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Monitoring of soil biodiversity: Challenges and lessons learnt from the second year of the Biodiversa+ pilot "Soil biodiversity in protected, near-natural forests"
No full textThis document is the second-year report from the Biodiversa+ pilot project "Soil biodiversity in protected semi-natural forests" (launched January 2023). The pilot’s objectives include developing feasible experimental design and common protocols, testing eDNA methods for high-resolution data, evaluating the applicability of soil biodiversity-related Essential Biodiversity Variables (EBVs), linking the pilot to international and EU policies, and assessing transnational coordination and governance. This report focuses on the methodological challenges encountered in transnational soil biodiversity monitoring, presenting a comparative analysis of traditional methods (pitfall traps and hand-sorting of soil cores) and molecular methods (eDNA metabarcoding). The report details the findings from applying these methods, highlighting their respective strengths and limitations for monitoring soil macro- and mesofauna. Traditional methods proved effective for evaluating macro-invertebrates at the family level but are time-consuming and require expert knowledge for species-level identification. The application of eDNA using universal 18S primers showed potential but also revealed significant methodological issues requiring further development. These include limitations in taxonomic resolution for key invertebrate groups, the need for increased soil sample quantity for DNA extraction, the incompleteness of reference databases, challenges related to sample storage, and complexities in data interpretation (e.g., PCR amplification bias affecting abundance estimates). The report concludes that traditional methods remain valuable for assessing macro-invertebrates at the family level but are time-consuming and require expert knowledge. Molecular methods, particularly eDNA, show promise but require significant improvements in primers, sample quantity, reference databases, and data interpretation before standard adoption for soil invertebrate monitoring. This report offers critical insights for establishing robust transnational soil biodiversity monitoring
Phosphore : mieux gérer la ressource, mieux protéger les milieux aquatiquesEtat des lieux et pistes opérationnelles
No full textPhosphore : mieux gérer la ressource, mieux protéger les milieux aquatiquesEtat des lieux et pistes opérationnellesInternational audiencePhosphore : mieux gérer la ressource, mieux protéger les milieux aquatiques État des lieux et pistes opérationnellesSynthèse du cycle de webinaires organisé par l'Office français de la biodiversité (OFB), de novembre 2022 à février 2023, en collaboration avec les agences de l'eau. AVRIL 2025 N° 97 LES Rencontres La pollution par le phosphore, cause majeure de l'eutrophisation des milieux aquatiques, a largement reculé au cours des années 1990 sous l'effet d'actions publiques. Cependant, depuis deux décennies, les concentrations stagnent et augmentent même dans certaines masses d'eau, entraînant ainsi leur dégradation et des impacts croissants sur les écosystèmes. Quelles en sont les raisons, entre legs des pratiques passées et apports actuels ? Comment le phosphore se retrouve-t-il dans les eaux ? Quels leviers techniques et/ou sociétaux permettraient de réduire les rejets à la source ou en limiter les flux ? Reposant sur un état des lieux du phosphore dans les milieux aquatiques, ces webinaires dressent un panorama des solutions et des pistes pour retrouver une trajectoire vertueuse, du traitement des eaux usées aux pratiques agricoles, et ouvrent la réflexion pour une gestion plus sobre et raisonnée de cette précieuse ressource. Nuage de mots créé lors du webinaire d'ouverture du 10 novembre 2022 : « Le phosphore, en un mot, qu'évoque-t-il pour vous (enjeu, problématique…) ? » Source : N. Bougon, 2022. N°97 AVRIL 2025 LES Rencontres Figure 2. Les neuf limites planétaires (Source : Azote pour Stockholm Resilience Centre,d'après Richardson et al., 2023).</div
Pourquoi les ruminants extensifs sont centraux pour des systèmes agrialimentaires durables en Europe: Comment la prise en compte de la courte durée de vie du méthane avec le PRG* permet de résoudre le nexus biodiversité/climat
