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 Public Library of Science
Résumé : International audience
Regeneration of artificially induced lesions was monitored in nubbins of the branching coral Acropora muricata at two reef-flat sites representing contrasting environments at Réunion Island (21u079S, 55u329E). Growth of these injured nubbins was examined in parallel, and compared to controls. Biochemical compositions of the holobiont and the zooxanthellae density were determined at the onset of the experiment, and the photosynthetic efficiency (F v /F m) of zooxanthellae was monitored during the experiment. Acropora muricata rapidly regenerated small lesions, but regeneration rates significantly differed between sites. At the sheltered site characterized by high temperatures, temperature variations, and irradiance levels, regeneration took 192 days on average. At the exposed site, characterized by steadier temperatures and lower irradiation, nubbins demonstrated fast lesion repair (81 days), slower growth, lower zooxanthellae density, chlorophyll a concentration and lipid content than at the former site. A trade-off between growth and regeneration rates was evident here. High growth rates seem to impair regeneration capacity. We show that environmental conditions conducive to high zooxanthellae densities in corals are related to fast skeletal growth but also to reduced lesion regeneration rates. We hypothesize that a lowered regenerative capacity may be related to limited availability of energetic and cellular resources, consequences of coral holobionts operating at high levels of photosynthesis and associated growth.
ISSN: 1932-6203

hal-01369712
http://hal.univ-reunion.fr/hal-01369712
http://hal.univ-reunion.fr/hal-01369712/document
http://hal.univ-reunion.fr/hal-01369712/file/journal.pone.0072618.PDF
DOI : 10.1371/journal.pone.0072618

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 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 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-01359419
https://hal.archives-ouvertes.fr/hal-01359419
DOI : 10.1016/j.bse.2015.08.011

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
AimThe global biodiversity crisis requires the identification of regions with high evolutionary potential, i.e. evolutionary hotspots (evospots). We created an analytical framework based on comparative phylogeography and coalescent methods to assess the dynamics of diversification and population persistence in the reef ecosystem of a little-studied region: the Southwestern Indian Ocean (SWIO).LocationCoral reefs of the SWIO, with comparative data from the Pacific Ocean.MethodsWe generated sequences of mitochondrial DNA (COI and 16S) for 10 widespread brittle-stars (345 specimens) from 21 localities (8 in the SWIO). We analysed them by combining comparative phylogeography approaches, coalescent-based methods, molecular clocks and the concept of evolutionarily significant units (ESUs) to draw conclusions about the drivers of biodiversity in the region.ResultsCryptic diversity was prevalent, increasing lineage diversity within the 10 nominal species by 70% within the SWIO and by 200% across the Indo-West Pacific. All seven new SWIO lineages meet the criteria for ESUs and at least six are biological species. We detected likely intraregional diversifications dating to the Plio-Pleistocene, supporting the SWIO as a generator of biodiversity. Geographical restriction of ESUs, long coalescent times (> 80 ka) and old in situ diversification (> 1 Ma) point to the persistence of populations over multiple glacio-eustatic cycles. We provide data suggesting demographic expansion during sea-level high stands. Regional connectivity was lower, and cryptic differentiation higher in lecithotrophs than in planktotrophs.Main conclusionsThe analytical framework based on a biodiversity survey makes it possible to identify evospots by assessing the potential of a region to maintain and generate biodiversity and by evaluating the evolutionary processes and potential drivers at play.
ISSN: 0305-0270

