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 Wiley
Résumé : International audience
Genetic diversity is crucial for species' maintenance and persistence, yet is often overlooked in conservation studies. Species diversity is more often reported due to practical constraints, but it is unknown if these measures of diversity are correlated. In marine invertebrates, adults are often sessile or sedentary and populations exchange genes via dispersal of gametes and larvae. Species with a larval period are expected to have more connected populations than those without larval dispersal. We assessed the relationship between measures of species and genetic diversity, and between dispersal ability and connectivity. We compiled data on genetic patterns and life history traits in nine species across five phyla. Sampling sites spanned 600km in the northwest Mediterranean Sea and focused on a 50-km area near Marseilles, France. Comparative population genetic approaches yielded three main results. (i) Species without larvae showed higher levels of genetic structure than species with free-living larvae, but the role of larval type (lecithotrophic or planktotrophic) was negligible. (ii) A narrow area around Marseilles, subject to offshore advection, limited genetic connectivity in most species. (iii) We identified sites with significant positive contributions to overall genetic diversity across all species, corresponding with areas near low human population densities. In contrast, high levels of human activity corresponded with a negative contribution to overall genetic diversity. Genetic diversity within species was positively and significantly linearly related to local species diversity. Our study suggests that local contribution to overall genetic diversity should be taken into account for future conservation strategies.
ISSN: 0962-1083

hal-01681650
https://hal.archives-ouvertes.fr/hal-01681650
DOI : 10.1111/mec.14389

Éditeur(s) : HAL CCSD Linnean Society of London
Résumé : Disentangling the impact of landscape features such as rivers and historical events on dispersal is a challenging but necessary task to gain a comprehensive picture of the evolution of diverse biota such as that found in Amazonia. Adenomera andreae, a small, territorial, terrestrial frog species of the Amazonian forest represents a good model for such studies. We combined cytochrome b sequences with 12 microsatellites to investigate the genetic structure at two contrasted spatial scales in French Guiana: along a similar to 6-km transect, to evaluate dispersal ability, and between paired bank populations along a similar to 65-km stretch of the Approuague river, to test the effect of rivers as barriers to dispersal. We observed significant spatial genetic structure between individuals at a remarkably small geographical scale, and conclude that the species has a restricted dispersal ability that is probably tied to its life-history traits. Mitochondrial and microsatellite data also indicate a high level of differentiation among populations on opposite banks of the river, and, in some cases, among populations on the same riverbank. These results suggest that the observed population structure in A. andreae is the result of restricted dispersal abilities combined with the action of rivers and Quaternary population isolation. Given that Amazonia hosts a great portion of anurans, as well as other small vertebrates, that display life-history traits comparable with A. andreae, we argue that our analyses provide new insights into the complex interactions among evolutionary processes shaping Amazonian biodiversity. (c) 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 356373.
ISSN: 0024-4066

hal-01032422
https://hal.archives-ouvertes.fr/hal-01032422
DOI : 10.1111/j.1095-8312.2012.01871.x

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 Elsevier
Résumé : International audience
Resolving the early diversification of animal lineages has proven difficult, even using genome-scale datasets. Several phylogenomic studies have supported the classical scenario in which sponges (Porifera) are the sister group to all other animals (''Porifera-sister''3 hypothesis), consistent with a single origin of the gut, nerve cells, and muscle cells in the stem lineage of eumetazoans (bilaterians + ctenophores + cnidarians). In contrast, several other studies have recovered an alternative topology in which ctenophores are the sister group to all other animals (including sponges). The ``Ctenophora-sister'' hypothesis implies that eumetazoan-specific traits, such as neurons and muscle cells, either evolved once along the metazoan stem lineage and were then lost in sponges and placozoans or evolved at least twice independently in Ctenophora and in Cnidaria + Bilateria. Here, we report on our reconstruction of deep metazoan relationships using a 1,719-gene dataset with dense taxonomic sampling of non-bilaterian animals that was assembled using a semi-automated procedure, designed to reduce known error sources. Our dataset outperforms previous metazoan gene superalignments in terms of data quality and quantity. Analyses with a best-fitting site-heterogeneous evolutionary model provide strong statistical support for placing sponges as the sister-group to all other metazoans, with ctenophores emerging as the second-earliest branching animal lineage. Only those methodological settings that exacerbated long-branch attraction artifacts yielded Ctenophora-sister. These results show that methodological issues must be carefully addressed to tackle difficult phylogenetic questions and pave the road to a better understanding of how fundamental features of animal body plans have emerged.
ISSN: 0960-9822

hal-01681528
https://hal.archives-ouvertes.fr/hal-01681528
DOI : 10.1016/j.cub.2017.02.031