No full textCe powerpoint est une synthèse de l’étude commandée par l’OFB à AScA sur le thème : Analyse des métriques climat et conséquences sur la compréhension de la contribution des ruminants au changement climatique et sur l’agenda de conservation de la biodiversitéIl présente les principaux points du raisonnement et de conclusions faisant l’objet de deux documents constitutifs du corps de l’étude, mais ne remplace pas tous les points de cadrage et de méthode développés dans ces documents- 1er document : Comportement du méthane dans l’atmosphère et analyse des enjeux techniques du PRG100 et du PRG* - application au secteur des ruminants en France et en Europe (Poux, Allen, Cain, Patel, 2025) — Identifiant HAL : hal-05033353- 2nd document : Revisiter les enjeux climat et biodiversité en lien avec les ruminants en Europe à l’aune des nouvelles métriques climat : arguments pour un élevage agroécologique favorable au climat et à la biodiversité (Poux, 2025)Pourquoi les ruminants extensifs sont centraux pour des systèmes agrialimentaires durables en EuropeComment la prise en compte de la courte durée de vie du méthane avec le PRG* permet de résoudre le nexus biodiversité/climat Synthèse de l'étude OFB : Analyse des métriques climat et conséquences sur la compréhension de la contribution des ruminants au changement climatique et sur l'agenda de conservation de la biodiversité</div
Multilayer Network Analysis Reveals Connectivity Synergies Between Protected Area Levels Across Various Taxonomic Groups
No full textInternational audienceAssessing connectivity among protected areas (PAs) is vital for conserving species movement in fragmented landscapes; yet, most studies consider only a few taxa and ignore interactions between protection levels. We combined a recently developed framework to identify ecological continuities with a multilayer spatial network approach to quantify connectivity among strict and non‐strict PAs, and their synergies, across metropolitan France. This was carried out for 397 vertebrate, invertebrate, and plant species from the national PA plan at an ecologically relevant 1‐km 2 resolution. Results emphasized that non‐strict PAs largely contribute to protected habitat accessibility across taxa, though connectivity patterns varied between taxonomic groups. Importantly, we showed that non‐strict protections can synergize with strict protections to substantially enhance the amount of accessible protected suitable habitats. Our findings highlight the need for coherent PA expansion, strategically improving connectivity. Synergistic PA planning and corridor designation, leveraging new conservation tools, should notably provide viable solutions
How the built environment influences pollinator diversity in urban landscapes: An analysis of French cities using participative data
No full textInternational audienceMost of our knowledge of the factors favoring pollinating insects in urban areas arises from studies focused on urbanization gradients. However, when it comes to differentiating among types of built fabric according to their capacity to host pollinators, few information can be found. In this paper, we study the influence of built fabric patterns on pollinating insects using open data from citizen science and covering the whole of France. With pollinator richness as the response variable in a model focused on urban agglomerations, we test the relevance of spatial metrics describing the building patterns while accounting for other drivers such as plant species, season, climate, and the connectivity of herbaceous habitats. We divide the data into subsets covering varying ranges of building densities, to explore those for which built fabric types exhibit the greatest differences. Our results show that only a focus on moderate building densities reveals clear differences between built fabric types. In this case, the areas with old individual housing appear to be more favorable than other patterns dominated by individual housing built in the post-war period and in the late twentieth century. These results outline the potential of the coupling of participative naturalist data with geographical data
Exploring reserve and depth refuge effects on marine fish communities: Insights from environmental DNA metabarcoding
No full textInternational audienceAbstract Marine protected areas (MPAs) have been increasingly developed to protect fish communities and restore their ecological services. Shallow water fish populations may also find a natural refuge in the depths of the mesophotic reefs to escape overfishing and climate change. While a lot of knowledge has been acquired in the last decades about the effect of MPAs and, more recently, about mesophotic ecosystems, thanks to advances in monitoring methods, little is known about the effect of the interaction between protection and depth. Using environmental DNA metabarcoding, we sampled rocky fish assemblages of the Cap Roux no‐take marine reserve and the surrounding fished areas, covering several depth strata ranging from the surface to mesophotic depths. We found that protection, depth, and their interaction had a significant effect on fish diversity and assemblage composition. The vast majority of the 66 fish taxa identified in this study were detected inside the MPA. On the other hand, depth had a negative impact, with mesophotic reefs harboring the lowest diversity. Shallow protected locations were composed of rich fish assemblages, including targeted and threatened species that were rarely detected or even undetected outside the MPA and/or at mesophotic depths. In this study, depth does not seem to act as an efficient refuge for shallow communities. We suggest that the only effective protection comes from the MPA, highlighting the importance of these management tools for the long‐term conservation of fish populations
