSD
Résumé : Master
La biodiversité peut être mesurée de nombreuses façons. La dualité entropie-diversité fournit un cadre clair et rigoureux pour le faire. L’entropie est la surprise moyenne fournie par les individus d’une communauté. Le choix de la fonction d’information qui mesure cette surprise à partir des probabilités d’occurence des espèces (ou d’autres catégories) permet de définir les mesures de diversités neutres, fonctionnelles ou phylogénétique présentées ici. L’entropie est transformée en diversité au sens strict par une fonction croissante (l’exponentielle déformée), ce qui simplifie son interprétation en tant que nombre équivalent d’espèces.L’entropie phylogénétique généralise les indices de diversité classique, intègre si nécessaire la distance entre espèces, peut être écomposée et corrigée des biais d’estimation. Sa transformation en diversité au sens strict permet d’interpréter les valeurs sous une forme unique : un nombre équivalent d’espèces et un nombre équivalent de communautés. La diversité de Leinster et Cobbold généralise à son tour la diversité phylogénétique et permet d’autres définitions de la distance entre espèces. Le paramétrage des mesures (l’ordre de la diversité) permet de donner plus ou moins d’importance aux espèces rares et de tracer des profils de diversité.La construction de ce cadre méthodologique est présentée en détail ainsi que plusieurs approches différentes, qui constituent l'état de l'art de la mesure de la biodiversité.
https://hal-agroparistech.archives-ouvertes.fr/cel-01205813
Kourou, France

cel-01205813
https://hal-agroparistech.archives-ouvertes.fr/cel-01205813
https://hal-agroparistech.archives-ouvertes.fr/cel-01205813v2/document
https://hal-agroparistech.archives-ouvertes.fr/cel-01205813/file/Mesures_de_la_Biodiversite.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We isolated and characterized 26 microsatellite loci for Macrorhynchia phoenicea (Busk, 1852), a rather common tropical hydrozoan from the Indo-Pacific. The number of alleles per locus ranged from 4 to 24. The observed heterozygosity ranged from 0.000 to 0.970 and the expected heterozygosity from 0.029 to 0.833. Ten loci were at HardyeWeinberg equilibrium. No pair of loci presented linkage disequilibrium. Transferability of up to 18 loci was positive across four other Aglaopheniidae species from different genera. These loci will be used in studying reef population connectivity for these particular species at the scale of the Indo-Pacific, a promising but little explored research field.
ISSN: 0305-1978

hal-01253779
https://hal.archives-ouvertes.fr/hal-01253779
https://hal.archives-ouvertes.fr/hal-01253779/document
https://hal.archives-ouvertes.fr/hal-01253779/file/Biochemical%20Systematics%20and%20Ecology%202015%20Postaire_hal.pdf
DOI : 10.1016/j.bse.2015.08.011

Éditeur(s) : HAL CCSD
Résumé : International audience
Many countries are legally obliged to embrace ecosystem-based approaches to fisheries management. Reductions in bycatch and physical habitat damage are now commonplace, but mitigating more sophisticated impacts associated with the ecological functions of target fisheries species are in their infancy. Here we model the impacts of a parrotfish fishery on the future state and resilience of Caribbean coral reefs, enabling us to view the tradeoff between harvest and ecosystem health. We find that the implementation of a simple and enforceable size restriction of >30 cm provides a win:win outcome in the short term, delivering both ecological and fisheries benefits and leading to increased yield and greater coral recovery rate for a given harvest rate. However, maintaining resilient coral reefs even until 2030 requires the addition of harvest limitations (<10% of virgin fishable biomass) to cope with a changing climate and induced coral disturbances, even in reefs that are relatively healthy today. Managing parrotfish is not a panacea for protecting coral reefs but can play a role in sustaining the health of reefs and high-quality habitat for reef fisheries.
http://hal.univ-reunion.fr/hal-01369752

hal-01369752
http://hal.univ-reunion.fr/hal-01369752
DOI : 10.1073/pnas.1601529113

