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Quelles salamandres tachetées trouve-t-on dans le sud-ouest de la France ?
No full textInternational audienceThe taxonomy and diversity of French populations of the fire salamander (Salamandra salamandra) have recently regained scientific interest, due to advances in genetic methods that help identify and define taxa. This study reanalyzes molecular data from two recent studies to clarify the distribution of S. salamandra subspecies in southwestern France. First, genome-wide RAD sequencing of 30 samples confirms the existence of two highly divergent genetic groups in the Pyrenees: one in the central and western parts, corresponding to S. s. fastuosa, and another in the eastern Pyrenees and the rest of France. This second group actually includes three distinct phylogeographic lineages that diverged during the Pleistocene: S. s. terrestris, and two others (in the Spanish Pyrenees and Montseny Mountains) linked to the debated S. s. “hispanica”, whose genetic traces also appear in France. Second, mitochondrial DNA sequencing of 98 individuals using minibarcoding refines the distribution boundaries of S. s. fastuosa and S. s. terrestris/“hispanica”, particularly identifying a transition zone in the central Pyrenees in the area where RAD data suggest genetic introgression. The findings support the intraspecific status of S. s. fastuosa and suggest that S. s. “hispanica” is absent from France in its pure form. This work lays the foundation for better understanding subspecies distributions and gene flow in French S. salamandra.La systématique et la diversité des populations françaises de Salamandre tachetée (Salamandra salamandra) a récemment reçu un regain d'intérêt scientifique, principalement en raison de nouvelles opportunités offertes par les méthodes génétiques pour mieux identifier et définir les taxons. Cet article propose une analyse des données moléculaires issues de deux récentes études afin de clarifier la distribution des sous-espèces de S. salamandra supposées dans le sud-ouest de la France. Premièrement, les analyses de milliers de marqueurs génomiques obtenus sur une trentaine d' échantillons par une approche RAD (Restriction Associated DNA) confirment l' existence de deux groupes génétiques très divergents dans les Pyrénées, l'un distribué sur la partie centrale et occidentale du massif, correspondant à S. s. fastuosa, l'autre occupant la partie orientale et s' étendant sur le reste de la France. Ce deuxième groupe consiste en trois lignées phylogéographiques distinctes ayant récemment évolué pendant le Pléistocène, l'une correspondant à S. s. terrestris, et les deux autres, restreintes aux Pyrénées espagnoles et au massif du Montseny, associées à la controversée S. s. "hispanica", dont des traces génétiques se retrouvent également en France. Deuxièmement, le séquençage d'un fragment d' ADN mitochondrial chez une centaine d'individus Pyrénéens par une approche de minibarcoding (génotypage de marqueurs code-barres) confirme et affine les aires respectives de S. s. fastuosa et S. s. terrestris/"hispanica" dans le sud-ouest français, notamment la présence d'une transition dans les Pyrénées centrales, là où les données RAD suggèrent de l'introgression génétique. Cette synthèse, qui soutient le statut intraspécifique de S. s. fastuosa et l'absence de S. s. "hispanica" en France, du moins sous sa forme pure, constitue un point de départ pour approfondir les connaissances sur la distribution géographique des sous-espèces de Salamandre tachetée et pour examiner les processus qui régulent le flux de gènes entre elles
The benefits of biodiversity for livestock farming
No full textLe résumé de la journéeThis issu follows on from the Carrefour de l'innovation agronomique, forum dedicated to Grazing livestock : the contribution of biodiversity, from soils to landscapes event that took place on 12 December 2024 at the Institut Agro in Rennes, France. It provide an update on knowledge and feedback showing the trajectories of agroecological livestock farms that make the most of wild and domestic biodiversity and the interactions between them. The development of agroecological practices is necessary to adapt agri-food systems to climate change and its impacts, and to mitigate their environmental impact. Biodiversity has been identified as a key factor in the sustainability of farming systems in their environmental ecosystems, combining the genetic diversity of domestic species with that of wild species. This Agronomic Innovation Forum will present results on domestic biodiversity in herbivore farming and the environmental biodiversity impacted and mobilised, from the scale of soils to that of landscapes.International audienceLivestock farming and biodiversity are at the heart of local and global issues, particularly in relation toclimate change. Although antagonisms are sometimes observed, biodiversity, whether agrobiodiversityor spontaneous biodiversity, must be seen as an asset for the sustainability of livestock farming and alever for redesigning production systems. In particular, grassland biodiversity can play a central role.Multiple benefits can be expected in terms of productivity, including quality, but also resilience to a numberof hazards, including climatic ones. By adopting the principles of agroecology, it is possible to fosterpositive interactions and avoid antagonisms. The corresponding approaches must consider thecharacteristics of the system concerned and ensure that aspects other than biodiversity are alsoconsidered (workload, farm economic model, etc.)
