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The penetration of sunflower root tissues by the parasitic plant Orobanche cumana is intracellular
No full textInternational audienceKey message: Combination of in vivo confocal, large field and transmission electron microscopy approaches revealed how intimate the relationship between the parasitic plant broomrape (Orobanche cumana Wallr.) and its sunflower host (Helianthus annus L.) is at very early stages of their interaction
A framework for national-scale predictions of forage dry mass in Senegal: UAVs as an intermediate step between field measurements and Sentinel-2 images
No full textInternational audienceMonitoring available feed for livestock is a key factor for developing pastoralism in the Sahel, and satellite images has proven useful in monitoring dry mass on large spatial scales. This approach requires field measurements of dry mass (herbaceous and woody plants) to calibrate such models based on Earth observation data. However, the need for representative field measurements can be a challenge when considering the low spatial resolution of available satellite data. Unmanned Aerial Vehicles (UAV) can produce very high-resolution images, so we tested UAVs as an intermediate step between field measurements and satellite images, to bridge the difference in spatial scale. We used 43 orthomosaics from a red-green-blue (RGB) UAV sensor in combination with field measurements of herbaceous and woody dry biomass at sites located primarily in the northern/central and southernmost parts of Senegal. We developed a dry mass model trained with filed observed measurements to be applied on the UAV orthomosaics. The dry mass information obtained from these UAV maps was subsequently related to vegetation indices derived from Sentinel-2 data to produce a national-scale 10 m spatial resolution baseline map of herbaceous and woody dry mass for Senegal in 2020. We obtained a high correlation between dry mass derived from UAV and Sentinel-2 indices (R-2 = 0.91), suggesting a robust basis for national-scale mapping. Lastly, our map was compared with a state-of-the-art annual reference map based on satellite remote sensing. This comparison showed a difference of 21 million tons of dry mass at national level. We concluded that bridging the spatial gap between field and satellite observations using spatially representative UAV data collection is a cost-effective approach for accurate mapping of dry mass at national level using freely available Sentinel-2 satellite data
Hy-TeC: a hybrid vision transformer model for high-resolution and large-scale mapping of canopy height
No full textInternational audienceAccurate and timely monitoring of forest canopy height is critical for assessing forest dynamics, biodiversity, carbon sequestration as well as forest degradation and deforestation. Recent advances in deep learning techniques, coupled with the vast amount of spaceborne remote sensing data offer an unprecedented opportunity to map canopy height at high spatial and temporal resolutions. Current techniques for wall-to-wall canopy height mapping correlate remotely sensed information from optical and radar sensors in the 2D space to the vertical structure of trees using lidar's 3D measurement abilities serving as height proxies. While studies making use of deep learning algorithms have shown promising performances for the accurate mapping of canopy height, they have limitations due to the type of architectures and loss functions employed. Moreover, mapping canopy height over tropical forests remains poorly studied, and the accurate height estimation of tall canopies is a challenge due to signal saturation from optical and radar sensors, persistent cloud cover, and sometimes limited penetration capabilities of lidar instruments. In this study, we map heights at 10 m resolution across the diverse landscape of Ghana with a new vision transformer (ViT) model, dubbed Hy-TeC, optimized concurrently with a classification (discrete) and a regression (continuous) loss function. This model achieves significantly higher accuracy than previously employed convolutional-based approaches (ConvNets) optimized with only a continuous loss function. Hy-TeC results show that our proposed discrete/continuous loss formulation significantly increases the sensitivity for very tall trees (i.e., > 35 m). Overall, Hy-TeC has significantly reduced bias (0.8 m) and higher accuracy (RMSE = 6.6 m) over tropical forests for which other approaches show poorer performance and oftentimes a saturation effect. The height maps generated by Hy-TeC also have better ground sampling distance and better sensitivity to sparse vegetation. Over these areas, Hy-TeC showed an RMSE of 3.1 m in comparison to a reference dataset while the baseline ConvNet model had an RMSE of 4.3 m. Hy-TeC, which was used to generate a height map of Ghana using free and open access remotely sensed data with Sentinel-2 and Sentinel-1 images as predictors and GEDI height measurements as calibration data, has the potential to be used globally
Biofortification versus diversification to fight micronutrient deficiencies: an interdisciplinary review
