Bridgehead Effect in the Worldwide Invasion of the Biocontrol Harlequin Ladybird

Recent studies of the routes of worldwide introductions of alien organisms suggest that many widespread invasions could have stemmed not from the native range, but from a particularly successful invasive population, which serves as the source of colonists for remote new territories. We call here this phenomenon the invasive bridgehead effect. Evaluating the likelihood of such a scenario is heuristically challenging. We solved this problem by using approximate Bayesian computation methods to quantitatively compare complex invasion scenarios based on the analysis of population genetics (microsatellite variation) and historical (first observation dates) data. We applied this approach to the Harlequin ladybird Harmonia axyridis (HA), a coccinellid native to Asia that was repeatedly introduced as a biocontrol agent without becoming established for decades. We show that the recent burst of worldwide invasions of HA followed a bridgehead scenario, in which an invasive population in eastern North America acted as the source of the colonists that invaded the European, South American and African continents, with some admixture with a biocontrol strain in Europe. This demonstration of a mechanism of invasion via a bridgehead has important implications both for invasion theory (i.e., a single evolutionary shift in the bridgehead population versus multiple changes in case of introduced populations becoming invasive independently) and for ongoing efforts to manage invasions by alien organisms (i.e., heightened vigilance against invasive bridgeheads)

Patrimoines gastronomiques. Définitions, typologies et enjeux de conservation

Depuis l’inscription, en novembre 2010, du repas gastronomique des Français sur la Liste représentative du Patrimoine culturel immatériel de l’humanité, l’intérêt et les questionnements autour de la gastronomie, envisagée comme fait patrimonial, n’ont cessé de croître. Cette reconnaissance internationale a de fait affirmé, avec une force incontestablement inédite, la dimension sociale, culturelle et patrimoniale de l’alimentation. Les aspects culturels et éducatifs du patrimoine gastronomique..

Un manifeste patrimonial pour la gastronomie

Si sa reconnaissance par l’Unesco, en 2010 a attiré sur le repas gastronomique des Français l’attention internationale, le fait alimentaire et culinaire dans les enjeux des politiques patrimoniales en France est plus ancien. Ce numéro de In Situ. Revue des patrimoines questionne ainsi de multiples manières, pluridisciplinaires et complémentaires, la notion même de « patrimoines gastronomiques » et la façon dont ceux-ci sont, depuis près de cinquante ans maintenant, identifiés, constitués, étudiés, conservés, protégés, valorisés et transmis. Les spécialistes du patrimoine, dans leur quotidien professionnel, se sont adaptés à l’essor sans précédent de la recherche appliquée au domaine de la gastronomie. En explorant les relations entre nourriture et patrimoine et phénomènes de patrimonialisation, les sciences du patrimoine ont profité de l’implication renouvelée des chercheurs et fait de la gastronomie un objet d’étude total, qui ne peut plus exclure aujourd’hui l’ampleur des études et des recherches menées par les professionnels des services patrimoniaux eux-mêmes. De l’objet au monument, la gastronomie, dans son acception patrimoniale, se rattache à un large éventail d’espaces spécialisés : jardins, potagers et vergers, conservatoires de plantes alimentaires et horticoles, restaurants, cafés, usines de production alimentaire, commerces de produits de bouche, cuisines, salles à manger, salles des fêtes, lieux de restauration collective…, la typologie des lieux associés, à divers titres, à la notion, est l’une des plus riches qui soit. Dans leurs spécialités respectives, les acteurs du patrimoine ont progressivement défriché le champ des pratiques culinaires, à travers l’instauration et la valorisation de jardins patrimonialisés et de conservatoires de plantes alimentaires, les études du patrimoine gastronomique conduites par les services de l’Inventaire général du patrimoine culturel, les chantiers de restauration ou de réhabilitation du cadre architectural de la gastronomie, les protections au titre des monuments historiques des lieux, des monuments et des objets mobiliers liés aux arts culinaires, la collecte de fonds spécialisés, dits parfois « fonds gourmands », par les archives et les bibliothèques et la constitution de collections d’objets par les musées, en particulier les écomusées et les musées de société. Le patrimoine culturel immatériel, qui met en valeur les pratiques, les savoirs et les savoir-faire des détenteurs de traditions vivantes, constitue l’avènement patrimonial le plus récent du champ culinaire. Ainsi, bien avant l’inscription du repas gastronomique des Français par l’Unesco, et même dès les années 1960 selon les secteurs, les professionnels du patrimoine se sont penchés sur le terrain tout matériel de la culture alimentaire et culinaire : cet intérêt pour l’infinie variété des éléments matériels de la culture alimentaire et du fait culinaire s’est développé sur tout le territoire français, hexagonal et ultramarin, à travers autant de démarches décisives pour identifier, étudier, préserver et valoriser ce patrimoine, tantôt bâti, tantôt mobilier, tantôt écrit, tantôt anthropologique. L’observation sur le temps long et la prise en compte synoptique des principaux secteurs institutionnels que propose ce numéro de In Situ. Revue des patrimoines donnent une cohérence à cette approche du domaine de la gastronomie par le patrimoine matériel et immatériel, c’est-à-dire, à l’échelle nationale, régionale ou locale, par la voie des inventaires, des protections juridiques, des collectes d’archives et d’objets d’art ou des projets scientifiques, didactiques et pédagogiques.If its recognition by UNESCO in 2010 drew international attention to the gastronomic meal of the French people, the food and culinary fact in the stakes of heritage policies in France is older. This issue of In Situ. Revue des patrimoines thus questions in multiple, multidisciplinary and complementary ways the very notion of "gastronomic heritage" and the way in which it has been identified, constituted, studied, conserved, protected, enhanced and transmitted for nearly fifty years now. Heritage specialists, in their daily professional lives, have adapted to the unprecedented growth of applied research in the field of gastronomy. By exploring the relationship between food and heritage and heritage phenomena, heritage sciences have benefited from the renewed involvement of researchers and have made gastronomy a subject of total study, which can no longer exclude the scope of studies and research carried out by heritage services professionals themselves. From objects to monuments, gastronomy, in its heritage sense, is linked to a wide range of specialized spaces: gardens, vegetable gardens and orchards, conservatories of food and horticultural plants, restaurants, cafés, food production plants, shops selling food products, kitchens, dining rooms, party rooms, collective catering places..., the typology of the places associated, in various ways, with the concept is one of the most rich. In their respective specialities, heritage actors have gradually cleared the field of culinary practices, through the establishment and enhancement of heritage gardens and food plant conservatories, studies of the gastronomic heritage conducted by the services of the General Inventory of Cultural Heritage, work to restore or rehabilitate the architectural framework of gastronomy, protection of historic monuments, monuments and movable objects related to the culinary arts, the collection of specialised funds, sometimes called "gourmet funds", by archives and libraries and the constitution of collections of objects by museums, in particular ecomuseums and social museums. The intangible cultural heritage, which highlights the practices, knowledge and skills of the holders of living traditions, is the most recent heritage development of the culinary field. Thus, well before the inclusion of the French gourmet meal by UNESCO, and even as early as the 1960s, depending on the sector, heritage professionals focused on the field of all material aspects of food and culinary culture: this interest in the infinite variety of material elements of food and culinary culture developed in France, through so many decisive steps to identify, study, preserve and enhance this heritage, sometimes built, sometimes movable, sometimes written, sometimes anthropological. Observation over time and synoptic consideration of the main institutional sectors, as proposed in this issue of In Situ. Revue des patrimoines, give coherence to this approach to the field of gastronomy through tangible and intangible heritage, i.e., at the national, regional or local level, through inventories, legal protection, collection of archives and works of art or scientific, didactic and educational projects

