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Which shrimp are we catching? Cryptic species in the North Brazil Shelf
No full textShrimps of genus Penaeus are among the main exploited resources in the North Brazil Shelf Large Marine Ecosystem. Despite their economic importance, there is still a lack of consensus regarding their taxonomy and species distribution. The inability to identify commercially important species has a direct impact on both fishery management and ecosystems conservation, causing difficulties in monitoring and stock evaluations. This study aims to compare different barcoding sequences of commercially fished shrimps collected from three countries on the North Brazil Shelf Large Marine Ecosystem. Although the sampled individuals were expected to be a mix of the well-known commercial Penaeus subtilis and the cryptic species Penaeus isabelae, only P. isabelae was present in the catches. The exclusive presence of P. isabelae in the catches may indicate the complete absence of P. subtilis, or it could reflect the rarefaction of this species in the area which could be due to isolation mechanisms acting as barriers to larval dispersal around the Amazon area. Our results suggest that the distribution range of the two species needs to be re-evaluated and the use of a precautionary approach should to be applied on the management of brown shrimp resources since the biology and demographic parameters of the two cryptic species can differ and impact stock assessment results
Nest Exposure to Marine Flooding and Impacts on Green Turtle (Chelonia Mydas) Embryos Under Rapid Sea Level Rise: The Role of Beach Geomorphology and Hydrodynamics
No full textInternational audienceClimate change-induced sea-level rise increases the risk of sea turtles' nests being flooded which could threaten their populations. However, impacts on embryonic development remain limited, and the mechanisms driving nest flooding are still poorly understood. Our multidisciplinary study aimed to determine the geomorphological and hydrodynamic factors exposing nests to flooding, and to better understand the effects of flooding on embryonic development under natural conditions. The research was conducted on Mayotte Island (France, Indian Ocean), where a seismic crisis between 2018 and 2020 caused subsidence, resulting in a relative rise in sea level. Thirty green turtle nests on a primary nesting reef beach were monitored from March to June 2022 using pressure sensors to measure flooding. The hydrodynamics were measured, and the beach morphology was mapped. Approximately 30% of the nests were flooded, mainly due to their relatively low position on the beach, with the flooding likely to have been influenced by water level fluctuations related to the tidal cycle. The early and late incubation phases were particularly sensitive to flooding. Emergence success was 1% for flooded nests, significantly lower than 85% for non-flooded nests. This study provides new insights and reveals that under natural conditions, nests are more sensitive to flooding than previously reported in controlled laboratory studies. However, flooding does not always directly impact embryonic mortality; other related factors may be involved, requiring further research
Formation Théorique Gestion et Ouverture des Données de la Recherche en Sciences du Vivant et de l'Environnement
No full textNational audienceCette formation aborde tous les aspects théoriques de la gestion et de l'ouverture des données de la recherche en se basant sur chacune des étapes du logigramme de déroulement d'un projet de recherche. De nombreux outils et de nombreuses ressources sont fournies. Cette formation se complète par un atelier pratique de mise en application des concepts abordés
L'océan, patrimoine culturel du pays Né kwiè pu morü
No full textL'océan est un espace à forte valeur patrimoniale pour tous les Calédoniens. Pour les Kanak, il est essentiel en raison de sa richesse en faune et en flore et il se situeau coeur de la conception du monde et de l'organisation des sociétés. Plus largement, la majorité des peuples océaniens pensent leur origine mythologique commeissue de la mer. Porteur et révélateur de liens sociaux, de pratiques de pêche et de navigation, de savoirs traditionnels et de relations intimes au monde naturel, l'océanest donc partie intégrante de la société. La relation à l'océan constitue donc un patrimoine fondamental de l'identité du pays. L'ambition de ce chapitre est de rendrecompte, d'une part, de la relation du peuple kanak à l'océan et, d'autre part, du tissage ou du maillage serré qui se crée dans la durée avec tous les autres,humains et non-humains du pays et de la région. Le parc naturel de la mer de Corail, immensité océanique peu fréquentée aujourd'hui, présente toujours un intérêtmajeur pour les différentes communautés de la Nouvelle-Calédonie, qui l'appréhendent depuis leurs lieux de vie
Monitoring Olive Tree and Identifying Olive-Growing Formation Using Very High Satellite Imagery : A Case Study of the Ouezzane Province in Morocco