BDRest, une base de données française des opérations de restauration en milieux terrestres
No full textNational audienceThe Nature Restoration Regulation, which came into force on August 18, 2024, combines an overall long-term nature restoration goal for the EU's land and sea areas with binding restoration targets for specific habitats and species. What is the current status? How much land has been restored? Which ecosystems have been restored? What restoration targets have been set? What techniques have been used? It is currently impossible to answer these questions (in France and in most other countries). This is because there is no inventory of restoration operations that takes into account the characteristics of the areas that have undergone ecological restoration. However, this is essential not only for evaluating the achievement of national objectives, but also for informing government agencies, practitioners, students, and researchers about the occurrence of restoration operations in their areas of expertise or geographical zones. The long-term goal of the BDRest database is to list all ecological restoration operations and their metadata. The test filling phase ended in 2025. We will present the possible uses of the database, a preliminary summary of the operations already entered in the database, and discuss possible developments for the database. This will involve identifying as many restoration projects as possible while establishing links with France's national restoration plan and the various stakeholders involved in ecological restoration.Le Règlement pour la Restauration de la Nature, entré en vigueur le 18 août 2024, combine un objectif global de restauration de la nature à long terme dans les zones terrestres et maritimes de l’UE avec des objectifs contraignants de restauration pour des habitats et des espèces spécifiques. Où en est-on actuellement ? Quelle surface a fait l’objet d’une opération de restauration écologique ? Quels écosystèmes ont été restaurés ? Quels objectifs de restauration ont été fixés ? Quelles techniques ont été utilisées ? Il est actuellement impossible de répondre à ces questions (en France, et dans la plupart des autres pays). En effet, il n’existe pas de recensement des opérations de restauration prenant en compte les caractéristiques des espaces ayant fait l’objet d’opérations de restauration écologique. C’est pourtant primordial pour non seulement évaluer l’atteinte d’objectifs nationaux, mais aussi pour informer services de l’état, praticiens, étudiants ou chercheurs de l’occurrence d’opération de restauration dans leurs domaines d’expertise ou leurs zones géographiques. La base de données BDRest a pour objectif, à long terme, de répertorier l’ensemble des opérations de restauration écologique et leurs métadonnées. La phase de remplissage test s'est terminé en 2025. Nous présenterons les usages qui peuvent être faits de la base de données, une synthèse préliminaire des opérations déjà entrées dans la base et discuterons des évolutions possibles de la base de données. Il s’agira notamment de recenser un maximum d’opérations de restauration tout en créant du lien avec le plan national de restauration français et les différents acteurs de la restauration écologique
Colluding against Environmental Regulation
No full textNational audienceWe study collusion among firms against imperfectly monitored environmental regulation. Firms increase variable profits by violating regulation and reduce expected noncompliance penalties by violating jointly. We consider a case of three German automakers colluding to reduce the effectiveness of emissions control technology. By estimating a structural model of the European automobile industry from 2007 to 2018, we find that collusion lowers expected noncompliance penalties substantially and increases buyer and producer surplus. Due to increased pollution, welfare decreases by €1.57–5.57 billion. We show how environmental policy design and antitrust play complementary roles in preventing noncompliance
Human-Robot Interactions in Investment Decisions
No full textNational audienceWe study the introduction of robo-advising on a large set of Employee Saving Plans. Differently from many services that fully automate portfolio decisions, our robo-advisor proposes investment and rebalancing strategies, leaving investors free to follow or ignore them. The resulting human-robot interactions occur both at the time of the subscription and over time, as the robot sends alerts when the investor’s portfolio gets too far from the target allocation. We show that the robo-service is associated with an increase in investors’ attention and trading activities. Following the robot’s alerts, investors change their rebalancing behaviors so as to stay closer to their target allocation, which results in larger portfolio returns. Counterfactual returns induced by automatic rebalancing by the robot would be only slightly higher, suggesting that on average the financial cost of letting investors retain control is not large
