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Grazing Modulates the Multiscale Spatial Structure of Dryland Vegetation
No full textInternational audiencePlants can facilitate their local environment and create a two‐phase spatial structure of vegetation and bare soil in drylands, which largely influences ecosystem functioning. Although an increasing number of studies have examined how global change drivers like aridity influence vegetation spatial structure in drylands (e.g., the patch size distribution), it remains unclear how grazing impacts differ from those of climatic gradients, how these effects vary with herbivore feeding habits, and which plant‐level traits—such as size and life form—mediate these spatial responses. Here, we coupled spatial vegetation pattern analyses of ecosystem images with field data analyses of the size distribution and dominant life forms of plants from 326 plots sampled across 25 countries and six continents to explore the effects of herbivores on the spatial structure of dryland vegetation. The effects of herbivores on vegetation spatial structure were opposite to the effects of aridity. Specifically, vegetation in grazed areas was clustered into larger patches, with fewer small patches, which skewed the patch‐size distribution towards larger patches. These effects differed between browsing and grazing herbivores. Grazing effects were partially explained by the fact that grazing reduced average plant size, increased shrub density, and promoted facilitation among species of contrasting sizes. Similar effects were also confirmed by using model simulations that accounted for positive plant interactions. By linking remotely sensed images, a global field survey, and a mathematical model, our study uncovers the species‐level mechanisms by which herbivores shape ecosystem‐level spatial patterns and provides insights into the consequence of herbivory pressure on the resilience of drylands
Sensitivity Study of Atmospheric DMS Simulated in WRF‐Chem to Various Oceanic DMS Fields Over the South West Pacific
No full textInternational audienceAbstract Marine emission of the volatile gas dimethyl sulfide (DMS) is the most substantial source of natural sulfur in the global atmosphere. DMS is believed to play a significant role in the Earth's climate system as a precursor to new particle formation and cloud condensation nuclei in the pristine marine atmosphere. To simulate the global distribution of seawater DMS, atmospheric models use DMS climatologies. In this study, we tested the sensitivity of atmospheric DMS concentrations over the Southwest Pacific Ocean, simulated with the WRF‐Chem regional model, to five seawater DMS climatologies developed over the last two decades together with seawater DMS inferred from a recently developed relationship from nanophytoplankton satellite retrievals. Comparisons with in situ observations recently obtained in the Southwest Pacific and the Southern Ocean revealed that oceanic DMS climatologies are less accurate for latitudes south of 65°S than between 40°S and 65°S. In addition, in our study area, the spatial distribution of marine DMS is more accurately reproduced in the 40–65°S latitudes when deduced from a surface ocean biological variable, particularly when using a recently derived relationship from nanophytoplankton satellite retrievals, rather than from observation‐based climatologies. Simulated atmospheric DMS levels were sensitive to the oceanic DMS climatology used but the atmospheric DMS concentration variability was mostly dependent on the atmospheric dynamics. Atmospheric DMS concentrations and variability measured off the New‐Zealand coast are fairly well reproduced in WRF‐Chem using accurate phytoplanktonic assemblages and the nanophytoplankton‐related seawater DMS concentration
Quelles protections pour le Parc ?