Le numéro en bref – Patrimoines gastronomiques : définitions, typologies et enjeux de conservation

Les contours du patrimoine gastronomique sont difficiles à cerner, d’où l’usage fréquent de l’expression au pluriel. À la fois matériel, immatériel et mémoriel, aux confins des champs de recherche de l’alimentation, de la botanique, de l’architecture, des arts décoratifs ou encore de la sociabilité, ce patrimoine protéiforme exige pour son étude la mobilisation de nombreuses disciplines scientifiques ; il a renouvelé, au plan national et international, le regard des professionnels du patrimoi..

Botany, Genetics and Ethnobotany: A Crossed Investigation on the Elusive Tapir's Diet in French Guiana

While the populations of large herbivores are being depleted in many tropical rainforests, the importance of their trophic role in the ecological functioning and biodiversity of these ecosystems is still not well evaluated. This is due to the outstanding plant diversity that they feed upon and the inherent difficulties involved in observing their elusive behaviour. Classically, the diet of elusive tropical herbivores is studied through the observation of browsing signs and macroscopic analysis of faeces or stomach contents. In this study, we illustrate that the original coupling of classic methods with genetic and ethnobotanical approaches yields information both about the diet diversity, the foraging modalities and the potential impact on vegetation of the largest terrestrial mammal of Amazonia, the lowland tapir. The study was conducted in the Guianan shield, where the ecology of tapirs has been less investigated. We identified 92 new species, 51 new genera and 13 new families of plants eaten by tapirs. We discuss the relative contribution of our different approaches, notably the contribution of genetic barcoding, used for the first time to investigate the diet of a large tropical mammal, and how local traditional ecological knowledge is accredited and valuable for research on the ecology of elusive animals

Architecture of an Antagonistic Tree/Fungus Network: The Asymmetric Influence of Past Evolutionary History

Compartmentalization and nestedness are common patterns in ecological networks. The aim of this study was to elucidate some of the processes shaping these patterns in a well resolved network of host/pathogen interactions.Based on a long-term (1972-2005) survey of forest health at the regional scale (all French forests; 15 million ha), we uncovered an almost fully connected network of 51 tree taxa and 157 parasitic fungal species. Our analyses revealed that the compartmentalization of the network maps out the ancient evolutionary history of seed plants, but not the ancient evolutionary history of fungal species. The very early divergence of the major fungal phyla may account for this asymmetric influence of past evolutionary history. Unlike compartmentalization, nestedness did not reflect any consistent phylogenetic signal. Instead, it seemed to reflect the ecological features of the current species, such as the relative abundance of tree species and the life-history strategies of fungal pathogens. We discussed how the evolution of host range in fungal species may account for the observed nested patterns.Overall, our analyses emphasized how the current complexity of ecological networks results from the diversification of the species and their interactions over evolutionary times. They confirmed that the current architecture of ecological networks is not only dependent on recent ecological processes

Long-term thermal sensitivity of Earth’s tropical forests

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe