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Naturalization of introduced plants is driven by life‐form‐dependent cultivation biases
No full textInternational audienceAims: Most naturalized plants are escapees from cultivation. Inventories of cultivated introduced species thus offer unique, still underutilized, opportunities to assess naturalization drivers of introduced plants. We used a comprehensive inventory of 13,718 introduced species cultivated in China's botanical gardens to test which species characteristics distinguish the 739 species that have naturalized. Locations China. Methods: We used generalized linear models to test whether the naturalization of cultivated introduced plants in China is associated with functional traits, propagule pressure, environmental niche and introduction history. To test direct and indirect effects of those variables and their relative importance in driving naturalization, we used structural equation models. Results: We showed that species were more likely to naturalize when they originate from the Americas, are more widely cultivated, and have a longer residence time. Moreover, species were more likely to naturalize if they have a good environmental match, are short‐lived herbs, are predominantly propagated from seeds, and, in the case of herbs, are relatively tall compared to other herbs. Part of the latter effects are mediated by how these variables relate to propagule pressure proxies, and this varies among short‐lived herbs, long‐lived herbs and woody plants. Main Conclusions: Naturalization is partly driven by life‐form‐dependent cultivation biases
Quels dispositifs d'accompagnement des acteurs des territoires pour lutter contre la désertification ?
No full textOrchestrer la politique de la géothermie profonde. Étude à partir du cas de l’exploitation du Dogger parisien (1950-1990)
No full textInternational audienceLa géothermie du Dogger parisien (1970-mi 1980’s) est érigée en France, voire à l’international, comme un cas exemplaire de développement d’une ressource en géochaleur grâce à un soutien ambitieux des pouvoirs publics. Ce chapitre propose une analyse historique et critique de ces développements. Il s’agit de suivre les temps et les contretemps qui ont marqué cette expérience et qui ont pu en troubler le déploiement et les apprentissages. L’analyse aborde la géothermie profonde comme un cas de système énergétique polyrythmique à la recherche de ses modalités d’orchestration. Elle étudie la mise en place de cette politique et de ses développements locaux à l’aune de la pulsation des fossiles (les chocs et contre-chocs pétroliers) et des fluctuations du milieu géologique. Si cette politique parvient dans les années 70’s à réunir les conditions de son déploiement, elle découvre progressivement les liens qu’elle entretenait avec des mutations économiques et des processus bio-géologiques dont elle sous-estimait l’importance et qui mettent à l’épreuve ses moyens et ses ambitions au cours des années 1980’s. Alors que la France s’apprête à réengager une politique ambitieuse de développement de la géothermie profonde après plusieurs décennies de désinvestissement de ce secteur (PPE, 2019), cette analyse souhaite contribuer à dégager les leçons de cette expérience pionnière
First flower inclusion and fossil evidence of Cryptocarya (Laurales, Lauraceae) from Miocene amber of Zhangpu (China)
No full textInternational audienceLauraceae have one of the oldest fossil records of angiosperms with the earliest known evidence from the mid-Cretaceous. However, most of these records are based on leaves, especially from the Cenozoic of Asia, which are often challenging to assign to extinct or extant genera or species. In contrast, fossils of reproductive organs are more informative, but remain scarce. We here described the first Cenozoic Lauraceae flower of Asia and confirmed the presence of Cryptocarya in the Miocene Zhangpu flora (Fujian Province, southeastern China) based on an amber inclusion. We scanned the specimen using synchrotron radiation-based micro-computed tomography (SRμCT) and then compared the fossil with extant flowers of the genus. The present fossil flower is small, bisexual, and polysymmetric, with a whorled and trimerous perianth and androecium along with a hypanthium around the gynoecium. The perianth comprises six undifferentiated tepals, the androecium consists of nine stamens and three innermost staminodes, and the gynoecium of a single carpel with a superior, unilocular (and uniovulate) ovary. Our study also shows that the fossil shares an unusual position of the typical staminal glands and a short androecial tube on the rim of the hypanthium with at least one extant Australian species of Cryptocarya, which have not been reported before. Nowadays, Lauraceae are still present in tropical to subtropical regions, mostly in American and Asian rainforests. The discovery of many Lauraceae leaf fossils in Zhangpu, as well as the amber flower of this study, is consistent with the current reconstruction of the amber source environment as a megathermal seasonal rainforest during the Mid-Miocene
