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Fire and Herbivory as Architects of Mediterranean Biodiversity
No full textInternational audienceThe Mediterranean region hosts exceptional biodiversity shaped by millennia of interactions between climate, and disturbances: both fire and herbivores. This study reconstructs 8000 yrs of habitats combustibility and herbivores (domestic and wild) dynamics in the Crau Plain using paleoecological records.Richness, evenness and turnover of vegetation dynamics were calculated to tackle the interconnexion with herbivores dynamics. Our results demonstrate a strong positive correlation between herbivores (indicated by coprophilous fungal spores) and palynological richness, determining the role of grazing by both wild and domesticated herbivores in maintaining ecological heterogeneity. The decline in grazing during the past millennium has coincided with an increase in woody vegetation, posing heightened fire risks under current climate change scenarios.On the other hand, the palynological records has been converted into habitats and their relative combustibility. Early periods (7200–3900 cal. BP) exhibited lower habitat diversity dominated by less combustible vegetation correlated with cooler and wetter climate. However, from 3900 cal. BP, increased pastoralism and fire activity fostered the expansion of grasslands and fire-prone ecosystems.By linking long-term ecological dynamics with modern conservation challenges, this study underscores the importance of integrating grazing management and fire regulation into biodiversity conservation strategies to sustain Mediterranean landscape resilience
Parole d'étudiants - JET 8 et application à la Côte d’Azur
No full textInternational audienceProjet tutoré par Sylvie Christofle et Carine Fournier : enquête auprès de professionnels du tourisme azuréens sur notre thématique « Du durable au régénératif ».Du développement durable à l'approche régénérative dans le tourisme et l'événementiel : une étude du Master 2 MHI de l'IAE de NiceFace aux urgences climatiques, sociales et économiques, le tourisme et l'événementiel touristique doivent aujourd'hui dépasser la simple durabilité pour s'inscrire dans une logique véritablement régénérative. Notre travail, mené dans le cadre du Master 2 Management de l’Hôtellerie Internationale (MHI) de l’IAE de Nice, s'est fixé un double objectif : comprendre comment les acteurs du secteur peuvent non seulement réduire leurs impacts, mais aussi contribuer activement à revitaliser les territoires, et proposer des pistes opérationnelles pour accélérer cette transition.Notre étude s'est articulée autour de trois axes. Nous avons d'abord retracé l’évolution des modèles de durabilité, analysant l’émergence du paradigme régénératif qui place la restauration des écosystèmes, la valorisation des communautés locales et la création de bénéfices partagés au cœur des projets.Dans un second temps, un travail de terrain approfondi a été mené via des entretiens qualitatifs auprès de professionnels du tourisme, de l’événementiel et de collectivités. Cette enquête a révélé des pratiques innovantes, mais aussi des freins persistants : manque d’outils, difficultés organisationnelles, contraintes réglementaires et faible lisibilité du concept.Enfin, une analyse croisée des retours d’expérience et des benchmarks internationaux a permis de dégager des recommandations concrètes. Celles-ci concernent la gouvernance collective, la coopération inter-acteurs, l’intégration des communautés locales, la mesure d’impact, la formation et la transformation des modèles économiques.Ce projet, fruit d'un processus collaboratif impliquant l'ensemble de notre promotion, ouvre des perspectives encourageantes. Il propose des clés d’action essentielles pour un secteur qui, demain, ne se contentera plus de limiter ses effets négatifs, mais contribuera activement au bien-être des habitants, des voyageurs et de la planète.Etudiants du Master 2 Tourisme Management de l’Hôtellerie internationale de l’IAE NICE - Promotion « Happy Hour » : Albort Tessa, Boendermaker Guillaume, Botta Giorgia, Boutry Zoé, Budayova Martina, Dessimond Louise, Fabre,Rezzesi Ticia, Faurien,Desplaces Juliette, Feydieu Eléonore, Heyko Maksym, Judde de Larivière Marion, Mansour Rihem, Marchadour Anwen, Marchich Oussama, Mardoyan Tsovinar, Rakotomavo Anastacia, Riffaud Christophe, Roquebert Clémentine, Soares Correia Denise, Umbumba Hajezy Zayss, Yvonnou Cécili
vtamR : un package R pour l’analyse reproductible et modulable de données de métabarcoding