No full textAssurer la protection du parc naturel de la mer de Corail soulève de nombreux défiset nécessite l'intervention des autorités publiques ayant compétence pour édicterdes règles. Dix ans après la création du Parc, il existe en effet des règles s'appliquantà l'ensemble du domaine, ainsi que deux types de réserves soumises à des réglemen-tations particulières : les réserves naturelles et les réserves intégrales. À cette complexiténormative s'ajoute l'inscription des atolls d'Entrecasteaux au patrimoine mondial del'Unesco depuis 2008. Quelles protections pour le Parc ? Quelles réglementationsont été pensées et demandent encore à être adoptées pour assurer une protectionajustée de cet immense espace de près de 1,3 million de km²? Qui est impliqué dansce processus ? Ce chapitre entend répondre à ces questions et rendre compte tant descontraintes du droit international, auquel est soumise toute gestion d'un tel espace,que des contraintes et opportunités que rencontre le collectif de gestion multisecto-riel et multi-acteurs du Parc, qui évolue dans un mille-feuille de normes et de valeurs. Ilmet en lumière des dynamiques innovantes qui aident à penser une gestion plus ajustéeet inclusive intégrant les différents registres de savoirs
Table ronde: Le rôle de la recherche et de l’enseignement dans le développement de pratiques agricoles durables
No full textTable ronde Le rôle de la recherche et de l’enseignement dans le développement de pratiques agricoles durablesexemples de collaborations recherche/agriculture vertueuses pour améliorer l'environnement et la productio
Points relais et flux de colis : les formes physiques mal connues du e-commerce. L'exemple du SCoT du Bassin de Vie d'Avignon
No full textArticle issu de l'appel à projets Plan Urbanisme Construction Architecture « Quelle place pour quel travail en ville ? Les conditions économiques, sociales et environnementales de la ville productive », 2020-2022 : Les formes physiques du e-commerce dans le SCoT du Bassin de Vie d’AvignonInternational audienceIn France, shopping habits have changed fast during the last decade and a high percentage of consumers now shop online. E-commerce generates a significant demand for dedicated delivery services and results in increasingly difficult last mile logistics. However, alternative delivery solutions to home delivery services have been developed, especially in metropolitan areas, by delivery operators which developed pick-up points.Nowadays, the system of pick-up points delivery is familiar to French consumers, yet this spatial incarnation of e-commerce, this corner stone of urban logistic, remains little known, both statistically and geographically. Nevertheless, a better understanding of pick-up points, and of their logistics, appears to be strategic both for defining commercial planning and transport policies, and more specifically those regarding urban logistics.In this context, the purpose of this article is to draw up a portrait of pick-up points in the SCoT du Bassin de Vie d'Avignon in terms of types of stores involved, expected benefits and experienced drawbacks of the PR activity and logistical management of parcels. It also looks at the relationship between customers and pick-up points, studying in particular their accessibility and how they are chosen. The work is based on two surveys. The first was carried out among all relay points in the Avignon area, and the second among a sample of 167 of their customers.En France, les habitudes de consommation ont changé rapidement au cours de la dernière décennie et de nombreux consommateurs effectuent désormais leurs achats sur internet. Le e-commerce génère une forte demande de services dédiés de livraison et crée des difficultés croissantes dans la logistique du dernier kilomètre. Pour y faire face, des alternatives à la livraison à domicile, en particulier la livraison en points relais, ont été développées par les opérateurs de livraison de colis.Si le système de livraison en points relais est aujourd'hui bien connu des consommateurs, cette incarnation physique du e-commerce dans les territoires demeure mal cernée dans ses implantations et dans son fonctionnement. Pourtant, une meilleure connaissance des points relais et de leur logistique apparaît stratégique, à la fois pour définir les politiques d'aménagement commercial et les politiques de transport de marchandises. Dans ce contexte, cet article vise à dresser un portrait des points relais du SCoT du Bassin de Vie d'Avignon en termes de types de magasins concernés, d'avantages escomptés et d'inconvénients vécus et de gestion logistique des colis. Il traite aussi de la relation entre les clients et les points relais, en étudiant notamment leur accessibilité et comment ils sont choisis. Le travail se base sur deux enquêtes. La première conduite auprès de tous les points relais du SCoT d'Avignon et la seconde conduite auprès d'un échantillon de 167 de leurs clients.</p
Modelling crop water demand under climate change: the case of Sardinia region