hal-01369697
http://hal.univ-reunion.fr/hal-01369697
DOI : 10.1111/jbi.12155

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 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 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
Résumé : Designing biodiversity conservation plans requires knowledge on the biogeographic distribution of taxabut also accurate estimates of species richness and diversification processes. However, measuring the phyleticrichness can be biased by the use of inappropriate taxonomical characters, leading to erroneous speciesdelimitation and diversity estimates.This work explores the phyletic richness at several taxonomic levels (generic, specific and intraspecific) ofthe hydrozoan family Aglaopheniidae (Marktanner-Turneretscher, 1890), with a particular focus on the South-Western Indian Ocean. Firstly, using several newly constructed phylogenies based on mitochondrial andnuclear markers, this study reveals that the phyletic diversity of this family is at underestimated by at least 50%:all studied genera are polyphyletic or with doubtful monophyletic status. Then, using several speciesdelimitation methods based on molecular markers, it sheds light on the richness of cryptic diversity of thisfamily, enlightening the potential of using an integrative taxonomic approach on these morphologically simpleorganisms. Finally, the population genetics of an Aglaopheniidae brooding species shows a high populationsstructuring with pervasive pattern of isolation by distance at several geographic scales (several to thousands ofkilometres), implying a potentially high cryptic diversity existing in this family.The results of this work provide new insights on Aglaopheniidae diversity, underlining the potentialinfluence of reproductive mode on the phyletic diversity and diversification processes of brooding hydrozoanbrooders. This thesis further highlights the relevance of using several complementary
La conservation et la gestion sur le long terme de la biodiversité nécessitent une connaissance de larépartition des taxons, mais également une estimation précise de leur diversité spécifique ainsi que desprocessus de spéciation ayant permis leur formation. Cependant, la mesure de la richesse phylétique peut êtrebiaisée par l’utilisation de caractères taxinomiques ne permettant pas de délimiter les espèces de manièreappropriée.Ce travail de thèse propose d’explorer la diversité phylétique à plusieurs niveaux taxinomiques(générique, spécifique et intra-spécifique) des Aglaopheniidae, une famille d’hydrozoaires, notamment présentedans le Sud-Ouest de l’océan Indien. Dans un premier temps, en utilisant des phylogénies basées sur plusieursmarqueurs (mitochondriaux et nucléaires), ce travail démontre que la diversité phylétique de cette famille est,au minimum, sous-estimée de moitié: tous les genres de la famille sont polyphyléthiques ou présentent un statutmonophylétique restant à confirmer. Dans un deuxième temps, l’utilisation de méthodes de délimitationd’espèces basées sur des données moléculaires met en évidence la diversité cryptique très élevée des morphoespècesétudiées, révélant l’intérêt potentiel des protocoles de taxinomie intégrative chez les organismesmorphologiquement simples. Enfin, l’étude de génétique des populations d’une espèce incubatriced’Aglaopheniidae révèle l’importance de la structuration des populations et de l’isolement par la distance chezcette espèce à plusieurs échelles géographiques (de quelques kilomètres à plusieurs milliers), impliquant unepotentielle diversité cryptique extrêmement élevée chez cette famille.L’ensemble des connaissances acquises lors de ce travail de thèse fournit un nouveau regard sur ladiversité de la famille des Aglaopheniidae, soulignant le potentiel impact du cycle de reproduction sur ladiversité phylétique et les processus de spéciation des hydrozoaires incubateurs. Cette thèse met en évidence lapertinence de l’utilisation de plusieurs procédures complémentaires de délimitation d’espèces pour étudier ladiversité des organismes morphologiquement simples.
https://hal.archives-ouvertes.fr/tel-01359424

tel-01359424
https://hal.archives-ouvertes.fr/tel-01359424
https://hal.archives-ouvertes.fr/tel-01359424/document
https://hal.archives-ouvertes.fr/tel-01359424/file/These%20manuscrit%20final.pdf

