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Ground-WAG-Er: A serious game for co-designing groundwater management instruments in Tunisia
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616694/) * Autres projets (id;sigle;titre): ;ClimBeR Initiative;(FRA) Building Systemic Resilience against Climate Variability and Extremes//International audienceExisting groundwater management instruments often fail to address groundwater degradation and overexploitation. In this article, we present a role-playing game, Ground-WAG-Er, developed to support local stakeholders in co-designing alternative management instruments for the sustainable management of groundwater resources on their territory. The game was played six times in Tunisia involving a total of 31 participants. We analyse three aspects: (1) the combinations of management instruments selected by the players, (2) the minimum conditions participants consider necessary for these instruments to be acceptable, and (3) players' behavioural intentions regarding the adoption of these instruments in reality. Our results reveal the game's limitations in achieving transformative impact on its own, and emphasize the need to integrate it into a broader participatory process. We provide several concrete avenues to enhance the game's impact
Influence of forest thinning on the soil fauna: a systematic review of current knowledge and research gaps
No full textInternational audienceAbstract Key message This systematic review shows that thinning effects on soil fauna abundance and species richness vary with thinning strategy and methodological approach. Positive responses are due to improved resources and favorable microclimate conditions, whereas negative responses were mainly associated with unfavorable microclimate conditions. However, current evidence remains fragmented, highlighting the need for standardized, comprehensive experiments to draw robust conclusions and generalize management recommendations. Context As harvesting and reforestation expand to meet bio-economy and renewable energy demands, forests face increasing pressure from both unsustainable practices and climate change. Forest thinning, widely used across many regions, alters forest structure, vegetation and microclimate, leading to cascading effects on soil biodiversity. Yet, compared to microbial communities, soil fauna remains comparatively understudied despite their diversity and central role in ecosystem functioning. Aims We conducted a systematic review to assess how forest thinning influences soil fauna. Results Only 41 articles were identified: 27 focused on macrofauna (170 observations), 20 on mesofauna (96), and 6 on microfauna (13). These experiments varied considerably in their forest thinning strategies, sampling methods and soil fauna metrics, making it difficult to conclude whether soil fauna abundance or species richness respond to thinning in a consistent way. Both positive and negative effects were reported. Reducing forest cover can lead to less favorable microclimatic conditions with cascading negative effects on soil fauna. Conversely, the resulting increase in understory vegetation biomass and diversity caused by forest opening can create more heterogeneous microhabitats and resources with cascading positive effects on soil fauna. Conclusion The observed variability in research approaches limits our mechanistic understanding of soil fauna response to thinning. We therefore emphasized recommendations for future research to improve methodological consistency and the robustness of findings
Advanced strategies for discrete simulations with three-dimensional R-shapes in Rockable framework
No full textInternational audienceThe Discrete Element Method (DEM) is widely used to simulate the mechanical behavior of granular materials across a broad range of applications and industrial domains. Particle shape is a key feature playing a crucial role for physics-fidelity of DEM simulations. However, accurately representing complex particle shapes within DEM frameworks presents significant challenges such as defining unambiguous contact normals or managing geometric singularities. Rigid particles are often modeled as convex polyhedra, which inherently suffer from ill-defined outward normal vectors at sharp edges and vertices. To represent non-convex geometries, these polyhedra must typically be combined, further increasing the computational and geometric complexity. In this work, we adopt an efficient and robust strategy to overcome these limitations by using R-shapes, defined as rounded-edge shapes, also known as sphero-polyhedra, obtained by sweeping a sphere of radius R along the edges and faces of a base polyhedral shape. This construction results in smooth surface transitions and circumvents common issues associated with traditional polygonal representations. This paper provides a detailed presentation of the implementation, structure, and advantages of R-shapes in DEM simulations. The proposed solutions are implemented in a fully open-source software package called Rockable, developed in C++, which integrates state-of-the-art numerical techniques and shared-memory parallelization for enhanced performance. Beyond the geometric modeling aspects, we also address several methodological challenges, including the treatment of contact elasticity and the numerical integration scheme. The combined contributions of this work offer a practical and efficient framework for simulating complex particle shapes in DEM with high physics fidelity and computational efficiency. Program summary Program Title:Rockable CPC Library link to program files: (to be added by Technical Editor) Developer’s repository link: https://github.com/richefeu/rockable Licensing provisions:CeCILL-B Programming language:C++11 Supplementary material: Nature of problem(approx. 