No full textInternational audienceWater scarcity is one of the foremost concerns for the agricultural sector due to limited water resources, increasing water demand, and climate change. Currently, the agricultural sector accounts for 70% of global freshwater withdrawals, and an increase in freshwater withdrawals and use for irrigation is already expected by 2050. In this study, the impact of climate change on crop water demands, and yield losses due to water shortage, were assessed using the Simulation of Evapotranspiration of Applied Water model. This crop-soil-water model was implemented in a typical Mediterranean environment (Sardinia, Italy) across a full range of relevant crops (wheat, barley, sugar beet, potato, lentil, almond, maize, wine grape, table grape, tomato, artichoke, alfalfa, olive, irrigated pasture, and orange). The simulations were driven by climate data from five earth system models dynamically downscaled at 11 km with regional climate models and available from EURO-CORDEX for baseline (1976-2005) and future (2036-2065) climate conditions under RCP2.6, RCP4.5 and RCP8.5 scenarios. Results show that wheat and barley will foresee the most significant increase in water demand of 12%, 13%, and 14% under RCP2.6, RCP4.5 and RCP8.5, respectively, based on the ensemble mean of the climate models. Water demand for almond, maize, wine grape, and pasture were projected to increase by about 5%, 7%, and 4% under RCP2.6, RCP4.5, and RCP8.5, respectively. The increasing crop water demand represents a considerable challenge for water resource management, especially considering the shortage of water supplies and increasing competition with other sectors. This work provides a wide climate risk evaluation across most relevant crops in the Mediterranean environment to support policymakers in developing adaptation strategies and sustainable regional plans, to support food and water securities
Hégémonie, esclavage et modélisation des discours de domination sous les premiers empires au Proche-Orient médiéval
No full textInternational audienceHegemony, Slavery, and the Modelling of Discourses of Domination in the Early Empires of the Medieval Middle East:The Arab victories over the great Persian and Byzantine Empires ultimately resulted in annexing vast territories. These sudden and rapid conquests had a profound effect on the social and institutional foundations of the ancient cities of the Arabian Peninsula. One of the effects of conquest was the rise to power of an Arab military oligarchy which, with the help of its cronies among the notables of the defeated countries, confiscated property and land for its own benefit. This new order brought with it a sudden increase in violence and atrocities. In this medieval historical context, people living under colonial rule were often treated like animals, stripped of all human dignity. Not only were they treated with contempt and categorised according to race, but they were also marginalised by a policy of oppression and systematic, widespread looting. These profound changes took place in the second half of the 7th century. One of their most significant consequences was the birth of a powerful empire established by the Umayyad caliphs. These caliphs, descendants of the notables of the Meccan clan of ʿAbd S̲h̲ams, ruled from Damascus between 661 and 750 AD. After their fall, it was time for their rivals, the Abbasids, to impose their rule, from Baghdad, over people and territories stretching from the Arabian Sea to the Persian Gulf, the Red Sea, the Mediterranean, and the Atlantic and Indian Oceans.This article aims to provide a historical and critical analysis of social, economic, and cultural relations in the medieval Middle East at a time marked by the emergence and apogee of the first two Arab colonial empires. One of the major challenges of this study is to move away from trying to tell an edifying story and to adopt a methodological approach that sheds light on the fundamental shifts of a very long history. This approach favours a careful rereading of first-hand sources, paying attention to the precise meaning of words and the informative value of testimony. This information is obtained from chancellery documents, dīwān or offices of royal secretaries, tax books (kharādj), medical treatises, geographical and literary sources, historical annals, etc. There is no doubt that the available corpus is rather limited, incomplete, and often laudatory. These texts generally tend to embellish the realities they describe. In some cases, however, significant information can be gleaned that can help us reconstruct the real situation.Admittedly, these data are not without their shortcomings. Nevertheless, they help us tobetter understand the facts and to situate them in the infinite variety of reality, while at the same time widening the fields of investigation into the discourses of otherness, the evolution of mentalities, the emergence of colour prejudice, social hierarchies, and biological and cultural identities.Hegemonía, esclavitud y modelización de los discursos de dominación bajo los primeros imperios en el Próximo Oriente medieval :Las victorias logradas por los árabes sobre los dos grandes imperios persa y bizantino dieron lugar a la anexión de inmensos territorios. Estas conquistas repentinas y fulgurantes trastocaron los fundamentos sociales e institucionales de las viejas ciudades de la península arábiga. Uno