References of "Sturaro, Nicolas"
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See detailTrophic specializations of damselfishes are tightly associated with reef habitats and social behaviours
Gajdzik, Laura ULg; Parmentier, Eric ULg; Sturaro, Nicolas ULg et al

in Marine Biology (2016), 163

Despite the increasing need to understand factors shaping community assembly, few studies have simultaneously explored the influence of niche-based and phylogenetic processes. Here, we investigate the ... [more ▼]

Despite the increasing need to understand factors shaping community assembly, few studies have simultaneously explored the influence of niche-based and phylogenetic processes. Here, we investigate the relationships between diet, habitat and social behaviour in damselfishes (Pomacentridae) collected in 2014 at Moorea Island (17°30′S, 149°50′W), French Polynesia. Isotope ratios of carbon and nitrogen, in association with stomach contents, delineate three trophic groups: pelagic feeders consuming zooplankton, benthic feeders mainly grazing on algae and an intermediate group feeding on prey from the whole bentho-pelagic compartment. Sulphur isotope ratios indicate segregation between species of the outer reef mostly depending on oceanic input of zooplankton and the lagoonal species relying on locally produced resources or even on terrestrial supply. We demonstrate a tight association between dietary specializations, habitat characteristics and social behaviours, and these correlations are further confirmed by integrating the phylogeny of Pomacentridae. We also provide evidence of phylogenetic conservatism for the stomach content and the habitat–behaviour characters. However, the isotopic trait is evolutionarily more labile probably because it thoroughly depicts the ecological niche of species. To summarize, pelagic feeders (mainly from the Chrominae) usually form shoals in areas close to the open ocean at a maximum depth of 20 m. Benthic feeders (well represented in the Stegastinae) are ubiquitous, solitary and mostly territorial species found at various depths. The intermediate group includes gregarious species from three subfamilies that forage in the lagoon usually above 12 m depth. Overall, we give insight into processes that have structured the damselfish community in Moorea. [less ▲]

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See detailDiversity, dynamics and trophic ecology of animal communities associated to Posidonia oceanica (L.) Delile macrophytodetrital accumulation: synthesis of a ten year study
Lepoint, Gilles ULg; Borges, Alberto ULg; Champenois, Willy ULg et al

Poster (2016, October 17)

In the Mediterranean, Neptune grass Posidonia oceanica, produces a huge quantity of detrital biomass. These macrophytodetritus may accumulate in shallow waters, forming litter accumulations colonised by ... [more ▼]

In the Mediterranean, Neptune grass Posidonia oceanica, produces a huge quantity of detrital biomass. These macrophytodetritus may accumulate in shallow waters, forming litter accumulations colonised by abundant, yet understudied, animal communities. These accumulations are especially foraged by juvenile and adult fishes. Here, we aim to synthesize results obtained over the last ten years regarding diversity, dynamics and trophic ecology of associated meio- and macrofauna. Accumulations are found throughout the year but important seasonal and short-term variability in composition, quantity and physico-chemical parameters inside the accumulation is observed. Accumulations are dominated by respiration (litter degradation), however, primary production occurs at exposed surfaces (epiphytic production). Meio- and macrofauna have distinct traits in comparison to adjacent habitats (seagrass meadows or epilithic algae communities). A physico-chemical gradient occurs inside accumulations which partially defines assemblage composition and distribution. Meiofauna, in particular harpacticoid copepods, is diverse, abundant and composed of species from seagrass meadows, water column and sediment. In contrast, macrofaunal assemblages are simplified compared to the ones occurring in the seagrass meadows and are dominated by amphipods. Litter accumulations display a lower macrofaunal diversity than do seagrass meadows, but a higher abundance and animal biomass. Meio- and macrofauna show a high trophic diversity, dominated by ingestion and assimilation of epiphytes (macroalgae and, probably, detrivorous microbiota). Moreover, direct or indirect assimilation of carbon originating from seagrass detritus is demonstrated for many species. Although diverse trophic niches were observed, the assemblage showed a simplified trophic web structure compared to the seagrass meadows. Detritivorous organisms dominate this assemblage and are more abundant in the litter than in the living meadows. Consequently, according to its abundance and the fact it consumes directly and indirectly seagrass material, fauna associated to litter accumulation may play a significant role in the degradation and transfer to higher trophic level of detrital seagrass carbon. [less ▲]