Éditeur(s) : HAL CCSD Western Indian Ocean Marine Science Association
Résumé : International audience
Juan de Nova is one of the scattered islands known as Iles Eparses in the Mozambique Channel (Western Indian Ocean). Historically, they have been isolated from many anthropogenic influences which makes them ideal areas to study biodiversity for comparison with areas that are heavily impacted by urbanization and fishing. The programme BioReCie (Biodiversity, Resources and Conservation of Eparses Islands) undertook inventories of several marine groups, including echinoderms, which had hitherto not been assessed in Juan de Nova. A multidisciplinary team surveyed the reef slopes of the island using SCUBA to a depth of 25 m as well as the reef flats at low tide, collecting specimens and taking photos for identification. Sixty echinoderm species were found, with 51 occurring on the reef flats and in the lagoon and 22 on the reef slopes, comprising 21 species of Holothuroidea, 16 Ophiuroidea, 10 Echinoidea, 7 Asteroidea, and 6 Crinoidea. Commercial species of Holothuroidea, some of which are classified as endangered in the IUCN red list, i.e. Thelenota ananas and Holothuria nobilis, were present on the reef flats, reef slopes and in the lagoon of the island, indicating the value that protection has on biodiversity.
ISSN: 0856-860X

hal-01306709
http://hal.univ-reunion.fr/hal-01306709
http://hal.univ-reunion.fr/hal-01306709/document
http://hal.univ-reunion.fr/hal-01306709/file/A%20First%20Inventory%20of%20Echinodermata%20at%20Juan%20de%20Nova_hal.pdf

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
Marine ecosystems cover about 70% of the planet surface and are still an underexploited source of useful metabolites. Among microbes, filamentous fungi are captivating organisms used for the production of many chemical classes of secondary metabolites bound to be used in various fields of industrial application. The present study was focused on the collection, isolation, screening and genotyping of pigmented filamentous fungi isolated from tropical marine environments around La Réunion Island, Indian Ocean. About 150 micromycetes were revived and isolated from 14 marine samples (sediments, living corals, coral rubble, sea water and hard substrates) collected in four different locations. Forty-two colored fungal isolates belonging to 16 families, 25 genera and 31 species were further studied depending on their ability to produce pigments and thus subjected to molecular identification. From gene sequence analysis, the most frequently identified colored fungi belong to the widespread Penicillium, Talaromyces and Aspergillus genera in the family Trichocomaceae (11 species), then followed by the family Hypocreaceae (three species). This study demonstrates that marine biotopes in La Réunion Island, Indian Ocean, from coral reefs to underwater slopes of this volcanic island, shelter numerous species of micromycetes, from common or uncommon genera. This unstudied biodiversity comes along with the ability for some fungal marine inhabitants, to produce a range of pigments and hues.
ISSN: 2309-608X

hal-01657071
http://hal.univ-reunion.fr/hal-01657071
http://hal.univ-reunion.fr/hal-01657071/document
http://hal.univ-reunion.fr/hal-01657071/file/14-%20Fouillaud%20et%20al.%2C%20J.%20of%20Fungi%202017.pdf
DOI : 10.3390/jof3030036

