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Auteur (up) Derolez, V.; Bec, B.; Munaron, D.; Fiandrino, A.; Pete, R.; Simier, M.; Souchu, P.; Laugier, T.; Aliaume, C.; Malet, N. url  doi
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  Titre Recovery trajectories following the reduction of urban nutrient inputs along the eutrophication gradient in French Mediterranean lagoons Type Article scientifique
  Année 2019 Publication Revue Abrégée Ocean & Coastal Management  
  Volume 171 Numéro Pages 1-10  
  Mots-Clés Coastal lagoons; Nutrients; Oligotrophication; Recovery; Urban inputs  
  Résumé French Mediterranean coastal lagoons have been subject to huge inputs of urban nutrients for decades leading to the eutrophication of these vulnerable ecosystems. In response to new environmental regulations, some of the lagoons have recently been the subject of large-scale management actions targeting the waste water treatment systems located on their watersheds. While the eutrophication of coastal ecosystems is well described, recovery trajectories have only recently been studied. To assess the rapidity and the extent of the effect of the remediation actions, we analysed data from a 14-year time series resulting from the monitoring of nutrients, biomass and the abundance of phytoplankton in the water column of French Mediterranean coastal lagoons covering the whole anthropogenic eutrophication gradient. Following a 50% to 80% reduction in total phosphorus (TP) and total nitrogen (TN) urban loadings from the watershed of hypertrophic and eutrophic ecosystems, the integrative parameters chlorophyll a, TN and TP, provide evidence for a rapid response (1 to 3 years) and for an almost complete recovery, suggesting no hysteresis for the eutrophic lagoon. However, our findings also show that recovery patterns depend on the eutrophication status before remediation and may include feedback responses. The different responses revealed by our results should help stakeholders prioritise remediation actions and identify appropriate restoration goals, especially in light of the targets of the Water Framework Directive (WFD).  
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  ISSN 0964-5691 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2493  
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Auteur (up) Diaz, F.; Bănaru, D.; Verley, P.; Shin, Y.-J. url  doi
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  Titre Implementation of an end-to-end model of the Gulf of Lions ecosystem (NW Mediterranean Sea). II. Investigating the effects of high trophic levels on nutrients and plankton dynamics and associated feedbacks Type Article scientifique
  Année 2019 Publication Revue Abrégée Ecological Modelling  
  Volume 405 Numéro Pages 51-68  
  Mots-Clés End-to-end model; Fisheries; Food web functioning; Plankton; Two-ways coupling  
  Résumé The end-to-end OSMOSE-GoL model parameterized, calibrated and evaluated for the Gulf of Lions ecosystem (Northwestern Mediterranean Sea) has been used to investigate the effects of introducing two-ways coupling between the dynamics of Low and High Trophic Level groups. The use of a fully dynamic two-ways coupling between the models of Low and High Trophic Levels organisms provided some insights in the functioning of the food web in the Gulf of Lions. On the whole microphytoplankton and mesozooplankton were found to be preyed upon by High Trophic Levels planktivorous groups at rates lower than 20% and 30% of their respective natural mortality rates, but these relatively low rates involved some important alterations in the infra-seasonal and annual cycles of both High and Low Trophic Levels groups. They induced significant changes in biomass, fisheries landings and food web interactions by cascading effects. Spatial differential impacts of High Trophic Levels predation on plankton are less clear except in areas in which primary productivity is high. Higher predation rates on plankton groups were encountered within the area of the Rhone river’s influence and in areas associated to the presence of mesoscale eddies in the Northwestern part of the Gulf of Lions, especially. Generally, the pressure of the High Trophic Levels predation was the highest in areas of highest biomass whatever the plankton group considered. The two-ways coupling between Low and High Trophic Levels models revealed both bottom-up and top-down controls in the ecosystem with effects on planktivorous species similar to those observed in the field. The use of the end-to-end model enabled to propose a set of potential mechanisms that may explain the observed decrease in small pelagic catches by the French Mediterranean artisanal fisheries over the last decade.  
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Auteur (up) Díaz, S.; Settele, J.; Brondízio, E.S.; Ngo, H.T.; Agard, J.; Arneth, A.; Balvanera, P.; Brauman, K.A.; Butchart, S.H.M.; Chan, K.M.A.; Garibaldi, L.A.; Ichii, K.; Liu, J.; Subramanian, S.M.; Midgley, G.F.; Miloslavich, P.; Molnár, Z.; Obura, D.; Pfaff, A.; Polasky, S.; Purvis, A.; Razzaque, J.; Reyers, B.; Chowdhury, R.R.; Shin, Y.-J.; Visseren-Hamakers, I.; Willis, K.J.; Zayas, C.N. url  doi
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  Titre Pervasive human-driven decline of life on Earth points to the need for transformative change Type Article scientifique
  Année 2019 Publication Revue Abrégée Science  
  Volume 366 Numéro 6471 Pages  
  Mots-Clés  
  Résumé The time is now

For decades, scientists have been raising calls for societal changes that will reduce our impacts on nature. Though much conservation has occurred, our natural environment continues to decline under the weight of our consumption. Humanity depends directly on the output of nature; thus, this decline will affect us, just as it does the other species with which we share this world. Díaz et al. review the findings of the largest assessment of the state of nature conducted as of yet. They report that the state of nature, and the state of the equitable distribution of nature's support, is in serious decline. Only immediate transformation of global business-as-usual economies and operations will sustain nature as we know it, and us, into the future.