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See detailAxIOM: Amphipod crustaceans from insular Posidonia oceanica seagrass meadows
Michel, Loïc ULg; Sturaro, Nicolas ULg; Heughebaert, André et al

in Biodiversity Data Journal (2016), 4

Background The Neptune grass, Posidonia oceanica (L.) Delile, 1813, is the most widespread seagrass of the Mediterranean Sea. This foundation species forms large meadows that, through habitat and trophic ... [more ▼]

Background The Neptune grass, Posidonia oceanica (L.) Delile, 1813, is the most widespread seagrass of the Mediterranean Sea. This foundation species forms large meadows that, through habitat and trophic services, act as biodiversity hotspots. In Neptune grass meadows, amphipod crustaceans are one of the dominant groups of vagile invertebrates, forming an abundant and diverse taxocenosis. They are key ecological components of the complex, pivotal, yet critically endangered Neptune grass ecosystems. Nevertheless, comprehensive qualitative and quantitative data about amphipod fauna found in Mediterranean Neptune grass meadows remain scarce, especially in insular locations. New information Here, we provide in-depth metadata about AxIOM, a sample-based dataset published on the GBIF portal. AxIOM is based on an extensive and spatially hierarchized sampling design with multiple years, seasons, day periods, and methods. Samples were taken along the coasts of Calvi Bay (Corsica, France) and of the Tavolara-Punta Coda Cavallo Marine Protected Area (Sardinia, Italy). In total, AxIOM contains 187 samples documenting occurrence (1775 records) and abundance (10720 specimens) of amphipod crustaceans belonging to 72 species spanning 29 families. The dataset is available at http://ipt.biodiversity.be/resource?r=axiom. [less ▲]

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See detailThe secret life of a Mediterranean seagrass litter macrofauna community : a history of oxygen
Remy, François ULg; Michel, Loïc ULg; Sturaro, Nicolas ULg et al

Conference (2016, February 12)

Most of the foliar primary production of Posidonia oceanica, a major Mediterranean seagrass, sheds in autumn and is exported from the meadow to adjacent areas to form "Exported Macrophytodetritus ... [more ▼]

Most of the foliar primary production of Posidonia oceanica, a major Mediterranean seagrass, sheds in autumn and is exported from the meadow to adjacent areas to form "Exported Macrophytodetritus Accumulations", EMAs. These EMAs are a habitat, shelter and feeding place for an abundant and diverse community of macrofauna. Being very dynamic places and potentially playing a role of transition compartment between water column and sediment, EMAs present high variability in term of physicochemical conditions and more specifically in term of oxygen concentration. Mild to severe hypoxic periods (2 - 0.01 mL O2.L-1) can be observed in situ at different moments of the year, and this variability thus potentially play a structuring role on the macrofauna community. During this study, our main specific questions were (1) Does oxygen stratification occur inside EMAs? (2) If present, how long does it take to observe this stratification? (3) Is the macrofauna impacted and do the dominant species occupy defined positions inside the different micro-habitats? To assess the importance of this impact, an experimental study was conducted in October 2014 near the STARESO oceanographic station (Calvi, Corsica) using an original "layer-sampling" design. The experimental construction was put underwater inside an EMA for 48 hours at a depth of 8m. Samples were collected (N=8) in a 20cm thick EMA using "sealed" boxes to sample every 5cm, from the sediment, to the water column. Oxygen, nutrients and of course the litter itself (containing the macrofauna) were sampled carefully to make sure no exchange occurred between the 4 different layers. After data analysis, the assessment was clear: oxygen stratification occurred in less than 48h and oxygen level inside the layer close to the sediment experienced a fast decrease below the hypoxia threshold (2 mL O2.L-1). Diversity was highly impacted, showing a clear positive link with oxygen concentration. Macrofauna also appeared to follow this oxygen stratification but this response was very species specific. Some species didn't follow oxygen and are present in every layer and most of them were strongly positively linked to oxygen concentration. But a few (Nebalia strausi and Athanas nitescens) were strongly negatively linked to oxygen concentration and were present only in the more hypoxic layers. This experimentation thus confirmed our in situ observations. Oxygen stratification occurred quickly (< 48h) when EMAs were experiencing calm weather. This stratification observed from the water column to the sediment was very marked. Diversity and abundance of most abundant macrofauna species were drastically influenced by this stratification, showing the importance of these micro-habitats in structuring of this macrofauna community. [less ▲]