No full textNational audiencevtamR (https://github.com/meglecz/vtamR) is an R-based reimplementation of the VTAM 1 metabarcoding pipeline, designed to provide greater accessibility and modularity. It is a cross-platform R package built on widely used tools (Swarm 2 , Blast 3 , Vsearch 4 , Cutadapt 5). vtamR includes all core steps -from raw fastq processing to validated ASV or mOTU tables -while optimizing filtering parameters using mock and negative controls. It enables reproducible and adaptable metabarcoding analyses for diverse datasets.ContexteVTAM [1] (Validation and Taxonomic Assignation of Metabarcoding Data) est un pipeline de métabarcoding qui inclut les analyses depuis les fichiers fastq bruts jusqu’à la production des tables d’Amplicon Sequence Variants (ASV) validées et assignées à des groupes taxonomiques. Toutefois, son utilisation reste limitée par la nécessité d’un environnement Linux et par une flexibilité restreinte dans l’organisation des étapes de filtrage. Pour répondre à ces contraintes, j’ai développé vtamR, une réimplémentation de VTAM sous forme de package R, plus accessible et modulable.RésultatsvtamR propose l’ensemble des étapes du pipeline initial : filtrage qualité, fusion des reads appariés, démultiplexage, déréplication et filtrage des ASV en fonction de témoins (contrôles négatifs, communautés artificielles) et assignation taxonomique. Il prend en charge les réplicats techniques ou biologiques, assure la reproductibilité et permet d’intégrer des jeux de données multiples ou des marqueurs chevauchants. Parmi ses nouveautés, vtamR inclut un débruitage avec Swarm [2], des options graphiques, des statistiques pour chaque étape et des outils pour optimiser le regroupement des ASV en mOTU. Il s’appuie sur des programmes tiers bien connus, notamment BLAST, VSEARCH, Cutadapt et Swarm, intégrés directement dans le flux d’analyse.ConclusionsCompatible avec tous les systèmes d’exploitation et utilisable depuis RStudio, vtamR constitue un outil flexible et accessible pour concevoir des pipelines de métabarcoding personnalisés, adaptés à des jeux de données variés et à une large gamme de questions écologiques et évolutives
Current and future state of sorghum in the 21st century
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/615797/)International audienceSorghum, the fifth-ranked cereal, is a competitive crop in semiarid regions and is used principally for food in sub-Saharan Africa and parts of Asia, and elsewhere for animal feed. While it has decreased as a percentage of total cereal production, it has been consistent in global production and in recent decades is of increased importance in Africa. As such, innovations in western Sahelian countries have shown potential new and expanding markets for sorghum. Its drought tolerance may position sorghum a competitive crop in regions affected by climate change. Sorghum grain has a range of physicochemical properties and color types that produce a wide variety of products. Tan plant types can produce near-white neutral-flavored milled products with potential for use in numerous processed foods. Furthermore, purported health-related properties associated with polyphenols, slow starch digestion, moderated glycemic response, and satiety effect may help position sorghum for expanded use
ClimBurst: A Novel Method to Detect Climatological Anomalies Over Time and Space
No full textInternational audienceDetecting abnormal climate events is crucial for understanding, predicting, and managing climate risks. However, most existing methods require prior knowledge about when and where to search for these events, limiting their effectiveness. In this study, we introduce ClimBurst, a new method to identify climate-related anomalies that does not require any prior information about their duration or spatial extent. We propose computing climate bursts to detect abnormal seasonal activity. The ClimBurst approach can detect anomalies at any time scale. The approach also compares anomalies at neighboring locations enabling the tracking of events across time and space. We apply our method on sea surface temperature data from the Mediterranean Sea between 1960 and 2021, where we detect particularly strong warm anomalies that can last from a few days to a few months over a few kilometers to hundreds, such as the 2015 marine heatwave. Our results reveal a noticeable increase in the frequency, magnitude and the spatial extent of these hot anomalies over time. Researchers and practitioners can use ClimBurst to detect and study climate anomalies, providing a basis for event attribution and long-term trend analysis
Is litter biomass a driver of soil volatile organic compound fluxes in Mediterranean forest?
