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Earliest Danian outer neritic elasmobranch assemblages reveal an environmentally controlled faunal turnover at the Cretaceous–Palaeogene boundary in the northern Tethyan Realm (Austria)
No full textInternational audienceAbstract This study reports elasmobranch remains from two fossil‐rich horizons in the earliest Danian Olching Formation at Waidach, Austria. These outer neritic assemblages complement previous fine‐scale bulk‐sampling of latest Maastrichtian horizons at Waidach and document a regional elasmobranch faunal turnover across the Cretaceous–Palaeogene (K–Pg) boundary. The Danian assemblages show homogeneity in species richness and are dominated by squaliforms. The fauna comprises 16 species belonging to 12 genera including several new taxa ( Centrodeania rugosa gen. et sp. nov., Centrodeania annae gen. et sp. nov., Incognitorapax fernsebneri gen. et sp. nov., Scyliorhinus alaformis sp. nov.). Comparison with latest Maastrichtian assemblages from Waidach revealed a marked faunal turnover across the K–Pg boundary associated with an increase in species richness and shift in abundance from Squaliformes to Carcharhiniformes. This is associated with marked environmental changes from a deep marine, dysoxic setting in the Maastrichtian to a more oxygenated, shallower environment in the earliest Danian. The turnover was driven by environmentally induced regional changes in species geographic ranges. High diversity in the Danian fauna suggests that the habitability of the corresponding palaeoenvironment was preserved or recovered immediately after the K–Pg event. Comparison with other elasmobranch assemblages across the K–Pg boundary highlights a strong control of local palaeoenvironmental settings over the timing and magnitude of the turnover. Our study emphasizes the importance of successive sampling to disentangle local from general patterns of faunal turnover during the K–Pg event and to better assess the consequences of this extinction event over elasmobranch diversity
Integration of very high-resolution stereo satellite images and airborne or satellite Lidar for Eucalyptus canopy height estimation
No full textInternational audienceEucalyptus plantations cover extensive areas in tropical regions and require accurate growth monitoring for efficient management. Traditional in-situ measurements, while necessary, are labor-intensive and impractical for large-scale assessments. Very high-resolution satellite stereo imagery is playing an increasingly important role in the estimation of fine Digital Surface Models (DSMs) across landscapes. However, its ability to estimate canopy height models (CHMs) has not been widely investigated. This study investigates the integration of highresolution satellite stereo imagery from the Pleiades sensor with airborne or satellite Lidar data to estimate canopy height over eucalyptus plantations. Two study sites were selected in Brazil, representing flat and semimountainous topographies, Mato Grosso do Sul (MS) and Sao Paulo (SP), respectively. Digital Surface Models generated from Pleiades images (DSM P ) were combined with Digital Terrain Models extracted from airborne Lidar data (DTM ALS ) to create Canopy Height Models (CHM ALS ). The evaluation of the CHM ALS was based on two in situ canopy height measurements (H max and H mean ). For the SP site, the CHM ALSmax , which is the average height of top 10% pixel values within each plot, correlated well with in situ H mean , which is the average height of 10 central trees (r = 0.98), showing a bias of 1.4 m, RMSE of 3.1 m, and rRMSE of 18.5%. At the MS site, CHM ALSmax demonstrated a bias of 1.9 m, RMSE of 2.3 m, rRMSE of 17.3%, and r correlation of 0.92. Despite a tendency to underestimate heights below 20 m in young tree plantations with open canopy, the results indicate reliable canopy height estimation. The study also investigates the potential of Global Ecosystem Dynamics Investigation (GEDI) elevation data as an alternative to DTM ALS in absence of airborne Lidar data. The resulting CHM Gedi is promising but slightly less accurate than Lidar-based CHMs. The best GEDI-based CHM (CHM Gedimax ) showed a bias and rRMSE of 1.3 m and 20.5% for the SP site, and 2.2 m and 24.9% for the MS site. These findings highlight the potential for integrating Pleiades and Lidar data for efficient and accurate canopy height monitoring in eucalyptus plantations.</div
Quelles lectures en management international des sorties de marchés des grands distributeurs ? Illustration par le cas de Carrefour en Asie
No full textNational audienceWhile they are as numerous as cases of international entry, market divestment have received little interest from academic research and have often been assimilated to commercial, strategic or financial failures, through analyzes empirical studies often limited to organizational and national levels. In this qualitative empirical research based on a collection of external data (press and activity reports) and applied to the Carrefour entry in Asia, we analyze the entry-exit movements of the French distribution firm in a longitudinal perspective (2000 -2020) in order to explain its main exits from Asian markets. In the space of 20 years, the French group exits from almost all Asian countries (Japan, India, China, Indonesia, Thailand, etc.) even though this region was considered as a priority in the early 1990s. The results confirm the need for a combined analysis of exit motives and modalities