HAL Portal UG Universite de Guyane
Not a member yet
4796 research outputs found
Sort by
Résurgence du paludisme aux Comores : où en est-on de son élimination ?
No full textDepuis vingt ans, une lutte intensive est engagée contre le paludisme aux Comores, en Afrique australe. À terme, l’élimination de cette maladie dans ce pays n’est pas un rêve impossible, mais cet objectif demeure encore lointain. On fait le point sur la stratégie dite de « traitement de masse » mise en œuvre sur l’archipel, ses succès et ses limites.Lire plus : https://theconversation.com/resurgence-du-paludisme-aux-comores-ou-en-est-on-de-son-elimination-25996
Beyond Ecology: Land–Sea Governance, Policy, and Research in Réunion Island (2000–2024)
No full textInternational audienceCoastal areas are increasingly exposed and vulnerable to environmental degradation and climate change, requiring adaptive governance approaches that integrate the climate-environment-health nexus. In Réunion Island, a French overseas department and EU region, two decades of science-policy initiatives have aimed to improve coastal governance through stakeholder engagement, scientific knowledge integration, and deliberative processes. Building on the evolutionary governance theory framework, this study analyzes a body of 281 scientific research articles (2000-2024), 4 participatory projects (2005-2020), and 12 expert insights to identify land-sea governance challenges and opportunities. Scientific articles remain focused on diagnosing environmental problems rather than elaborating systemic solutions, with a predominance of ecological and conservation science. Participatory governance and long-term strategic foresight are underdeveloped, and while digital tools are widely used for environmental monitoring, their integration into decision-making remains insufficient. Key barriers include administrative fragmentation, weak institutional coordination, and difficulties in integrating scientific knowledge into policy processes. Four enablers emerge: strong political leadership, long-term institutional support, a shared strategic vision, and regional cooperation aligned with European and international frameworks. Additionally, Réunion's hybrid sociability, shaped by its colonial history, presents both challenges and opportunities for governance. While it may foster exclusivity, it can also facilitate trust-based collaboration. A dedicated land-sea governance structure could enhance multi-scale and multi-level coordination among stakeholders
SARRA-Py: A Python-based geospatial simulation framework for agroclimatic modeling
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/612815/)International audienceSARRA-Py is an open-source, Python-based adaptation of the long-standing SARRA crop model family–specifically building upon SARRA-H to enable spatially explicit agroclimatic simulations in tropical and data-limited environments. By leveraging Python's geospatial libraries (e.g., Xarray), SARRA-Py extends SARRA-H's proven crop physiology routines to large-scale, raster-based analyses, streamlines ingestion of diverse climate inputs with minimal preprocessing, and eases model customization via a modular code structure. Users interact with SARRA-Py primarily through Jupyter notebooks that provide guided workflows for data preparation, parameter configuration, and visualization of results. This design closes the gap between point-based crop models and broader geospatial frameworks, offering a practical tool for agricultural risk management, climate adaptation studies, and yield forecasting. Consequently, SARRA-Py fosters reproducible, scenario-based analyses and informs decision-making in vulnerable regions where water deficits, sparse ground observations, and climate variability threatens food security
Les enfants de l'or : entre la pépite et le brevet des collèges: Les expériences scolaires d'enfants de familles orpailleuses à Maripasoula, Guyane française
No full textInternational audiencePlus grande commune de France et implantée dans la forêt amazonienne, Maripasoula est frontalière du Suriname et du Brésil. Découverte, puis administrée pour ses richesses aurifères, la commune abrite encore aujourd’hui une activité d’orpaillage dense. Si les premiers orpailleurs du début du XXe siècle étaient des hommes seuls venus des Antilles, aujourd’hui, ce sont des familles avec femmes et enfants, qui arrivent et s’installent dans le territoire-frontière de Maripasoula. Pour certaines familles, la perspective de la réussite se situe dans la découverte d’une pépite qui changera le cours de leur vie, pour d’autres, l’école française de Maripasoula apparaît comme une possible intégration à la société. Toutefois, l’or des travailleurs et des travailleuses de Guyane reste une chimère qui maintient souvent les familles les plus précaires dans une dette permanente : celle qui les oblige à retourner « en forêt » quand les gains sont épuisés, celle qui les maintient dans l’attente. Comment les familles migrantes de l’or allient-elles la scolarisation de leurs enfants et leur activité d’orpaillage illégal ? Est-ce tout simplement possible ? Quelle place prend le territoire-frontière autour de Maripasoula dans les stratégies et les expériences scolaires vécues par les enfants et les jeunes migrants de l’or
