References of "Sturaro, Nicolas"
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See detailFacultative paedomorphosis as a mechanism promoting intraspecific niche differentiation
Lejeune, Benjamin ULiege; Sturaro, Nicolas ULiege; Lepoint, Gilles ULiege et al

in Oikos (in press)

Organisms with complex life cycles are characterized by a metamorphosis that allows for a major habitat shift and the exploitation of alternative resources. However, metamorphosis can be bypassed in some ... [more ▼]

Organisms with complex life cycles are characterized by a metamorphosis that allows for a major habitat shift and the exploitation of alternative resources. However, metamorphosis can be bypassed in some species through a process called paedomorphosis, resulting in the retention of larval traits at the adult stage and is considered important at both micro- and macroevolutionary scales. In facultatively paedomorphic populations of newts, some individuals retain gills and a fully aquatic life at the adult stage (paedomorphs), while others undergo complete metamorphosis (metamorphs), allowing for a terrestrial life-stage. Because facultative paedomorphosis affects trophic structures and feeding mechanism of newts, one hypothesis is that it may be maintained as a trophic polymorphism, with the advantage to lessen intraspecific competition during the shared aquatic life-stage. Here, we tested this hypothesis combining stomach content data with stable isotope techniques, using carbon and nitrogen stable isotopes, in facultatively paedomorphic alpine newts Ichthyosaura alpestris. Both stomach content and stable isotope analyses showed that paedomorphs had smaller trophic niches and were more reliant on pelagic resources, while metamorphs relied more on littoral resources, corresponding to a polyphenism along the littoral-pelagic axis and the extension of the population's trophic niche to otherwise ‘underused’ pelagic resources by paedomorphs. Interestingly, stable isotopes revealed that the trophic polyphenism was less marked in males than in females and potentially linked to sexual activity. Although paedomorphosis and metamorphosis are primarily seen as results of tradeoffs between the advantages of using aquatic versus terrestrial habitats, this study provides evidence that additional forces, such as intraspecific trophic niche differences between morphs and trophic niche expansion, may play an important role in the persistence of this dimorphism in heterogeneous environments. Moreover, the different patterns found in males and females show the importance of considering sex to understand the evolutionary ecology of trophic polymorphisms. [less ▲]

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See detailMercury stable isotopes discriminate different populations of European seabass and trace potential Hg sources around Europe
Cransveld, Alice; Amouroux, David; Tessier, Emmanuel et al

in Environmental Science & Technology (in press)

Our study reports the first data on mercury (Hg) isotope composition in marine European fish, for seven distinct populations of the European seabass, Dicentrarchus labrax. The use of δ20230 Hg and Δ19931 ... [more ▼]

Our study reports the first data on mercury (Hg) isotope composition in marine European fish, for seven distinct populations of the European seabass, Dicentrarchus labrax. The use of δ20230 Hg and Δ19931 Hg values in SIBER enabled us to estimate Hg isotopic niches, successfully discriminating several populations. Recursive-partitioning analyses demonstrated the relevance of Hg stable isotopes as discriminating tools. Hg isotopic values also provided insight on Hg contamination sources for biota in coastal environment. The overall narrow range of δ202 Hg around Europe was suggested to be related to a global atmospheric contamination while δ202 Hg at some sites was linked either to background ontamination, or with local contamination sources. Δ199 Hg was related to Hg levels of fish but we also suggest a relation with ecological conditions. Throughout this study, results from the Black Sea population stood out, displaying a Hg cycling similar to fresh water lakes. Our findings bring out the possibility to use Hg isotopes in order to discriminate distinct populations, to explore the Hg cycle on a large scale (Europe) and to distinguish sites contaminated by global versus local Hg source. The interest of using Hg sable isotopes to investigate the whole European Hg cycle is clearly highlighted. [less ▲]

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See detailFrom seascape level to functional ecology: A case study over P. oceanica seagrass meadows in Calvi, Corsica
Lapeyra Martin, Jon ULiege; Abadie, Arnaud; Richir, Jonathan ULiege et al

in Actes du colloque Carhamb'ar 2017 (in press)

see long abstract

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See detailFurther insight into the iterative ecological radiation of damselfishes (Pomacentridae)
Gajdzik, Laura ULiege; Lepoint, Gilles ULiege; Michel, Loic et al

Conference (2017, October 05)

The evolutionary history of Pomacentridae (damselfishes) is a rare example of the occurrence of an iterative ecological radiation in the ocean. Damselfishes have experienced many repeated convergences ... [more ▼]

