eKhSACIR інституційному репозитарії Харківської державної академії культури
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RECOTOX, un réseau de sites de recherche pour suivre, comprendre et atténuer les impacts éco-toxicologiques des polluants sur les agroécosystèmes
No full textDepuis de nombreuses années, la communauté scientifique souligne le manque de suivi sur le long terme et à large échelle des effets des produits chimiques sur les écosystèmes. Par ailleurs, les études écotoxicologiques réalisées s’appuient sur des protocoles qui sont très souvent éloignés des conditions environnementales réalistes. De ce fait, notre capacité à comprendre et prévoir ces effets reste limitée.Dans ce contexte, le réseau RECOTOX (https://www6.inra.fr/ecotox/Animation-nationale/Infrastructures/RECOTOX) ambitionne :- De promouvoir une recherche transversale et intégrée pour répondre aux challenges scientifiques visant à comprendre et anticiper les impacts environnementaux et sanitaires des pesticides (composés organiques et métalliques, biopesticides…),- D’analyser la chaine “pressions-expositions-impacts“ en coordonnant et en intégrant l’observation et l’expérimentation in natura en écotoxicologie et toxicologie,- De partager au sein de ses sites une culture commune autour de l’écotoxicologie.Il s’appuie sur les compétences, activités et moyens spécifiques de sites instrumentés en France métropolitaine et aux Antilles, représentatifs de différents contextes agro-pédo-climatiques, pour réaliser des enquêtes, des observations et des expérimentations. Ces sites appartiennent pour la plupart à des structures labellisées (SOERE RBV, réseaux de bassins versants ; SOERE RZA, réseau des zones ateliers ; essais systèmes de cultures INRA, autres sites universitaires…)
Pratiques et représentations des éleveurs ovins viande envers leurs agneaux mis en allaitement artificiel et leur mortalité
No full textInternational audienc
Is it possible to mitigate greenhouse gas emissions from agricultural soil by introduction of temporary grassland into cropping cycles ?
No full textInternational audienceAgriculture contributes strongly to greenhouse gas emissions, in particular through the emission of N2O. In this study, we investigated the intensity of such emissions from French grassland soils under contrasting management by combining an experimental and a modelling approach. The objectives of this study were to measure and estimate N2O emissions and C storage at field scale and to assess the effects of grassland management on the processes determining soil organic C-storage and greenhouse gas emissions. Our conceptual approach included modelling of N2O emissions from grasslands and the investigation of the controls of N2O emissions by means of the characterisation of soil organic matter (SOM) composition as well as microbial communities. We continuously measured greenhouse gas emissions at long term grassland experiments in France. Moreover, we investigated the nature of SOM and the abundance and the activities of microbial communities in the soils from the different grassland managements. Our data indicated that grassland management practices, such as grazing, mowing, animal density, fertilisation and length of grassland periods, influenced soil C-storage, SOM composition and microbial abundance and activity. Such effects may be observed as legacy effects even after several years of cropping. Greenhouse gas emissions, in particular those of N2O, are strongly influenced by the management practices and their effects on SOM and soil microbial parameters. As they are contrasting, a compromise has to be found in order to ensure optimal ecosystem services of grassland systems
Addressing the trade-off between food production and other ecosystem services: scenarios on multiples spatial levels
No full textInternational audienceIncreasing food production while maintaining the same level of ecosystem services is a great challenge of this century, given the higher request of proteins from an increasing population and the need of a sustainable use of resources. Such a challenge could be addressed at different spatial levels, i.e., the spatial boundaries within which food production should be increased with no-loss of other ecosystem services can be more or less extended. In this work, we investigated how the conflict between food production and other ecosystem services can be addressed at different spatial levels. For doing this, we calibrated ecological production functions for predicting animal production, crop production, carbon sequestration, and timber growth starting from land cover and land use management variables. We then ran scenarios optimizing animal production on the French territory posing constraints of no-loss on other ecosystem services. The scenarios differed by the spatial level at which the no-loss constraints were posed: at the department level (NUTS 3, the smaller level), at the regional level (NUTS 2, medium level), and at the national level (largest level). Our findings showed, on the one hand, that constraints posed at larger spatial levels allowed higher values of animal production than constraints posed at smaller spatial levels. On the other hand, constraints posed at smaller spatial levels allowed a homogeneous distribution of ecosystem services in the territory, whereas with constraints posed at the larger level, ecosystem services were more heterogeneously distributed, leading to social inequalities. Our study implies that extending the spatial level can indeed help solving conflicts between ecosystem services, but the price to pay is social inequality. Research is needed to find the best spatial level into which defining the conflict between ecosystem services, finding the best tradeoff between food production and social equality