Éditeur(s) : HAL CCSD Wiley Open Access
Résumé : International audience
Assessing population connectivity is necessary to construct effective marine protected areas. This connectivity depends, among other parameters, inherently on species dispersal capacities. Isolation by distance (IBD) is one of the main modes of differentiation in marine species, above all in species presenting low dispersal abilities. This study reports the genetic structuring in the tropical hydrozoan Macrorhynchia phoenicea (sensu Postaire et al., 2016a), a brooding species, from 30 sampling sites in the Western Indian Ocean and the Tropical Southwestern Pacific, using 15 microsatellite loci. At the local scale, genet dispersal relied on asexual propagation at short distance, which was not found at larger scales. Considering one representative per clone, significant positive F-IS values (from -0.327*** to 0.411***) were found within almost all sites. Gene flow was extremely low at all spatial scales, among sites within islands (<10km distance) and among islands (100 to >11,000km distance), with significant pairwise F-ST values (from 0.035*** to 0.645***). A general pattern of IBD was found at the Indo-Pacific scale, but also within ecoregions in the Western Indian Ocean province. Clustering and network analyses identified each island as a potential independent population, while analysis of molecular variance indicated that population genetic differentiation was significant at small (within island) and intermediate (among islands within province) spatial scales. As shown by this species, a brooding life cycle might be corollary of the high population differentiation found in some coastal marine species, thwarting regular dispersal at distances more than a few kilometers and probably leading to high cryptic diversity, each island housing independent evolutionary lineages.
ISSN: 2045-7758

hal-01681593
https://hal.archives-ouvertes.fr/hal-01681593
DOI : 10.1002/ece3.3236

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 Public Library of Science
Résumé : International audience
The Southwest Indian Ocean (SWIO) is a striking marine biodiversity hotspot. Coral reefs in this region host a high proportion of endemics compared to total species richness and they are particularly threatened by human activities. The island archipelagos with their diverse marine habitats constitute a natural laboratory for studying diversification processes. Rocky shores in the SWIO region have remained understudied. This habitat presents a high diversity of molluscs, in particular gastropods. To explore the role of climatic and geological factors in lineage diversification within the genus Nerita, we constructed a new phylogeny with an associated chronogram from two mitochondrial genes [cytochrome oxidase sub-unit 1 and 16S rRNA], combining previously published and new data from eight species sampled throughout the region. All species from the SWIO originated less than 20 Ma ago, their closest extant relatives living in the Indo-Australian Archipelago (IAA). Furthermore, the SWIO clades within species with Indo-Pacific distribution ranges are quite recent, less than 5 Ma. These results suggest that the regional diversification of Nerita is closely linked to tectonic events in the SWIO region. The Reunion mantle plume head reached Earth's surface 67 Ma and has been stable and active since then, generating island archipelagos, some of which are partly below sea level today. Since the Miocene, sea-level fluctuations have intermittently created new rocky shore habitats. These represent ephemeral stepping-stones, which have likely facilitated repeated colonization by intertidal gastropods, like Nerita populations from the IAA, leading to allopatric speciation. This highlights the importance of taking into account past climatic and geological factors when studying diversification of highly dispersive tropical marine species. It also underlines the unique history of the marine biodiversity of the SWIO region.
ISSN: 1932-6203

hal-01185713
https://hal.archives-ouvertes.fr/hal-01185713
https://hal.archives-ouvertes.fr/hal-01185713/document
https://hal.archives-ouvertes.fr/hal-01185713/file/PLoS%20ONE%202014%20Postaire.pdf
DOI : 10.1371/journal.pone.0095040

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
We isolated and characterized 16 polymorphic microsatellite loci for Lytocarpia brevirostris (Aglaophe- niidae), a hydrozoan common in the tropical Indo-Pacific region. Four to 34 alleles per locus were detected at the Indo-Pacific scale. At the population level, observed (Ho) and expected (He) heterozygosities ranged across 0.100–0.625 and 0.097–0.597, respectively. Three markers showed significant deviation from Hardy–Weinberg equi- librium, all of them presenting null alleles. Linkage dis- equilibrium was detected in three pairs of loci among 120. These primers provide powerful tools for studying popu- lation genetic diversity and the implication of life cycle strategies on population differentiation in tropical hydro- zoans. This will be valuable for the conservation of coral reefs biodiversity and the design of marine protected areas.
ISSN: 1877-7252

hal-01185722
https://hal.archives-ouvertes.fr/hal-01185722
https://hal.archives-ouvertes.fr/hal-01185722/document
https://hal.archives-ouvertes.fr/hal-01185722/file/Postaire%20et%20al.%20-%202015%20-%20Isolation%20and%20characterisation%20of%2016%20microsatellit_hal.pdf
DOI : 10.1007/s12686-014-0407-1