de los efectos inherentes a la conquista fue el ascenso de una oligarquía militar árabe que, respaldada por los notables de los países vencidos, confiscó bienes y tierras en beneficio propio. Este nuevo orden resultó ser propicio a un brusco aumento de violencias y exacciones. En este contexto histórico medieval, las poblaciones colonizadas fueron a menudo reducidas al estado de bestias, consideradas carentes de sensibilidad humana. Además de sufrir el desprecio y categorizaciones raciales, se las excluyó en virtud de una política de opresión y de expoliaciones masivas y sistemáticas.Estas transformaciones profundas aparecieron desde la segunda mitad del siglo VII. Una de sus consecuencias decisivas fue el nacimiento de un potente imperio edificado por el califato omeya. Descendientes de los notables afiliados al clan mecano de los Abd S̲h̲ams, estos dinastas reinaron en Damas entre 661 y 750 d. C. Tras su caída, fueron sus rivales, los Abasidas, quienes impusieron su dominio desde Bagdad sobre pueblos y territorios, repartidos en ambos lados del mar de Arabia, en el golfo Pérsico, el Mar Rojo, el Mediterráneo y los océanos Atlántico e Índico.Este artículo pretende ofrecer un análisis histórico y crítico de las relacionales sociales,económicas y culturales en Oriente Próximo medieval, en una época marcada por el nacimiento y el apogeo de los dos primeros imperios coloniales árabes. Uno de los desafíos de este estudio es adoptar un enfoque metódico, por fuera de abordajes edificantes, que permita comprender los movimientos profundos de una historia tan larga. Se trata de un enfoque que enfatiza una atenta relectura de las fuentes de primera mano y que presta atención al sentido preciso de las palabras y al valor informativo de los testimonios. Estas informaciones provienen de documentos de cancillería, administraciones (dīwān) u oficinas de secretarios reales, de libros de impuestos (jarach), de tratados médicos, de fuentes geográficas y literarias, de anales históricos,etc. Se trata de un corpus sin duda bastante reducido, incompleto y a menudo de carácter celebratorio. Estos documentos tienden por lo general a edulcorar las realidades que describen. Sin embargo, se puede encontrar en ellos indicaciones significativas que permiten reconstituir la trama de lo acontecido. Estos datos, incluso imperfectos, nos pueden ayudar a entender mejor los hechos y a ubicarlos en la infinita variedad de lo real, permitiendo a su vez ampliar los campos de investigación respecto a los discursos sobre la alteridad, la evolución de las mentalidades, al rol de los prejuicios de color, de las jerarquías sociales y las identidades biológicas y culturales.Les victoires remportées par les Arabes sur les deux grands Empires perse et byzantin se sont soldées par l’annexion d’immenses territoires. Ces conquêtes soudaines et fulgurantes ont bouleversé les fondements sociaux et institutionnels des vieilles cités dela péninsule Arabique. Un des effets inhérents à la conquête est la montée en puissanced’une oligarchie militaire arabe qui, aidée par ses affidés parmi les notables des pays vaincus, confisqua à son profit les biens et les terres, ceci entraînant une brusque recrudescence des violences et des exactions. Dans ce contexte, les populations colonisées furent souvent réduites à l’état de bêtes brutes, dénuées de sensibilité humaine. En plus du mépris et des catégorisations raciales, elles furent frappées d’exclusion en vertu d’une politique d’oppression et de spoliations massives et systématiques.Ces transformations profondes apparurent dès la deuxième moitié du VIIe siècle. Une deleurs conséquences décisives est la naissance d’un puissant empire édifié par les califesomeyyades. Descendant des notables affiliés au clan mecquois des ʿAbd S̲h̲ams, ces dynastes régnèrent à Damas entre 661 et 750 apr. J.-C. Après leur chute, ce fut au tour de leurs rivaux, les Abbassides, d’imposer leur domination depuis Bagdad sur des peuples et des territoires répartis sur des côtes aussi diverses que celles de la mer d’Arabie, du golfe Persique, de la mer Rouge, de la Méditerranée et des deux océans Atlantique et Indien.Cet article entend fournir une analyse historique et critique des rapports sociaux, économiques et culturels au Proche-Orient médiéval, à une époque marquée par lanaissance et l’apogée des deux premiers empires coloniaux arabes. L’un de ses principaux enjeux est de sortir d’une histoire édifiante pour retrouver une approche méthodique, permettant de comprendre les mouvements profonds d’une si longue histoire. Il s’agit d’une démarche qui privilégie une relecture serrée des sources de première main et fait attention aux sens précis des mots et à la valeur informative des témoignages. Ces renseignements proviennent des documents de chancellerie, des dīwān ou bureaux des secrétaires royaux, des livres des impôts (Kharādj), des traités médicaux, des sources géographiques et littéraires, des annales historiques, etc. Ces corpus dont nous disposons sont sans doute assez réduits, incomplets et souvent laudatifs. Ils tendent généralement à édulcorer les réalités qu’ils décrivent. Il arrive néanmoins d’y trouver des indications significatives permettant de reconstituer la tramedu