No full textInternational audienceTwo plant production-based strategies – biofortification and dietary diversification – have been advocated to overcome micronutrient deficiencies, which are major contributors to morbidity and mortality worldwide. The respective benefits and effectiveness of these two strategies are the subject of controversy. Expanding the scope of this debate beyond the sole nutritional outcomes, and using a food system approach, this interdisciplinary review aims to providing a novel and holistic perspective on the ongoing debate. The literature shows that biofortification can be an effective medium-term strategy to tackle nutritional risk in vulnerable populations in some contexts, but that it also may have negative environmental, economic, and social impacts. Dietary diversification, on the other hand, is known to be a sustainable way to overcome micronutrient deficiencies, bringing with it long-term benefits, including nutritional, and beyond, the provision of ecosystem services. Dietary diversification is however challenging to implement, with benefits that are not immediate. Biodiversity as a basis of human diets is critically important to improving both human and environmental health. Diet diversification through increased mobilisation of biodiversity in food systems deserves much more attention and support in policies for food and nutrition in low- and middle-income countries
Impact of unhealthy food and beverage consumption on children’s risk of dental caries: a systematic review
No full textInternational audienceContextThe impact of unhealthy foods and beverages, namely those high in sugar, salt, and saturated or trans fats, has been studied extensively in relation to weight, body composition, and noncommunicable diseases, but less so in relation to the risk of dental caries. Few previous reviews have examined the evidence from all countries globally. ObjectiveA systematic review was conducted to assess the impact of unhealthy food and beverage consumption on the risk of dental caries in children aged ≤10 years, commissioned by the World Health Organization to inform updated complementary feeding recommendations. Data SourcesSystematic searches were conducted in the PubMed, Cochrane, and Embase databases for articles meeting the inclusion criteria dating from January 1971 to March 2022; supplementary searches were undertaken for articles from that period to June 2022. Data ExtractionUnhealthy foods and beverages were identified using nutrient- and food-based approaches. Risk of bias was assessed using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I). Data AnalysisA total of 30 023 unique citations were screened, yielding 37 studies for inclusion. Studies were conducted in high-income (n = 23 [62.2%]) or middle-income countries (n = 14 [37.8%]). Evidence synthesis was performed narratively, stratified by age (0 years to <2 years, 2 years to <5 years, and 5 years to ≤10 years) and exposure (unhealthy foods and unhealthy beverages). The heterogeneity of the exposures and comparators across studies was high. Almost all studies (n = 34) reported positive associations between the consumption of sugar-sweetened beverages or foods high in free sugars and dental caries. However, 67.6% of studies were assessed as having serious risk of bias. Conclusion The evidence indicates that the consumption of unhealthy food and beverages in children ≤10 years appears to increase the risk of dental caries. Further longitudinal studies with high-quality dietary assessments, including studies in low-income countries and children aged >5 years at baseline, are recommended in order to build a more robust evidence base for use in the development of policy recommendations. Systematic Review Registration PROSPERO registration no. CRD42020218109
Defining a dichotomous indicator for population-level assessment of dietary diversity among pregnant adolescent girls and women : a secondary analysis of quantitative 24-h recalls from rural settings in Bangladesh, Burkina Faso, India and Nepal
No full textInternational audienceBackgroundThe Minimum Dietary Diversity for Women of Reproductive Age (MDD-W) indicator was validated as a proxy of micronutrient adequacy among non-pregnant women in low- and middle-income countries (LMICs). At that time, indeed, there was insufficient data to validate the indicator among pregnant women, who face higher micronutrient requirements.ObjectiveThis study aimed to validate a minimum food group consumption threshold, out of the 10 food groups used to construct MDD-W, to be used as a population-level indicator of higher micronutrient adequacy among pregnant women aged 15-49 years in LMICs.MethodsWe used secondary quantitative 24-hour recall data from 6 surveys in 4 LMICs (Bangladesh, Burkina Faso, India and Nepal, total n=4909). We computed the 10-food group Women's Dietary Diversity Score (WDDS-10) and calculated the mean probability of adequacy (MPA) of 11 micronutrients. Linear regression models were fitted to assess the associations between WDDS-10 and MPA. Sensitivity, specificity and proportion of individuals correctly classified were used to assess the performance of MDD-W in predicting an MPA >0.60.ResultsIn the pooled sample, median values (interquartile range) of WDDS-10 and MPA were 3 (1) and 0.20 (0.34), respectively, while the proportion of pregnant women with an MPA >0.60 was 9.6%. The WDDS-10 was significantly positively associated with MPA in each survey. Although the acceptable food group consumption threshold varied between 4 and 6 food groups across surveys, the threshold of 5 showed the highest performance in the pooled sample with good sensitivity (62%), and very good specificity (81%) and percentage of correctly classified individuals (79%).ConclusionsThe WDDS-10 is a good predictor of dietary micronutrient adequacy among pregnant women aged 15-49 years in LMICs. Moreover, the threshold of 5 or more food group for the MDD-W indicator may be extended to all women of reproductive age, regardless of their physiological status
Farm buildings and agri-food transitions in Southern France: mapping dynamics using a stakeholder-based diagnosis