Physiological and behavioural responses of wandering albatross chicks (Diomedea exulans) to novel and non-novel predators
No full textInternational audienceIn long-standing predator-prey systems, prey typically evolve costly responses to predation risk. How prey respond to novel predators is less investigated. We explored physiological (corticosterone, triglyceride), morphological (body condition) and behavioural (defensive posture) responses of wandering albatross (Diomedea exulans) chicks to a novel predator, the feral cat (Felis catus) in Kerguelen archipelago. We implemented a semi-experimental design to increase the variance in cat abundance by regulating cat populations in certain zones of the study colony. The aforementioned chick traits were then monitored and analysed at the zone scale, by comparing nests located within regulated and non-regulated zones, and at the nest scale, by recording cat abundance through intensive camera traps monitoring. This fine-scale approach further enabled us to investigate how chicks responded to southern giant petrels (Macronectes giganteus), an opportunistic predator-scavenger that has co-evolved with albatrosses. Cat abundances had no effect on chick traits. In contrast, higher abundances of giant petrel were associated with an elevated rate of corticosterone increase and lower triglyceride levels. In accordance with these results suggesting a more accurate perception of predation risk mediated by giant petrels than by cats, chicks were more prone to display a defensive posture when facing a giant petrel than a cat. We discuss these results in the light of contrasting evolutionary histories and predation patterns between albatrosses and their predators, and we emphasise that studies of predator impacts on prey populations must consider both the direct and indirect effects of all predators, as well as their interactions
Exact Multiple Change-Point Detection Via Smallest Valid Partitioning
No full textWe introduce smallest valid partitioning (SVP), a segmentation method for multiple change-point detection in time-series. SVP relies on a local notion of segment validity: a candidate segment is retained only if it passes a user-chosen validity test (e.g., a single change-point test). From the collection of valid segments, we propose a coherent aggregation procedure that constructs a global segmentation which is the exact solution of an optimization problem. Our main contribution is the use of a lexicographic order for the optimization problem that prioritizes parsimony. We analyze the computational complexity of the resulting procedure, which ranges from linear to cubic time depending on the chosen cost and validity functions, the data regime and the number of detected changes. Finally, we assess the quality of SVP through comparisons with standard optimal partitioning algorithms, showing that SVP yields competitive segmentations while explicitly enforcing segment validity. The flexibility of SVP makes it applicable to a broad class of problems; as an illustration, we demonstrate robust change-point detection by encoding robustness in the validity criterion
Which factors impact calcium bioaccessibility in dairy and plant-based products during static in vitro digestion?
No full textInternational audienceCalcium deficiency is widespread worldwide. In western countries, the main source of dietary calcium are dairy products, although some plant foods can also contribute. This work aimed to determine the solubility and the bioaccessibility of calcium from various food sources and to investigate how food components impact these two properties. A static in vitro gastrointestinal digestion model (INFOGEST) was used for two types of samples: (1) model solutions consisting in calcium solutions to which a compound present in dairy or plant products presumed to interact with calcium was added and (2) plant and dairy products. Calcium bioaccessibility was determined by measuring the soluble calcium concentration relative to total calcium concentration in the samples. The soluble calcium content was measured at different times during gastric and intestinal digestion using inductively coupled plasma-optical emission spectrometry. In vitro digestion indicated that the low pH during the gastric phase promoted the calcium solubilization. During the intestinal phase, however, calcium solubility decreased due to the pH increase to about 7. Phosphate, palmitic acid, micellar casein and phytate appear to interact with calcium, decreasing its solubility in the intestinal phase, probably through the formation of insoluble complexes. The calcium bioaccessibility of dairy matrices (yogurt, cheese, milk) was particularly high (between 19 and 34 %). However, calcium bioaccessibility was more disparate for plant-based dairy alternatives (between 5 and 20 %) and whole plant foods (between 1 and 27 %). In terms of the quantity of bioaccessible calcium per serving, dairy products (yogurt, cheese, milk) were the best sources