réel. Ces données sont sans doute loin d’être sans défauts. Elles nous aident cependant à mieux cerner les faits pour les replacer dans l’infinie variété du réel tout en élargissant les champs d’investigation au sujet des discours sur l’altérité, de l’évolution des mentalités, de l’entrée en jeu des préjugés de couleur, des hiérarchies sociales et desidentités biologiques et culturelles.Hegemonia, escravidão e conformação dos discursos de dominação sob os primeiros impérios no Médio Oriente medieval :As vitórias alcançadas pelos Árabes sobre os dois grandes impérios persa e bizantino deram lugar a anexação de vastos territórios. Estas conquistas repentinas e fulgurantes abalaram os fundamentos sociais e institucionais das antigas cidades da Península Arábica. Um dos efeitos inerentes à conquista foi a ascensão de uma oligarquia militar árabe que, apoiando-se nos seus aliados entre as elites dos países vencidos, confiscou bens e terras. Esta nova ordem propiciou um aumento abrupto das violências e exações.Nesse contexto histórico medieval, as populações colonizadas foram muitas vezes reduzidas ao estado de besta bruta, desprovida de sensibilidade humana. Para além do desprezo e das categorizações raciais, elas também sofreram a exclusão devida a uma política de opressão e de espoliação maciça e sistemática. Essas transformações profundas surgiram logo na segunda metade do século VII. Uma das consequências determinantes foi o nascimento de um império poderoso fundado pelos califes omíadas. Descendentes de notáveis afilhados ao clã dos Abd Shams, esses dinastas reinaram em Damasco entre 661 e 750 depois J.-C. Após sua caída, foi a vez dos seus rivais, os Abásidas, impor sua dominação desde Bagdad sobre povos e territórios repartidos de ambos os lados do mar de Arábia, do golfo Pérsico, do mar Vermelho, do Mediterrâneo e dos dois oceanos Atlântico e Índico.Este artigo pretende oferecer uma análise histórica e crítica das relações sociais, económicas e culturais no Médio Oriente medieval numa época marcada pelo nascimento e o apogeu dos dois primeiros impérios coloniais árabes. Um dos desafios deste estudo é de encontrar uma abordagem metódica, afastando-se de uma história edificante, para entender os movimentos profundos de uma tão longa história. Trata-se de uma abordagem que privilegia uma releitura intensiva das fontes e atenta o significado exato das palavras e do valor informativo dos testemunhos.Essas informações provêm dos documentos de chancelaria, dos dīwān ou secretarias régias, dos livros dos impostos (Kharādj), dos tratados médicos, das fontes geográficas e literárias, dos anais históricos, etc. Os corpus à nossa disposição são com certeza reduzidos, incompletos e muitas vezes laudatários. Eles tendem geralmente a suavizar as realidades que descrevem. No entanto, também desvelam indicações valiosas permitindo reconstituir a trama da realidade. Esses dados têm obviamente defeitos. Mas ajudam-nos a circunscrever melhor os factos para situá-los na variedade indefinida do real alargando o campo de investigação em torno dos discursos sobre a alteridade, da evolução das mentalidades, da intervenção dos preconceitos de cor, das hierarquias sociais e das identidades biológicas e culturais
L'édification d'une « Europe sociale » au prisme des rapports entre l'Union européenne et le Comité européen des droits sociaux
No full textInternational audienc
Phenolic compound/polysaccharide interactions in plant-based products: organoleptic and nutritional consequences
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Que reste-t-il de l’attentat du 14 juillet 2016 sur la Promenade des Anglais ? Tensions mémorielles socio-spatiales à Nice
No full textInternational audienceOur research focuses on the attack of July 14, 2016 in Nice, and takes an interest, from a perspective that articulates geography and anthropology, in the memorial effects of this event on the Promenade des Anglais, an emblematic space in the city. The research highlights the tensions and contradictions between the erasure of traces of the attack and collective and individual memory initiatives. Through official memorials and more intimate ones, the work examines their insertion in public space, the uses and practices that mobilize them, and the staging and discourses that frame them. It focuses in particular on l'Ange de la Baie, the memorial work by artist J-M. Fondacaro, which aims to reconcile life and death, in movement, and which is gradually taking its place in the city.Que reste-t-il de l'attentat du 14 juillet 2016 sur la Promenade des Anglais ?Tensions mémorielles socio-spatiales à Nice Résumé : La recherche met en lumière les tensions et les contradictions entre l'effacement des traces de l'attentat du 14 juillet 2016 à Nice et les initiatives de mises en mémoire, collective et individuelle. L'étude des mémoriaux officiels et d'autres plus intimistes, montre leurs insertions dans l'espace public, les usages et les pratiques qui les mobilisent, les mises en scène et les discours qui les encadrent. Par exemple, L'Ange de la Baie, l'oeuvre mémorielle de l'artiste Jean-Marie Fondacaro, vise à concilier vie et mort, dans le mouvement, et prend progressivement sa place en ville.</div