Portail Hal-l'Institut Agro Rennes-Angers
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Fisheries impact on marine fish populations
No full textInternational audienceFish make up the bulk of the world’s fishing catch, and thus significantly contribute to food security objectives, particularly in developing countries. At the same time, however, fishing affects natural fish populations and is considered the primary driver of marine biodiversity decline. Exploitation directly affects the demography, and therefore the abundance of exploited stocks, but also their genetic diversity. More indirectly, fishing modifies habitats and species assemblages, and ultimately the structure and functioning of marine ecosystems, as well as the place occupied by fish. These various impacts of fishing are presented in this chapter, along with the main implications for the definition of sustainable fisheries management
Agriculture, aquaculture and fishing: impact of food standards on biodiversity. Summary of the scientific report of the study
No full textThe 2021 French Climate and Resilience Act introduced an Eco-labelling display on food products to inform consumers of the environmental cost of their purchases. The construction of this eco-labelling scheme has given rise to significant methodological work with stakeholders. An interim assessment highlighted the difficulty of capturing all the dimensions of biodiversity. With this in mind, the Ministries of Ecological Transition and Agriculture and Food, along with ADEME, called on INRAE and Ifremer in 2022 to better document this biodiversity component, focusing on production practices. In order to inform public policy more widely, the public authorities have chosen to rely on voluntary standards that require the certification of practices. The development of these voluntary standards are also at the heart of many debates on the relationship between sustainable production and consumption. The study, entitled «BiodivLabel», was carried out by a multidisciplinary committee of scientific experts from public research and higher education organizations
Agriculture, aquaculture et pêche : impacts des modes de production labellisés sur la biodiversité. Synthèse du rapport scientifique de l'étude
No full textLa loi Climat et résilience de 2021 a instauré la mise en place d’un affichage environnemental sur les produits alimentaires afin d’informer les consommateurs du coût environnemental de leurs achats. La construction de cet affichage a suscité un important travail méthodologique ouvert aux acteurs. Un bilan intermédiaire a souligné la difficulté à appréhender toutes les dimensions de la biodiversité. C’est dans ce cadre que les ministères en charge de la transition écologique, et de l’agriculture et de l’alimentation, ainsi que l’ADEME, ont sollicité INRAE et l’Ifremer courant 2022 pour mieux documenter ce volet biodiversité, en se focalisant sur les pratiques de production. Afin d’éclairer plus largement les politiques publiques, les pouvoirs publics ont choisi de s’appuyer sur les labels dont les cahiers des charges certifient des pratiques et parce que leur développement les place au cœur de nombreux débats sur les relations entre production et consommation durables. L’étude, intitulée « BiodivLabel », a été menée par un comité pluridisciplinaire d’experts scientifiques issus d’organismes publics de recherche et d’enseignement supérieur
Host specialisation or generalism? Population genetics of the aphid Myzus persicae reveals dominance of superclones across diverse host plants
No full textInternational audienceMost phytophagous insect species are specialized to feed on a narrow range of host plants, typically within the same genus or family, and sometimes even on a single plant species. However, some insect taxa are able to feed on plants from different families and are therefore considered to be generalists. Nevertheless, these generalist species can sometimes form cryptic species complexes or differentiate into host-based populations or races. Moreover, the host breadth of generalists is often measured under laboratory conditions, which may not accurately reflect the more challenging natural environments they encounter, and thus may lead to an overestimation of generalism. In this study, we used a population genetics approach to test whether Myzus persicae, a highly polyphagous aphid, is composed of hostspecialized populations or clones, or