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Thinning enhances hydraulic safety but not growth resistance to drought in Atlas cedar on the long-term
No full textInternational audienceReducing forest stand density through thinning has the potential to improve tree vigor and mitigate hydraulic risk as it reduces competition for water, thereby improving soil water availability at the tree level. However, these positive effects might be compensated over time by the growth of the remaining trees and understory, an aspect that remains understudied. We investigated the long-term effects of thinning on vegetation regrowth, growth resistance to drought and hydraulic risk in a 1968 Cedrus atlantica plantation in southeastern France where contrasting thinning intensities were applied in 1992, resulting in stand densities of 1200 (unthinned control), 800, 600 and 400 trees.ha-1. Field measurements were conducted in 2017, 25 years after thinning, during the most severe drought since the trial's establishment. To explore underlying mechanisms, they were complemented by a modeling test using SurEau within the cohort-based model MEDFATE. Our results show that 25 years after thinning, despite similar stand leaf area index across all thinning treatments, trees in thinned stands exhibited significantly higher growth and reduced hydraulic risk (i.e., higher water potential, wider hydraulic safety margins, lower native embolism) than in the unthinned control. Model simulations suggest that this long-term reduction of hydraulic risk by thinning may result from niche partitioning between the overstory and the understory, either spatially (due to differences in rooting depth) or temporally (due to differences in ecophysiological properties). Interestingly, growth resistance to drought did not differ significantly among thinning treatments. Our results emphasize the potential long-lasting role of thinning in reducing hydraulic risk despite vegetation regrowth. Moreover, this study shows that ecophysiological indicators provide a more accurate understanding of tree drought responses during a specific drought event than the commonly used growth-based indicators
Présentation de la collection "Recherche et Création" (Hermann, Paris) à la Librairie Tschann (Paris)
No full textPrésentation de la collection "Recherche-Création"Présentation des douze ouvrages parus dans la collection "Recherche et Création" des Editions Hermann (Paris) entre septembre 2023 et décembre 2025. Librairie Tschann (Paris), en présence des autrices et auteurs de la collection
No impact of black-eye symptom on foraging behaviour and reproductive success of Northern gannets following highly pathogenic avian influenza
No full textInternational audienceHighly Pathogenic Avian Influenza Virus (HPAIV) is currently causing major wild animal population crashes all over the world including Antarctica. Yet, there are important knowledge gaps on the implications of long-lasting symptoms for the ecology of surviving individuals and the conservation of their populations. Using GPS tracking devices and long-term demographic data, we examined the effects of HPAIV on a seabird population of Northern gannets (Morus bassanus) in the colony of Rouzic, France. One year after the HPAIV outbreak of 2022, the breeding gannet population declined by 38 % and 22.3 % of surviving breeders were zombie birds: they had darkened irises, a black-eye symptom indicative of past infection to HPAIV. Importantly, we demonstrate that black eyes were not associated with detectable differences in the foraging behaviour and habitat use of surviving breeding gannets. Compared to years prior to the outbreak, the foraging effort of breeding individuals was lower and breeding success was higher, aligning with Ashmole's halo hypothesis, which posits that smaller seabird populations face lower intra-specific competition for food in the vicinity of their breeding colony and thereby, have a reduced foraging range. Our results highlight the importance of density-dependant mechanisms in population responses to sudden mass-mortalities, but raise conservation concerns, especially for species facing cumulative threats. In the long-term, locally depleted populations may reach critical thresholds where individual abundance and productivity may not be sufficient to maintain a positive demographic growth rate, ultimately leading to local population extinctions
Material Tradition: The Graphic Registers of the Magical Bricks Ritual in Chapter 151 of the Book of the Dead
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A narrative review of the impact of anthropogenic light and noise on owls
No full textInternational audienceToday, owls are exposed to increasingly brightly lit nights and noisy environments because of human activities. To understand the impacts of artificial light at night (ALAN) and anthropogenic noise we performed an evidence synthesis. We searched four literature databases and Google Scholar and we collected 39 relevant articles (1945-2024) providing 125 cases (64 on light pollution and 61 on noise pollution), targeting 25 species (c. 10% of owl species). We found harmful effects of both sensory pollutants on several outcomes. First, ALAN tends to reduce acoustic communication and to be associated with a lower occurrence of owl species, although it is difficult to confirm whether ALAN leads to silent or absent owls. Moreover, ALAN disturbs owl-prey interactions. Although light probably