No full textInternational audienceIn Morocco, olive groves are a predominant feature of many agricultural landscapes, resulting from both a long agricultural history and more recent national programs such as the Green Morocco Plan Plan Maroc Vert. Within this context, the ClimOliveMed and Future for Olive projects aimed to test a deliberative approach involving scientists, farmers, and olive sector stakeholders to identify desirable solutions and future scenarios for olive cultivation. From an environmental perspective, the project pursued two main objectives: (i) to identify the different types of olive groves, and (ii) to assess whether environmental factors such as -- topography -- influence their spatial distribution. Using very high resolution Pléiades satellite imagery 2023, we developed a methodology combining supervised classification with spatial analysis based on geometric features, in order to map the different types of olive groves and examine the correlation between topography and the distribution of olive cultivation. For this study, we focused on the site of Bni Quolla (covering an area of 192 km²) as a pilot site to validate the method prior to its application at the scale of the Ouezzane province
Satellite monitoring of surface water and humidity to inform surveillance of environmental bacterial diseases
No full textInternational audienceBacterial diseases resulting from exposure to bacteria present in surface water and soil are generally poorly diagnosed, even though they are likely to have a major impact in terms of public health. This is particularly the case for leptospirosis and melioidosis, which are common diseases in the intertropical zone but are rarely reported in most countries. Their epidemiology remains largely linked to the rainy season, but epidemics can also be fostered by extreme climatic events such as flooding.In response to this situation, we are developing tools for predicting the environmental conditions that are conducive to the transmission of these diseases, in order to bring this knowledge to health managers and set up early-warning systems. We use information from Sentinel-1 and Sentinel-2 satellites, obtained timely on a fine scale to produce a routine monitoring of relevant health indicators.This presentation will provide an update on this work, currently underway in South-East Asia, with the development of local satellite data processing capabilities and the implementation of dashboards or health information systems that integrate climatic and environmental data, with a specific focus on leptospirosis and other climate-sensitive diseases
Monitoring individual rice field flooding dynamics over a large scale to improve mosquito surveillance and control
No full textInternational audienceBackground Progress in malaria elimination has been hindered by recent changes in mosquito behaviour and increased insecticide resistance in response to traditional vector control measures, such as indoor residual spraying and long-lasting insecticidal nets. There is, therefore, increasing interest in the use of larval source management (LSM) to supplement current insecticide-based interventions. However, LSM implementation requires the characterization of larval habitats at fine spatial and temporal scales to ensure interventions are well-placed and well-timed. Remotely sensed optical imagery captured via drones or satellites offers one way to monitor larval habitats remotely, but its use at large spatio-temporal scales has important limitations. Methods A method using radar imagery is proposed to monitor flooding dynamics in individual rice fields, a primary larval habitat, over very large geographic areas relevant to national malaria control programmes aiming to implement LSM at scale. This is demonstrated for a 3971 km 2 malaria-endemic district in Madagascar with over 17,000 rice fields. Rice field mapping on OpenStreetMap was combined with Sentinel-1 satellite imagery (radar, 10 m) from 2016 to 2022 to train a classification model of radar backscatter to identify rice fields with vegetated and open water, resulting in a time-series of weekly flooding dynamics for thousands of rice fields. ResultsFrom these time-series, over a dozen indicators useful for LSM implementation, such as the timing and frequency of flooding seasons, were obtained for each rice field. These monitoring tools were integrated into an interactive GIS dashboard for operational use by vector control programmes, with results available at multiple scales (district, sub-district, rice field) relevant for different phases of LSM intervention (e.g. prioritization of sites, implementation, follow-up).Conclusions Scale-up of these methods could enable wider implementation of evidence-based LSM interventions and reduce malaria burdens in contexts where irrigated agriculture is a major transmission driver.</div
Shifting trait coordination along a soil‐moisture‐nutrient gradient in tropical forests