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See detailIs individual consistency in body mass and reproductive decisions linked to individual specialization in foraging behavior in a long-lived seabird?
Dehnhard, Nina; Eens, Marcel; Sturaro, Nicolas ULg et al

in Ecology and Evolution (2016)

Individual specialization in diet or foraging behavior within apparently generalist populations has been described for many species, especially in polar and temperate marine environments, where resource ... [more ▼]

Individual specialization in diet or foraging behavior within apparently generalist populations has been described for many species, especially in polar and temperate marine environments, where resource distribution is relatively predictable. It is unclear, however, whether and how increased environmental variability – and thus reduced predictability of resources – due to global climate change will affect individual specialization. We determined the within- and among-individual components of the trophic niche and the within-individual repeatability of d13C and d15N in feathers and red blood cells of individual female southern rockhopper penguins (Eudyptes chrysocome) across 7 years. We also investigated the effect of environmental variables (Southern Annular Mode, Southern Oscillation Index, and local sea surface temperature anomaly) on the isotopic values, as well as the link between stable isotopes and female body mass, clutch initiation dates, and total clutch mass. We observed consistent red blood cell d13C and d15N values within individuals among years, suggesting a moderate degree of within-individual specialization in C and N during the prebreeding period. However, the total niche width was reduced and individual specialization not present during the premolt period. Despite significant interannual differences in isotope values of C and N and environmental conditions, none of the environmental variables were linked to stable isotope values and thus able to explain phenotypic plasticity. Furthermore, neither the within-individual nor among-individual effects of stable isotopes were found to be related to female body mass, clutch initiation date, or total clutch mass. In conclusion, our results emphasize that the degree of specialization within generalist populations can vary over the course of 1 year, even when being consistent within the same season across years. We were unable to confirm that environmental variability counteracts individual specialization in foraging behavior, as phenotypic plasticity in d13C and d15N was not linked to any of the environmental variables studied. [less ▲]

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See detailEffects of fish predation on Posidonia oceanica amphipod assemblages
Sturaro, Nicolas ULg; Gobert, Sylvie ULg; Pérez-Perera, Amanda et al

in Marine Biology (2016), 163

Amphipod assemblages that inhabit Posidonia oceanica seagrass meadows are potentially relevant trophic resources for ichthyofauna. However, the effects of fish predation on amphipod assemblages in this ... [more ▼]

Amphipod assemblages that inhabit Posidonia oceanica seagrass meadows are potentially relevant trophic resources for ichthyofauna. However, the effects of fish predation on amphipod assemblages in this system have received little attention. To address this gap in knowledge, experimental manipulations of predation intensity (exclusion and inclusion cages) were conducted at two sites in a Mediterranean marine protected area, where different levels of fish predation were expected to occur. We found that in the absence of predatory fishes (exclusion cages), total amphipod density and biomass were higher than in uncaged areas and partially controlled cages. At the species level, Caprella acanthifera and Iphimedia minuta responded to caging with increased abundance, while in most cases different species did not exhibit differences in density or biomass between treatments. The presence of one enclosed labrid fish predator (inclusion cages) resulted in a lower density and biomass of Aora spinicornis and a lower biomass of Phtisica marina, although total amphipod density and biomass were unchanged. In the inclusion cages, a size-frequency analysis revealed that predators mainly targeted large A. spinicornis and Apherusa chiereghinii individuals. Our results suggest that predation by fish may be an important factor in controlling amphipod abundances and biomasses in P. oceanica meadows. Overall, amphipod community composition was not affected by exclusion or inclusion of fish predators. However, some significant effects at the species level point to more complex interactions between some amphipods and fish. [less ▲]

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See detailLandings profile of small-scale fisheries in Senegal: The case of the Kayar Marine Protected Area
Gueye, Ndiapaly; Diop, Mamadou; Denis, Antoine ULg et al

Poster (2015, October 08)

As marine fisheries in Senegal are in serious decline due to overexploitation, the management of sustainable fisheries requires effective tactics based on scientific data. In order to characterize the ... [more ▼]

