Alpha-linolenic acid: A promising nutraceutical for the prevention of stroke

International audienceStroke is a worldwide main cause of mortality and morbidity. Most of the preventive and neuroprotective treatments identified in preclinical studies failed in clinical trials. Although there is a consensus that nutrition is important for health, its role is underestimated in stroke. Indeed an increase consumption of salt and fatty foods may promote hypertension and obesity, which are well known risk factors of stroke. In contrast it is more difficult to identify a risk factor arising from a deficiency in an essential nutrient in the diet. Western modern diets are deficient in omega-3 polyunsaturated fatty acids, which are essential for brain health. Such deficiency may constitute by itself a risk factor for stroke. Furthermore, an imbalance in the consumption of omega-6 and omega-3 progressively took place in the past 40 years leading to omega-6/omega-3 ratios that are far above the WHO healthy recommendations. A consequence of this imbalanced ratio has been the fostering of elevations in and increased prevalence of inflammatory cardiovascular diseases and obesity. In this context, this review outlines a promising therapeutic opportunity by integrating a nutritional-based approach focusing on omega-3 alpha-linolenic acid as nutraceutical to prevent the devastating damage caused by brain ischemia

Bilan des connaissances, inventaires 2016 et cartographie de cinq coléoptères saproxyliques d’intérêt communautaire dans les sites Natura 2000 de la région PACA : Stephanopachys linearis, Stephanopachys substriatus, Limoniscus violaceus, Osmoderma eremita et Rosalia alpina

Sept espèces de coléoptères saproxylophages inscrites à l'annexe 2 de la directive Habitats (DH2) sont connues avec certitude en région PACA. Une huitième a été signalée : Cucujus cinnaberinus (Cucujidae), dont une ancienne mention dans le secteur de Saint-Martin-Vésubie semble plausible (Brustel & Gouix, 2012

Do species interactions prevent Limoniscus violaceus from living in suitable basal hollow trees?

The violet click beetle (Limoniscus violaceus) is an endangered beetle that is protected in Europe. Its conservation required better knowledge on its biology. Recently, a study revealed that the probability of occurrence of L. violaceus in hollows increases with increasing tree circumference at 30 cm above ground and with increasing hollow decay stage (Gouix et al., submitted). However, the model showed that it was easier to identify unoccupied hollows than to identify the occupied ones. As tree hollows harbour a ränge of associated and facultative species living within a relatively small habitat, we may suspect some species interactions (competition and/or predation) that prevent Limoniscus violaceus from occupying suitable basal hollow trees. We studied beetle and Spider assemblages emerging from 73 basal hollow trees located within a Single forest site of 3500 ha (in France). All trees were considered to be suitable for Limoniscus violaceus (i.e. trees with a circumference at 30 cm above ground greater than 235 cm and cavity at an advanced stage of decay). We used the probabilistic approach to test for statistically significant pair-wise patterns of species co-occurrence. In total, 4805 species pairs were analyzed and 9.6 % had non-random patterns. We detected very few negative co-occurrence patterns (19) compared with positive ones (444). Regarding Limoniscus violaceus, we highly linked to the presence of tree hollows in mature trees. Moreover, the interaction between saproxylic insects and hollows shows specialised interacting patterns that model the structure and stability of these saproxylic assemblages. The objective of this work is to evaluate how interacting patterns of saproxylic insect networks vary according to woodland sites. We selected three representative Mediterranean woodlands in the Park: one sclerophyllous oak woodland of Quercus rotundifolia; one mixed deciduous oak woodland of Quercus pyrenaica and Quercus faginea; and one ash riparian woodland of Fraxinus angustifolia. We considered 30, 30 and 27 tree hollows, respectively, which were covered with emergence traps. Our study lasted one year, during which traps were emptied monthly and pots were replaced. We selected Coleoptera and Syrphidae (Diptera) as study groups. They were sorted according to trophic guilds: xylophagous, saproxylophagous, saprophagous, xylomycetophagous and predators. We used Aninhado and Modular programmes to evaluate the network architecture, and bipartite for R programme to study interacting attributes in the hollow-saproxylic insect interaction in each woodland site. Saproxylic insect-hollow networks presented a significant nested pattern, which means that most of the interactions are established with the most generalist nodes/species at both trophic levels (in this case, the lower trophic level is composed of hollows and the higher trophic level is composed of insects). Not all studied forests showed the same level of connectance (proportion of possible links between trees and species), the deciduous oak woodland being the forest with the most densely interconnected network

Voyage d’étude en Occitanie: " Écosystèmes forestiers et impact de la gestion sur leur fonctionnement à long terme"