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 WILEY-BLACKWELL Wiley
Résumé : International audience
Connectivity among populations determines the dynamics and evolution of populations, and its assessment is essential in ecology in general and in conservation biology in particular. The robust basis of any ecological study is the accurate delimitation of evolutionary units, such as populations, metapopulations and species. Yet a disconnect still persists between the work of taxonomists describing species as working hypotheses and the use of species delimitation by molecular ecologists interested in describing patterns of gene flow. This problem is particularly acute in the marine environment where the inventory of biodiversity is relatively delayed, while for the past two decades, molecular studies have shown a high prevalence of cryptic species. In this study, we illustrate, based on marine case studies, how the failure to recognize boundaries of evolutionary-relevant unit leads to heavily biased estimates of connectivity. We review the conceptual framework within which species delimitation can be formalized as falsifiable hypotheses and show how connectivity studies can feed integrative taxonomic work and vice versa. Finally, we suggest strategies for spatial, temporal and phylogenetic sampling to reduce the probability of inadequately delimiting evolutionary units when engaging in connectivity studies.
ISSN: 0962-1083

hal-01218810
https://hal.archives-ouvertes.fr/hal-01218810
DOI : 10.1111/mec.13048

Éditeur(s) : HAL CCSD Le Cherche midi CNRS
Résumé : 192 pages
National audience
https://hal.archives-ouvertes.fr/hal-01118878

ISBN : 978-2-7491-4075-9
hal-01118878
https://hal.archives-ouvertes.fr/hal-01118878

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 Springer Verlag
Résumé : International audience
Ants figure prominently among the worst invasive species because of their enormous ecological and economic impacts. However, it remains to be investigated which species would be behaviourally dominant when confronted with another invasive ant species, should two species be introduced in the same area. In the future, many regions might have suitable environmental conditions for several invasive ant species, as predicted under climate change scenarios. Here, we explored interactions among several highly invasive ant species, which have been shown to have overlapping suitable areas. The aim of this study was to evaluate the performance in interference competition of seven of the world's worst invasive ant species (Anoplolepis gracilipes, Paratrechina longicornis, Myrmica rubra, Linepithema humile, Lasius neglectus, Wasmannia auropunctata and Pheidole megacephala). We conducted pairwise confrontations, testing the behaviour of each species against each of the six other species (in total 21 dyadic confrontations). We used single worker confrontations and group interactions of 10 versus 10 individuals to establish a dominance hierarchy among these invasive ant species. We discovered two different behavioural strategies among these invasive ants: three species displayed evasive or indifferent behaviour when individuals or groups were confronted (A. gracilipes, Pa. longicornis, M. rubra), while the four remaining species were highly aggressive during encounters and formed a linear dominance hierarchy. These findings contrast with the widespread view that invasive ants form a homogeneous group of species displaying the `invasive syndrome', which includes generally aggressive behaviour. The dominance hierarchy among the four aggressive species may be used to predict the outcome of future competitive interactions under some circumstances. Yet, the existence of several behavioural strategies renders such a prediction less straightforward.
ISSN: 1387-3547

hal-01444816
https://hal.archives-ouvertes.fr/hal-01444816
DOI : 10.1007/s10530-015-0892-5