improves owl vision, the light-avoidance behaviour of small mammals could result in poorer hunting success of owls feeding on mammals. Conversely, ALAN enhances food provisioning and even breeding of owls feeding on insects that are attracted by light, to the detriment of these prey populations. Second, human-induced noise clearly tends to reduce owl vocalization, yet that vocalization may be essential to communication between individuals. The ability of owls to detect prey (hunting success) is also reduced under noise exposure (even at low amplitude), probably as the result of masking and distraction. Studies also demonstrate that anthropogenic noise can cause physiological and behavioural stress and disturbance to owls. Such adverse effects may contribute to declines in reproduction and occurrence of owls observed in noisy areas. As a result, we recommend reduction of both sensory stressors as much as possible, for owls and for ecosystem stability, for example by maintaining and restoring quiet and dark areas. We also recommend more consideration of owls in sensory ecology research to fill knowledge gaps.De nos jours, les rapaces nocturnes sont exposés à des nuits de plus en plus lumineuses et à un environnement de plus en plus bruyant en raison des activités humaines. Pour comprendre l'impact potentiel de la lumière artificielle nocturne et du bruit anthropique, nous avons réalisé une revue de littérature. Nous avons interrogé 4 bases de données bibliographiques et Google scholar et nous avons collecté 39 articles pertinents (1945–2024) fournissant respectivement 125 cas (64 sur la pollution lumineuse et 61 sur la pollution sonore), ciblant en tout 25 espèces (~10% des Strigiformes ). Nous avons trouvé plusieurs effets néfastes des pollutions lumineuse et sonore. Tout d'abord, la lumière artificielle tend à diminuer la communication acoustique et est associée à une occurrence plus faible, bien qu'il soit difficile de confirmer si les chouettes sont plus silencieuses ou absentes. Il est indéniable que l'éclairage nocturne perturbe les interactions entre les rapaces nocturnes et leurs proies, ce qui peut expliquer en partie cette situation pour les espèces qui se nourrissent de rongeurs, selon les effets documentés de la luminosité de la lune: alors que la lumière améliore la vision des chouettes/hiboux, le comportement d'évitement de la lumière des petits mammifères pourrait entraîner un moins bon succès de chasse. Inversement, l'éclairage artificiel améliore l'approvisionnement en nourriture et même la reproduction des chouettes insectivores, probablement au détriment des populations de proies attirées par la lumière. Deuxièmement, les sons artificiels tendent clairement à diminuer la vocalisation des chouettes, pourtant essentielle à la communication (par exemple entre partenaires). La capacité des Strigiformes à détecter leurs proies (succès de chasse) est également réduite en cas d'exposition au bruit (même à faible amplitude), sûrement par un effet de masquage et de distraction. Les données démontrent également que le bruit anthropique provoque du stress et des perturbations, tant au niveau physiologique que comportemental. Ces effets négatifs peuvent être responsables de la tendance à la baisse de la reproduction et de l'occurrence des rapaces nocturnes qui est également observée dans les zones bruyantes. Par conséquent, nous recommandons de réduire autant que possible les deux facteurs de stress sensoriel—pour les chouettes/hiboux et pour la stabilité des écosystèmes—par exemple en maintenant et en rétablissant des zones calmes et sombres. Nous demandons également que les Strigiformes soient davantage pris en compte dans la recherche en écologie sensorielle afin de combler les lacunes en matière de connaissances
Discours du cyberharcèlement : sexisme, « culture du lol » et contre-discours
No full textInternational audienceThe article analyzes the expression of cyberbullying against a French female influencer on social media platforms in September 2023. While X (formerly Twitter) was the most conducive space for observing such violence, much of it sexist, this work is looking back at the role played by YouTube’s broadcasting of the event in the production of this cyberviolence. On the one hand, the platform hosted “critical analyses” of French YouTubers belonging to the “culture du lol”, a practice close to masculinist and conservative thinking, and on the other hand, the victim’s counter-speech. The study examines the modes of production of mobilized discourses during this cyberbullying. The collection and the analysis (in qualitative and quantitative ways) of a large corpus of tweets, videos posted on YouTube and their comments led to the creation of a set of lexical resources built on the expression of anti-feminism and the rejection of “woke” ideology. Secondly, computational linguistics made it possible to address the sexist argumentative strategies of certain Internet users, as a means of detecting hateful content. As misogynistic discourse can be implicit, we explored other avenues of analysis, in particular the assignment to the femininity of the influencer of numerous undesirable consequences, illustrating one of the mainsprings of the “culture du lol”.L’article analyse l’expression du cyberharcèlement subi par une influenceuse française sur les réseaux sociaux en septembre 2023. Si X (anciennement Twitter) a été l’espace le plus propice à l’observation de telles violences, pour une grande