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Permanence and impermanence of landscapes: a study of the changing relationship between societies and water in coastal wetlands
No full textInternational audienceAtlantic coastal wetlands, once productive areas, are now protected for their natural character. They are now facing new challenges as sea levels rise. By reconstructing the landscape trajectory of the Payré estuary and marshes (Vendée, France), this paper first identifies the drivers of change that have produced landscape heritages that are now protected. Secondly, the analysis of water management evolution characterises the renewal of hydrosocial cycles. In the past, water was productive; today two hydrosocial cycles are coexisting. One is promoting water as a source of biodiversity through ‘ecological’ management, but also as a commodity through the development of green tourism. The other emphasises ancient practices that give the site its identity. These two hydrosocial cycles coexist because of the hybrid nature of this site and the attachment to landscape heritages.Les zones humides littorales atlantiques, autrefois productives, sont aujourd’hui protégées pour leur caractère naturel. Elles sont aujourd’hui confrontées à de nouveaux défis liés à l’élévation du niveau de la mer. En reconstituant la trajectoire paysagère de l’estuaire et marais du Payré (Vendée, France), cet article identifie premièrement les facteurs de changement qui ont produit les héritages paysagers aujourd’hui protégés. Dans un second temps, l’analyse de l’évolution de la gestion de l’eau révèle un renouvellement des cycles hydrosociaux. Aujourd’hui, deux cycles hydrosociaux coexistent et remplacent un cycle qui valorisait une eau source de production. L’un promeut l’eau comme source de biodiversité à travers une gestion « écologique », mais aussi comme marchandise à travers le développement du tourisme vert. L’autre met en avant les pratiques anciennes qui donnent au site son identité. Ces deux cycles hydrosociaux coexistent en raison de la nature hybride de ce site et de l’attachement aux patrimoines paysagers
Are plant protein ingredients efficient egg white replacers in foams ?
No full textInternational audienceTo meet the increasing demand for protein and environment sustainability, there is a necessity to support protein transition by expanding the range of plant-based protein products. Foams are particularly challenging applications as they required protein with high solubility, fast diffusion towards the interface, flexibility and interactions ability. Egg white proteins are often considered as reference proteins for foaming. This study compared 7 plant protein ingredients (5 isolates – potato (2 proteins fractions), pea, soy and gluten; 2 concentrate – pea and soy) as egg white replacer in foams. Ingredient composition, physical and hydration properties of ingredient powders and foaming properties as well as foam texture have been characterized. Three ingredients out of the seven tested formed stable foams when rehydrated at minimum 3% (w/v) in water (2 potato protein isolates and 1 gluten isolate). The foaming properties of these ingredients and egg white were mainly explained by the ingredient composition and powder physical properties whereas the solution properties were not correlated with foaming properties. Optimization using experimental design and data analysis for protein content and pH were then performed on these ingredients. Predictive models were obtained for foaming capacity, foam stability against drainage, foam firmness, adhesiveness and cohesion as a function of pH and protein content for each ingredient. These models can be used by foam manufacturers to choose the best egg replacer considering the pH and the protein content of its application
Towards a disruption in the manufacture of extremely low-cost micro-resonators using additive technologies and 3D printers outside the cleanroom : Story plus Laboratory visit
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On-the-fly adaptive SNR protocol to accelerate Brillouin microscopy
No full textInternational audienceThis article presents an innovative method for accelerating Brillouin microscopy imaging. The proposed technique, called One-pass, dynamically adjusts the signal-to-noise ratio (SNR) during data acquisition. It identifies essential spectra in real-time and adapts the laser exposure time accordingly. This approach considerably reduces acquisition time (by a factor around 2.2 and 3.5) while maintaining acceptable image quality, as demonstrated on simulations and real biological samples (HeLa and SK-N-SH cells). The method improves the stability and efficiency of Brillouin imaging compared with conventional techniques, i.e., raster scan with a single long exposure time or the recently introduced two-pass approach
Molecular responses of chicken embryos to maternal heat stress through DNA methylation and gene expression: a pilot study
No full textInternational audienceClimate change, with its repercussions on agriculture, is one of the most important adaptation challenges for livestock production. Poultry production is a major source of proteins for human consumption all over the world. With a growing human population, improving poultry's adaptation to environmental constraints becomes critical. Extensive evidence highlights the influence of environmental variations on epigenetic modifications. The aim of this paper is therefore to explore chickens' molecular response to maternal heat stress. We employed Reduced Representation Bisulfite Sequencing to generate genome-wide single-base resolution DNA methylation profiling and RNA sequencing to profile the transcriptome of the brains of embryos hatched from dams reared under either heat stress (32 ∘ C) or thermoneutrality (22 ∘ C). We detected 289 significant differentially methylated CpG sites (DMCs) and one differentially methylated region (DMR) between heat stressed and control groups. These DMCs were associated with 357 genes involved in processes such as cellular response to stimulus, developmental processes, and immune function. In addition, we identified 11 genes differentially expressed between the two groups of embryos, and identified ATP9A as a target gene of maternal heat stress on offspring. This study provides a body of fundamental knowledge on adaptive mechanisms concerning heat tolerance in chickens