Unraveling the interplay between root exudates, microbiota, and rhizosheath formation in pearl millet
No full textInternational audienceBackgroundThe rhizosheath, a cohesive soil layer firmly adhering to plant roots, plays a vital role in facilitating water and mineral uptake. In pearl millet, rhizosheath formation is genetically controlled and influenced by root exudates. Here, we investigated the impact of root exudates on the microbiota composition, interactions, and assembly processes, and rhizosheath structure in pearl millet using four distinct lines with contrasting soil aggregation abilities.ResultsUtilizing 16S rRNA gene and ITS metabarcoding for microbiota profiling, coupled with FTICR-MS metabonomic analysis of metabolite composition in distinct plant compartments and root exudates, we revealed substantial disparities in microbial diversity and interaction networks. The ß-NTI analysis highlighted bacterial rhizosphere turnover driven primarily by deterministic processes, showcasing prevalent homogeneous selection in root tissue (RT) and root-adhering soil (RAS). Conversely, fungal communities were more influenced by stochastic processes. In bulk soil assembly, a combination of deterministic and stochastic mechanisms shapes composition, with deterministic factors exerting a more pronounced role. Metabolic profiles across shoots, RT, and RAS in different pearl millet lines mirrored their soil aggregation levels, emphasizing the impact of inherent plant traits on microbiota composition and unique metabolic profiles in RT and exudates. Notably, exclusive presence of antimicrobial compounds, including DIMBOA and H-DIMBOA, emerged in root exudates and RT of low aggregation lines.ConclusionsThis research underscores the pivotal influence of root exudates in shaping the root-associated microbiota composition across pearl millet lines, entwined with their soil aggregation capacities. These findings underscore the interconnectedness of root exudates and microbiota, which jointly shape rhizosheath structure, deepening insights into soil–plant-microbe interactions and ecological processes shaping rhizosphere microbial communities. Deciphering plant–microbe interactions and their contribution to soil aggregation and microbiota dynamics holds promise for the advancement of sustainable agricultural strategies
Nouveaux taxons pour la Kabylie dans le bassin de l'oued Sahel (Djurdjura / Bibans, Algérie du nord)
No full textInternational audienceWith the aim of updating our knowledge of our natural heritage, a study was carried out on the vegetation of the Oued Sahel valley (North Algerian), an area of Kabylia that is little studied. The sampling of the flora revealed the existence of three new species for the flora of Kabylia, sector of Djurdjura/ Bibans (Dipcadi serotinum, Silybum eburneum, Cyperus laevigatus subsp. distachyos) and five taxa rediscovered for the study area (Silene muscipula subsp. muscipula, Platycapnos tenuiloba, Deverra scoparia subsp. scoparia, Juncus subulatus, Cistanche phelypaea s.l.). The habitat of these species is threatened by human activities, such as grazing and intensive water pumping. These discoveries enrich the flora of Oued Sahel in particular and that of Djurdjura and Bibans' Kabylia in general; two sectors already recognized as key biodiversity areas (Important Plants Areas).Dans l’objectif d’actualiser les connaissances sur le patrimoine naturel, une étude a été réalisée sur la végétation de la vallée d’Oued Sahel (Nord Algérien), un secteur de Kabylie qui est très peu étudié. L’échantillonnage de la flore a révélé l’existence de trois espèces nouvelles pour la flore de la Kabylie, secteur Djurdjura / Bibans (Dipcadi serotinum, Silybum eburneum, Cyperus laevigatus subsp. distachyos) et cinq taxons redécouverts pour la zone d’étude (Silene muscipula subsp. muscipula, Platycapnos tenuiloba, Deverra scoparia subsp. scoparia, Juncus subulatus, Cistanche phelypaea s.l.). L’habitat de ces espèces est menacé par les activités humaines, comme le pâturage et le pompage intensif de l’eau. Ces découvertes enrichissent la flore d’Oued Sahel en particulier et celle de la Kabylie du Djurdjura et des Bibans en général, deux secteurs déjà reconnus comme zones clés de biodiversité (Zones Importantes pour les Plantes)
Nematodes associated with saffron II: Bioindication for soil health assessment and impact of agricultural practices