Science, this issue p. eaax3100

Structured Abstract

BACKGROUNDHuman actions have long been known to drive declines in nature, and there is growing awareness of how globalization means that these drivers increasingly act at a distance (telecoupling). However, evidence from different disciplines has largely accumulated in parallel, and the global effects of telecouplings have never been addressed comprehensively. Now, the first integrated global-scale intergovernmental assessment of the status, trends, and future of the links between people and nature provides an unprecedented picture of the extent of our mutual dependence, the breadth and depth of the ongoing and impending crisis, and the interconnectedness among sectors and regions.

ADVANCESHuman impacts on life on Earth have increased sharply since the 1970s. The world is increasingly managed to maximize the flow of material contributions from nature to keep up with rising demands for food, energy, timber, and more, with global trade increasing the geographic separation between supply and demand. This unparalleled appropriation of nature is causing the fabric of life on which humanity depends to fray and unravel: Most indicators of the state of nature, whether monitored by natural and social scientists or by Indigenous Peoples and local communities, are declining. These include the number and population size of wild species, the number of local varieties of domesticated species, the distinctness of ecological communities, and the extent and integrity of many terrestrial and aquatic ecosystems. As a consequence, nature’s capacity to provide crucial benefits has also declined, including environmental processes underpinning human health and nonmaterial contributions to human quality of life. The costs are distributed unequally, as are the benefits of an expanding global economy.These trends in nature and its contributions to people are projected to worsen in the coming decades—unevenly so among different regions—unless rapid and integrated action is taken to reduce the direct drivers responsible for most change over the past 50 years: land and sea use change, direct harvesting of many plants and animals, climate change (whose impacts are set to accelerate), pollution, and the spread of invasive alien species. Exploratory scenarios suggest that a world with increased regional barriers—resonating with recent geopolitical trends—will yield more negative global trends in nature, as well as the greatest disparity in trends across regions, greater than a world with liberal financial markets, and much greater than one that prioritizes and integrates actions toward sustainable development. Evidence from target-seeking scenarios and pathways indicates that a world that achieves many of the global biodiversity targets and sustainability goals related to food, energy, climate, and water is not—yet—beyond reach, but that no single action can get us there.

OUTLOOKOur comprehensive assessment of status, trends, and possible futures for nature and people suggests that action at the level of direct drivers of nature decline, although necessary, is not sufficient to prevent further deterioration of the fabric of life on Earth. Reversal of recent declines—and a sustainable global future—are only possible with urgent transformative change that tackles the root causes: the interconnected economic, sociocultural, demographic, political, institutional, and technological indirect drivers behind the direct drivers. As well as a pan-sectoral approach to conserving and restoring the nature that underpins many goals, this transformation will need innovative governance approaches that are adaptive; inclusive; informed by existing and new evidence; and integrative across systems, jurisdictions, and tools. Although the challenge is formidable, every delay will make the task even harder. Crucially, our analysis pinpoints five priority interventions (“levers”) and eight leverage points for intervention in the indirect drivers of global social and economic systems where they can make the biggest difference. <img class=“fragment-image” aria-describedby=“F1-caption” src=“https://science.sciencemag.org/content/sci/366/6471/eaax3100/F1.medium.gif”/> Download high-res image Open in new tab Download Powerpoint Traditional diversity-rich human landscapes, and the livelihoods and identities that depend on them, face global threats.Mosaics of crops, forest, and pasture have been maintained for millennia around the world. Now, they are under increasing threat from climate change and large-scale land use change to accommodate global demands for commodities. So are the livelihoods and cultural identity of the peoples that live in them, such as this woman collecting fodder for her flock in the Checacupe district, Perú.Photo credit www.estebantapella.com

The human impact on life on Earth has increased sharply since the 1970s, driven by the demands of a growing population with rising average per capita income. Nature is currently supplying more materials than ever before, but this has come at the high cost of unprecedented global declines in the extent and integrity of ecosystems, distinctness of local ecological communities, abundance and number of wild species, and the number of local domesticated varieties. Such changes reduce vital benefits that people receive from nature and threaten the quality of life of future generations. Both the benefits of an expanding economy and the costs of reducing nature’s benefits are unequally distributed. The fabric of life on which we all depend—nature and its contributions to people—is unravelling rapidly. Despite the severity of the threats and lack of enough progress in tackling them to date, opportunities exist to change future trajectories through transformative action. Such action must begin immediately, however, and address the root economic, social, and technological causes of nature’s deterioration.
 