Le projet PastSatAb pour reconstruire des séries temporelles d’abondance et de taux d’exploitation du saumon atlantique en France
No full textInternational audienceLe projet PastSatAb, porté par le pôle OFB-INRAe-Institut Agro-UPPA pour la gestion des migrateurs amphihalins dans leur environnement (MIAME), a pour objectif de reconstruire les séries temporelles d’abondance et de taux d’exploitation du saumon en France afin d’alimenter les modèles d’évaluation de stock développés par le groupe de travail sur le saumon de l'Atlantique Nord du Conseil international pour l’exploration de la mer (CIEM WGNAS). Une approche de modélisation bayésienne intégrée, combinant des données hétérogènes de captures, d’abondances (régionales ou locales) et de surface d’habitat saumon a été mise en œuvre pour valoriser au mieux la connaissance disponible. Le modèle bayésien hiérarchique développé a permis de reconstruire les séries temporelles d’abondance et de taux d’exploitation, par classes d’âge de mer, sur la période de 1970 à 2020 pour les cinq grandes régions qui hébergent des populations de saumon, à savoir, le Nord, la Bretagne, la Loire-Allier, la Garonne-Dordogne et l’Adour.Grâce à l'intégration de données et d'expertise à l’échelle régionale, le projet a permis de mettre en évidence la diversité régionale des dynamiques de population et d’exploitation. L’agrégation de ces dynamiques régionales à une échelle nationale apporte un nouveau regard sur l’évolution des abondances, notamment sur le déclin des saumons à court séjour marin, qui s'avère moins prononcé que ce qui était estimé jusqu’à présent.Des ajustements sont nécessaires pour intégrer ces nouvelles estimations dans le processus d’évaluation de stock du WGNAS. Une approche méthodologique devra être mise en place pour actualiser chaque année les estimations du modèle dans un contexte où les données nécessaires pour produire les estimations pourraient être amenées à se raréfier
Effect of climate change on potato yield and starch content
No full textInternational audiencePotato (Solanum tuberosum L.) ranks as the fourth most important food crop after rice, wheat, and maize. In the literature, models have been developed to predict potato yield evolution due to climate change, projecting a decrease in production across various regions. This study was conducted on field data collected over 31 years in five contrasting sites in the Western Alps, Switzerland. Results show that 24 % of yield variation can be explained by the genotype, and 50 % by the environment. Among the studied meteorological conditions influencing the yield, 1) "total precipitation from tuber initiation to tuber harvest", 2) "sum of solar irradiation from planting to maturity", 3) "average temperature from planting to maturity" and, 4) "sum of daily maximal temperature from planting to maturity", were the most important variables. The third variable exhibits a positive linear relationship with yield up to an average temperature of 16.5 • C during the growth season. Beyond this threshold, the relationship becomes negative and results in yield loss. Using this unprecedented dataset, we estimated potential yield losses in the Western Alps of Switzerland by the end of the century under three different Representative Concentration Pathway (RCP) scenarios (i.e. 2.6, 4.5, 8.5). In the short term, by 2035, yield losses are projected to range from 3.2 % to 15.0 % regardless of the scenarios. By 2060, RCP 4.5 and RCP 8.5 predict the highest losses, reaching 22.7-50.3 % compared to the 1990-2020 average yield. The most significant loss was predicted under the RCP 8.5 long-term scenario, by 2085, with yield losses ranging from 24.2 % to 84.6 %. These losses are attributed to an estimated precipitation decrease of 42 % compared to the average of the past 30 years and a +7.2 • C increase in average temperature during the potato growth season. Except in the case of RCP 2.6, which estimates low yield losses compared to 1990-2020, this study anticipates significant yield losses by the end of the century in Switzerland. To mitigate these losses due to climate change, potential adaptation strategies include the adoption of drought or heat-stress-resistant genotypes, enhancements in irrigation systems, adjustments of planting schedules, and relocating planting sites to higher elevations. In addition, the G x E interaction effect should be considered in breeding strategies, to cope with climate change impacts on potato yield and to grow genotypes better adapted to their environment
How coevolution in daily activity rhythms governs encounters between predator and prey