Éditeur(s) : HAL CCSD
Résumé : Integrating ecological connectivity into marine ecosystem management and planning is important, especially in a global context of severe fish stocks depletion and growing habitat degradation. Environmental tools such as Marine Protected Areas have been proposed to protect biodiversity, restore damaged ecosystems, sustain fisheries, and rebuild overexploited stocks. The effectiveness of marine protected areas depends in part on the maintenance of connectivity between marine populations, linked by ecological processes such as larval dispersal. In this thesis, we applied a biophysical model driven by ocean currents derived from satellite altimetry to evaluate connectivity between Western Indian Ocean reefs and across the current MPA system in the Mediterranean Sea. We applied different methods of analysis such as graph-theoretic and clustering. In the Western Indian Ocean, marine connectivity analyses show that the number of connections between reefs increases with fish pelagic larval duration. It also highlights a low connectivity across the region and a high interconnectivity within several regions (Mozambique Channel, Mascarene archipelago). In the Mediterranean Sea, connectance is globally low at the regional scale. This connectance is more important in Western than Eastern Mediterranean. Moreover, the marine connectivity analyses revealed high domestic connectivity rates. Depending on the study area, priority reefs or sites for MPA implementation are proposed. Finally, implications for transboundary marine policies and regional cooperation are discussed.
Intégrer les connaissances sur la connectivité écologique dans la gestion des écosystèmes marins est essentiel, surtout dans un contexte d'appauvrissement des ressources marines et de dégradation des habitats côtiers à l'échelle mondiale. Des outils environnementaux, tels que les Aires Marines Protégées ont été mises en œuvre pour protéger la biodiversité, restaurer les écosystèmes endommagés, soutenir les pêcheries et reconstituer les stocks surexploités. Leur efficacité dépend en partie du maintien de la connectivité entre les populations marines, assurée à travers divers processus écologiques dont la dispersion larvaire. Dans le cadre de ce travail de thèse, un modèle biophysique intégrant des données de courants, issues de mesures d'altimétrie par satellite, a été utilisé pour évaluer la connectivité entre les récifs de l'océan Indien d'une part, et à travers le réseau d'AMP de Méditerranée d'autre part. Différentes méthodes d'analyse ont été utilisées, telles que la théorie des graphes et le clustering. Dans l'océan Indien occidental, l'analyse des connectivités marines montre que le nombre de connexions entre les récifs augmente avec la durée de vie larvaire des poissons. Elle met également en évidence une faible connectivité à l'échelle de la région, mais une forte inter-connectivité au sein de plusieurs sous-régions (Canal du Mozambique, Mascareignes). En Méditerranée, la connectance est globalement faible à l'échelle régionale, bien que plus importante dans le bassin occidental que le bassin oriental. L'analyse des connectivités marines montre également un taux de connectivité élevé à l'échelle d'un même pays. Selon le cas d'étude, une liste de récifs ou de sites prioritaires dans la mise en œuvre des AMP a été proposée. Enfin, les implications de ces résultats en termes de politiques transfrontalières et de coopération régionale sont discutées.
https://tel.archives-ouvertes.fr/tel-01269631

NNT : 2015LARE0003
tel-01269631
https://tel.archives-ouvertes.fr/tel-01269631
https://tel.archives-ouvertes.fr/tel-01269631/document
https://tel.archives-ouvertes.fr/tel-01269631/file/2015lare0003_ECrochelet.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A comprehensive inventory of global biodiversity would be greatly improved by automating methods for species delimitation. The Automatic Barcode Gap Discovery method, the Poisson tree processes algorithm and the Generalized mixed Yule coalescent model have been proposed as means of increasing the rate of biodiversity description using single locus data. We applied these methods to explore the diversity within the Aglaopheniidae, a hydrozoan family with many species widely distributed across tropical and tem perate oceans. Our analyses revealed widespread cryptic diversity in this family, almost half of the morpho species presenting several independent evolutionary lineages, as well as support for cases of synonymy. For two common species of this family, Lytocarpia brevirostris and Macrorhynchia phoenicea, we compared the outputs to clustering analyses based on microsatellite data and to nuclear gene phylo genies. For L. brevirostris, microsatellite data were congruent with results of the species delimitation methods, revealing the existence of two cryptic species with Indo Pacific distribution. For M. phoenicea, all analyses confirmed the presence of two cryptic species within the South Western Indian Ocean. Our study suggests that the diversity of Aglaopheniidae might be much higher than assumed, likely related to low dispersal capacities. Sequence based species delimitation methods seem highly valuable to reveal cryptic diversity in hydrozoans; their application in an integrative framework will be very useful in describing the phyletic diversity of these organisms.
ISSN: 1055-7903

hal-01359407
https://hal.archives-ouvertes.fr/hal-01359407
https://hal.archives-ouvertes.fr/hal-01359407/document
https://hal.archives-ouvertes.fr/hal-01359407/file/Postaire-etal2016MolPhylEvol_sp_delim_hydraires_HAL.pdf
DOI : 10.1016/j.ympev.2016.08.013

