Conservation de la nature et dynamiques agricoles dans le territoire d’un Parc National

Introduction Dans sa version la plus répandue, un parc national est une opération de sauvetage d’une portion de nature menacée par les activités humaines. Il résulte d’une négociation territoriale où différents acteurs finissent par trouver un compromis et par dessiner deux périmètres : celui d’une zone cœur, qui contient les espaces marqués par une très forte naturalité et faisant désormais l’objet d’une protection maximale, et celui d’une zone de contact, où sont tolérées des activités huma..

Localization of Secondary Metabolites in Marine Invertebrates: Contribution of MALDI MSI for the Study of Saponins in Cuvierian Tubules of H. forskali

BACKGROUND: Several species of sea cucumbers of the family Holothuriidae possess a particular mechanical defense system called the Cuvierian tubules (Ct). It is also a chemical defense system as triterpene glycosides (saponins) appear to be particularly concentrated in Ct. In the present study, the precise localization of saponins in the Ct of Holothuria forskali is investigated. Classical histochemical labeling using lectin was firstly performed but did not generate any conclusive results. Thus, MALDI mass spectrometry Imaging (MALDI-MSI) was directly applied and completed by statistical multivariate tests. A comparison between the tubules of relaxed and stressed animals was realized. RESULTS: These analyses allowed the detection of three groups of ions, corresponding to the isomeric saponins of the tubules. Saponins detected at m/z 1287 and 1303 were the most abundant and were apparently localized in the connective tissue of the tubules of both relaxed and stressed individuals. Saponins at m/z 1125 and 1141 were detected in lower amount and were present in tissues of relaxed animals. Finally, saponin ions at 1433, 1449, 1463 and 1479 were observed in some Ct of stressed holothuroids in the outer part of the connective tissue. The saponin group m/z 14xx seems therefore to be stress-specific and could originate from modifications of the saponins with m/z of 11xx. CONCLUSIONS: All the results taken together indicate a complex chemical defense mechanism with, for a single organ, different sets of saponins originating from different cell populations and presenting different responses to stress. The present study also reflects that MALDI-MSI is a valuable tool for chemical ecology studies in which specific chemical signalling molecules like allelochemicals or pheromones have to be tracked. This report represents one of the very first studies using these tools to provide a functional and ecological understanding of the role of natural products from marine invertebrates

On contempory ruins : dystopic visions and reminiscence of urban spectres

Allégorie du temps, la ruine conjugue depuis toujours Savoir et Imaginaire. Pourtant, depuis le XXe siècle, la douce mélancolie ruiniste telle que nous la connaissons depuis la Renaissance connaît une véritable subversion. En effet, l’apparition des ruines de guerre, l’horreur des évènements et la brutalité du monde contemporain plongent la ruine dans un nouveau paradigme esthétique, celui du tragique, voire du kitsch. La ruine ne renvoie plus seulement au passé, mais bel et bien à un présent qui voit son pouvoir de destruction changer d’échelle. Si nos sociétés postmodernes entrainent dans leur chute de plus en plus d’espaces qu’elles jettent, laissent à l’abandon au profit de nouveaux systèmes économiques, le concept de ruine peine à trouver sa place dans un monde qui n’est plus en mesure de produire les conditions mêmes de son existence. Cette réapparition inopinée d’un nouveau genre de ruines (industrielles, écologiques ou guerrières) bouleverse le vocabulaire communément établi et tend à faire disparaître la ruine comme réalité mais aussi comme concept fondé sur l’autonomie, le fragment et la temporalité. Aussi, cette recherche propose-t-elle de s’interroger sur la manière d’appréhender ces espaces délaissés ou « en suspens » dont la vision, parfois brutale, perturbe nos sens, nos repères esthétiques et historiques. À Détroit et à Beyrouth, les ruines en milieu urbain se présentent comme autant de cicatrices d’un tissu qui aurait brutalement perdu sa fonctionnalité et son identité. De la pratique photographique du ruins porn au tourisme noir, leur contemplation soulève de vives interrogations autant qu’elle donne lieu à de nouveaux discours et à des approches esthétiques et artistiques inédites.An allegory of time, the ruin has always associated Knowledge and Imagination. Since the XXth century, however, the ruin has been extensively subverted, shattering the gentle melancholy familiar to us since the Renaissance. With the appearance of ruins of war, alongside the horrifying events and brutality of the modern world, ruin has plunged into a new aesthetic paradigm, marked by tragedy or even kitsch. Ruin no longer takes us back solely to the past. It also conjures up a present whose powers of destruction have reached a new scale. Our postmodern societies are caught in a downward plunge, taking with them more and more spaces that they discard and abandon, replacing them with new economic systems. Yet the concept of ruin is struggling to find its place in a world that is no longer able to provide the conditions necessary for its existence. The unexpected reappearance of a new type of ruin (industrial, ecological or created by war) throws our common vocabulary into disarray, tending to efface ruin not only as a reality but also as a concept in its independent, fragmented and temporal nature. This research therefore explores the way we understand these abandoned or suspended spaces. Sometimes brutal to look at, they disturb our senses as well as our aesthetic and historic references. In Detroit and in Beirut, for different reasons, the ruins of the urban environment can be seen as scars in a fabric that has suddenly lost its function and its identity. From the photographic movement of ruin porn to dark tourism, the contemplation of these ruins raises pressing questions while, at the same time, giving rise to new propositions and new aesthetic and artistic approaches