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  ISSN 0036-8075, 1095-9203 ISBN Médium  
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Auteur (up) Donati, G.F.A.; Parravicini, V.; Leprieur, F.; Hagen, O.; Gaboriau, T.; Heine, C.; Kulbicki, M.; Rolland, J.; Salamin, N.; Albouy, C.; Pellissier, L. doi  openurl
  Titre A process-based model supports an association between dispersal and the prevalence of species traits in tropical reef fish assemblages Type Article scientifique
  Année 2019 Publication Revue Abrégée Ecography  
  Volume Numéro Pages  
  Mots-Clés biodiversity; body-size; dispersal; diversification; diversity; extinction rates; genetic-structure; geographic range size; global patterns; latitudinal gradient; mechanistic models; propagule dispersal; reef fish; speciation; traits  
  Résumé Habitat dynamics interacting with species dispersal abilities could generate gradients in species diversity and prevalence of species traits when the latter are associated with species dispersal potential. Using a process-based model of diversification constrained by a dispersal parameter, we simulated the interplay between reef habitat dynamics during the past 140 million years and dispersal, shaping lineage diversification history and assemblage composition globally. The emerging patterns from the simulations were compared to current prevalence of species traits related to dispersal for 6315 tropical reef fish species. We found a significant spatial congruence between the prevalence of simulated low dispersal values and areas with a large proportion of species characterized by small adult body size, narrow home range mobility behaviour, pelagic larval duration shorter than 21 days and diurnal activity. Species characterized by such traits were found predominantly in the Indo-Australian Archipelago and the Caribbean Sea. Furthermore, the frequency distribution of the dispersal parameter was found to match empirical distributions for body size, PLD and home range mobility behaviour. Also, the dispersal parameter in the simulations was associated to diversification rates and resulted in trait frequency matching empirical distributions. Overall, our findings suggest that past habitat dynamics, in conjunction with dispersal processes, influenced diversification in tropical reef fishes, which may explain the present-day geography of species traits.  
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  Volume de collection Numéro de collection Edition  
  ISSN 0906-7590 ISBN Médium  
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  Notes WOS:000487946300001 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2647  
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Auteur (up) Draredja, M.A.; Frihi, H.; Boualleg, C.; Gofart, A.; Abadie, E.; Laabir, M. doi  openurl
  Titre Seasonal variations of phytoplankton community in relation to environmental factors in a protected meso-oligotrophic southern Mediterranean marine ecosystem (Mellah lagoon, Algeria) with an emphasis of HAB species Type Article scientifique
  Année 2019 Publication Revue Abrégée Environ. Monit. Assess.  
  Volume 191 Numéro 10 Pages 603  
  Mots-Clés coastal lagoons; Diversity; dynamics; Environmental conditions; HAB species; Mediterranean lagoon; nutrients; particulate matter; patterns; Phytoplankton monitoring; sea; temporal variations; thau lagoon; venice lagoon; water-quality  
  Résumé The spatial and temporal variation of phytoplankton communities including HAB species in relation to the environmental characteristics was investigated in the protected meso-oligotrophic Mellah lagoon located in the South Western Mediterranean. During 2016, a biweekly monitoring of phytoplankton assemblages and the main abiotic factors were realized at three representative stations. Taxonomic composition, abundance, and diversity index were determined. In total, 227 phytoplankton species (160 diatoms and 53 dinoflagellates) were inventoried. There was a clear dominance of diatoms (62.9%) compared with dinoflagellates (36.8%). Diatoms dominated in spring and dinoflagellates developed in summer and early autumn in Mellah showing a marked seasonal trend. Data showed that the dynamic of the phytoplankton taxa evolving in the lagoon was mainly driven by temperature and salinity. For the first time, a number of potentially toxic species have been identified, including 2 diatoms (Pseudo-nitzschia group delicatissima, Pseudo-nitzschia group seriata) and 5 dinoflagellates (Alexandrium minutum, Alexandrium tamarense/catenella, Dinophysis acuminata, Dinophysis sacculus, Prorocentrum lima). These harmful species could threat the functioning of the Mellah lagoon and human health and require the establishment of a monitoring network. Finally, our study suggests that the observed decrease of the phytoplankton diversity between 2001 and 2016 could result from the reduction in water exchanges between the lagoon and the adjacent coast following the gradual clogging of the channel.  
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  ISSN 0167-6369 ISBN Médium  
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  Notes WOS:000484493700001 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2635  
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