No full textInternational audienceHighlights: • High diversity of nematodes communities is detected in the Moroccan saffron field. • Saffron soils health are degraded in Taliouine-Taznakht regions. • Plant parasitic index (PPI) is strongly influenced by the high frequency of Traditional irrigation. • Agricultural practices are significantly impacted (MI) and (SI) indices and saffron nematodes trophic groups.Abstract: Background: Saffron cultivation is vital in the Taliouine-Taznakht regions, but the influence of agricultural practices on soil nematode communities, critical for soil health and plant productivity, is not well understood. This study characterizes nematode communities in saffron fields of the Taliouine-Taznakht regions, assessing the impact of various agricultural practices on these communities, with a focus on their diversity, functional roles, and potential as bio-indicators of soil health. A total of 163 soil samples were collected from saffron fields in Taliouine-Taznakht. Nematode communities were identified, quantified, and their functional diversity analyzed. Principal Component Analysis (PCA) was used to visualize relationships between nematode communities and sampling sites. Co-inertia analysis assessed the impact of agricultural practices on nematode diversity. The nematode communities were diverse and varied across regions. PCA identified unique nematode community compositions in different saffron fields. Omnivorous nematodes were strongly linked with Taouyalte (TA), and herbivorous ones were prevalent at Agadir Melloul (AM) and Sidi Hssaine (SH). Modern crop types, high-frequency irrigation, and alfalfa-barley rotation were positively correlated with predator nematode abundance, potentially controlling plant parasitic nematodes and encouraging nutrient cycling. Conversely, monocropping, traditional irrigation, and long plantation age correlated with reduced structure and maturity indices, suggesting a less stable ecosystem. This study unveils the intricate relationships between nematode communities in Taliouine-Taznakht saffron fields and agricultural practices. Findings indicate that specific practices, such as crop rotation and modern irrigation techniques, can foster beneficial nematode groups that improve soil health and potentially regulate harmful plant parasitic nematodes. This knowledge is crucial for crafting sustainable and effective saffron cultivation strategies
Comment j’ai découvert l’analyse des réseaux et pourquoi j’ai trouvé ça cool: Retranscription de la keynote de Michel Grossetti lors de la troisième édition de Frognet
No full textLes conférences Frognet visent à organiser les échanges au sein de la communauté des personnes pratiquant l'analyse de réseaux en français. En 2024 s'est tenue la troisième édition de cet évènement, accueillie par l'école de Sciences Po Bordeaux du mercredi 29 au vendredi 31 mai. Elle a rassemblé 24 communications sur des thèmes variés, et inscrites dans diverses disciplines. La journée du jeudi 30 mai a été ponctuée par un discours de Michel Grossetti, intitulé « Comment j'ai découvert l'analyse des réseaux et pourquoi j'ai trouvé ça cool »
A new Darwin wasp (Ichneumonidae: Novichneumoninae) from mid-Cretaceous Kachin amber
No full textInternational audienceIchneumonid wasps, also known as Darwin wasps, are relatively rare in Cretaceous amber deposits, with only the highest diversity documented from mid-Cretaceous Kachin amber. In order to enhance our understanding of the past diversity of this group, we describe and illustrate a new species belonging to the genus Rasnichneumon Kopylov et al., ., 2021, named Rasnichneumon nevergo sp. nov. This newly discovered species is based on an exquisitely preserved specimen and can be readily distinguished from the congeners by its forewing, with 2-Rs slightly longer than 2+3-M. With the addition of this new species, the diversity of the genus Rasnichneumon now encompasses five species, and we anticipate the description of more species in the future
Overview of GeoLifeCLEF 2024: Species Composition Prediction with High Spatial Resolution at Continental Scale using Remote Sensing
No full textInternational audienceUnderstanding the spatiotemporal distribution of species is a cornerstone of ecology and conservation. Pairing species observations with geographic and environmental predictors allows us to model the relationship between an environment and the species present at a given location. In light of that, we organize an annual competition, GeoLifeCLEF, which focuses on benchmarking and advancing state-of-the-art species distribution modeling using available bioclimatic and remote sensing data. The GeoLifeCLEF 2024 dataset spans across Europe and encompasses most of its flora. The species observation data comprises over 5 million Presence-Only (PO) occurrences and approximately 90 thousand Presence-Absence (PA) surveys. Those data are paired with various high-resolution rasters, including remote sensing imagery, land cover, and elevation, and are combined with coarse-resolution data such as climate, soil, and human footprint variables. In this paper, we present (i) an overview of the GeoLifeCLEF 2024 competition, (ii) a description of the provided data, (iii) an overview of approaches used by the participating teams, and (iv) the main results analysis