A quoi ressemble une forêt sans transformation anthropique majeure, intérêt de leur étude, différences fondamentales entre une forêt gérée en "bon père de famille" et un écosystème forestier naturel. Gestion de la cohabitation d’une activité pastorale, des ongulés sauvages (et de leur chasse), de la fourniture de bois de chauffage aux sociétaires et de la production de bois d’œuvre. Itinéraires sylvicoles adaptés à certains sols chimiquement très pauvres

Landscape composition and life-history traits influence bat movement and space use: Analysis of 30 years of published telemetry data

Aim Animal movement determines home range patterns, which in turn affect individual fitness, population dynamics and ecosystem functioning. Using temperate bats, a group of particular conservation concern, we investigated how morphological traits, habitat specialization and environmental variables affect home range sizes and daily foraging movements, using a compilation of 30 years of published bat telemetry data. Location Northern America and Europe. Time period 1988–2016. Major taxa studied Bats. Methods We compiled data on home range size and mean daily distance between roosts and foraging areas at both colony and individual levels from 166 studies of 3,129 radiotracked individuals of 49 bat species. We calculated multi-scale habitat composition and configuration in the surrounding landscapes of the 165 studied roosts. Using mixed models, we examined the effects of habitat availability and spatial arrangement on bat movements, while accounting for body mass, aspect ratio, wing loading and habitat specialization. Results We found a significant effect of landscape composition on home range size and mean daily distance at both colony and individual levels. On average, home ranges were up to 42% smaller in the most habitat-diversified landscapes while mean daily distances were up to 30% shorter in the most forested landscapes. Bat home range size significantly increased with body mass, wing aspect ratio and wing loading, and decreased with habitat specialization. Main conclusions Promoting bat movements through the landscape surrounding roosts at large spatial scales is crucial for bat conservation. Forest loss and overall landscape homogenization lead temperate bats to fly further to meet their ecological requirements, by increasing home range sizes and daily foraging distances. Both processes might be more detrimental for smaller, habitat-specialized bats, less able to travel increasingly longer distances to meet their diverse needs

Inventaire et évaluation des vieilles forêts des Pyrénées de Midi-Pyrénées

Les 11, 12 et 13 février 2016, ce sont déroulées les 5e Rencontres Naturalistes de Midi-Pyrénées dans le Gers, à Auch. Tous les 3 ans, ce rendez-vous incontournable des amateurs et professionnels de la biodiversité de Midi-Pyrénées et d’ailleurs, a rassemblé plus de 600 participants sur les 3 jours. Le succès de cet événement n’aurait pas été aussi complet sans l’aide des bénévoles et des associations partenaires. Les 5e Rencontres Naturalistes se sont ouvertes sur les discours de Nadia Baïtiche-Moine, Adjointe au Maire d’Auch, de Jérôme Calas, Président de Nature Midi-Pyrénées et de Ronny Guardia-Mazzoleni, Conseiller régional Languedoc-Roussillon-Midi-Pyrénées. Au cours de ces 3 jours, ce sont près de 35 communications sur la faune, la flore et les espaces naturels, agricoles et forestiers qui ont été présentées : une véritable synthèse des différents travaux menés en Midi-Pyrénées depuis 3 ans dans le domaine de la connaissance et de la préservation de notre riche patrimoine naturel régional. Les nombreux participants d’horizons divers (associations, conservatoires, services de l’Etat, laboratoires de recherche, établissements scolaires, PNR ou collectivités) ont eu également l’occasion de profiter des temps de pause pour échanger autour d’une vingtaine de posters scientifiques et de différentes expositions

Gestion forestière et biodiversité, les enjeux de conservation d'une espèce parapluie : Limoniscus violaceus (Coleoptera)

