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De la perception aux strategies d’adaptation : pratiques de gestion locale du changement climatique en Nouvelle-Calédonie et Vanuatu
No full textInternational audienceAt the 92nd ACFAS conference, which took place from 5–9 May 2025 in Canada and was themed “Cross-Disciplinary Research Perspectives on Responsible Management Practices”, the CLIPSSA project (South Pacific Climate, Local Knowledge and Adaptation Strategies) showcased Pacific Island agriculture. In a presentation entitled 'From perception to adaptation strategies: local climate change management practices in New Caledonia and Vanuatu', Samson Jean Marie, a doctoral student in anthropology and geography working on the CLIPSSA project, presented the initial results of field surveys conducted as part of the project. He explained how farmers in these territories, who are at the forefront of climate change, are adapting their practices to cope with it.À l’occasion du 92e colloque de l’ACFAS, qui s’est tenu du 5 au 9 mai 2025 au Canada sur le thème « perspectives de recherche croisées sur les pratiques de gestion responsable », le projet CLIPSSA (Climat du Pacifique Sud, Savoirs Locaux et Stratégies d’Adaptation) a porté la voix des agricultures insulaires du Pacifique. Dans une communication intitulée « De la perception aux stratégies d’adaptation : pratiques de gestion locale du changement climatique en Nouvelle-Calédonie et au Vanuatu », Samson Jean Marie, doctorant en anthropologie et géographie au sein de ce projet, a présenté les premiers résultats de ces enquêtes de terrain. Il a exposé comment les agriculteurs de ces territoires, en première ligne face aux dérèglements climatiques, adaptent leurs pratiques pour y faire face
Deep-sea echinoderms (except holothurians) collected during the AleutBio expedition around the Bering Sea and the Aleutian Trench.
No full textInternational audienceDeep-sea ecosystems harbour a high amount of unknown species and echinoderms belong to the most abundant megafaunal taxa encountered in these habitats. In this work we present the echinoderms belonging to the classes Asteroidea, Echinoidea, Ophiuroidea and Crinoidea collected from the Bering Sea and the Aleutian Trench (3498–7254 m) during the AleutBio expedition (SO293) onboard the German vessel RV Sonne. The AleutBio expedition represents a significant addition to the general knowledge on deep-sea echinoderms (holothurians excepted) from the North East Pacific Ocean with 6115 specimens collected, belonging to 39 species within 31 genera, confirmed as distinct genetic entities using a barcoding approach. Several new putative species are discussed together with preliminary biogeographic patterns suggesting a wide distribution for many of the deep-sea echinoderms species. The role of the Aleutian Trench as a biogeographic barrier is unlikely for echinoderms and estimations of its richness are higher than previously thought
Un modèle combiné densité - vitesse sismique sous la France, le défi d’y intégrer la gradiométrie.
No full textNational audienceLe développement du réseau sismologique large-bande à l’échelle nationale dans le cadre de Résif, puis d'Epos-France, permet d’avoir une quantité, une qualité et une couverture de données inégalée sur le territoire français. Le projet FRlitho3D, financé par l'ANR, a pour objectif d’utiliser ces données pour fournir des modèles géophysiques de référence à l’échelle lithosphérique. Il s'agit par exemple d’inverser conjointement les délais de temps aux stations du réseau RLBP et les données gravimétriques et gradiométriques pour délivrer un modèle combiné de densité et de vitesses sismiques sous l’ouest de l’Europe, ce qui présente des problèmes de compatibilité des données
Effects of agricultural practices and crops on soil fauna and soil properties in tropical agroecosystems
No full textInternational audienceAt the interface with the other compartments of the earth, soil performs many vital functions for the planet and its inhabitants and is subject to current global changes. Today, more than ever, soil and its management are at the heart of many issues (food security, climate change, environment, health…) and maintaining its biodiversity through appropriate agricultural practices is a key challenge. The overall objective of this study was to assess soil fauna abundance and richness across different tropical cropping systems (intensive versus agroecological) and crop type (tomato, yam, pasture). We assumed that (i) agroecological practices will increase soil fauna abundance and taxonomic richness; (ii) agroecological practices will positively affect the ability of soil fauna to influence soil ecological properties, such as soil aggregation and chemical properties. Our results showed that the abundance and richness of soil macrofauna increased in the agroecological system compared to the conventional system. Our study also showed that crop type influenced soil fauna and should be taken into account to better understand the impact of agricultural practices on soil ecological properties
Detectability of the daily evapotranspiration cycle in superconducting gravimeter timeseries according to the measurement configuration