and suggest the integration of a macro-regional and multi-level view of internationalization. Finally, this research offers several complementary readings. Our results suggest explanations of international divestment in terms of links between entries and exits, an analysis by the strategic actions-reactions of groups and competitors and outline the contours of a “step by step” model of firms’ exits from the international markets.Alors qu’ils sont aussi nombreux que les cas d’entrées à l’international, les retraits de marchés ont reçu peu d’intérêt de la recherche académiques et ont souvent été assimilés à des échecs commerciaux, stratégiques ou financiers, à travers des analyses empiriques souvent limités à des niveaux organisationnels et nationaux. Dans cette recherche empirique qualitative basée sur un recueil de données externes (presse et rapports d’activité) et appliquée à la présence asiatique de Carrefour, nous analysons les mouvements d’entrées-sorties de la firme de distribution française dans une optique longitudinale (2000-2020) afin d’expliquer ses principaux retraits des marchés asiatiques. En l’espace de 20 ans, le groupe français s’est retiré de la quasi-totalité des pays asiatiques (Japon, Inde, Chine, Indonésie, Thaïlande, etc.) alors que cette région était considérée comme prioritaire au début des années 90. Les résultats confirment la nécessité d’une analyse combinée des motifs et des modalités de sortie et suggèrent l’intégration d’un regard macro régional et multi-niveaux de l’internationalisation. Enfin cette recherche propose plusieurs lectures complémentaires. Nos résultats suggèrent des explications des retraits internationaux en termes de liens entre les entrées et les sorties, une analyse par les actions-réactions stratégiques des groupes et des concurrents et esquissent les contours d’un modèle « séquentiel » des sorties des firmes des marchés
Cranial anatomy of Indohyus indirae (Raoellidae), an artiodactyl from the Eocene of India, and its implications for raoellid biology
No full textInternational audienceThe raoellid artiodactyl Indohyus indirae is known from northern Pakistan and northwestern India, with substantial skeletal material found in the Sindkhatudi locality near Kalakot in Kashmir. Eight specimens from this locality, two of which exhibit deciduous dentitions, offer invaluable insights into cranial osteology of Indohyus indirae. We present a comprehensive examination of the cranial osteology of Indohyus, highlighting detailed unique features using this material. These specimens, though flattened dorsoventrally and mediolaterally, allow for anatomical observations. Previous literature has extensively employed these specimens for phylogenetic analyses indicating that Indohyus is a close relative of cetaceans. These findings are partly based on the material described here. Notably, the cranial morphology of Indohyus differs in several aspects from that of most early and middle Eocene artiodactyls. For instance, the rostrum of Indohyus is longer than that of most middle Eocene artiodactyls, resembling Eocene cetaceans. The positioning of the nasal opening above the incisors is similar to terrestrial artiodactyls. However, the ventral wall of the nasopharyngeal duct does not extend to the ear region, which distinguishes it from Eocene cetaceans. Moreover, the frontal bone is thick and has a concave profile, forming a dorsal shield for the laterally facing orbits. Furthermore, the tympanic bone has an involucrum, a feature that characterizes all cetaceans. These cranial features may be indicative of specific cranial functions and, given their similarity in some regards to Eocene cetaceans, could be related to the land-to-water transition. Further research, including explicit functional studies, is required to investigate these hypotheses
L’abattage rituel musulman entre enjeux moraux et industriels
No full textInternational audienceIssue de ma recherche doctorale, cette communication vise à rendre compte des controverses sur l’abattage rituel musulman des animaux d’élevage, que je propose d’analyser sous l’angle d’une friction, interne à l’industrie d’abattage, entre deux « économies morales » : l’une, dominante, de type humanitaire, l’autre, déviante de type islamique. A l’appui d’une enquête de terrain réalisée dans une quinzaine d’abattoirs (de bovins et de volailles) et auprès d’une centaine d’acteurs (industriels, services d’inspection de l’Etat, sacrificateurs et théologiens musulmans, etc.), je présenterai dans cette communication deux grands résultats issus de ma recherche. Je montrerai dans un premier temps qu’il existe en abattoir un « conflit d’intolérables » entre les deux économies morales qui se cristallise sur la question de l’étourdissement des animaux et se structure autour de l’opposition conscience/inconscience (côté humanitaire) versus vie/mort (côté islamique). Je montrerai dans un second temps que ce conflit masque en fait des similitudes dans les relations que les deux économies morales entretiennent avec l’industrie d’abattage. Je terminerai ma présentation en soulignant le fait que cette dialectique humanitaire-islamique, par le renvoi systématique des préoccupations morales et religieuses vers la question de l’étourdissement, sature à tel point l’espace moral qu’elle conduit à un affaiblissement, si ce n’est un effacement, de la critique des systèmes d’abattage industriels
Collaborative sensing of industrial pollution in the Gulf of Fos (France) – A return to common sense?