As marine fisheries in Senegal are in serious decline due to overexploitation, the management of sustainable fisheries requires effective tactics based on scientific data. In order to characterize the current state of the artisanal fishery of the Kayar Marine Protected Area (MPA), a daily survey of fish landings was carried out between October 2013 and May 2015, and a database was created. Results showed that the landings are largely dominated by pelagic species in terms of weight. In total, 84 taxa were registered, including the species Sardinella aurita, which has been the most landed (30.5%), followed by Trichiurus lepturus (18.9%). These species are mainly captured by means of purse seine. The other types of fishing gear used in the area are the long line and the single line, which target particular species (e.g., Epinephelus aeneus). The temporal evolution of landings shows a period of abundance between May and June, while fishing effort is generally increasing. Regarding the spatial distribution, landings originate primarily from the MPA, where the landing per unit of effort was higher in the Angleterre area compared to other studied areas. These temporal and spatial variations seem to be related to the upwelling intensity which is highly seasonal, habitat features (i.e., presence of an underwater canyon in the MPA), the ecological behaviour of fish species and overexploitation. Our results confirm the need for detailed and extensive population monitoring across fish species. As a result of this study, we hope to provide the first essential information for the integrated management of fisheries in the Kayar MPA and its surrounding area. [less ▲]

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See detailApplications of stable isotopes in environmental studies at the University of Liege
Sturaro, Nicolas ULg; Borges, Alberto ULg; Das, Krishna ULg et al

Poster (2015, March 26)

Measurement and use of stable isotope ratios have a long history at the University of Liege (Belgium). Since at least 30 years, applications of stable isotopes in marine ecosystems have been developed ... [more ▼]

Measurement and use of stable isotope ratios have a long history at the University of Liege (Belgium). Since at least 30 years, applications of stable isotopes in marine ecosystems have been developed within the Laboratory of Oceanology and, more recently, within the Chemical Oceanography Unit. In the Laboratory of Oceanology, one research axis is the measurement of stable isotope composition (C, N, S) in organic matter to delineate trophic web structure and to study animal diet, their trophic niches and their alteration by human activities. This methodology has been successively applied worldwide in different habitats and ecosystems (marine, freshwater, terrestrial) in temperate and tropical areas. Mediterranean food web and fish trophic ecology have received a particular attention. Coupling between trophic ecology and ecotoxicology is another area of investigation. This has been applied mainly to marine vertebrates and freshwater ecosystems. Stable isotope labelling is also used in our laboratory to study and quantify various ecological processes such as inorganic nitrogen incorporation and trophic transfers. The laboratory facilities, renewed in 2012 and managed by Dr. Gilles Lepoint, are composed of an elemental analyser (EA, vario MICRO cube, Elementar) and a gas chromatography (GC, Agilent) coupled to an isotope ratio mass spectrometer (IRMS, Isoprime 100). The GC is also equipped with a quadrupole mass spectrometer. In 2014, the Chemical Oceanography Unit, headed by Dr. Alberto Borges, has acquired and implemented an off-axis cavity ring-down spectroscopy (CRDS) for the measurements of δ15Nα, δ15Nβ, δ18O of N2O. This enables characterization of the N2O origin in a variety of aquatic environments including groundwater in Wallonia, rivers and lakes in Wallonia and Africa, coastal environments (Scheldt estuary, Lake Grevelingen, North Sea), Mediterranean seagrass beds, and Antarctic and Arctic sea-ice. [less ▲]

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See detailMultiscale variability of amphipod assemblages in Posidonia oceanica meadows
Sturaro, Nicolas ULg; Lepoint, Gilles ULg; Vermeulen, Simon et al

in Journal of Sea Research (2015), 95

The study of spatial patterns is of ecological importance in order to understand the causes of the distribution and abundance of organisms, and it also provides valuable basis for management and ... [more ▼]

The study of spatial patterns is of ecological importance in order to understand the causes of the distribution and abundance of organisms, and it also provides valuable basis for management and conservation. Amphipod crustaceans are key organisms in seagrass ecosystems. However, little attention has been paid to the spatial scales at which amphipod assemblages may vary. We examined variability patterns of amphipod populations inhabiting Posidonia oceanica meadows, over spatial scales spanning four orders of magnitude (1 to 1000 metres) and for two consecutive years. This study reports the scales that contributed most to spatial variation of amphipod assemblages and explores the potential processes of the observed patterns, with particular emphasis on habitat features. The number of species, the diversity and the density of some species, exhibited high variation across years. Most species showed the highest spatial variation in density and biomass at small scales (~1 and 10 m). Based on density data, the structure of amphipod assemblages did not differ at any scales investigated. The patchiness that occurred at small scales may have been only weakly related to habitat features. Instead, we postulated that behavioural processes of amphipods were likely good explanatory factors. Although, the small scale spatial variability can be an important feature of amphipod assemblages in P. oceanica meadows, many patterns probably remained undetected as they may occur at scales smaller than those investigated. [less ▲]