Modelling networks of causal relationships in stress ecology using Structural Equation Model: an example linking fate and impact of metals in contaminated soils
No full textTesting the complex hypotheses reflecting the effect of stressors in natural conditions needs advanced multivariate analyses. This study presents a promising multivariate analysis (structural equation model: SEM) able to model networks of causal relationships and conceptual (latent) variables reflected by several observed variables. The aim is to show the interest of SEM for analysing monitoring data based on the example of the bioavailability of metals to earthworm. The concept of bioavailability perfectly illustrates the key features of SEM relevant for field data analysis (e.g. causal relationships and numerous variables supposedly reflecting bioavailability). A SEM reflecting the causal assumptions: the more metals are available in the soil the more they enter the organism, and an effect can only appear if metals have entered the organism, was tested. This definition involves 3 sub-concepts: 1) environmental availability: available metals in soil, measured by e.g. chemical metal extractions, 2) environmental bioavailability: metal absorbtion by the organism, measured by internal metal concents, and 3) toxicological bioavailability: internal metals leading to effects, measured by biomarkers. In the SEM each sub-concept was a latent variable reflected by several observed variables. The SEM was tested based on a large dataset for a relevant earthworm species: Aporrectodea caliginosa exposed to 31 field soils. The first interest of SEM was the possibility to test for causal relationships. For Cd, the SEM was supported by the data and suggested that earthworms may not be exposed only to readily available metals (e.g. dissolved Cd content in soil), but possibly also to metals bound to soil particles ingested by earthworms. Another key feature of SEM was to model unmeasured concepts reflected by several indicators. The observed variables of a latent are correlated in SEM. This is an important advantage of SEM, valuable when analysing monitoring data and dealing with the issue of inter-correlations between e.g. physico-chemical variables. This study shows that SEM can elucidate the causal links involved in the exposureeffects of chemical stressors. The potentialities of this modelling framework applied on large datatsets such as monitoring data are tremendous. The ability to model networks of interacting components will help refining our causal understanding of the effects of stressors on biodiversity and ecosystem functioning in natural environments
Les fibres alimentaires limitent le stockage de lipides hépatiques en situation de surnutrition : quels mécanismes et quels médiateurs ?
No full textSession Métabolisme des macro- et micronutrimentsNational audienc
La cascade de l'azote : que va-t-on encore faire avec les mesures ?
No full textNational audienceDans le cadre du projet ANR Escapade, 4 sites ont été instrumentés pour constituer une base de données nécessaire à la validation des modèles mis en œuvre pour appréhender la cascade de l'Azote à l'échelle des paysages. Outre l'acquisition des flux d'azote vers les hydrosystèmes déjà en place pour la majorité des sites, des équipements nouvellement acquis ont permis de mesurer les flux d'oxyde nitreux (N2O) en fonction de l'occupation des sols et de leurs caractéristiques et de déterminer les concentrations atmosphériques en NH3.Ces données montrent des flux d'azote en général plus élevés pour le Naizin (Bretagne), tant par sa pluviométrie élevée que son système agricole dominé par l'élevage, à la différence des autres sites essentiellement dominés par la grande culture. Les sites des Avenelles (en Brie) et OS2 (en Beauce) présentent des résultats assez semblables. Le régime hydrologique de type semi-aride de l'Auradé introduit plus de la variabilité qu'ailleurs. Au-delà de constituer des données de validation des modèles et de nourrir des bases de données nationales, européennes et mondiales, nécessaires pour alimenter les directives, ces données peuvent servir à la compréhension du fonctionnement de petits territoires grâce à l'établissement de bilans, et ces connaissances par sites peuvent être mises en perspectives pour mieux comprendre les facteurs qui déterminent leurs spécificités (climat, caractéristiques des sols, pratiques agricoles, systèmes, etc.). Les bilans et la modélisation sont ainsi appelés à se nourrir réciproquement
Validation d’un distributeur automatique d’aliment comme outil de phénotypage de la croissance, de la consommation et du comportement alimentaire individuels de canards élevés en lot