The evolutionary history of Pomacentridae (damselfishes) is a rare example of the occurrence of an iterative ecological radiation in the ocean. Damselfishes have experienced many repeated convergences wherein subclades radiated across similar trophic strategies (i.e. pelagic foragers, benthic feeders, and an intermediate group) and similar morphologies. The presence of evolutionary convergences in damselfishes was recently highlighted by the combination of ecological and morphological data, and the use of phylogenetic comparative methods. Nevertheless, many other aspects of these replicated sets of lineages remain unexplored. For example, little is known about the functional diversity of assemblages including convergent lineages that emerged from iterative processes of ecological radiation, or which of the niche-related processes and phylogenetic conservatism are the major factors shaping these assemblages. Here, we conducted a quantitative comparison of these processes in damselfish assemblages that belong to three distinct Indo-Pacific coral reefs differing in taxonomic composition, morphology and degree of human disturbance. Using various metrics, we compared the functional diversity (based on a dataset of eight functional traits) and the isotopic diversity (a proxy of trophic diversity) among assemblages, grasping many aspects of the eco-functional diversity of Pomacentridae. We also tested whether these eco-functional traits displayed some evolutionary conservatism. Our results demonstrate that the eco-functional diversity of damselfishes follows similar patterns among Indo-Pacific coral reefs. The trophic space remains equivalent despite gradient in species richness, whereas the number of functional entities occupied by taxa dictates the size of the functional space. In each assemblage, eco-functional niches are highly differentiated and evenly distributed in spaces of similar size. The inconsistent phylogenetic structure of eco-functional traits suggests that the similarity in the diversity of damselfish assemblages is mainly driven by niche-based processes and not by phylogenetic relatedness. We suggest that a broader application of our approach will help to uncover the mechanisms of reef fish community assembly over space and time. [less ▲]

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See detailUsing amino acid stable isotopes to estimate trophic position
Sturaro, Nicolas ULiege

Conference (2017, July 04)

Estimating the trophic positions of animals in food webs is useful in addressing many fundamental ecological and ecotoxicological questions. These estimates are generally based on gut content and stable ... [more ▼]

Estimating the trophic positions of animals in food webs is useful in addressing many fundamental ecological and ecotoxicological questions. These estimates are generally based on gut content and stable isotope analyses, which have become essential tools for ecotoxicologists. While these tools have proven their usefulness, they involve several pitfalls that can result in large errors in the estimation of animals’ trophic positions. Relatively recently, these tools were improved with the analysis of the compound-specific amino acid nitrogen stable isotopes. The approach is based on the fact that certain amino acids (e.g., glutamic acid) exhibit metabolic isotope fractionation and others (e.g., phenylalanine) are incorporated into the tissues of consumers in a conservative manner. Indeed, amino acids of the latter category exhibit only a small change in their nitrogen isotope composition, which is similar to that found in primary producers. Therefore, the trophic position of an animal species is estimated based on a comparison of the nitrogen isotope composition of these two groups of amino acids from a single organism. This lecture will try to show the potential of the compound-specific stable isotope analysis of amino acids to illustrate food-web structure and estimate trophic positions in wild animal populations. It will summarize recent advances from field and laboratory studies and present case studies taken from the aquatic environment. In addition, this lecture will discuss the benefits, current limitations and analytical challenges related to this approach, which continues to open new research routes in many fields of ecology, including ecotoxicology. [less ▲]

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See detailThe use of stable isotopes in marine animal trophic ecology
Sturaro, Nicolas ULiege; Lepoint, Gilles ULiege; Frederich, Bruno ULiege et al

Conference (2017, May 05)

Stable isotope analysis has been recognised as a useful tool for studying animal diet, identifying trophic relationships, and delineating food web structures as well as their alteration by human ... [more ▼]

