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Uncertainty sources in a large ensemble of hydrological projections: Regional Climate Models and Internal Variability matter
No full textInternational audienceMulti-scenario, multi-model ensembles of hydrological projections are widely used to describe possible futures of regional hydrology and inform adaptation strategies. The Explore2 dataset is such an ensemble of river flow projections in Metropolitan France. It provides future simulations for 1735 catchments with modeling chains composed of different hydrological models forced by 36 regional climate projections based on bias-adjusted EUROCORDEX simulations. This study assesses the uncertainties of this ensemble with QUALYPSO, a method specifically designed to deal with incomplete ensembles and to disentangle and quantify all uncertainty sources, including that due to internal variability. Focusing on results obtained at the end of the century, this study shows a strong agreement between modeling chains towards decreases in low flows in a large southern part of France for a high-emission scenario, and very uncertain changes for the annual mean and high flows. Emission scenario uncertainty is the dominant source of uncertainty for low flows over the whole of France, and for mean annual flows in southeastern France. The contribution of the global and regional climate models is important for mean and high flows, especially in rainfall-dominated areas. Regional climate models contribute considerable uncertainty to low flows, much more than global models. The contribution of hydrological model uncertainty is large for low flows, moderate for mean annual flows, and small for high flows. For all climate and hydrological indicators, internal variability is often large and cannot be overlooked. It is often of the same order and sometimes larger than the uncertainty on the climate change response
Land Use Optimization in Small Islands: A Water-Energy-Food Nexus Approach
No full textDue to their isolation, limited resources, and high population density, small islands are particularly vulnerable to multi-sectoral crises. The study of sustainability on small islands raises, among other challenges, the need to balance the use of local resources -such as water, food and energy-while effectively managing urban sprawl. This paper introduces a systemic approach that explores the interdependencies among multiple resources and production systems, framed within the Water-Energy-Food (WEF) nexus, with a specific focus on assessing land use competition driven by the dynamics of land use change. In this paper, we propose a novel approach of the WEF nexus through the optimization of scenarios that make use of Geographical Information Systems (GIS) integrated with a robust optimization model. The contributions include constructing integrated scenarios that encompass agricultural production, electricity production, and urban sprawl dynamics, highlighting their impacts on land use change and their combined effects on energy and food production from several local resources by 2035. The model is applied to Reunion Island, using real-world data to build insightful scenarios that facilitate informed decision-making. Our proposed model functions as a spatial analysis tool, enabling the identification of optimal agricultural parcels for urban development and potential areas for electricity and food production within a systemic approach. Besides, it provides medium-term projections regarding the impact of integrated scenarios on local food and energy production. As such, it serves as a relevant decision-support tool for local policymakers at the island scale
Abiotic and biotic controls of non-native perennial plant success in drylands
No full textInternational audienceDrivers of non-native plant success in drylands are poorly understood. Here we identify functional differences between dryland native and non-native perennial plants and assess how biotic, abiotic and anthropogenic factors shape the success of the latter. On the basis of plant community and functional trait data from 98 sites across 25 countries, we report a total of 41 non-native plant species at 31 sites. Non-natives tend towards faster growth strategies than natives. Non-native plant richness is higher at sites with greater grazing pressure and under environmental conditions associated with higher soil fertility, decomposition and fungal richness-conditions that tend to occur in less arid regions-and lower where native plant and herbivore richness are greater. Non-native plant cover correlates positively with grazing pressure and negatively with native plant richness. Taken together, our results suggest that non-native plant success in drylands is facilitated when high grazing pressure coincides with elevated resource availability. Such context-dependence of non-native plant success and linkages with native plant and herbivore diversity highlight the need for managing grazing and conserving biodiversity across the world's dryland
Concentration en particules fines à Nice mesurée à l'aide des capteurs Mobilair développés par AirCarto
No full textData setDans le cadre de leur projet tutoré de deuxième année, les étudiants de la Licence Sciences & Humanités parcours environnement de l'Université Nice Côte d'Azur ont arpenté pendant 2 semaines (7-19 janvier 2026) un espace géographique autour de la gare SNCF de Nice munis d'un micro capteur développé par la Société AirCarto d'AtmoSud. Ce capteur délivre toutes les 10 secondes des mesures de PM1, PM2.5 et PM10. Au total ce sont plus de 60.000 mesures qui ont été collectées, qui sont mises en Open source ici
Determination of Water Content in Vanilla Pods and Powder Using Near-Infrared Spectroscopy
No full textInternational audienceThe quality of vanilla depends heavily on its water content, a key parameter that influences its stability, preservation, and sensory properties. Conventional moisture determination by loss-on-drying, while accurate, is slow and destructive. In this study, a rapid, non-destructive approach based on near-infrared (NIR) spectroscopy combined with chemometric modeling was developed to predict the moisture content of vanilla samples. A total of 123 samples were analyzed by NIR spectroscopy and thermogravimetric analysis (reference values). Principal component analysis revealed a strong correlation between spectral variance and water content in the 7400-4000 cm⁻¹ region. A partial least squares (PLS) regression model was optimized and validated, showing optimal performance with four latent variables (R² = 0.99, RMSEC = 0.98). Prediction on an independent set of 20 samples yielded a Q² of 0.99 and an RMSEP of 0.82, confirming the robustness and generalization of the model. Repeatability tests further demonstrated high stability and low variability of the predicted values. The method demonstrates strong potential for routine industrial quality control. Expanding the calibration set could support broader applicability across vanilla varieties
Effects of a biocontrol cocktail from Trichoderma asperellum on earthworms and microbial communities: a mesocosm study