No full textPrecision breeding is a major research topic in animal productions. With a significant economic feed cost,numerous studies finely describe the feeding behavior and feed intake of poultry in conditions close to those ofproduction farms. A single place electronic feeder (SEF) is available to measure accurately intake and feedingbehavior of group-housed ducks. To assess the effect of this tool on growth and intake performance, two groupsof ducks of the three genetic types were raised in parallel with a SEF and a linear conventional feeder. Data wereanalyzed from 5 to 7 weeks of age for the two feeding conditions. During the test and weekly, individual averagedaily gain, group feed intake and feed conversion ratio were compared between SEF and control conditions foreach genetic type. Overall, the SEF did not affect the growth performance of the animals. Feed intake wassimilar between the two conditions, expect for Muscovy ducks which data suffered from the highly gregariousbehavior of these animals leading to 12% of lost visits due to multiple identifications, for which consumption isnot attributable. This limit is currently dealt with the modification of the access to the SEF. In addition to thegrowth traits that indicate no impact of raising ducks with SEF, this tool also provides automated data on thefeeding behavior of animals.L’élevage de précision constitue un enjeu majeur pour les recherches en productions animales. Avec son coûtéconomique important, l’alimentation fait l’objet de nombreuses études pour décrire le comportement et laconsommation alimentaires des volailles dans des conditions proches de celles des élevages de production. Undistributeur automatique de concentré (DAC) est disponible pour mesurer précisément les quantités ingérées et lecomportement alimentaire de canards élevés en lot. Pour évaluer l’effet de cet outil sur les performances decroissance et d’ingéré, deux lots de canards de chacun des trois types génétiques d’élevage ont été conduits enparallèle au DAC et à la mangeoire linéaire. Les données collectées ont été analysées de 5 à 7 semaines d’âgepour les deux modes d’alimentation, avec des lots de 25 à 64 animaux par combinaison type génétique xalimentation. A l’échelle de la semaine et du test, le gain moyen quotidien individuel, la consommationalimentaire et l’indice de consommation par lot ont été comparés entre DAC et témoin par type génétique. Ledispositif DAC ne montre pas d’effet significative sur la croissance des animaux. Les consommationsalimentaires sont similaires entre les deux modes d’alimentation, sauf pour le canard de Barbarie pour lequelenviron 12% des données sont perdues au DAC en raison de visites de plusieurs canards à la fois, pour lesquellesla consommation n’est donc pas attribuable. Ce point est en cours de résolution par modification de l’accès audispositif. Au-delà des données de performances qui confirment que l’élevage des canards au DAC n’a pasd’influence majeure sur leurs performances, cet outil permet également l’obtention automatisée de donnéesinnovantes sur le comportement alimentaire des animaux
Incremental learning with the minimum description length principle
No full textWhereas a large number of machine learning methods focus on offline learning over a single batch of data called training data set, the increasing number of automatically generated data leads to the emergence of new issues that offline learning cannot cope with. Incremental learning designates online learning of a model from streaming data. In non-stationary environments, the process generating these data may change over time, hence the learned concept becomes invalid. Adaptation to this non-stationary nature, called concept drift, is an intensively studied topic and can be reached algorithmically by two opposite approaches: active or passive approaches. We propose a formal framework to deal with concept drift, both in active and passive ways. Our framework is derived from the Minimum Description Length principle and exploits the algorithmic theory of information to quantify the model adaptation. We show that this approach is consistent with state of the art techniques and has a valid probabilistic counterpart. We propose two simple algorithms to use our framework in practice and tested both of them on real and simulated data
Increased soil organic carbon stocks under agroforestry: A survey of six different sites in France
No full textIntroduction: Agroforestry systems are land use management systems in which trees are grown in combinationwith crops or pasture in the same field. In silvoarable systems, trees are intercropped with arable crops, andin silvopastoral systems trees are combined with pasture for livestock. These systems may produce forage andtimber as well as providing ecosystem services such as climate change mitigation. Carbon (C) is stored in theaboveground and belowground biomass of the trees, and the transfer of organic matter from the trees to the soilcan increase soil organic carbon (SOC) stocks. Few studies have assessed the impact of agroforestry systems oncarbon storage in soils in temperate climates, as most have been undertaken in tropical region