Intra-wet season variation in rangeland fodder quality influences feed conversion, growth and methane emissions in West African zebu cattle
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616495/) * Autres projets (id;sigle;titre): FOOD/2019/410-169;CaSSECS;(EU) Carbon Sequestration and Greenhouse Gas Emissions in (Agro) Sylvopastoral Ecosystems in the Sahelian CILSS States// ;DeSIRA;(EU) Development Smart Innovation through Research in Agriculture//International audienceLivestock in sub-Saharan Africa is a major contributor to greenhouse gas emissions, particularly enteric methane (eCH4), with emissions intensities and yield often elevated. In this region, wet-season rangeland fodder is the primary feed source for livestock. This study evaluated the effects of fodder growth stage and feed allowance on feed intake, digestibility, average daily gain (ADG), feed conversion ratio (FCR), and eCH4 emissions in cattle. Over a 112-day period, including a 14-day adaptation and a 98-day data collection phase, ten Sudanese Fulani zebu bulls (52 ± 1.2 months of age, 195 ± 14.6 kg body weight) were fed green rangeland fodder. They were divided into two groups of five animals each: one received fodder at a high allowance level of 4.5 % of body weight (BW) dry matter (DM) basis (4.5ING), while the other received 2.5 % of BW (2.5ING). Voluntary intake, digestibility, and eCH4 (GreenFeed®) were measured daily across three fodder growth stages: vegetative stage (VeS), reproductive stage (ReS), and mature stage (MaS). ADG and FCR were assessed fortnightly. DM intake decreased progressively from VeS to MaS with the highest values recorded for 4.5ING (P < 0.05). Digestibility was affected only by growth stage, decreasing from VeS to MaS (P < 0.05). Both ADG and FCR were influenced by fodder growth stage and feed level. The lowest eCH4 yield and intensity were observed in VeS (P < 0.05). Fodder level influenced eCH4 intensity (P < 0.05). Intra-wet season fodder growth stage significantly affected intake, digestibility, growth, and eCH4 emissions in cattle, while feed allowance influenced performance and eCH4 intensity. Significant interactions effects were observed between fodder growth stage and feed allowance for all parameters except digestibility. The best animal performance, along with the lowest eCH4 yield and intensity were observed in 4.5ING animals during VeS. These findings suggest that optimizing feed availability at the beginning of the wet season is an effective feeding strategy to enhance productivity while mitigating methane emissions in extensive livestock systems
Solid and liquid fractions of digestate: manure or slurry just like any others?
No full textInternational audienceBiogas digestates are increasingly used as organic fertilizers. However, their impact on soil microbiota quality remains debated. Indeed, little is known about soil microbial communities responses to a given digestate depending on i) the fraction applied – whole (FYM_WD), liquid (FYM_LD), or solid (FYM_SD) – and/or ii) the physicochemical properties of the receiving soil. In a 42-day microcosm experiment, we applied different fractions of a same digestate to three soils with contrasting physicochemical and climatic characteristics and compared their effects on the abundance and diversity of the soil microbial communities. The experiment also included four additional treatments: cattle manure (CM), cattle slurry (CS), a mineral fertilizer, and an unfertilized control. Forty-two days after application, a significant ‘treatment’ effect was observed on soil microbial indicators for the two coarser-textured soils (P < 0.05). In the sandy loam-textured soil, FYM_SD resulted in a 40 % greater soil microbial biomass than FYM_WD or FYM_LD (P = 0.05). The effect of FYM_SD on soil microbial biomass was equivalent to that of CM or CS (P > 0.05), whereas the effect of FYM_LD more closely resembled that of CS. Moreover, FYM_SD input resulted in a significantly different prokaryotic community structure compared to FYM_LD-fertilized soil, but was equivalent to that of the CM-fertilized soil (P > 0.05). In the loam-textured soil, FYM_SD input resulted in a 20 % lower prokaryotic richness than FYM_LD. Similarly, the fungal community structure was affected the digestate fraction (P = 0.04), and the effects of FYM_SD and CM on fungal community structure were comparable (P > 0.05). Overall, these results demonstrate that digestate fraction influence soil microbial communities in a soil-type dependent manner