Stable isotope analysis has been recognised as a useful tool for studying animal diet, identifying trophic relationships, and delineating food web structures as well as their alteration by human activities. Over the past decade, the number of studies using stable isotopes of carbon and nitrogen in marine trophic ecology has increased rapidly as technological advancements greatly facilitate their use. This tool is now among the most popular in ecology and several fields of investigations have developed, including the extension of analyses to more ‘difficult’ stable isotope ratio measurements such as sulfur, the use of isotope mixing models, and the creation of compound-specific stable isotope analysis. Here, we present three case studies taken from our own investigations and previously published literature. The first investigates seagrass detritus ecosystem in which the coexistence of a rich number of species of crustacean raises the question of whether trophic diversity exist among these species. The second examines the feeding habits of coral reef fish and explores whether habitat choice on the reef and their behaviour emerges as good predictors of diet. The third presents the potential use of stable isotope analysis in studying the nutrition of scleractinian corals, which are complex symbiotic organisms that usually present both autotrophic and heterotrophic pathways. This tool has enhanced our understanding of coral species biology, yet it remains underused. Overall, we aim to provide initial insights into stable isotope analysis for illustrating their utility and potential applications to better understand food web structures and species diet in the waters around Taiwan. [less ▲]

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See detailTo be plastic is fantastic: delineate coral species niches for assessing their tolerance to changes
Denis, Vianney; Sturaro, Nicolas ULiege; Yang, Shan-Hua et al

Conference (2017, May 05)

Climatic and anthropogenic disturbances alter coral reefs by reconfiguring existing coral assemblages. Surviving species are selected by the new environment based on particular traits that they may ... [more ▼]

Climatic and anthropogenic disturbances alter coral reefs by reconfiguring existing coral assemblages. Surviving species are selected by the new environment based on particular traits that they may exhibit, with the plasticity in traits defining ecological strategies associated with contrasting degrees of tolerance to changes. In this process, specialists are expected to tolerate few changes to the environmental conditions and are restricted to specific habitat, while generalists can cope with a wider range of environmental conditions by readjusting traits according to the habitat’s features. Ecological strategies in corals have been exclusively defined according to species’ trait averages, irrespective of individual variations. Challenges representing the acquisition and use of energy have also tended to be oversimplified, specifically by the choice of easy traits in the absence of strong scientific evidence. In this study, we propose a re-examination of strategies in scleractinian corals by focusing on the intraspecific variation of traits. We will investigate how the characteristics of a given species niche can help coral species to tolerate changes. Our multidisciplinary approach will focus on three major characteristics of the coral holobiont (its physiology, trophic ecology, and associated microbiome) which together can define the ecological plasticity of species. This work is of tremendous importance for enhancing the understanding of coral response to environmental changes and for ensuring functions as well as the services of this ecosystem to future generations. [less ▲]

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See detailQuantifying coral colony morphology to assess their roles in ecosystem processes
Chen, Qi; Yang, Emma; Sturaro, Nicolas ULiege et al

Poster (2017, May 04)

Colony morphology is among the best predictors of the scleractinian coral’s function in the reef ecosystem. However, morphological traits are categorical and to convert this information into a ... [more ▼]

Colony morphology is among the best predictors of the scleractinian coral’s function in the reef ecosystem. However, morphological traits are categorical and to convert this information into a quantitative value remains a real challenge to quantify the influence of this parameter on ecosystem processes. Recently, the ratio between colony mass and surface area (CMA) has been proposed to represent a suitable proxy of species morphologies and their growth. Hypothetically, CMA could be used to assess a broad range of biological, ecological, and evolutionary processes in coral reef ecosystem. Here, we propose to test CMA as a predictor of coral morphology and focus on the intraspecific variation of this parameter. We used historical coral collection from the Museum of Zoology (National Taiwan University) and our own specimens collected from contrasting environments to establish a database of coral models using a high-resolution David 3D scanner. From these models, we extracted surface area and volume of the coral colonies. Colony mass was measured on a Mark S Bel balance. CMA was compared for its power in predicting species morphology with other traits such as skeleton density. Eventually, we tested the use of CMA at an intraspecific level to detect plasticity in growth rate. Our 3D models are available online (http://www.dipintothereef.com/corals.html) and constitute a valuable resource for estimating the roles of corals in the ecosystem. [less ▲]

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See detailIsotopic half-life and enrichment factor in two species of European freshwater fish larvae: an experimental approach
Latli, Adrien; Sturaro, Nicolas ULiege; Dujardin, Nelson et al

in Rapid Communications in Mass Spectrometry (2017), 31(8), 685-692

RATIONALE: Stable isotope ratios of carbon and nitrogen are valuable tools for field ecologists to use to analyse animal diets. However, the application of these tools requires knowledge of the tissue ... [more ▼]