50-250 words): The open-source software Rockable addresses key challenges in simulating the mechanical behavior of granular materials using the Discrete Element Method (DEM), widely applied in both industrial applications and academic studies particularly where particle shape plays a critical role. Accurate modeling of the diversity of particle shapes in DEM remains non-trivial, due in part to ambiguities in defining contact normals. Rigid particles are often represented as convex polyhedra, which suffer from poorly defined outward normals at edges and vertices. Additionally, modeling non-convex shapes typically requires aggregating multiple convex elements, increasing complexity. Rockable resolves these issues through the use of R-shapes, or sphero-polyhedra, obtained by sweeping a sphere of radius R along the edges and faces of a polyhedral base. Developed in C++, Rockableintegrates state-of-the-art numerical techniques and supports shared-memory parallelism for high-performance simulations. It also addresses key physical modeling challenges, including contact elasticity and particle breakage. Solution method(approx. 50-250 words): Rockable implements a geometry-based contact detection algorithm for R-shapes, relying on the classification of contacts into four elementary types: vertex-vertex, vertex-edge, vertex-face, and edge-edge. This systematic approach provides a unified framework for computing contact points and their associated local frames. A key advantage of this method is its ability to reduce complex contact scenarios, such as face-face interactions, into combinations of these fundamental cases. This modular treatment not only improves robustness and computational efficiency but also extends naturally to non-convex and hollowed shapes. The framework is designed to be extensible, making Rockable a versatile tool for DEM-based modeling of irregular and evolving particle geometries
Nutrient Enrichment by Poultry Biochar Reshapes Soil Microbial Networks, Reducing Interaction Complexity in Tropical Sandy Soils
No full textInternational audiencePurpose This study evaluated how poultry manure-derived biochar influences the structure, diversity, and co-occurrence networks of soil bacterial communities in nutrient-poor tropical sandy soils. We examined the trade-off between improved soil fertility and potential simplification of microbial networks, testing the hypothesis that high biochar rates would enhance nutrient availability but reduce microbial complexity and diversity. Methods A field experiment was conducted over two years in sandy soils of northeastern Brazil, applying poultry biochar. We used six treatments: (a) control (no amendments), (b) low-rate biochar (Bio_10t = 10 t ha⁻¹), (c) high-rate biochar (Bio_40t = 40 t ha⁻¹), (d) chicken manure (E.Av = 5 t ha⁻¹), (e) synthetic mineral fertilizer (Mineral = NPK), and (f) poultry manure (C.Av = 10 t ha⁻¹). Soil chemical properties were assessed, and bacterial communities were analyzed using 16 S rRNA gene sequencing. Network analyses were performed using SparCC and NetCoMi, and multivariate statistics determined key environmental drivers. Results High biochar inputs increased organic C, P, and K levels, leading to a distinct shift in microbial community structure. However, this nutrient enrichment reduced amplicon sequence variants richness by 22.4% (from 3,250 to 2,521) and Shannon diversity by 3.6% (from 7.16 to 6.90) relative to the control. Network analysis showed substantial simplification of microbial interactions: the control treatment had 3,116 co-occurrence edges, which fell to 1,423 under low biochar (Bio_10t) and 1,849 under high biochar (Bio_40t)—reductions of 54% and 40%, respectively
Isolation and characterization of 16 new microsatellite loci markers for the European red squirrel (Sciurus vulgaris)
No full textInternational audienceBackground Eurasian red squirrels (Sciurus vulgaris) are common in Europe and Asia, but are declining in many regions across their range. As continental European populations are now facing current and future threats from invasive species in addition to existing anthropogenic pressures it will be important to carefully monitor these populations. Non-invasive genetic sampling methods are a useful tool in conservation assessments, but often require techniques such as microsatellite markers that can be used with lower quality DNA. It remains helpful to increase the resolution of these assessments by identifying additional genetic markers.We describe new microsatellite markers developed from European red squirrels from France and use them to assess genetic diversity in populations in southern France. Methods and ResultsWe used Illumina sequencing to characterize microsatellites from tissue samples of S. vulgaris. Using 7 tissue samples we assessed amplification and polymorphism in 48 microsatellite inserts and further evaluated 16 of these microsatellite loci in hair samples from 120 individuals from four populations. In the 104 samples for which those loci amplified, there was an average of 6.1 alleles amplified per locus, with mean observed and expected heterozygosities of 0.44 and 0.59, respectively. Only one locus showed significant deviation from HWE across all populations.The same locus exhibited a likely presence of null alleles.Conclusions We describe 16 new microsatellite loci, with caution required for one locus in analyses sensitive to null alleles. These new loci can help provide increased resolution in population genetic assessments of red squirrels in continental Europe.</div
Défi TextMine 2026 : « De la similarité sémantique aux grands modèles de langage »
No full textInternational audienceThis work explores different methods for the TextMine 2026 challenge, from simple semantic similarity to transformer-based models and Large Language Models (LLMs). I evaluate open-source and proprietary LLMs, including hybrid and RAG-enhanced approaches, and compare their performance on both public and private test splits. The best performance is achieved by GPT-5 combined with a RAG pipeline, demonstrating that TextMine is challenging enough to be an excellent benchmark for modern LLMs.Ce travail explore différentes méthodes pour le défi TextMine 2026, allant de la simple similarité sémantique aux modèles basés sur les transformers et aux modèles de langues de grande taille (LLMs). J’évalue des LLMs open-source et propriétaires, y compris des approches hybrides et enrichies par RAG, et compare leurs performances sur les jeux de test publics et privés. La meilleure performance est obtenue par GPT-5 combiné à un pipeline RAG, montrant que TextMine constitue un benchmark suffisamment exigeant pour évaluer les LLMs modernes