No full textInternational audienceEvapotranspiration (ET) is a key process of the water cycle in general and in ecohydrology in particular. Measuring ET in forest eco-hydrosystems allows us to gain a better understanding of the response of forests to drought events, and to better anticipate the effects of climate change. Punctual (e.g. lysimeters or sapflow measurements) or integrative measurement methods (e.g. eddy covariance tower) can be used to estimate ET at the forest stand scale but these methods are not without limitations (e.g., resolution issues, representativeness, not adapted to mountainous areas).Superconducting gravimeters can be used to study ET. These gravimeters can be deployed in both flat and mountainous environments. In this work, we studied the hydrological residuals (i.e., hydrologically induced gravity variations) of 5 superconducting gravimeters located in different contexts. We interpreted the daily decreases in the stacked hydrological residual as the loss of water mass due to evapotranspiration. These results were compared with those of the SimpKcET water balance model.The results underline that the detectability of the ET signal depends strongly on the configuration of the gravimetric station, the topography and the type of ecosystem. We show that gravimeters located on summit area and in a forested context can detect the seasonality of ET. Conversely, gravimeters located in flat or underground areas and with a significant masking effect are unable to detect ET.Gravimetry therefore has a strong complementarity with conventional methods used to study ET and could contribute to a better understanding of water fluxes in forested ecosystems
Concatenation fails to describe the anomalous radiation of giant cockroaches (Blattodea: Blaberidae) despite moderate to low discordance
No full textInternational audienceBackground Patterns of discordance between gene trees and the species trees they reside in are crucial to the coalescent vs. concatenation debate and may be key to resolving rapid radiations. However, errors in gene trees complicate the issue as topological errors can cause gene trees to appear erroneously discordant with the species tree. In this study, we evaluate the prevalence of discordance between gene trees and their species tree using an empirical dataset for a clade with a rapid radiation (Blaberidae). One key advance of our study is the use of complex, computationally intensive, selection-based codon models (FMutSel0 and SelAC) to identify the maximum likelihood gene tree. Our main hypothesis predicted that, if there are two competing topologies for a particular gene tree, then the one that is less discordant with the species tree will have less systematic error. ResultsOur experimental framework failed to show evidence for this, but only when discordance was measured in reference to a concatenation topology. In follow-up tests we see that the best candidate gene set yielded a coalescent species tree that was less discordant with gene trees. ConclusionsWe conclude from these tests that, although the frequency of discordance is on the low end of what is predicted by a range of modelling strategies, it is still extremely common overall and must be accounted for in order to achieve a biologically realistic outcome. These results allow us to support other relationships among blaberid cockroaches that were previously in flux as they now demonstrate molecular and morphological congruence. We suggest a few key improvements to the Blaberidae phylogeny, including identification of an anomaly zone spanning 10 backbone nodes and 6 additional nodes.</div
Marine heatwaves imperil emblematic reef fishes by altering the energetic landscape of coral reefs
No full textInternational audienceMarine heatwaves are increasingly common due to human‐induced climate change. Under prolonged thermal stress on coral reefs, corals can undergo bleaching, leading to mass coral mortality and large‐scale changes in benthic community composition. While coral mortality has clear, negative impacts on the body condition and populations of coral‐dependent fish species, the mechanisms that drive these changes remain poorly resolved. Specifically, little is known about the effects of coral bleaching on (1) the nutritional quality of corals, (2) nutrient acquisition in coral‐feeding butterflyfishes and (3) fish dietary selectivity and potential supplementary consumption of non‐coral prey. Here, we evaluate the response of obligate coral‐feeding butterflyfishes to a mass coral bleaching event in French Polynesia, which resulted in high coral mortality and a 50% decline in obligate corallivore density. We examine benthic and butterflyfish community composition over two decades, including a mass bleaching event in 2019 and multiple prior disturbances. We couple these data with surveys of butterflyfish feeding selectivity, high‐resolution molecular assays of gut contents and nutrient acquisition before, during and after the bleaching event. Contrary to previous studies, obligate corallivores did not strongly alter their feeding preferences for different coral genera in response to bleaching. They did not increase their consumption of non‐corals in response to coral mortality, and hard corals continued to dominate their diets (>90%). Instead, butterflyfishes targeted partially bleached corals that were likely releasing nutrient‐rich mucus, and they avoided fully bleached and dead corals that were likely nutrient‐depleted. Moreover, after bleaching, butterflyfishes exhibit reduced nitrogen assimilation, indicating that coral stress may adversely impact butterflyfish nutrient acquisition. Coupled with the increasing frequency of recurrent bleaching events, severe, long‐term nutritional impacts of coral bleaching on butterflyfish populations may jeopardize the persistence of coral‐feeding fishes in the future