RATIONALE: Stable isotope ratios of carbon and nitrogen are valuable tools for field ecologists to use to analyse animal diets. However, the application of these tools requires knowledge of the tissue enrichment factor (TEF) and half-life (HL). We experimentally compared TEF and HL in two freshwater fish larvae. We hypothesised that chub had a better growth/tissue replacement ratio than roach, due to the use of a food closer to their natural diet. METHODS: We determined the isotopic HL, the TEF and the contribution of growth or metabolic tissue replacement to dynamic isotopic incorporation. After yolk sac resorption, larvae were fed for 5 weeks with prey similar to their natural diet (Artemia nauplii) up to the isotopic equilibrium followed by Chironomid larvae. Stable isotope measurements were carried out using a continuous flow isotope ratio mass spectrometer coupled to an elemental analyser. RESULTS: Changes in isotopic composition strongly followed the predictions of exponential growth and time-dependent models. The isotopic HL varied between 8.2 and 12.6 days and the TEF of nitrogen and carbon ranged from 1.7 to 2.1‰ and from –0.9 to 1.2 ‰, respectively. The incorporation of dietary 13C was due more to the production of new tissue (between 56 and 79%) than to the metabolic process. Chub allocated more energy to growth than roach and the Chironomidae diet contributed more to the consumers’ growth than the Artemia diet. CONCLUSIONS: Metabolic rates seemed lower for chub than for roach, especially when they were fed with Chironomidae. A Chironomidae-based diet would be more profitable to chub, and the high associated growth rate could increase the development of the fish larvae. The HL and TEF were in the range of those reported in the literature. These results will be helpful for field-based studies, because they can help to increase the accuracy of models. [less ▲]

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See detailTo be plastic is fantastic: delineate coral species niches for assessing their tolerance to changes
Denis, Vianney; Sturaro, Nicolas ULiege; Yang, Shan-Hua et al

Conference (2017, April 24)

Climatic and anthropogenic disturbances alter coral reefs by reconfiguring existing coral assemblages. Surviving species are selected by the new environment based on particular traits that they may ... [more ▼]

Climatic and anthropogenic disturbances alter coral reefs by reconfiguring existing coral assemblages. Surviving species are selected by the new environment based on particular traits that they may exhibit. The plasticity in traits will define ecological strategies associated with contrasted degrees of tolerance to changes. In this process, specialists are expected to tolerate few changes to the environmental conditions and are restricted to specific habitat. To contrast, generalists can cope with a wider range of environmental conditions by readjusting traits according to the habitat’s features. Ecological strategies in corals have been exclusively defined according to species’ trait averages, irrespective of individual variations. Challenges representing the acquisition and use of energy have also tended to be oversimplified, specifically by the choice of easy traits in the absence of strong scientific evidence. Here, we propose a framework to re-examine strategies in scleractinian corals by focusing on the intraspecific variation of traits. We will show how the characteristics of a given species niche can help coral species to tolerate changes, illustrating this approach with examples taken from high-latitude locations and mesophotic coral ecosystems. We will demonstrate that multidisciplinary approach focusing on three major characteristics of the coral holobiont (its physiology, trophic ecology, and associated micriobiome), we can enhance the comprehension of ecological plasticity of coral species and predict future ecosystem reconfiguration. [less ▲]

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See detailCarbon, Nitrogen and Sulphur isotopic fractionation in captive juvenile hooded seal (Cystophora cristata): application for diet analysis
Pinzone, Marianna ULiege; Acquarone, Mario; Huyghebaert, Loreen ULiege et al

in Rapid Communications in Mass Spectrometry (2017)

Rationale: Intrinsic biogeochemical markers, such as stable isotope ratios of carbon, nitrogen and sulphur are increasingly used to trace the trophic ecology of marine top predators. However, insufficient ... [more ▼]

Rationale: Intrinsic biogeochemical markers, such as stable isotope ratios of carbon, nitrogen and sulphur are increasingly used to trace the trophic ecology of marine top predators. However, insufficient knowledge of fractionation processes in tissues continues to hamper the use of these markers.Methods: We performed a controlled feeding experiment with eight juvenile hooded seals (Cystophora cristata) that were held on a herring-based diet (Clupea harengus) for two years. Stable isotope ratios were measured via isotope ratio mass spectrometry in three of their tissues and related to values of these markers in their diet. Results: Diet-tissue isotope enrichment (trophic enrichment factor, TEF) values between dietary herring and seal tissues for carbon (Δ13C) were + 0.7 ‰ for red blood cells, + 1.9 ‰ for hair and + 1.1 ‰ for muscle. The TEFs for nitrogen trophic (Δ15N) were + 3.3 ‰ for red blood cells, + 3.6 ‰ for hair and + 4.3 ‰ for muscle. For sulphur, the Δ34S values were +1.1 ‰ for red blood cells, + 1.0 ‰ for hair and + 0.9 ‰ for muscle.Conclusions: These enrichment values were greater than those previously measured in adult seals. This increase may be related to the higher rate of protein synthesis and catabolism in growing animals. This study is the first report on sulphur isotope enrichment values for a marine mammal species. [less ▲]