No full textInternational audienc
Revue de l'Hypothèse de Variation Spectrale : Vingt ans dans la mer tumultueuse de l'estimation de la biodiversité par télédétection
No full textInternational audienceTwenty years ago, the Spectral Variation Hypothesis (SVH) was formulated as a means to link between different aspects of biodiversity and spatial patterns of spectral data (e.g. reflectance) measured from optical remote sensing. This hypothesis initially assumed a positive correlation between spatial variations computed from raster data and spatial variations in the environment, which would in turn correlate with species richness: following SVH, areas characterized by high spectral heterogeneity (SH) should be related to a higher number of available ecological niches, more likely to host a higher number of species when combined. The past decade has witnessed major evolution and progress both in terms of remotely sensed data available, techniques to analyze them, and ecological questions to be addressed. SVH has been tested in many contexts with a variety of remote sensing data, and this recent corpus highlighted potentials and pitfalls. The aim of this paper is to review and discuss recent methodological developments based on SVH, leading progress in ecological knowledge as well as conceptual uncertainties and limitations for the application of SVH to estimate different dimensions of biodiversity. In particular, we systematically review more than 130 publications and provide an overview of ecosystems, the different remote sensing data characteristics (i.e., spatial, spectral and temporal resolution), metrics, tools, and applications for which the SVH was tested and the strength of the association between SH and biodiversity metrics reported by each study. In conclusion, this paper serves as a guideline for researchers navigating the complexities of applying the SVH, offering insights into the current state of knowledge and future research possibilities in the field of biodiversity estimation by remote sensing data
La crise du Covid-19 a-t-elle modifié les opinions à l’égard de l’interventionnisme public ? Une enquête auprès d’étudiants français
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Enteric methane emissions from zebu cattle are influenced by seasonal variations in rangeland fodder quality and intake
No full textInternational audienceRangeland fodder resources used to feed ruminants in the Sahel decline considerably in both quantity and quality from the wet to dry seasons. While it is widely assumed worldwide that this seasonality of fodder supply impacts intake levels and therefore enteric methane (eCH4) emissions, there are very few references based on in vivo measurements of eCH4 in this region. The purpose of this study was to test the assumption that the seasonality of fodder supply impacts intake levels and consequently eCH4 in ruminants. Thus, eCH4 was measured in vivo in Sudanese Fulani zebu cattle during three main seasons of the year (wet season: WS, cold dry season: CDS, and hot dry season: HDS). The experiment was carried out on 10 steers aged 32 months with an average (+/- SD) initial BW of 138 +/- 5.8 kg (i.e. 0.55 Tropical Livestock Unit - TLU) and kept in individual pens. Animals were fed with natural rangeland fodder harvested each season following herders' practices, i.e. green fodder in the WS and dry fodder hay in the CDS and HDS. Different levels of fodder were offered to the animals to reproduce the gradient of fodder availability on rangelands over the year (six trials): 3.3% BW during the CDS; 3.3, 2.3, and 1.4% BW successively during the HDS; and 2.3% in two sequential studies in the WS. Each trial lasted 3 weeks, split into 2 weeks of fodder adaptation and 1 week of data collection. The BW, quantity of voluntary DM intake, digestibility of DM digestibility and of OM digestibility, and eCH4 (GreenFeed (R) system) were measured for each animal. Fodder composition varied considerably between seasons (P < 0.05). The DM intake (g/kg BW per day) varied from 23.9 in CDS to 15.7 in HDS and 22.3 in WS (P < 0.001). The DM digestibility varied from 0.50 in CDS to 0.46 in HDS and 0.57 in WS. The eCH4 yields (g/kg DM intake per day) varied significantly from 25.2 in the CDS to 31.8 in the HDS and 20.5 in the WS. When extrapolated over a full year and irrespective of season, eCH4 emissions for steers amounted to 68.1 g/d (24.6 g/kg DM intake per day, 46.7 +/- 3.34 kg of eCH4/TLU per year). Variations in the various parameters recorded in different areas and during the main seasons must therefore be accounted for in national inventories to refine eCH4 data for ruminants in Sub-Saharan Africa