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See detailAre amphipods influenced by Posidonia oceanica seagrass features?
Sturaro, Nicolas ULg; Lepoint, Gilles ULg; Michel, Loïc ULg et al

Poster (2014, December 12)

In the Mediterranean Sea, the seagrass Posidonia oceanica plays an important role as habitat for invertebrates, among which amphipod crustaceans represent a dense and diverse assemblage. Recent studies ... [more ▼]

In the Mediterranean Sea, the seagrass Posidonia oceanica plays an important role as habitat for invertebrates, among which amphipod crustaceans represent a dense and diverse assemblage. Recent studies have observed that amphipod density and biomass vary significantly on small spatial scales. This patchiness may be caused by different factors, such as recruitment, competition, and predation; however, habitat features, resulting in availability of resources such as food or shelter, may also be important in structuring these assemblages. This study examined the relationships between amphipod and habitat features in a P. oceanica meadow of the Revellata Bay (Corsica). The sampling was carried out in a continuous meadow colonizing soft substrates at constant depth in August 2008. We quantified the density and biomass of each amphipod species, as well as habitat features, namely shoot density, leaf and epiphyte biomasses, percentage of leaves per shoot having alteration marks and litter biomass. Using multiple regression analyses, few weak significant relationships were identified between amphipod and habitat features. The number of species and the diversity appeared unaffected by the measured habitat features. In contrast, total amphipod density and biomass were generally positively related to the shoot density and epiphyte biomass of P. oceanica, respectively. Overall, habitat features accounted for 0-30% of the variation in the densities of the amphipod species. A distance-based linear model explained a total of 25.8% of the variation of the amphipod assemblages (of which 18.6% was explained by litter biomass). Amphipods are therefore influenced by some P. oceanica features, but only weakly. Furthermore, some features appeared to influence individual species whereas others functioned at the assemblage level. The main challenge remains in evaluating the scale at which these features act and the way in which they influence the structure of assemblages. [less ▲]

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See detailAbstract Book of ZOOLOGY 2014, 21st Benelux Congress of Zoology
Lepoint, Gilles ULg; Michel, Loïc ULg; Schnitzler, Joseph ULg et al

Book published by Royal Belgian Zoological Society (2014)

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See detailSeagrass amphipod assemblages in a Mediterranean marine protected area: a multiscale approach
Sturaro, Nicolas ULg; Lepoint, Gilles ULg; Pérez-Perera, Amanda et al

in Marine Ecology. Progress Series (2014), 506

Marine protected areas (MPAs) are a key tool for conservation purposes, but few studies have assessed the responses of small macrozoobenthic assemblages to different protection levels in the Mediterranean ... [more ▼]

Marine protected areas (MPAs) are a key tool for conservation purposes, but few studies have assessed the responses of small macrozoobenthic assemblages to different protection levels in the Mediterranean Sea. In this study, we used a hierarchical sampling design spanning three orders of magnitude (1-10-100 metres) to investigate whether a marine protected area exerts an effect on amphipod assemblages associated with Posidonia oceanica meadows. This study reports spatial and temporal variability patterns of amphipod assemblages in four different protection levels and discusses potential confounding effects, such as habitat features. The structure of amphipod assemblages based on density data was patchy at all spatial scales investigated, but differed markedly among protection levels. Among outstanding points, multiscale analyses showed that lower densities and/or biomasses of several taxa occurred within fully protected and external areas in comparison with partially protected areas (PPAs). Furthermore, Posidonia oceanica meadow features (shoot density, leaf and epiphyte biomasses, coefficient A and litter biomass) accounted for only a low proportion of the total variability. We can consequently infer that the observed patchiness is likely to occur for multiple and interconnected reasons, ranging from the ecological and behavioural traits of amphipod species to protection-dependent processes (e.g. fish predation). Long term multiscale spatial and temporal monitoring, as well as experimental manipulations, are clearly needed to fully understand the effects of protection on macrozoobenthic assemblages. [less ▲]

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See detailProtection effects or natural variability? The case of seagrass amphipods
Sturaro, Nicolas ULg; Lepoint, Gilles ULg; Pérez-Perera, Amanda et al

Conference (2013, October)

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