whether generalism is an intrinsic characteristic of the species as a whole. We sampled M. persicae over four consecutive years in northern France from a variety of host plants belonging to different botanical families. We found that populations of M. persicae in northern France were predominantly composed of superclones, namely multilocus genotypes identified in many copies. In particular, four superclones dominated M. persicae populations, occurring in high proportions on a broad range of unrelated host plants in each year of the study. Moreover, the array of characterized genotypes of M. persicae formed distinct genetic clusters, but with no clear association to specific host plants. This study shows that under natural conditions and at the very fine genetic level of a single clone, the generalist characteristic of M. persicae holds. Thus, M. persicae remains an exceptional example of a true generalist species
Agri‐food trade liberalization, export prices, and quality upgrading: Evidence from the meat and chocolate sectors in OECD countries
No full textInternational audienceThis article examines the impact of trade liberalization on export prices and quality. The article is innovative in two respects. First, unlike previous studies, it considers both input and output tariffs simultaneously in a theoretical model. Second, it empirically tests the effects of a combination of specific and ad‐valorem tariffs on quality improvement. The theoretical analysis suggests that when firms face reduced output and input tariffs, they tend to improve their export quality and increase export prices. Using export data from 33 OECD countries, the empirical analysis demonstrates that output tariff reduction increases export quality but decreases prices. However, the effects of input tariff reduction on price and quality depend on product differentiation. The results also indicate that the presence of specific tariffs increase product quality while amplifying the positive effects of the reduction of ad‐valorem tariffs on quality. This implies that to improve export quality, reducing ad‐valorem tariffs is more efficient than a specific tariff
PastSatAb - Reconstruction des séries historiques d’abondance et de taux d’exploitation du saumon en France: Une approche Bayésienne pour intégrer les données et l’expertise disponible à l’échelle régionale
No full textThe PastSatAb project carried out by the “pôle OFB-INRAe-Institut Agro-UPPA pour la gestion des migrateurs amphihalins dans leur environnement” (MIAME) was designed to reconstruct time series of abundance and exploitation rates of salmon in France, particularly for the North Atlantic Salmon Working Group of the International Council for the Exploration of the Sea (ICES WGNAS). An integrated Bayesian modeling approach was implemented, combining heterogeneous data on catches, abundance (regional or local), and salmon habitat, to take full advantage of the available knowledge. The developed hierarchical Bayesian model enabled the reconstruction of time series of abundance and exploitation rates, by sea-age classes, over the period from 1970 to 2020 for the five major regions hosting salmon populations: North, Bretagne, Loire-Allier, Garonne-Dordogne, and Adour.By integrating data and expertise at the regional scale, the project highlighted the regional diversity in population and exploitation dynamics. The aggregation of these regional dynamics at a national scale provides a new perspective on abundance trends, particularly regarding the decline of short-sea-age salmon, which appears to be less pronounced than previously estimated. Adjustments are needed to integrate these new estimates into the WGNAS stock assessment process. A methodological approach will need to be established to update annually the model's estimates in a context where the necessary data for these estimates may become increasingly scarce.Le projet PastSatAb, porté par le pôle OFB-INRAe-Institut Agro-UPPA pour la gestion des migrateurs amphihalins dans leur environnement (MIAME), a été conçu pour reconstruire les séries temporelles d'abondance et de taux d'exploitation du saumon en France, en particulier à destination du 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 oeuvre 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 5 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.</p
Minimizing CO2 and N2O emissions from urban lawns through sustainable management strategies.