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See detailExtreme intra-clutch egg size dimorphism is not coupled with corresponding differences in antioxidant capacity and stable isotopes between eggs
Poisbleau, Maud; Beaulieu, Michaël; Dehnhard, Nina et al

in Comparative Biochemistry and Physiology Part A : Molecular & Integrative Physiology (2017), 205

Oviparous females need to allocate resources optimally to their eggs in order to maximize their fitness. Among these resources, dietary antioxidants, acquired by females and transferred to the eggs during ... [more ▼]

Oviparous females need to allocate resources optimally to their eggs in order to maximize their fitness. Among these resources, dietary antioxidants, acquired by females and transferred to the eggs during egg formation, can greatly affect the development and survival of the embryo and chick. In crested penguins, incubation starts after the second and last egg is laid and, as opposed to many other bird species, this egg hatches first, thereby enhancing the survival of the chick. Here, we assessed whether antioxidant and isotopic composition could underlie these differences between eggs within clutches of southern rockhopper penguins (Eudyptes chrysocome chrysocome). The second-laid egg had higher total antioxidant capacity than the first-laid egg, although this was not due to higher antioxidant concentration but to its higher mass. This suggests that resources are allocated by females at a constant rate in both eggs within clutches. Accordingly, we found a strong correlation for isotopic compositions between eggs suggesting that resources were allocated similarly to each egg within the clutch. Overall, we found little evidence for a significant role of antioxidant and isotopic compositions to explain differences in terms of embryo/chick development between eggs in crested penguins. However, since our results suggest a constant rate of antioxidant transfer from females to eggs, limiting the mass of the first-laid egg might represent a strategy for females to spare antioxidant defences and preserve self-maintenance. [less ▲]

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See detailWho would want to live in there? A history of Posidonia oceanica detritus accumulations, the associated invertebrate community, and its food web…
Remy, François ULiege; Michel, Loïc ULiege; Darchambeau, François ULiege et al

Conference (2016, December 16)

Most seagrasses are rarely consumed directly by herbivore organisms. The "detrital pathway" thus represents a potentially important way of transfer of the seagrasses production to the coastal food webs ... [more ▼]

Most seagrasses are rarely consumed directly by herbivore organisms. The "detrital pathway" thus represents a potentially important way of transfer of the seagrasses production to the coastal food webs. The case of Posidonia oceanica is particularly interesting since up to 90% of its foliar primary production may constitute extensive and highly dynamic exported litter accumulations. Preliminary studies concerning these detritus accumulations suggest that an abundant community of vagile macro invertebrates (size > 500μm) lives inside them. We characterized for the first time this community in an exhaustive way (multi-site, seasonal and multi-year study), we linked the observed density and diversity variations to environmental parameters, but also described the trophic web these invertebrates compose. We sampled an abundant (up to 5000 organisms/m²) community composed of 115 species. We showed that crustaceans were massively dominant, followed by annelids and mollusks, and that one single amphipod species Gammarella fucicola represented from 20 to 85% of the whole sampled community. Observed variations appeared to be mostly linked to litter oxygen water concentration in a very species specific way. Most species were linked to no measured environmental parameter at all, but several dominant species were demonstrated (observation and in situ experimentation) to be linked positively or negatively to litter oxygen concentration. The described food web was composed of more than 3 trophic levels, indicating the presence of a trophic web composed of primary consumers/detritivore species, of omnivore species, but also of first and second order predators, each level occupying a distinct isotopic niche. From a specific point of view, we highlighted several different feeding preferences, with SIAR mixing model runs indicating that some species feed mostly on detrital material, other species feed on a mixture of detrital and algal material, other species feed on both animal and vegetal material and finally predator species feed exclusively on animal material. The fact that P. oceanica detritus constituted a non-negligible food source for some dominant species confirmed the importance of this macrofauna community as a key transfer link of seagrass organic matter from P. oceanica to the coastal food webs. [less ▲]

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See detailExploitation of coastal fish communities by harbour porpoises Phocoena phocoena during nursing periods in German Baltic waters.
Pinzone, Marianna ULiege; Michel, Loïc ULiege; Gallus, Anja et al