Construire des innovations couplées à l'échelle des territoires pour soutenir la réduction de l'usage des produits phytosanitaires en production maraîchère
No full textCe volume fait suite au Carrefour de l'innovation agronomique sur les leviers territoriaux pour réduire l’utilisation et les risques liés aux produits phytopharmaceutiques - restitution des projets lauréats Ecophyto II+ Recherche et Innovation qui s'est déroulé le jeudi 20 juin 2024 au ministère de l'agriculture.National audienceDespite the challenges of reducing the use of plant protection products to protect human health and the environment, the transition of market garden farms to agroecological cropping systems is proving difficult, particularly on farms oriented towards long distribution channels. How can we massify and accelerate their agroecological transition? Over a 4-year period, the INTERLUDE project combined interdisciplinary approaches (agronomy, ecology, plant health, economics) with agri-food system stakeholders in 4 territories in mainland France and the French West Indies. Through surveys of stakeholders in agri-food systems, we identified the barriers to the adoption of known agroecological practices or cropping systems capable of regulating pests and reducing the use of plant protection products. Then, thank to participatory methods, we co-designed and evaluated coupled innovations with stakeholders, that combine organizational, regulatory, institutional and/or social innovations to support the implementation of technical innovations (innovative agro-ecological cropping systems). A toolbox was developed to support stakeholders wishing to implement such agroecological design approaches in their territories. The role and expected skills of these facilitators of change were investigated. The results of the project encourage public policies to support change of agri-food system actors: training and financial support for change agents, and support for inter-knowledge and coordination mechanisms between actors of the territory and agri-food sector.Malgré les enjeux de réduction d'utilisation des produits phytosanitaires pour préserver la santé humaine et l'environnement, la transition des exploitations maraîchères vers des systèmes de culture agroécologiques se fait difficilement, en particulier dans les exploitations orientées vers les circuits longs. Comment massifier et accélérer leur transition agroécologique ? Le projet INTERLUDE a combiné pendant 4 ans des approches interdisciplinaires (agronomie, écologie, santé des plantes, économie) et participatives sur 4 territoires en France métropolitaine et aux Antilles. Grâce à des enquêtes auprès des acteurs des systèmes agri-alimentaires, nous avons identifié les freins à l'adoption de pratiques ou systèmes agroécologiques déjà connus, capables de réguler des bioagresseurs et de réduire l'usage des produits phytosanitaires. Par des dispositifs participatifs, nous avons co-conçu et évalué avec ces acteurs des prototypes d'innovations couplées, qui associent des innovations de natures organisationnelles, réglementaires, institutionnelles et/ou sociales afin de soutenir le déploiement d'innovations techniques (des systèmes de culture agroécologiques innovants). Une boite à outils pour soutenir les acteurs désireux de porter les démarches de conception dans les territoires a été produite. Le rôle et les compétences attendues de ces acteurs du changement ont été investigués. Les résultats du projet encouragent les politiques publiques à soutenir le changement des acteurs du système agri-alimentaire : formation et soutien financier des acteurs du changement, et soutien des dispositifs d'interconnaissance et de coordination entre acteurs des filières et des territoires