No full textInternational audienceSoil nutrients and water availability are strong drivers of tropical tree species distribution across scales. However, the physiological mechanisms underlying environmental filtering along these gradients remain incompletely understood. Previous studies mostly focused on univariate variation in structural traits, but a more integrative approach combining multiple physiological traits is needed to fully portray species functional strategies. We measured nine leaf functional traits related to trees' resource capture and hydraulic strategies for 552 individuals belonging to 21 tropical tree species across an environmental gradient in Amazonian forests. Our sampling included generalist and specialist species from terra firme (TF) and seasonally flooded (SF) forests. We tested the influence of the topographic wetness index, a proxy for soil moisture and nutrient gradients, on each trait separately and on the trait integration through multivariate indices computed from the eigenvalues of a principal component analysis on the traits of the species. Finally, we evaluated intraspecific trait variability (ITV) for generalists and specialists by calculating the coefficient of variation for each trait. Results showed that (1) the environment had a greater influence on trait syndromes than single trait variation. Moreover, (2) SF specialist species expressed a stronger leaf trait coordination than TF specialist species. Furthermore, (3) the ability of generalist species to occupy a broader range of environments was not reflected by a larger ITV than specialist species but by the capacity to change trait coordination across environments. Our work highlights the need to investigate functional strategies as multidimensional syndromes in physiological trait space to fully understand and predict species distribution along environmental gradients. Read the free Plain Language Summary for this article on the Journal blog.Les nutriments du sol et la disponibilité de l'eau sont des facteurs importants de la distribution des espèces d'arbres tropicaux à différentes échelles. Cependant, les mécanismes physiologiques à l'origine du filtrage environnemental le long de ces gradients restent mal compris. Les études précédentes se sont principalement concentrées sur la variation des traits de façon individuelle. Cependant, pour décrire pleinement les stratégies fonctionnelles des espèces, une approche plus intégrative, qui combine un ensemble de traits physiologiques (syndrome de trait) est nécessaire. Dans cette étude, nous avons mesuré neuf traits fonctionnels foliaires liés à l'acquisition des ressources et à la gestion de l'eau des arbres, sur 552 individus appartenant à 21 espèces d'arbres tropicaux, le long d'un gradient environnemental. L'échantillonnage comprend des espèces généralistes et spécialistes des forêts de terra firme et des forêts de bas‐fond en Guyane française. Nous avons utilisé un indice d'humidité topographique (TWI) comme indicateur de l'humidité et de l'accumulation des nutriments du sol. Nous avons testé l'influence de TWI sur chacun des traits séparément et de façon conjointe. Nous avons comparé la coordination des traits pour les espèces généralistes et spécialistes en fonction du TWI, grâce à des indices multivariés, obtenus en utilisant la gamme des valeurs propres d'une analyse en composantes principales sur les traits de l'espèce. Enfin, nous avons évalué la variabilité intraspécifique des traits (ITV) pour les généralistes et les spécialistes en calculant le coefficient de variation pour chaque trait. Les résultats illustrent que (1) l'environnement a une plus grande influence sur le syndrome de traits que sur la variation des traits pris un par un. De plus, (2) les espèces spécialistes des bas‐fond ont une plus forte coordination entre les traits que les spécialistes de terra firme. Enfin, (3) la capacité des espèces généralistes à occuper une plus large gamme d'environnements se traduit par leur capacité à changer la coordination de leurs traits à travers différents environnements plutôt que par une ITV plus importante que celle des espèces spécialistes. Notre travail plaide en faveur de l'utilisation de syndromes de traits pour étudier les stratégies fonctionnelles et comprendre les mécanismes de distribution des espèces le long des gradients environnementaux
Severe Impacts on Water Resources Projected for the Mediterranean Basin
No full textInternational audienceABSTRACT Water resources are becoming increasingly scarce in the Mediterranean Basin due to climate change. Through a systematic review of 262 catchment‐based Mediterranean studies, we provide improved and detailed indications that runoff is projected to decrease by 19%, with increasing severity towards the end of the century and with increasing emission scenarios (up to −39%). We also show negative consequences for other water resources (soil moisture, aquifer recharge, irrigation demand), hydrological extremes (low flows), and water and soil quality (nutrient concentration, soil salinity, soil erosion), with negative impacts on rainfed and irrigated agriculture in the Mediterranean Basin. To protect water security, climate change adaptation aiming at more efficient water use and water retention in soils will be needed. While these adaptation measures have the potential to reverse the impacts of climate change, they may reduce downstream water availability and may be insufficient under extreme climate conditions