part, sexistes, ce travail est l’occasion de revenir sur le rôle joué par la médiatisation sur YouTube de l’événement à l’origine du déferlement des cyberviolences. La plateforme a accueilli d’une part des « analyses critiques » formulées par des youtubeur⸱euses s’inscrivant dans la « culture du lol », pratique proche des pensées masculinistes et conservatrices, et d’autre part le contre-discours de la victime. L’étude examine la pluralité des modes de production des discours qui composent le cyberharcèlement de l’influenceuse. La collecte et l’analyse (qualitative et quantitative) d’un vaste corpus de tweets, de vidéos postées sur YouTube et de commentaires associés ont débouché sur la création d’un ensemble de ressources lexicales liées à l’expression de l’antiféminisme et au rejet de l’idéologie « woke ». Le recours à la linguistique outillée a permis, dans un second temps, d’aborder les stratégies argumentatives sexistes de certain·es internautes, comme moyen de détection de contenus haineux. Les discours misogynes pouvant être implicites, nous avons exploré d’autres pistes d’analyse, et notamment l’assignation à la féminité de l’influenceuse de nombreuses conséquences indésirables, illustrant ainsi l’un des ressorts de la « culture du lol »
Linguistic Signatures for Enhanced Emotion Detection
No full textInternational audienceEmotion detection is a central problem in NLP, with recent progress driven by transformer-based models trained on established datasets. However, little is known about the linguistic regularities that characterize how emotions are expressed across different corpora and labels. This study examines whether linguistic features can serve as reliable interpretable signals for emotion recognition in text. We extract emotion-specific linguistic signatures from 13 English datasets and evaluate how incorporating these features into transformer models impacts performance. Our RoBERTa-based models enriched with high level linguistic features achieve consistent performance gains of up to +2.4 macro F1 on the GoEmotions benchmark, showing that explicit lexical cues can complement neural representations and improve robustness in predicting emotion categories
Do large carnivores fare better in savannas when they get drier?
No full textInternational audienceBeyond rising temperatures, several parts of Africa are affected by aridification (more frequent and worsening droughts, lengthening dry seasons). Such drier conditions are likely to affect in several ways not only the many large herbivore species but also the rich carnivore guild that characterise African savannas, with consequences on the behavioural ecology of predator–prey interactions. Using data sets of exceptional quality on the feeding behaviour and the reproduction of leopards and lions covering 4 years of contrasting environmental conditions in a semi‐arid African savanna, Balme et al. analysed the effect of drought conditions on the carnivores' diet composition, kill rates, prey biomass acquisition but also cub production and survival. They showed that droughts led to a higher prey biomass consumption for the two carnivore species although the underlying mechanisms differed (higher kill rate for leopards and larger consumed prey for lionesses). Additionally, they revealed that the probability of cub survival was driven by factors other than drought‐driven food acquisition (such as intraguild predation by hyaenas for leopards and sarcoptic mange for lions). Balme et al. (2025) convincingly showed that droughts influence not only predator–prey interactions through several pathways, but also carnivore intraguild interactions. Altogether, their findings illustrate the difficulty to predict the impact of drier conditions on carnivore populations if we do not better unravel the mechanisms through which climate change affects both predator–prey and predator–predator interactions. Overall, this inspiring study invites us to conceptualise a larger framework to study interspecific interactions in African mammals in a context of a drier (and hotter) climate
Métaphore et comparaison, ellipses de l’analogie : convergences en linguistique et en Traitement Automatique du Langage Naturel
No full textInternational audienceL’article "Métaphore et comparaison, ellipses de l’analogie : convergences en linguistique et en Traitement Automatique du Langage Naturel", co-écrit par Emilia Hilgert et Jérémie Roux, réunit le point de vue linguistique et celui informatique dans la présentation de l’analogie comme base de la métaphore et de la comparaison. Ces deux approches s’éclairent mutuellement dans le but d’expliquer le fonctionnement sémantico-lexical de l’analogie sous la forme du carré analogique. Celui-ci révèle avec précision le processus inférentiel du glissement de sens métaphorique et génère la métaphore et la comparaison à deux ou trois termes par l’inférence, grâce à ses variantes à variables implicites. Les deux points de vue complémentaires se rencontrent aussi dans l’idée que l’analogie, qui peut être perçue intuitivement comme une ressemblance entre deux termes, fonctionne en fait grâce à l’activation automatique de deux autres termes supplémentaires et que ce sont les relations qui s’établissent avec ces termes de référence restrictive qui instruisent la prédication indirecte de l’analogie et de la métaphore, qui n’est qu’une ellipse de celle-ci. Les graphes informatisés générés par les moyens du TALN visualisent parfaitement ce processus