Human–nature relationships through the lens of reciprocity: Insights from Indigenous and local knowledge systems
No full textSpecial Feature: Examining human–nature relationships through the lens of reciprocity: insights from Indigenous and Local KnowledgeInternational audienceIn the context of climate change, biodiversity decline and social injustice, reciprocity emerges as a way of living and being in this world that holds transformative potential. Concepts of reciprocity vary and are enacted in specific cultural practices grounded in Indigenous and local knowledge systems. This editorial synthesises first‐hand evidence of how practising reciprocity can result in positive reciprocal contributions between people and nature. It also offers a theoretical justification of why considering reciprocity can lead to more equitable, inclusive and effective conservation and sustainability policy and practices, contributing to curving the colonial baggage of academic inquiry and development action. Nurturing reciprocal relations between people, especially between academics and Indigenous Peoples and local communities, is a necessary first step to identifying pathways whereby living in harmony with nature can be achieved.En el contexto actual de cambio climático, declive de la biodiversidad e injusticias sociales, la reciprocidad emerge como una forma de vivir y ser en este mundo con potencial transformador. Los conceptos de reciprocidad son diversos y se materializan en prácticas culturales específicas basadas en sistemas de conocimiento Indígenas y locales. Este artículo editorial sintetiza evidencia de cómo las prácticas de reciprocidad pueden dar lugar a contribuciones recíprocas positivas entre las personas y la naturaleza. El artículo también ofrece una justificación teórica de por qué la consideración de la reciprocidad puede conducir a políticas y prácticas de conservación y sostenibilidad más equitativas, inclusivas y eficaces, contribuyendo a reducir el bagaje colonial de la investigación académica y las estrategias de desarrollo sostenible. Fomentar las relaciones recíprocas entre personas, especialmente entre académicos y pueblos Indígenas y comunidades locales, es un primer paso necesario para identificar vías que permitan vivir en armonía con la naturaleza
Fonder la réglementation sur les réalités locales
No full textPour que les mesures de gestion des espaces et des espèces marines soient appropriées et appliquées, il importe de considérer les principaux acteurs concernés et les réalités locales. Les collectivités de la Nouvelle-Calédonie expérimentent différentes approches pour ajuster leurs politiques environnementales aux enjeux sociaux et écologiques
Coupling high resolution meteorological models with neural networks for flash flood forecasting: implementation on a Southern France basin
No full textInternational audienceFlash floods are an important hazard that particularly affects the Mediterranean region. Flood forecasting using simulation tools adapted to this context is therefore a crucial issue. In exposed regions, the difficulty of measuring and forecasting the spatial variability and intensity of rainfall, as well as the difficulty of identifying processes at the necessary time and space scales, has often led to the use of highly conceptual - or even statistical - models that make few assumptions about hydrological processes. Among these, neural networks have proven their relevance for flash flood forecasting. However, without hydrometeorological coupling, flow forecasting is often limited to the response time of the basin, i.e. a few hours in general. The purpose is to find a way of increasing this lead time, which is often too short for crisis management.A flood forecasting model for the Gardon de Mialet basin (Southern France) is being developed as part of the HydIA joint laboratory funded by the ANR (French National Research Agency) and the Synapse company, with the aim of developing a range of hydrometeorological forecasting services based on artificial intelligence approaches. The use of gridded observed data, like in a meteorological model, has enabled the neural network model implemented (Multilayer Perceptron) to reduce its sensitivity to support change.In the absence of rainfall forecasts, performance decreases with the lead time. With perfect forecasts (observed data used as future data), performance remains high for lead times up to 24h. The model has been coupled with two high resolution weather models, AROME and ARPEGE (2.5km and 10km respectively), implemented by Météo-France for short-range numerical weather prediction. The use of forecasts from these meteorological models for the 49 events in the database enables us to identify the error generated by the hydrological model and that generated by the meteorological model, in comparison with perfect forecasts. Analysis of these errors opens operational perspectives for crisis management. It also makes it possible to improve model training based on perfectible forecast data, and to correct rainfall forecasting biases to achieve higher performance
Regional soil profile data reveals the predominant role of geomorphology and geology in accurately deriving digital soil texture maps in a tropical area
No full textAccurate information related to soil texture is essential for understanding key biological, chemical, and hydrological processes. However, soil data is scarce and unevenly distributed, especially in tropical regions, and global soil information products lack regional assessments, leading to high uncertainty. Here, we leveraged an unprecedented dataset of soil observations in a particularly poorly documented region, French Guiana, to identify the drivers of soil texture in such territory, develop digital soil maps of textural components, and provide an independent assessment of existing soil products at a regional scale. Specifically, we employed the random forest (RF) model to predict sand, clay and silt contents from multiple environmental variables describing geology, climate, and geomorphology. Results were evaluated through k-fold random and spatial cross-validation. We used our model to derive a soil texture map for French Guiana. We tested our map and global soil texture maps from the Harmonized World Soil Database (HWSD) and SoilGrids against 72 independent soil profiles collected in the region. Geomorphology and geology were the most important predictors of sand, clay, and silt contents in our model, yielding relatively good predictions (random cross-validation: R2 = 0.54, 0.76, and 0.10; spatial cross-validation: R2=0.26, 0.64 and 0.05; RMSE=10.92%, 6.38%, and 6.50%, for sand, clay, and silt contents, respectively). When evaluated on the independent dataset, both SoilGrids and HWSD exhibited poor performance, characterised by lower R2 (<0.07) and higher RMSE values (> 13%). Furthermore, HWSD and SoilGrids failed to capture the spatial heterogeneity of soil texture in the region, calling for caution when using such global products at local scale. Overall, our study emphasises the need for sustained effort in assembling distributed soil information, as well as meaningful soil predictors at local and regional scales
Canopy functional trait variation across Earth’s tropical forests
No full textInternational audienceTropical forest canopies are the biosphere’s most concentrated atmospheric interface for carbon, water and energy1,2. However, in most Earth System Models, the diverse and heterogeneous tropical forest biome is represented as a largely uniform ecosystem with either a singular or a small number of fixed canopy ecophysiological properties3. This situation arises, in part, from a lack of understanding about how and why the functional properties of tropical forest canopies vary geographically4. Here, by combining field-collected data from more than 1,800 vegetation plots and tree traits with satellite remote-sensing, terrain, climate and soil data, we predict variation across 13 morphological, structural and chemical functional traits of trees, and use this to compute and map the functional diversity of tropical forests. Our findings reveal that the tropical Americas, Africa and Asia tend to occupy different portions of the total functional trait space available across tropical forests. Tropical American forests are predicted to have 40% greater functional richness than tropical African and Asian forests. Meanwhile, African forests have the highest functional divergence—32% and 7% higher than that of tropical American and Asian forests, respectively. An uncertainty analysis highlights priority regions for further data collection, which would refine and improve these maps. Our predictions represent a ground-based and remotely enabled global analysis of how and why the functional traits of tropical forest canopies vary across space
A la rencontre des singes de Guyane
No full textNational audienceLa Guyane compte 8 espèces de primates, qui présentent des enjeux de conservation et de gestion différents. Sept sont présents sur tout le territoire, mais leur abondance locale est liée à des facteurs environnementaux et anthropiques