No full textInternational audiencePredation risk in the wild varies across the day in a relatively predictable way, as a function of environmental conditions, such as light intensity and temperature, and of predator habits. Prey animals can thus adjust their own activity rhythm to avoid the most dangerous periods.We studied this situation in a coevolutionary perspective, considering that, if prey spread their activity across the day to counter predator temporal preferences, these preferences may in turn change to track prey activity.We therefore built a game-theoretical model to derive evolutionarily stable activity patterns for a predator constantly trying to maximize its chance of capture and a prey trying to minimize this probability. Key parameters concern circadian variations in environmental conditions and their influence on predator hunting efficiency and energy demands of the prey, which dictate its total amount of activity. The model predicts high levels of prey activity during periods of reduced predator efficiency. The predator may then either track these activity peaks and copy the activity patterns of its prey, or concentrate its hunting effort during periods when prey activity is low but conditions favour hunting. In the first case, predator and prey activity patterns will be synchronized. In the second one, they will exhibit strong temporal segregation. We show how these diverging scenarios emerge and how they can help to disentangle the wide variety of situations existing in the wild
ORIGAMI, un consortium interdisciplinaire pour identifier les freins et les leviers au développement de la production porcine biologique
No full textNational audienceEuropean and French pork production under Organic Farming (AB) specifications is underdeveloped compared with other plant and animal sectors. The ORIGAMI consortium has grouped scientists and engineers from INRAE, IFIP, ADIV and ITAB, working at animal, farming system, food chain and territorial levels, in an interdisciplinary and multi-scale approach. Interviews with stakeholders of the organic and non-organic sectors identified 164 barriers and 231 levers. Multiple-component analysis and classification were used to associate the obstacles and levers within five themes: livestock management, outlets and product development, diversity and complementarity of activities within farms, sectors and regions, training and support for farmers and future farmers, communication and dialogue with society to improve the image of the pig farming.La production porcine européenne et française sous cahier des charges Agriculture Biologique (AB) se développe peu comparativement aux autres filières végétales ou animales. Le consortium ORIGAMI a mis en réseau des chercheurs et ingénieurs de INRAE, de l’IFIP, de l’ADIV et de l’ITAB, travaillant sur le porc aux échelles de l’animal, des systèmes d’élevages, des filières et des territoires, et souhaitant s’impliquer dans des approches interdisciplinaires et multi-échelles. Des entretiens d’acteurs des filières bio en non bio ont permis d’identifier 164 freins et 231 leviers. Des analyses en composantes multiples et classification ont permis d’associer les freins et les leviers au sein de cinq thématiques : la conduite des élevages, les débouchés et à la valorisation des produits, les diversités et les complémentarités des activités au sein des exploitations, des filières et sur les territoires, la formation et l’accompagnement des éleveurs et des futurs éleveurs, la communication et le dialogue avec la société pour améliorer l’image de la production
Using informative priors to account for identifiability issues in occupancy models with identification errors
No full textInternational audienceNon-invasive monitoring techniques like camera traps, autonomous recording units and environmental DNA are increasingly used to collect data for understanding species distribution. These methods have prompted the development of statistical models to suit specific sampling designs and get reliable ecological inferences. Site occupancy models estimate species occurrence patterns, accounting for the possibility that the target species may be present but unobserved. Here, two key processes are crucial: detection, when a species leaves signs of its presence, and identification where these signs are accurately recognized. While both processes are prone to error in general, wrong identifications are often considered as negligible with in situ observations. When applied to passive bio-monitoring data, characterized by datasets requiring automated processing, this second source of error can no longer be ignored as misclassifications at both steps can lead to significant biases in ecological estimates. Several model extensions have been proposed to address these potential errors. We propose an extended occupancy model that accounts for the identification process in addition to detection. Similar to other recent attempts to account for false positives, our model may suffer from identifiability issues, which usually require another source of data with perfect identification to resolve them. As an alternative when such data are unavailable, we propose leveraging existing knowledge of the identification process within a Bayesian framework by incorporating this knowledge through an informative prior. Through simulations, we compare different prior choices that encode varying levels of information, ranging from cases where no prior knowledge is available, to instances with accurate metrics on the performance of the identification, and scenarios based on generally accepted assumptions. We demonstrate that, compared to using a default prior, integrating information about the identification process as a prior reduces bias in parameter estimates. Overall, our approach mitigates identifiability issues, reduces estimation bias, and minimizes data requirements. In conclusion, we provide a statistical method applicable to various monitoring designs, such as camera trap, bioacoustics, or eDNA surveys, alongside non-invasive sampling technologies, to produce ecological outcomes that inform conservation decisions