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
An original karstic system in a coastal alluvial plain located in a carbonate environment (Cassis, Provence -- SE France) was studied using a multi-method approach (electrical resistivity tomography, gravimetric, passive seismic survey), combined with geomorphologic methods, surface observations and drilling. Limestone dissolution and/or cavity collapse led to the development of a polje, which was filled rapidly by erosion of Aptian marls. The combination of several dating and paleoenvironmental proxies indicates that the polje was filled during a glacial period (MIS 6, 8 or 10, i.e. in the 130-360 ka age range). This discovery has implications for the understanding of karst processes. The connection between the polje and the three km-long Bestouan underwater karstic conduit with submarine outlet is strongly suggested by sedimentological studies and geophysical prospections.
ISSN: 0169-555X

hal-01054334
https://hal.archives-ouvertes.fr/hal-01054334
DOI : 10.1016/j.geomorph.2014.02.021

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

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

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
o abstract
ISSN: 0944-1344

hal-01444054
https://hal.archives-ouvertes.fr/hal-01444054
DOI : 10.1007/s11356-015-5714-x

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 0944-1344

Droits : info:eu-repo/semantics/OpenAccess
hal-01681607
https://hal.archives-ouvertes.fr/hal-01681607
https://hal.archives-ouvertes.fr/hal-01681607/document
https://hal.archives-ouvertes.fr/hal-01681607/file/2017%20Poggi-Varaldo%20et%20al%20%28Editorial%20ESPR%20SI%204ISEBE%29.pdf
DOI : 10.1007/s11356-017-0621-y

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Chlordecone (CLD) was an organochlorine insecticide whose previous use resulted in an extensive pollution of the environment with severe health effects and social consequences. A closely related compound, 5b-hydrochlordecone (5b-hydroCLD), has been searched for and often detected in environmental matrices from the geographical area where CLD was applied. The current consensus considered that its presence was not the result of a biotic or abiotic dechlorination of CLD in these matrices but rather the consequence of its presence as impurity (synthesis by-product) in the CLD released into the environment. The aim of the present study was to determine if and to what extent degradation of CLD into 5b-hydroCLD occurred in the field. To test this hypothesis, the ratios of 5b-hydroCLD and CLD concentrations in a dataset of 810 soils collected between 2006 and 2012 in Martinique were compared to the ratios measured in 3 samples of the CLD dust commercial formulations applied in the banana fields of French West Indies (FWI) and 1 sample of the technical-grade CLD corresponding to the active ingredient used in such formulations. Soil data were processed with a hierarchical Bayesian model to account for random measurement errors and data censoring. Any pathway of CLD transformation into 5b-hydroCLD occurring over the long term in FWI soils would indeed change the ratio of 5b-hydroCLD/CLD compared to what it was in the initially applied formulations. Results showed a significant increase of the 5b-hydroCLD/CLD ratio in the soils-25 times greater in soil than in commercial formulations-which suggested that natural CLD transformation into 5b-hydroCLD over the long term occurred in these soils. Results from this study may impact future decisions for the remediation of the polluted areas.
ISSN: 0944-1344

hal-01347150
https://hal.archives-ouvertes.fr/hal-01347150
https://hal.archives-ouvertes.fr/hal-01347150/document
https://hal.archives-ouvertes.fr/hal-01347150/file/Devault_15973.pdf
DOI : 10.1007/s11356-015-4865-0

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
The distribution of the lagoon cockle Cerastoderma glaucum is strongly fragmented and usually restricted to isolated, shallow and nontidal lagoons. A high level of genetic structuring was found among the European populations of this species based on mtDNA (COI) sequences, as well as allozymic and microsatellite markers. However, the strengths and geographic locations of the major divisions differed among markers. In the present study we characterized the diversity of a new, potentially universal exon-primed intron-crossing marker, i34, for 17 C. glaucum populations. Allele frequency data at the i34 locus were informative and relevant with respect to geography. Multivariate analyses of new data together with previously published microsatellites confirmed the divergent character of the Ionian Sea and the Aegean-Ponto-Caspian populations, but also revealed the existence of a genetic cline from the Bay of Biscay to the Baltic Sea. Some noncongruent patterns among loci were detected, which may reflect either differential introgression along the genome at the hypothetical contact zone, or selective sweeps. This strong genetic differentiation, and the occurrence of private alleles, may hint at the presence of cryptic species within C. glaucum.
ISSN: 0260-1230

hal-01444646
https://hal.archives-ouvertes.fr/hal-01444646
DOI : 10.1093/mollus/eyw019

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