No full textInternational audienceSoil biogenic volatile organic compound (BVOC) emissions have been studied in different biomes, showing that their emissions are considerable. However, so far, previous studies have neglected the role of litter accumulation (considered here to be the amount of litter) in soil BVOC fluxes, and most of them refer to coniferous and evergreen forests, while litter emissions from Mediterranean deciduous forests remain poorly explored. To fill these gaps, the present work aimed to study BVOC fluxes in a Mediterranean deciduous forest, with particular attention being paid to the relationships between litter biomass accumulation in soil, microbial abundance, and soil BVOC fluxes. Measurements were performed in southern France in the downy oak (Quercus pubescens Willd.) forest of the Observatoire de Haute Provence (O3HP) during the late spring of 2023 using dynamic chambers coupled to an online proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS). We investigated in situ daily BVOC fluxes from bare soil and different litter biomasses mimicking current, lower, or higher litter production as both decreases and increases in litter accumulation are expected in the Mediterranean region under the current context of climate change and greening management policies. The results showed a high BVOC diversity, with more than 135 emitted compounds. For a large majority of the measured compounds, fluxes were negative, suggesting that soil (bare soil covered by litter) takes up compounds through biochemical and/or physical processes. Some compounds, such as acetone, methanol, or sesquiterpenes, increased with increasing litter biomass, suggesting the importance of considering litter accumulation when assessing soil BVOC emissions from Mediterranean deciduous forests. Microbial abundance was highlighted as a potential driver of this relation between litter biomass and VOC fluxes
Tracing Ecological Metaphors in Discourses on Open Science using LLMs and Knowledge Graphs
No full textInternational audienceThe term "ecosystem" is frequently used to describe various concepts, not only in open science but also in broader discussions of research and innovation. Despite its widespread use, it is rarely explicitly defined, often functioning as a boundary object that facilitates communication across diverse communities. Systematically documenting its varied, context-dependent meanings presents a significant challenge. This work in progress explores the term "ecosystem" within the discourse of Open Science, offering a systematic approach to mapping its varied meanings and uses
Climate Trend in the Eastern Arctic: LST, Vegetation, and Regional Climate Parameters
No full textInternational audienceThis study examines the 24-year spatial and temporal variability of the thermal regime measured by LST, vegetation distribution by NDVI, and its relationship with the shift in climatic zones, derived from optimal reanalysis in Yakutia. Changes in land surface temperature (LST) play a pivotal role in the climate system and exert a considerable influence on ecosystems, hydrological regimes and human activities. However, the origin of the effect of climatic parameters, including precipitation, snow cover, and surface air temperature, on the spatial and temporal dynamics of LSTs remains poorly explored in the Siberian Arctic and Yakutia. The research conducted focuses on the relationships between LST and these climatic parameters in Yakutia from 2001 to 2024 based on the use of daily and monthly land surface temperature (LST) data derived from the MODIS MOD21C3.061 product, at 1 km spatial resolution. LST MODIS data combined with Climatic parameters (surface air temperature and precipitation) were obtained from climate reanalyses (GHCN-CAMS and CRU TS v4.05). The Mann-Kendall test and Sen's slope estimation were utilised to ascertain seasonal trends. The results suggest that during the spring and autumn months, the rise in LST is closely associated with a reduction in snow cover duration and an increase in air temperature. A strong positive correlation was observed between the increase in land surface temperature (LST) and the decrease in snow cover duration, as well as the rise in surface air temperature during the 24 years of monitoring. In contrast, during the summer months, variations in precipitation become a pivotal factor. A robust correlation between LST and precipitation was observed, as evidenced by the positive and negative values of Kendall's tau coefficient, contingent on the prevailing landscape and climatic conditions. The method of long-term trends of LST & NDVI data once again shows spatial and seasonal differences in the causes of significant changes in these variables. Snow cover plays a major role in LST changes, which demonstrates the prevalence of positive trends in the spring and autumn seasons. Climatic shifts are significant between the base period 1961-1990 and the present period 1991-2020, next 2021-2024
Cytoplasmic Male Sterility Declines in the Presence of Resistant Nuclear Backgrounds
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Impact of Hanks Kinase‐Dependent Phosphorylation of CodY on the Physiology and Virulence in Bacillus cereus
No full textInternational audienceCodY acts as a key regulatory protein involved in adaptive responses in low‐G+C Gram‐positive bacteria. This global transcriptional regulator diagnoses the nutritional status of the cell and responds by regulating transcription of genes involved in metabolism, differenciation and virulence. Phosphoproteomic studies evidenced that CodY is phosphorylated on its serine 215 in Bacillus subtilis . In Bacillus cereus , CodY is also phosphorylated by the Hanks kinases PrkC and YbdM. CodY phosphorylation negatively affects its DNA‐binding properties. We constructed B. cereus mutant strains where the codY wild‐type allele has been replaced by codY ‐S215D or codY ‐S215A, encoding a phosphomimetic or a phosphoablative CodY derivative, respectively. We showed that the phosphomimetic mutation leads to a notable reduction in CodY control over several critical cellular processes, including motility, biofilm formation, cytotoxic effects and pathogenicity. Lack of CodY phosphorylation and CodY overphosphorylation have opposite repercussions on gene expression, showing that CodY phosphorylation contributes to the adaptation of B. cereus to diverse environmental conditions. S215 is strictly conserved in CodY orthologs in firmicutes, suggesting that gene regulation mediated by Hanks kinase‐dependent CodY phosphorylation could be a general regulatory mechanism in this phylum