Farm motorization and expansion in Sub-Saharan Africa lead farmers to intensify legume cropping systems
No full textInternational audienceIn certain Sub-Saharan African countries, a transition is underway that involves increased motorization and herbicide use.This study is the first to investigate whether these recent changes are transforming the way legumes (cowpeas, ground-nuts, and Bambara beans) are grown by men and women across a range of farm types. Reducing this knowledge gap is crucial to ensure that legumes remain a sustainable lever for agroecological intensification in evolving farming systems.In Benin and Burkina Faso, 261 households were interviewed regarding their farming systems. A hierarchical clustering was used to identify farm types with contrasting constraints. Ten farm types were identified, ranging from a very small, highly constrained sorghum farm in Central-North Burkina (2.5 ha, no motorization) to a large maize-soybean farm owning tractors (62 ha). Our findings indicate that compared to home-consumed cereals (sorghum and maize) and cash crops (cotton and soybean), no farm prioritized traditional legumes at the farm level. While the most constrained farms in North Burkina Faso already dedicated 25–30% of their land to pure legume crops and frequently practiced legume-sorghum intercropping (61% of farms), an opposite trend was observed in West Burkina Faso and in Benin, where some constraints have been lifted with motorization. The use of motorization on the main crops and farm expansion has led farmers there to also intensify traditional legume cropping systems by using herbicides, simplifying crop rotations and avoiding intercropping. In all study sites, traditional legumes continue to be more highly valued by women than by men. This study identifies research perspectives tied to the dual challenge of implementing agroecological intensification with legumes in West Africa: small-scale subsistence farmers need financial and technical support due to land constraints, while larger, labor-constrained farms require mechanization and improved land access for women
: Anne-Laure Collard, Jeanne Riaux, Marcel Kuper (2024), Récits de recherche sur l’eau dans un monde interdisciplinaire, Éditions Quæ, 172 p. et Sami Bouarfa, Marielle Montginoul, Thomas Pelte et Éric Sauquet (2025), Comment partager l’eau en France à l’ère de l’anthropocène ?, Éditions Quæ, 184 p.
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Do stomatal movements have a limited dynamic range?
No full textStomatal movements are driven through the uptake and release of potassium (K + ) salts by guard cells, which surround a central pore. The extrusion of K + from guard cells occurs via GORK K + -efflux channels, but potentially the AtKUP2, 6 and 8 encoded K + - transporters also play role. To test the roles of At KUP and GORK proteins, gas-exchange experiments were conducted with mature Arabidopsis leaves. These experiments revealed that loss of KUP2, 6 and 8 lowered the stomatal conductance, while it increases in the GORK loss-of function mutant. Despite the difference in stomatal conductance, the changes in transpiration induced by light and ABA had the same amplitude in wild type and mutant lines. Our data suggest that stomata have a limited dynamic range that is not affected by mutations in KUP2, 6 and 8, or GORK. We propose that these rapid stomatal movements depend on uptake and release of K + , inorganic and small organic anions. Consequently, changes in stomatal opening beyond the dynamic range will depend on osmolytes that cannot be rapidly released, such as larger organic anions and amino acids
The BIOMASP+ project on biosphere-atmosphere exchanges and their role in air pollution in the subtropical megacity of São Paulo: motivations, methods and preliminary observations
No full textInternational audienceAir pollution, especially in urban areas, is the result of a complex mixture of natural and anthropogenic emissions and their atmospheric processing. It causes millions of premature deaths worldwide and affects plant metabolism, which in turn alters the emissions of Biogenic Volatile Organic Compound (BVOCs) by plants. By taking the subtropical Metropolitan Area of São Paulo (MASP) as a natural laboratory, the BIOMASP+ project (BIOsphere-atmosphere interactions in the Metropolitan Area of São Paulo - plus) a ims to evaluate the interplay between the biosphere and secondary pollution (ozone and SOA formation and aging). The Brazilian Atlantic Forest (Mata Atlântica) is the target ecosystem as the fifth biodiversity hotspot in the world. Here we present the scientific motivations of the project, its methodology and the preliminary observations from the Special Observation Periods of year 2023 (SOP1, 2, 3 and 4). BIOMASP+ is (i) integrative, by combining in-situ/remote/laboratory observations andmodeling, (ii) multidisciplinary, addressing micrometeorology, urban climate, atmospheric chemistry and biology. The project involves multiple nested scales: from leaf to above-canopy levels, from very short time (microseconds) to multi-year scale, from few millimeters (turbulence scale) to synoptic scale. In particular, the experimental effort relies on the implementation of two contrasting supersites (primary forest and urban forest) with a 30-m and 20-m flux towers, respectively, and a variety of state-of-the-art instruments. Ambient observations and the quantification of BVOC emissions have highlighted the complex interactions between meteorology, atmospheric composition of pollution, biogenic emissions of representative remnants of the Atlantic Forest and anthropogenic emissions