Operational monitoring of the water quality of French lakes and rivers from space
No full textInternational audienc
OPTILAC: Toward an operational in situ radiometric network in French lakes for remote sensing
No full textInternational audienceOptical remote sensing has become a key tool for monitoring the water quality of continental aquatic ecosystems, particularly lakes. To ensure robustness and operational reliability of this new monitoring, high-quality in situ radiometric measurements are essential for both the vicarious calibration of satellite sensors and the validation of water quality retrieval algorithms. The OPTILAC project aims to establish a network for measuring in situ optical properties of French lakes to support calibration/validation (CAL/VAL) activities related to remote sensing of surface temperature and watercolor. Within this framework, OPTICAL proposes the development of a standardized and robust protocol for measuring skin water surface temperature (Tskin) and water-leaving radiance in the solar spectrum, using different state-of-the-art radiometric systems installed on floating platforms in open water zones. A first prototype was deployed and tested in August on Lake Serre-Ponçon (France) to measure Tskin. The system operates at two spatial scales using infrared radiometers (IRTs) and temperature probes. At the station scale, Tskin is measured with two IRT radiometers (one pointing at the water, the other at the sky for glint correction), while sub-surface temperature (T-10, at 10 cm depth) is recorded with a submerged probe. At the pixel scale (4x4 m in this test), T-10 is measured using probes distributed homogeneously across the pixel area. This configuration allows for the estimation of Tskin variability at the pixel scale by extrapolating the Tskin–T-10 offset observed at the station scale. The probes are mounted on PVC rods anchored to the lakebed, forming a spatial grid. The probes are placed under the rods to limit the warming effect of sunlight. The radiometers are wired to a data controller (Raspberry Pi), while the temperature probes communicate via a LoRaWAN network. The IRT system and controller are powered by a 12V battery (transformed to 24 v) connected to a solar panel, and the probes have independent power supplies. Near real-time data transmission is enabled via 4G connectivity from the controller to a remote server. This poster presents the first measurements obtained using this system, including comparisons with airborne (drone) and satellite (Landsat) Tskin observations. This work contributes to the broader international effort to improve the availability and quality of in situ optical measurements of inland waters—data that are critical for advancing next-generation water quality remote sensing
Better to be bitten by a wolf or a dog? A quantitative comparative study of the jaw adductors architecture in wild and domestic canids
No full textInternational audienceVariability in the jaw musculature of canids has been studied in various species, including domestic dogs. Previous research suggests that despite significant morphological variation due to artificial selection, muscle architecture remains relatively stable in domestic dogs. However, the variability in the jaw musculature of wild grey wolves remains unexplored, primarily due to the difficulty of obtaining fresh cadavers. Here, we compare the muscle architecture (mass and physiological cross-sectional area) of a large sample of domestic dogs (n = 83) with that of French wolves (n = 91) and Alaskan wolves (n = 14). Our results reveal that wolves have a greater proportion of masseter muscle PCSA relative to total jaw adductors musculature, with values overlapping those observed in dog breeds selected for defense or attack (e.g., Mastiffs, Pit Bulls, and Dobermans). This adaptation likely enhances their ability to generate greater bite force at low jaw-opening angles, which is crucial for wolves when cracking the bones of large prey-deer constituting 55% and 75% of the diet in French and Alaskan wolves, respectively. Similarly, attack dogs benefit from this trait for capturing and restraining prey or threats. This study provides new insights into how natural selection shapes the jaw apparatus of wild canids and highlights the impact of artificial selection on domestic breeds