Conference (2016, December 11)

Baltic sub-populations of harbour porpoises Phocoena phocoena meet in in Southwestern waters in Spring when females reach the coastal areas for calving and nursing. In Autumn they separate again for ... [more ▼]

Baltic sub-populations of harbour porpoises Phocoena phocoena meet in in Southwestern waters in Spring when females reach the coastal areas for calving and nursing. In Autumn they separate again for reproduction : the Belt sea populations westwards in the Kattegat/Skarregat region, the Baltic proper population northwards in the central basin. The increased number of juvenile and newborn strandings along the German Baltic coasts give evidence for a possible existence of local calving grounds in this area. Calving and nursing habitats are the most important areas for management purposes. This project aimed to describe inhabitancy and diet of females and calves along the German Baltic coast, in order to achieve effective conservation measures. Nitrogen, carbon and, for the first time, sulphur stable isotopes (δ13C, δ15N and δ34S) were analysed in coastal species of fish and invertebrates in spring, autumn and winter 2015/2016 and in four different areas, to assess for seasonal and geographical variation of porpoises habitat use. The structure of ecological niches was inferred within and between communities using the SIBER model, and was compared to results from stomach content analysis. N, C and S values of fish and invertebrates strongly varied, seasonally and geographically, as a consequence of environmental factors characteristic of each sampling area. Additionally, each species presented large isotopic variability, suggesting possible intraspecific dietary specialisations. Females δ13C and δ34S signatures integrated both open-waters and coastal feeding, while juveniles presented a more coastal distribution. The absence of difference in δ15N values between age classes confirmed persistence of milk assimilation from the mothers. Niches structures and overlaps and stomach content analysis suggested gobies (Potamoschistus spp and Neogobius spp in particular), crabs and small coastal fish (ex. three-spined stickleback) as the main preys of juveniles. The integration of all three stable isotopes together permitted to well delineate even the highly dynamic food web of the Baltic German waters, confirming the use of sulphur isotopes in marine ecological studies. [less ▲]

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See detailAssessing edge-effects in Posidonia oceanica seagrass meadows: A multidisciplinary approach
Lapeyra, Jon; Abadie, Arnaud; Lejeune, Pierre et al

Conference (2016, December)

Structural boundaries in ecosystems play an important role both in the context of seascape architecture, ecological processes and biodiversity. The Mediterranean Seagrass Posidonia oceanica (L.) Delile is ... [more ▼]

Structural boundaries in ecosystems play an important role both in the context of seascape architecture, ecological processes and biodiversity. The Mediterranean Seagrass Posidonia oceanica (L.) Delile is considered an ecosystem engineer species, forming habitats of great ecological value and providing many ecosystem services. This study aims to (1) determine whether there are differences between seagrass-sand corridors edges and the adjacent continuous meadow, and (2) investigate whether anthropogenic pressures can cause disturbances in the measured parameters along the edges and the meadow. We have developed a multidisciplinary approach combining plant physiology, faunal canopy community studies and seagrass structural parameters characterization. We performed in situ chlorophyll fluorescence measurements using a Pulse Amplitude Modulated (Diving-PAM) fluorometry in order to assess the photosynthetic rate of the shoots. Vagile macrofauna of the leaf stratum was sampled by a hand-towed net, and the major taxonomic groups were sorted, counted, and identified. Meadow’s biometric measurements and the epiphytic biomass were also determined. Regarding edge-meadow matrix, results have shown highest differences on matrix structural parameters such as shoot density and shoot type proportions. Shoot density was found to decrease in edges considerably. We found c.a to 60 % plagiotropic shoots on edges while in continuous meadow orthotropics were predominant (up to 90 %). Howerver vagile-fauna population densities and diversity did not differ significantly among stations studied, neither by sites. Photosynthetic rate and leaf surface values also did not show changes between edges and continuous meadow. However, results did show that plagiotropic shoots had higher photosynthetic rate than orthotropics, and also that epiphyte abundance sorted out to be much higher (up to 54 %) on edges. [less ▲]

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See detailTrophic specializations of damselfishes are tightly associated with reef habitats and social behaviours
Gajdzik, Laura ULiege; Parmentier, Eric ULiege; Sturaro, Nicolas ULiege 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 ULiege; Borges, Alberto ULiege; Champenois, Willy ULiege 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 ULiege; Sturaro, Nicolas ULiege; 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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