No full textInternational audienceIn 2019, the European Commission adopted a series of proposals aimed at adapting the EU's climate, energy, transport and taxation policies with a view to reducing net GHG emissions by at least 55% by 2030 compared with 1990 levels (Green Deal). Therefore, local and regional authorities have a major role to play in the fight against climate change through their mitigation and adaptation actions. Among the possible levers, the greening of cities represents a major challenge in offsetting GHG emissions. Urban green spaces are diverse (urban forests, flowered areas, parks, lawns, allotments, etc.). In particular, lawns, which designate a grassed surface composed mainly of graminaceous, are the most representative type of UGS and account for 50 to 70% of the surface area of UGS worldwide. Fertilisation and irrigation stimulate particularly N2O emissions through nitrification and/or denitrification. However, other forms of management could reduce GHG emissions by encouraging soil C storage. Reducing the frequency of mowing, leaving grass clippings on site, or leaving tree litter are all innovative practices that may be considered ‘aesthetically dirty’ by residents, but which could increase C stocks in the soil through the decomposition of plant residues. The main objective of this study is to assess the impact of management methods for grassed areas on CO2 and N2O flows. To this end, a 9-month experiment was carried out in 2024 using several management methods for grassed areas, where CO2 and N2O flows were measured and correlated with climatic variables (temperature, soil moisture) and the soil mineral nitrogen content (NO3-, NH4+). These measurements were taken over three seasons: spring, summer and autumn, in order to assess the relevance of practices according to the seasons. The main conclusions of the study are that fertilization should be avoided, or organic fertilizers should be preferred to mineral ones, and the first fertilization in spring should be delayed to avoid nitrogen lixiviation risks. Leaving tree litter in place and reducing mowing frequency reduce GHG emissions. Green space managers are very sensitive to these changes, and are reluctant to leave litter in place for aesthetic reasons and because of the possible reduction in plant biodiversity
Effect of using Hevea seed meal at different levels on Isa brown laying hen performance and egg quality
No full textInternational audienceEgg consumption remains high in developing countries, yet the cost of poultry feed poses a significant challenge for farmers, limiting their ability to use commercial options. To address this, alternative feed sources for egg-laying hens need to be explored. In Côte d'Ivoire, Hevea brasiliensis trees' seeds are abundant but largely underutilized. These seeds have potential as dietary supplements in layer feed. This study aimed to evaluate the impact of incorporating H. brasiliensis seed meal into a white corn-based diet on laying performance, egg quality, yolk color, and composition. A total of 300 hens, 32 weeks of age, were randomly assigned to 30 pens with 10 hens per pen, and distributed across six dietary treatments with 5 replicates each over a period of 13 weeks. Two control groups received diets based on either yellow corn (Ye) or white corn (Wh). The remaining groups were fed on white corn diets supplemented with H. brasiliensis seed meal at inclusion rates of 2.5% (He2.5), 5% (He5), 7.5% (He7.5), and 10% (He10). The He2.5 diet led to improved egg production. Additionally, increasing levels of Hevea seed meal were associated with a decrease in yolk total cholesterol. However, higher inclusion rates also led to progressively yellow yolk colour compared to white corn-based diets. But, it did not fully restore the deep yellow pigmentation typically achieved with yellow corn. In conclusion, incorporating H. brasiliensis seed meal into white corn-based diets may be a costeffective strategy to enhance egg production and reduce cholesterol content in eggs, though it may affect yolk pigmentatio
Sobre : une formation continue au service des économies d’énergie dans les serres de recherche
No full textNational audienceSupported by INRAE’s division for Social and Environmental Responsibility, the “Sobre” project enabled the design and testing of a training program aimed at strengthening the skills of engineers and technicians responsible for managing research greenhouses and growth chambers. By leveraging optimization strategies for setpoint management, the program aims to allow the trainees to reduce energy consumption, particularly for heating and lighting. Having proven its effectiveness, this pilot initiative could be scaled up and delivered in a decentralized, remote format, thereby benefiting all personnel involved in controlled-environment plant research facilitiesSoutenu par la DRSE d’INRAE, le projet « Sobre » a permis de concevoir et d’expérimenter une formation continue destinée à renforcer les compétences des ingénieurs et techniciens responsables des serres et des salles de culture de recherche. Les compétences acquises permettront aux participants de s’appuyer sur des leviers d’optimisation des consignes, afin de réduire les consommations énergétiques, notamment concernant le chauffage et l’éclairage. Cette initiative pilote ayant démontré son efficacité, elle pourrait être déployée à plus grande échelle sous une forme décentralisée et à distance, et bénéficier ainsi à l’ensemble des agents intervenant dans les infrastructures de recherche végétale en conditions contrôlées