No full textInternational audienceThis study's goal is to present a dynamic portrait of the farm-buildings environment in Occitania (Southern France) in order to better identify the transitions underway in agri-food chains. To this end, we undertook a territorial diagnosis based on actor statements, using 28 semi-structured interviews across Occitania. This diagnosis was enriched by graphic modelling, which enabled the spatialization of the dynamics described. We show that the process of standardisation of farm buildings prevails in the majority of the territories studied. This phenomenon has intensified in recent years with the development of vast photovoltaic-roofed sheds, accentuating the farmland conversion and soil sealing. At the same time, in areas with strong environmental, landscape and heritage contexts, a ‘new adventure in farm buildings’ (2022 survey) is taking shape. It is primarily driven by local short food chains, which rely on self-construction, repurposing and refurbishment, the sharing of tools and equipment, and which favour the use and reuse of local resources. This study shows that farm-buildings dynamics crystallise many challenges confronting the reterritorialisation of agriculture and food production
Keep in touch: the soil-root hydraulic continuum and its role in drought resistance in crops
No full textInternational audienceDrought is a major threat to food security worldwide. Recently, the root-soil interface has emerged as a major site of hydraulic resistance during water stress. Here, we review the impact of soil drying on whole plant hydraulics and discuss mechanisms by which plants can adapt by modifying the properties of the rhizosphere either directly or through interactions with the soil microbiome
Impacts of neonicotinoids on biodiversity: a critical review
No full textInternational audienceNeonicotinoids are the most widely used class of insecticides in the world but they have raised numerous concerns regarding their effects on biodiversity. Thus, the objective of this work was to do a critical review of the contamination of the environment (soil, water, air, biota) by neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) and of their impacts on terrestrial and aquatic biodiversity. Neonicotinoids are very frequently detected in soils and in freshwater, and they are also found in the air. They have only been recently monitored in coastal and marine environments, but some studies already reported the presence of imidacloprid and thiamethoxam in transitional or semi-enclosed ecosystems (lagoons, bays and estuaries). The contamination of the environment leads to the exposure and to the contamination of non-target organisms, and to negative effects on biodiversity. Direct impacts of neonicotinoids are mainly reported on terrestrial invertebrates (e.g., pollinators, natural enemies, earthworms) and vertebrates (e.g., birds), and on aquatic invertebrates (e.g., arthropods). Impacts on aquatic vertebrate populations and communities, as well as on microorganisms, are less documented. In addition to their toxicity to directly exposed organisms, neonicotinoid induce indirect effects via trophic cascades as demonstrated in several species (terrestrial and aquatic invertebrates). However, more data are needed to reach firmer conclusions and to get a clearer picture of such indirect effects. Finally, we identified specific knowledge gaps that need to be filled to better understand the effects of neonicotinoids on terrestrial, freshwater and marine organisms, as well as on ecosystem services associated with these biotas
Deux nouvelles guêpes évanioïdes (Hymenoptera : Evaniidae ; Praeaulacidae) dans l’ambre du Kachin du Crétacé moyen
No full textInternational audienceTwo evanioid wasps are described from specimens entrapped in Kachin amber. The first species, Sinuevania pouilloni sp. nov., allows a revision of the diagnosis of the genus Sinuevania. The complex forewing venation (plesiomorphy) of this new species confirms that the genus Sinuevania belongs to the stem group of the family Evaniidae. Together with the new praeaulacine wasp Praegastrinus edithae gen. et sp. nov., Sinuevania pouilloni sp. nov. shows that the diversity of the superfamily Evanioidea in the mid-Cretaceous Kachin amber remains underestimated. New fossils of evaniid wasps from the Albo-Cenomanian amber of Charente-Maritime (France) are expected to extend the diversity and distribution of several genera. Based on the recent discovery, but not yet published, of new praeaulacid specimens from the mid-Cretaceous, we propose reclassifying Mesevania within the Praeaulacidae (Praeaulacinae).Deux guêpes évanioïdes sont décrites à partir de spécimens piégés dans l’ambre du Kachin. La première espèce, Sinuevania pouilloni sp. nov., permet une révision de la diagnose du genre Sinuevania. La nervation complexe de l’aile antérieure (plésiomorphie) de cette nouvelle espèce confirme que le genre Sinuevania appartienne au groupe souche de la famille des Evaniidae. Avec la nouvelle guêpe praeaulacine Praegastrinus edithae gen. et sp. nov., Sinuevania pouilloni sp. nov. montre que la diversité de la superfamille des Evanioidea dans l’ambre du Crétacé moyen du Kachin reste sous-estimée. De nouveaux fossiles de guêpes évaniides de l’ambre albo-cénomanien de Charente-Maritime (France) devraient étendre la diversité et la répartition de plusieurs genres. Sur la base de la découverte récente, mais non encore publiée, de nouveaux spécimens de praeaulacidés du Crétacé moyen, nous proposons de reclasser Mesevania au sein des Praeaulacidae (Praeaulacinae). Previous article in issu