The development of national sport policy and governance in Seychelles (1976–2014)
No full textInternational audienceThis article analyses the driving forces behind the development of politicaldiscourse and public policy on sport in the Seychelles between 1976 and2014. The data was collected through a detailed study of legislative textsgoverning local sport, coupled with a close reading of the archives of theSeychelles Nation, the main national daily; interviews with key stakeholders(policymakers, managers, foreign specialists on missions abroad) involved insport were also conducted during two field surveys. This analysis reveals howa small but determined network of stakeholders first had to make up for ashortage of sports facilities in the country and set up a centralisedorganisation. The Seychelles government then gradually adopted a rationalapproach to sport governance that focused both on democratisation (sportfor all, health, education, etc.) and on competitive aspects of sport
A new approach for proximal split minimization problems
No full textInternational audienceOne appealing a strategy that relies on an infimal post-composition approach very recently developed, we provide an alternative formulation of proximal split minimization problems. Then, Forward-Backward and Douglas-Rachford splitting algorithms will guide both the design and analysis of some split numerical methods. Their globally weakly convergence and remarks on the fact that these algorithms can be equipped with relaxed and/or inertial steps leading to improved 5 convergence guarantees are given
Référentiel des séquences génétiques des espèces de France : note pour la mise en place d'un nouvel outil national
No full textThe repository, which is the subject of this document, is a new national tool providing genetic sequences to:- Improve and objectify the reliability of taxonomic assignments derived from analyses of environmental samples or specimens using molecular techniques;- Improve the quality of occurrence data derived from molecular analyses of species present in French territories, and facilitate access, interoperability and reuse;- Pool efforts to construction, maintenance, and updating of reference sequence baseline by offering a public and shared reference systemCoordinated by PatriNat in collaboration with a scientific consortium that contributed to its construction and validation, the main aims of this document are to:1. Identify and characterize the needs and issues relating to the creation of a repository of genetic sequences under the Biodiversity Information System (BIS), by involving the stakeholders, including the National Museum of Natural History,2. Assess existing systems that could contribute to the creation of this repository,3. Propose a prefiguration of the genetic sequence repository through :- A list of quality criteria to be taken into account,- A taxonomic scope, a genetic scope and standards to be used,- Prefiguration of the repository architecture diagram,- Governance of the repository.While the priority groups are those targeted by public policies, the repository concerns eukaryotic species (Hexagon, Corsica and Overseas) present or having been present on national territory (native and introduced species) and species not present in France but for which France is setting up a specific monitoring system. The creation of this national repository thus represents a key issue for biodiversity inventory, monitoring and surveillance, and ultimately for biodiversity conservation.Le référentiel, dont il est question dans ce document, est un nouvel outil national mettant à disposition des séquences génétiques pour : • Améliorer et objectiver la fiabilité des assignations taxonomiques dérivées des analyses d’échantillons environnementaux ou de spécimens par des techniques moléculaires ;• Améliorer la qualité des données d’occurrence provenant d’analyses moléculaires portant sur les espèces présentes dans les territoires français, en faciliter l’accès, l'interopérabilité et leur réutilisation ;• Mutualiser les efforts de construction, de maintenance et d’alimentation des bases de séquences de référence, en proposant un référentiel public et partagé.Coordonné par PatriNat en collaboration avec un consortium scientifique qui a contribué à sa construction et sa validation, ce document a pour objectifs principaux de :1. Identifier et caractériser les besoins et les enjeux relatifs à la création d’un référentiel de séquences génétiques relevant du système d’information sur la biodiversité (SIB), en associant les parties prenantes, dont le Muséum national d’Histoire naturelle,2. Faire un état des lieux des dispositifs existants pouvant contribuer à la constitution de ce référentiel,3.Proposer une préfiguration du référentiel de séquences génétiques à travers :• Une liste de critères de qualité à prendre en compte,• Un périmètre taxonomique et un périmètre génétique et des standards sur lesquels s’appuyer,• Une préfiguration du schéma de l’architecture du référentiel,• Une gouvernance du référentiel.Si les groupes prioritaires sont ceux ciblés par des politiques publiques, le référentiel concerne les espèces Eucaryotes (Hexagone, Corse et Outre-mer) présentes ou ayant été présentes sur le territoire national (natives et introduites) et les espèces non présentes en France mais pour lesquelles la France met en place un dispositif spécifique de surveillance. La création de ce référentiel national représente ainsi un enjeu pour l’inventaire, le suivi et la surveillance de la biodiversité et in fine pour la conservation de la biodiversité