De la ruine contemporaine : quelques visions dystopiques et spectres de survivances urbaines

An allegory of time, the ruin has always associated Knowledge and Imagination. Since the XXth century, however, the ruin has been extensively subverted, shattering the gentle melancholy familiar to us since the Renaissance. With the appearance of ruins of war, alongside the horrifying events and brutality of the modern world, ruin has plunged into a new aesthetic paradigm, marked by tragedy or even kitsch. Ruin no longer takes us back solely to the past. It also conjures up a present whose powers of destruction have reached a new scale. Our postmodern societies are caught in a downward plunge, taking with them more and more spaces that they discard and abandon, replacing them with new economic systems. Yet the concept of ruin is struggling to find its place in a world that is no longer able to provide the conditions necessary for its existence. The unexpected reappearance of a new type of ruin (industrial, ecological or created by war) throws our common vocabulary into disarray, tending to efface ruin not only as a reality but also as a concept in its independent, fragmented and temporal nature. This research therefore explores the way we understand these abandoned or suspended spaces. Sometimes brutal to look at, they disturb our senses as well as our aesthetic and historic references. In Detroit and in Beirut, for different reasons, the ruins of the urban environment can be seen as scars in a fabric that has suddenly lost its function and its identity. From the photographic movement of ruin porn to dark tourism, the contemplation of these ruins raises pressing questions while, at the same time, giving rise to new propositions and new aesthetic and artistic approaches.Allégorie du temps, la ruine conjugue depuis toujours Savoir et Imaginaire. Pourtant, depuis le XXe siècle, la douce mélancolie ruiniste telle que nous la connaissons depuis la Renaissance connaît une véritable subversion. En effet, l’apparition des ruines de guerre, l’horreur des évènements et la brutalité du monde contemporain plongent la ruine dans un nouveau paradigme esthétique, celui du tragique, voire du kitsch. La ruine ne renvoie plus seulement au passé, mais bel et bien à un présent qui voit son pouvoir de destruction changer d’échelle. Si nos sociétés postmodernes entrainent dans leur chute de plus en plus d’espaces qu’elles jettent, laissent à l’abandon au profit de nouveaux systèmes économiques, le concept de ruine peine à trouver sa place dans un monde qui n’est plus en mesure de produire les conditions mêmes de son existence. Cette réapparition inopinée d’un nouveau genre de ruines (industrielles, écologiques ou guerrières) bouleverse le vocabulaire communément établi et tend à faire disparaître la ruine comme réalité mais aussi comme concept fondé sur l’autonomie, le fragment et la temporalité. Aussi, cette recherche propose-t-elle de s’interroger sur la manière d’appréhender ces espaces délaissés ou « en suspens » dont la vision, parfois brutale, perturbe nos sens, nos repères esthétiques et historiques. À Détroit et à Beyrouth, les ruines en milieu urbain se présentent comme autant de cicatrices d’un tissu qui aurait brutalement perdu sa fonctionnalité et son identité. De la pratique photographique du ruins porn au tourisme noir, leur contemplation soulève de vives interrogations autant qu’elle donne lieu à de nouveaux discours et à des approches esthétiques et artistiques inédites