The Violet Click Beetles - Limoniscus violaceus (Müller, 1821) - is a coleopteran species living within wood mould of hollow trees. Endangered in Europe, it is included in Annex II of the "Habitats" directive that aims to ensure the preservation of habitats and species of Community interest through the Natura 2000 network. Managers of this kind of area must consequently guarantee the favorable conservation status of the species. However, difficulties for detecting the species have limited the accumulation of knowledge about its biology and its ecology. This weakness has motivated this doctoral thesis. First, all data relative to the species' distribution are compiled. 184 localities in 17 countries are given. Several discordances with Natura 2000 data are highlighted. A survey method using emergence traps is developed and tested in 5 French Natura 2000 areas. A predictive model of the presence of Limoniscus violaceus based on two factors easy to handle (the degree of hollowing of the cavity and the circumference at 30 cm height) is identified. The study of these factors' thresholds and their confidence intervals leads to a decision rule for the assessment of habitats favorable to Limoniscus violaceus. Meanwhile, analysis of the composition of assemblages of species sampled result to the determination of 231 saproxylic beetles. Preservation of cavities favorable for Limoniscus violaceus appears beneficial for the majority of them, justifying it potentially being an umbrella species. For further prospection, a list of indicator species is identified. It helps to prioritize areas where monitoring of hollow trees and Limoniscus violaceus should be considered. Study of the dispersal from results of emergence traps crossed with bibliographic knowledge suggests that average population size is around 10 adults with 3 individuals dispersing per cavity each year. Sex-Ratio analysis gives complementary information about the functioning of the species populations. Finally, a case study of conservation strategy in the Forest of Grésigne is presented. To ensure the recruitment of trees that will guarantee the long term persistence of the species, management guidelines are given, based on the current forest management plan and on the results of a study on the origin of cavities.Le taupin violacé - Limoniscus violaceus (Müller, 1821) - est une espèce de coléoptère vivant dans le terreau des cavités d'arbres. Menacé d'extinction en Europe, il est inscrit en Annexe II de la directive " Habitats " dont l'objectif est d'assurer la préservation des habitats et des espèces d'intérêt communautaire au sein du réseau Natura 2000. Les gestionnaires d'espaces naturels où il est présent doivent assurer l'état de conservation de ses populations. Cependant, les difficultés de détection de l'espèce ont limité le développement des connaissances sur sa biologie et son écologie essentielles à la mise en place d'une stratégie de conservation. Cette lacune a motivé la réalisation de ce travail de thèse. Il commence par la compilation des données relatives à sa répartition: 184 localités à travers 17 pays. Plusieurs discordances avec les données énoncées par le réseau Natura 2000 sont mises en évidence. Une méthode de suivi de l'espèce par piégeage à émergence est développée et testée dans 5 sites Natura 2000 français. Les résultats obtenus associés à la description des cavités d'arbres et de leur environnement permettent l'identification d'un modèle prédictif des cavités habitées par Limoniscus violaceus dépendant de deux facteurs simples d'utilisation : l'état d'avancement de la cavité et la circonférence de l'arbre à 30 cm du sol. L'étude de leur valeur seuil et de leurs intervalles de confiance conduit à l'élaboration d'une règle de décision pour l'évaluation des habitats favorables à l'espèce. Parallèlement, l'analyse de la composition des assemblages d'espèces échantillonées se base sur la détermination de 231 coléoptères saproxyliques. La préservation des cavités favorables pour Limoniscus violaceus apparait bénéfique pour la majorité d'entre eux, justifiant le potentiel d'espèce parapluie qui lui est attribué. Dans une perspective de prospection, une liste d'espèces indicatrices est identifiée. Elle permet de prioriser les sites au sein desquels une stratégie de suivi des cavités basses favorables pour la biodiversité et pour Limoniscus violaceus doit être envisagée. L'étude du comportement de dispersion à partir des résultats d'échantillonnage par émergence associé aux connaissances bibliographiques suggère une taille des populations locales d'environ 10 adultes dont 3 dispersent par cavité chaque année. Un regard sur la sex-ratio apporte des éléments complémentaires de réflexion sur le fonctionnement des populations. Enfin, un cas concret de stratégie de conservation pour l'espèce en forêt de Grésigne est présenté. Afin d'assurer le recrutement d'arbres à cavité pour pérenniser les populations de Limoniscus violaceus, des recommandations de gestion fondées sur l'aménagement forestier en cours et l'étude des origines des cavités sont émises

Emergence trap, a new method to survey Limoniscus violaceus (Coleoptera: Elateridae) from hollow trees

International audienceThe study of insects inhabiting basal hollow trees presents a methodological challenge inducing the fact that there is very little research done on fauna of this habitat. Many endangered saproxylic species only develop in cavities located at ground level. One of the most emblematic species of the kind is the Violet Click Beetle (Limoniscus violaceus), included in Annex II of the UE ‘‘Habitats’’ Directive. Surveys have been conducted in five Natura 2000 areas using a new method to monitor L. violaceus: the emergence traps. A total of 376 beetle species, including 239 saproxylics, have been identified. Five are considered threatened and are registered on the European Red List of saproxylic beetles and three are included in Annex II of the ‘‘Habitats’’ Directive. Among 191 trees studied, 33 revealed the presence of L. violaceus. Sampling efforts required to detect at least one specimen have been evaluated. Our results show that sampling a minimum of 20 hollow trees in April and May with emergence traps is recommended to obtain a meaningful survey on the presence of the Violet Click Beetle

Coléoptères Rhysodidae en France : données complémentaires pour <em>Rhysodes sulcatus</em> (F., 1787) et incitation à la recherche d’<em>Omoglymmius (s. s.) germari</em> (Ganglbauer, 1892)

National audienceSome new French and Spanish records of Rhysodes sulcatus (F., 1787) are presented with up to date distribution maps. Occurence in France of Omoglymmius (s. s.) germari (Ganglbauer, 1892) is considered. Habitus of the four European species of Rhysodidae are presente