No full textInternational audienceThe wine industry is an important socio-economic agricultural sector at an international scale, but the cultivation of grape vine (Vitis vinifera) also involves intensive use of pesticides. Copper sulphatein Bordeaux mixture, used as a fungicide, affects various soil organisms that are essential for proper functioning of agroecosystems.The development of alternative practices to replace copper sulphate is of great importance. Trichoderma asperellum can produce bioactive compounds with antifungal properties. This study com-pared the effects of: (i) copper sulphate, (ii) a biocontrol cocktail from T. asperellum and (iii) their combination, at different doses, on the biological and physicochemical properties of a vineyard soil in mesocosms. Microbial (respiration, biomass and catabolic diversities of bacterial and fungal communities) and earthwormAporrectodea caliginosa (biomass, abundance and reproduction) properties were monitored after a 30-day incubation period. The results revealed that the biocontrol cocktail did not show any deleterious effects and even had beneficial effects: at certain doses, the biocontrol cocktail promoted microbial respiration andearthworm weight gain. On the other hand, the harmful impact of copper sulphate was confirmed on microbial biomass, bacterial catabolic activity, together with a change in the microbial catabolicprofiles. Furthermore, negative effects were observed from copper sulphate on the reproduction of the earthworms in terms of num-ber of individuals, hatched cocoons and time of cocoon hatchin
La sobriété numérique comme levier d’innovation pour les entreprises : une analyse sur données d’enquête
No full textInternational audienceThis article examines whether digital sobriety practices implemented by companies could act as a barrier to innovation. As investment in digital technology and equipment is a key factor in driving innovation, it is important to understand the implications of adopting more restrained digital practices on a company's innovation capabilities. To investigate this, we draw on a survey of 2,875 companies in Brittany and Pays de la Loire. Our findings reveal that companies most committed to digital sobriety are also those that innovate the most in terms of processes and products, although the positive relationship is more significant for process innovations. Thus, implementing responsible practices, particularly in digital areas, is not an obstacle to innovation and may even help companies move toward more sustainable organizational models.Cet article s’intéresse à la question de savoir si les actions de sobriété numérique mises en œuvre par les entreprises peuvent constituer ou non un frein à l’innovation. L’investissement dans les technologies et équipements numériques étant un facteur clé de l’innovation, il est important de comprendre les implications d’une plus grande sobriété numérique sur les capacités d’innovation des entreprises. Pour cela, nous mobilisons une enquête réalisée auprès de 2875 entreprises en Bretagne et Pays de la Loire. Nos résultats montrent que les entreprises les plus engagées dans des démarches de sobriété numérique sont aussi celles qui innovent le plus en procédé et en produit, même si la relation positive est plus significative pour les innovations de procédé. La mise en œuvre de pratiques responsables, notamment en matière de numérique, n’est donc pas un obstacle à l’innovation et peut même permettre aux entreprises d’aller vers des organisations plus durables. CODES JEL : L2, O3
Assessing the persistence of semi-natural species-rich grasslands under changes in grazing practices: Insights for grassland restoration
No full textInternational audienceGrazing practices are well-known to shape plant populations and communities in semi-natural grasslands and the conservation and restoration of these ecosystems relies heavily on maintaining traditional extensive grazing systems, which have persisted for centuries or even millennia. However the changes of grazing practices in relation to climate change and socio-economic factors can result in biodiversity loss, shifts in vegetation composition, soil degradation, and declines in ecosystem services and habitat quality. This study aimed to understand the medium-term (3-16 years) effects of changes in grazing practices by comparing two sheep grazing methods in semi-natural rangelands of Southern France: millennia-old traditional herding with shepherds and herding dogs, and the recent practice of fenced free grazing, which emerged at the beginning of the 21st century. Surveys were conducted at six paired study sites over three years, assessing vegetation, mesological data, and plant traits. While the five vegetation zones created by traditional herding remain identifiable, the transition to fenced grazing has induced, for the first time in these grasslands, a mid-term homogenization of plant communities, marked by the spread of xero-mesophilous species and the disappearance of the historical grazingintensity gradient. These findings highlight the ecological implications of altered grazing regimes, such as fenced grazing, for biodiversity conservation of rangelands with millennia-long grazing history, ecosystem functionality, and long-term persistence of high heritage value grasslands. They provide critical insights into designing adaptive and sustainable restoration strategies for degraded grasslands under changing environmental and socio-economic conditions
A new proposal for a statistically-derived biogeographical regionalization of Algeria, North Africa
No full textInternational audienceMost proposals relating to the biogeographic regionalization of Algeria have been made by traditional qualitative method (geography, geology, climatology, vascular flora), on the basis of expert’s opinions. A new biogeographic regionalization of Algeria is herein proposed, based on quantitative approach and using objective multivariate methods. Bio-geoclimatic datasets were analysed using cluster analysis techniques to define biogeographical units. A georeferenced floristic database for Algerian strict-endemic plants was compiled, including distribution information from different sources, to characterise the indicator species of these units. Our new proposal for Algeria encompasses 28 biogeographical units recognised within the country that reflect specific regional topography and ecoclimatic conditions. Eight distinct and spatially coherent sectors were identified, and 20 nested districts were detected, based on biogeographical features. All of these biogeographical units are listed and their position and boundaries are mapped. The main predictive environmental descriptors of the sectors were Thornthwaite aridity index, elevation, Min Temperature of Coldest Month (Bio6), Precipitation of Warmest Quarter (Bio18), Coefficient of variation of Enhanced Vegetation Index (EVI), Evenness of EVI, and soil organic carbon. We highlighted the endemic plants that define the districts, using the indicator species criterium. The use of a large dataset of environmental factors and endemic plant species, coupled with numerical analyses, makes this study novel and allows an enhanced bioregionalization system for Algeria. We provide a reliable sectorisation for use in conservation planning, biodiversity assessment, or climate change studies