Conservation de la nature et dynamiques agricoles dans le territoire d'un Parc National : difficile convergence

International audienceThe Cévennes National Park was created in 1970 with the aim of conserving landscapes, lifestyles, habitats and species in the less populated areas of the region. These landscapes had been previously described as ruined by animal rearing but were no longer despised. On the contrary they were praised for their originality, their beauty and their apparently unchanged nature. Among several options, the project of the Park is focused on the conservation of the current state. Unlike other National Parks, human activities are not excluded from the park’s core area. The management principles of the Park includes a close interest paid to human activities. However – at least at the outset, their importance for conservation and landscape structure is not fully understood. These activities will evolve under the effects of national and european policies. When setting up a management system in a small area, the values and traditions of different groups (conservationists, farmers, forest owners and managers, hunters ...) have been brought together. The relationships between those diverses professional cultures were complicated by the emergence of a politicsof territorial development, by public support for farmers and by the resulting changes in farm management. Several interdisciplinary research programs have accompanied and guided park management. This article analyses the phases in the encounters between farmers and conservationists from the end of the 19th century when the first environmental analyses of the territory were issued and when farming, in the Cévennes and more widely, in all western Europe, were at the beginning of a major tranformationLe Parc National des Cévennes a été créé en 1970 pour protéger les paysages, les modes de vie, les habitats et les espèces des "hautes terres", celles qui étaient les moins peuplées de la région. Ces paysages qui avaient été autrefois décrits comme ruinés par les activités pastorales, sont appréciés par les promoteurs du Parc pour leur orginalité, leurs qualités esthétiques et une apparence de nature immuable. Parmi plusieurs options, le projet de conservation de l'état actuel est retenu. Au contraire d'autres Parcs Nationaux, les activités humaines ne sont pas exclues de la zone centrale/coeur de parc. La conception de la gestion du Parc est ouverte à la prise en compte des activités humaines mais leur importance n'est, au moins au départ, pas clairement comprise et ces activités vont évoluer sous l'effet des politiques nationales ou européennes

MALDI-Imaging results shown in false colour representation.

<p>The color intensity reflects intensities of the selected mass signals: green, ions at <i>m/z</i> 843 used as a counterstain; red, the different saponin ions for which the <i>m/z</i> ratios are indicated below the images.</p

Comparison of saponins composition between stressed and relaxed holothuroids.

<p>(A) Pseudogel view of 300 mass spectra from the Cuvierian tubules of <i>Holothuria forskali</i>: spectra from stressed holothuroids (upper part) and from relaxed holothuroids (lower part). (B and C) scores plot of first, second and third principal component considering all the ions (B) or only the saponin ions (C) in the MALDI spectra. Each data point represents one mass spectrum (red, relaxed; green, stressed). (D) Scores plot of first, second and third loading considering only the saponin ions. Each data point represents one <i>m/z</i> ratio.</p

Molecular structures of saponins from the Cuvierian tubules of <i>Holothuria forskali</i>.

<p>Isomeric congeners are presented in columns (a) and (b). Structures and corresponding names are from Van Dyck <i>et al. </i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013923#pone.0013923-Vandyck1" target="_blank">[17]</a>.</p