Éditeur(s) : HAL CCSD National Shellfisheries Association
Résumé : International audience
Monitoring gonad maturation for protandrous and functional hermaphrodite species such as the giant clam Tridacna maxima is difficult due to the juxtaposition and relative proportion of male and female tissues in the gonad [gonadal sex ratio (GSR)]. Here, the relevance of the widely used gonadosomatic index (GSI) as proxy of giant clam gonad maturation is tested with a large dataset (n ¼ 265). Gonadosomatic index is compared with other indices, namely the proportion of the male part harboring spermatozoids, the proportion of empty oocyte follicles, the mean oocyte diameter, and the oocyte elongation. At gonad scale, high index variability highlighted partial spawning. At individual scale, male and female maturation proxies were contrasted, showing either asynchronous emissions of male and female gametes or contrasted spermatogenesis and oogenesis duration. The GSI was mostly driven by the number and diameter of oocytes and therefore it is recommended here as primary proxy for female maturity. Except for the oocyte elongation, all indices were affected by the GSR, which ruled out drawing conclusions at population scale. These results highlight the need for maturation stage proxies that are optimized for functional hermaphrodite species.
ISSN: 0730-8000

hal-01613648
https://hal.archives-ouvertes.fr/hal-01613648
https://hal.archives-ouvertes.fr/hal-01613648/document
https://hal.archives-ouvertes.fr/hal-01613648/file/Gaertner-Mazouni-2016-eio.pdf
DOI : 10.2983/035.035.0107

Éditeur(s) : HAL CCSD Magnolia Press
Résumé : International audience
Despite their importance in marine biodiversity, invertebrates are far less studied than vertebrates. Given the current globalbiodiversity crisis and insufficient taxonomic resources, sustained efforts need to be undertaken to assess species diversity,especially in the highly threatened ‘biodiversity hotspots’. Réunion is a young volcanic island lying in the Mascarene Islands(south-western Indian Ocean, SWIO), a marine biodiversity hotspot. A substantial sampling effort was conductedaround Réunion Island to document shallow water reef-associated ophiuroid (brittle-stars) diversity, a class recognised asthe most diverse among echinoderms. A total of 33 species were documented, increasing the known species richness ofthe island by 56%. Findings include 15 new records for Réunion, 11 for the Mascarene Islands and 8 for the Indian Ocean.The most diverse family was Ophiocomidae, a family of large, abundant and conspicuous tropical species. Even in thiswell studied family, a new species was revealed by this survey. Morphological variants together with DNA sequence variationswithin several species revealed cryptic species. We compared our results with the known fauna of other MascareneIslands and discuss biogeographic implications for the region.
ISSN: 1175-5326

hal-01327053
https://hal-univ-perp.archives-ouvertes.fr/hal-01327053
DOI : 10.11646/zootaxa.4098.2.4

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Bruggemann, J.H. (2016). Phylogenetic relationships within Aglaopheniidae (Cnidaria, Hydrozoa) reveal unexpected generic diversity. — Zoologica Scripta, 45, 103–114. Morphology can be misleading in the representation of phylogenetic relationships, especially in simple organisms like cnidarians and particularly in hydrozoans. These suspension feeders are widely distributed in many marine ecosystems, and the family Aglaopheniidae Marktanner-Turneretscher, 1890 is among the most diverse and visible, especially on tropical coral reefs. The taxonomy of this family is based on morphological characters with emphasis on reproductive structures for the identification of genera. This study is the most comprehensive molecular phylogeny of the Aglaopheniidae to date, including six genera and 38 species, of which 13 were investigated for the first time and sampled on tropical coral reefs throughout the Indo-Pacific region. For newly sampled individuals, we sequenced the 16S rRNA, the nuclear locus comprising the complete ITS1-5.8S rRNA gene-ITS2 and the first intron of the calmodulin nuclear gene. Phylogenetic analyses of the data revealed and confirmed a general polyphyly, or doubtful monophyly, of all sampled genera in tropical regions based on both the mitochondrial and nuclear markers. Our results revealed that several morphological characters used today are unsuited to resolve phylogenetic relationships between species and genera, as well as the high phyletic diversity within this family. Future revision of the classification of this family will require extensive geographic sampling and the use of an integrative approach.
ISSN: 0300-3256

hal-01359414
https://hal.archives-ouvertes.fr/hal-01359414
DOI : 10.1111/zsc.12135

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
Total genomic DNA of eight colonies for each of the two species, Acropora muricata and Porites lutea, sampled on the west coast of Reunion Island, was isolated using DNeasy Blood & Tissue kit (Qiagen™) following the manufacturer’s instructions and sent to GenoScreen, Lille, France (www.genoscreen.fr).
ISSN: 1877-7252

hal-01254248
https://hal.archives-ouvertes.fr/hal-01254248
https://hal.archives-ouvertes.fr/hal-01254248/document
https://hal.archives-ouvertes.fr/hal-01254248/file/G%C3%A9lin%20et%20al.%20-%202015%20-%20Isolation%20and%20characterization%20of%2022%20microsatellit_hal.pdf
DOI : 10.1007/s12686-015-0493-8

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Morphology can be misleading in the representation of phylogenetic relationships, especially in simple organisms like cnidarians and particularly in hydrozoans. These suspension feeders are widely distributed in many marine ecosystems, and the family Aglaopheniidae Marktanner-Turneretscher, 1890 is among the most diverse and visible, especially on tropical coral reefs. The taxonomy of this family is based on morphological characters with emphasis on reproductive structures for the identification of genera. This study is the most comprehensive molecular phylogeny of the Aglaopheniidae to date, including six genera and 38 species, of which 13 were investigated for the first time and sampled on tropical coral reefs throughout the Indo-Pacific region. For newly sampled individuals, we sequenced the 16S rRNA, the nuclear locus comprising the complete ITS1-5.8S rRNA gene-ITS2 and the first intron of the calmodulin nuclear gene. Phylogenetic analyses of the data revealed and confirmed a general polyphyly, or doubtful monophyly, of all sampled genera in tropical regions based on both the mitochondrial and nuclear markers. Our results revealed that several morphological characters used today are unsuited to resolve phylogenetic relationships between species and genera, as well as the high phyletic diversity within this family. Future revision of the classification of this family will require extensive geographic sampling and the use of an integrative approach.
ISSN: 0300-3256

hal-01253738
https://hal.archives-ouvertes.fr/hal-01253738
https://hal.archives-ouvertes.fr/hal-01253738/document
https://hal.archives-ouvertes.fr/hal-01253738/file/Phylogenetic%20relationships%20within%20Aglaopheniidae%20%28Cnidaria%2C._hal.pdf
DOI : 10.1111/zsc.12135

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
The newly-desribed Centropyge cocosensis has long been considered a variant of the lemonpeel pygmy angelfish C. flavissima because of their overall similarity in color patterns. DiBattista and co-authors [J. Hered. 107 (2016) 647–653] recently contested the validity of C. cocosensis, based on arguments that are challenged here.
ISSN: 0022-1503

ird-01525431
http://hal.ird.fr/ird-01525431
http://hal.ird.fr/ird-01525431/document
http://hal.ird.fr/ird-01525431/file/Letter%20to%20Editor_JHered%20p%20haL.pdf
DOI : 10.1093/jhered/esx008

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Seabirds concentrate nutrients from large marine areas on their nesting islands playing an important ecological role in nutrient transfer between marine and terrestrial ecosystems. Here we investigate the role of guano on corals reefs across scales by analyzing the stable nitrogen isotopic (delta N-15) values of the scleractinian coral Pocillopora damicornis on fringing reefs around two Pacific remote islets with large seabird colonies. Marine stations closest to the seabird colonies had higher nitrate + nitrite concentrations compared to more distant stations. Coral and zooxanthellae delta N-15 values were also higher at these sites, suggesting that guano-derived nitrogen is assimilated into corals and contributes to their nitrogen requirements. The spatial extent of guano influence was however restricted to a local scale. Our results demonstrate that seabird-derived nutrients not only spread across the terrestrial ecosystem, but also affect components of the adjacent marine ecosystem. Further studies are now needed to assess if this nutrient input has a positive or negative effect for corals. Such studies on remote islets also open fresh perspectives to understand how nutrients affect coral reefs isolated from other anthropogenic stressors.
ISSN: 2045-2322

hal-01681575
https://hal.archives-ouvertes.fr/hal-01681575
DOI : 10.1038/s41598-017-03781-y

Éditeur(s) : HAL CCSD CSIRO Publishing
Résumé : International audience
The present study assessed the occurrence of multiple paternity in four litters of bull shark Carcharhinus leucas (n¼5, 8, 9 and 11 embryos) sampled at Reunion Island in the Western Indian Ocean. Using 21 microsatellite loci, we revealed that two litters were generated from two sires each, demonstrating for the first time multiple paternity for this species. We also reported a high paternal skew (10 : 1 in Litter 1 and 7 : 1 in Litter 3), which may be because of postcopulatory or post-zygotic selection processes. These results contribute to a better understanding of the reproductive behaviour of the bull shark, which remains poorly documented. The present study must be expanded to assess the frequency of multiple paternity in this species, and to test for genetic or cryptic benefits (convenience polyandry), which is important for long-term conservation and management plans.
ISSN: 1323-1650

hal-01253775
https://hal.archives-ouvertes.fr/hal-01253775
https://hal.archives-ouvertes.fr/hal-01253775/document
https://hal.archives-ouvertes.fr/hal-01253775/file/Pirog%20et%20al.%20-%202015%20-%20First%20evidence%20of%20multiple%20paternity%20in%20the%20bull%20s_hal.pdf
DOI : 10.1071/mf15255

Éditeur(s) : HAL CCSD Springer Verlag/EDP Sciences
Résumé : International audience
The elucidation of relationships between biodiversity and ecosystem processes has been limited by the definition of metrics of biodiversity and their integration into experimental design. Functional trait screening can strengthen the performance of these designs.* We suggest the use of Rao's quadratic entropy to measure both functional diversity and phylogenetic diversity of species mixtures proposed for an experimental design, and demonstrate how they can provide complementary information.* We also present an index assessing the statistical performance of these independent variables in different experimental designs. Measurement of independent variables as continuous vs. discrete variables reduces statistical performance, but improves the model by quantifying species differences masked by group assignments.* To illustrate these advances, we present an example from a tropical forest tree community in which we screened 38 species for nine functional traits. The proposed TropiDEP design is based on the relative orthogonality of two multivariate trait axes defined using principal component analysis.* We propose that independent variables describing functional diversity might be grouped to calculate independent variables describing suites of different traits with potentially different effects on particular ecosystem processes. In other systems these axes may differ from those reported here, yet the methods of analysis integrating functional and phylogenetic diversity into experimental design could be universal.
La compréhension des relations pouvant exister entre biodiversité et fonctionnement des écosystèmes a été longtemps limitée par la définition de méthodes de quantification de la diversité biologique et la mise en œuvre de dispositifs expérimentaux permettant sa mesure. L'identification de syndromes de traits fonctionnels clefs influençant des fonctions écosystémiques particulières peut renforcer la performance de ces dispositifs.* Nous suggérons l'utilisation de l'entropie quadratique de Rao pour mesurer la diversité fonctionnelle et phylogénétique dans des assemblages synthétiques d'espèces, et montrons comment ces mesures de diversité sont complémentaires.* Nous présentons également un indice permettant de tester la performance statistique de ces variables indépendantes dans différents modèles expérimentaux. L'utilisation de variables indépendantes continues plutôt que discrètes réduit la performance statistique mais améliore le modèle en quantifiant les différences fonctionnelles entre espèces; différences généralement masquées lors de leur assignation en groupes fonctionnels.* Pour illustrer ces avancées, nous présentons un exemple d'assemblages synthétiques à partir de 38 espèces d'arbres de forêt tropicale sélectionnées pour 9 traits fonctionnels (TropiDEP). Le plan d'expérience de TropiDEP est basé sur l'orthogonalité relative de deux axes multivariés de traits fonctionnels définis par analyse en composantes principales.* Nous proposons que les variables décrivant la diversité fonctionnelle soient groupées pour calculer des variables indépendantes, divisées en plusieurs axes décrivant des combinaisons de différents traits pouvant influencer des processus différents de l'écosystème (e.g. processus du N et du C). Dans d'autres systèmes, ces axes peuvent différer de ceux présentés ici, mais les méthodes d'analyse peuvent être universelles.
ISSN: 1286-4560

Droits : info:eu-repo/semantics/OpenAccess
hal-00883621
https://hal.archives-ouvertes.fr/hal-00883621
https://hal.archives-ouvertes.fr/hal-00883621/document
https://hal.archives-ouvertes.fr/hal-00883621/file/hal-00883621.pdf
DOI : 10.1051/forest/2009110