WorldCat Identities

Amiaud, Bernard (19..-....).

Overview
Works: 15 works in 18 publications in 2 languages and 21 library holdings
Roles: Other, Opponent, Author, Thesis advisor
Publication Timeline
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Most widely held works by Bernard Amiaud
Phylogenetic patterns and phenotypic profiles of the species of plants and mammals farmed for food by Rubén Milla( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Integrating Agricultural and Ecological Goals into the Management of Species-Rich Grasslands: Learning from the Flowering Meadows Competition in France by Danièle Magda( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

Biodiversité et gestion des écosystèmes prairiaux en Franche-Comté by Leslie Mauchamp( Book )

2 editions published in 2014 in French and held by 2 WorldCat member libraries worldwide

Les écosystèmes prairiaux sont soumis à une pression anthropique, essentiellement liée à la gestion agricole, qui permet de maintenir ces milieux ouverts. Cependant, lorsque cette pression s'avère trop importante, elle peut conduire à une diminution de la diversité de la communauté végétale et, en outre, de toutes les communautés qui en dépendent (de consommateurs primaires et secondaire notamment). La biodiversité jouant un rôle reconnu pour la réalisation de diverses fonctions et services écosystémiques dont les sociétés humaines tirent profit chaque jour, les pressions anthropiques fortes peuvent altérer le maintien de ces services.Afin d'obtenir des informations complémentaires sur la réponse des communautés végétales aux différents facteurs anthropiques, il est nécessaire d'intégrer la complexité de la notion de diversité, et notamment inclure les facettes taxonomiques, phylogénétiques et fonctionnelles. Par ailleurs, l'échelle spatiale doit être considérée, en comparant les composantes alpha (intra-site) et beta (inter-sites) de la diversité gamma d'une parcelle ou d'une région.Dans ce projet, une attention particulière a été portée sur la complémentarité de ces approches de la diversité afin de rendre compte de la réponse des communautés végétales du massif jurassien aux modes de gestion agricoles pratiqués dans cette région. La production de différentes AOP fromagères, dont le Comté, offre un cadre original puisque l'existence d'une telle production implique des restrictions concernant la conduite agricole des surfaces prairiales aux exploitants. Nous avons étudié la végétation de 48 parcelles du massif jurassien réparties selon un gradient altitudinal (Premier plateau, Deuxième plateau, Haute-Chaîne) par le biais d'un protocole multi-échelle original pour des surfaces équivalentes à 0,01, 1, 10 et 1000 m². Sur ces mêmes parcelles, les pratiques agricoles ont été renseignées grâce à des enquêtes réalisées auprès des exploitants ; les conditions édaphiques ont elles aussi été étudiées grâce à des sondages de profondeur du sol et des analyses physico-chimiques réalisées sur des prélèvements dans l'horizon de surface.[...]En comparant la composition floristique de 150 relevés réalisés dans les années 1990 avec de nouvelles prospections réalisées en 2012 sur les mêmes surfaces, d'importants changements de la composition floristique sont apparus pour chacune des prairies. La tendance générale pour l'ensemble des parcelles suggère que les communautés actuelles sont davantage adaptées aux défoliations fréquentes et/ou intenses, présentent despréférences écologiques pour les milieux riches en substances nutritives et valeur pastorale plus élevée. La diversité phylogénétique s'avère également différente entre les deux sessions (ce qui n'est pas le cas de la diversité taxonomique de Simpson) et témoigne ainsi d'une réduction de la diversité des lignées avec le temps.[...]L'accumulation de phosphore dans les sols prairiaux, associée aux apports croissants d'azote apportés notamment par les engrais minéraux de synthèse, sont parmi les causes potentielles de ces changements. Bien qu'aucune diminution significative de la diversité taxonomique n'ait été enregistrée dans nos travaux, les changements de composition fonctionnelle déjà observés pourraient à l'avenir aboutir à une érosion de la diversité.[...]
Changes in physicochemical characteristics of a serpentine soil and in root architecture of a hyperaccumulating plant cropped with a legume by Ramez F Saad( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

After grazing exclusion, is there any modification of strategy for two guerrilla species: Elymus repens (L.) Gould and Agrostis stolonifera (L.)? by Bernard Amiaud( )

1 edition published in 2007 in English and held by 2 WorldCat member libraries worldwide

Hétérogénéité spatiale des composantes spécifiques et fonctionnelles des communautés prairiales subalpines dans un contexte de déprise pastorale by Claire Deleglise( )

1 edition published in 2011 in French and held by 2 WorldCat member libraries worldwide

Spatial heterogeneity is now widely recognized as a key component for diversity and functioning of grazed plant communities but is still often neglected for the analysis of the impact of different pastoral uses. Subalpine grassland communities are species-rich habitats of high conservative, economic and cultural values. In large regions of the Alps, these grasslands have experienced a decrease in pastoral use and even abandonment, in the last decades. The investigation of the spatial response of these communities to these changes in pastoral use can be a key issue to better predict ecological and agronomical consequences of such changes. The main objective of this study is to identify the spatial organization of species and traits of subalpine grassland communities in contrasted situations of pastoral use: traditional grazing and abandonment (~20 years), to understand grazing-induced mechanisms influencing this spatial organisation and to explore the potential consequences of the spatial organization of species and traits on the pastoral value of these grasslands. This work reveals that grazing cessation leads to strong modifications of the spatial organization of both species and aerial functional traits. The spatial variability of these components are systematically increased at different spatial scales following grazing abandonment which revealed a coarser grain of spatial heterogeneity in relation to a lower species and trait local coexistence and to a stronger functional convergence than under the fine-scale diversifying action of traditional grazing. Besides, despite we also observed a response in terms of spatial patterns, this one is not systematic which indicates the absence of strongly structuring action of grazing that especially acts on variability. An in situ experiment indeed showed that spatial pattern creation in response to selective defoliation is limited in these relatively low productive grassland communities. In addition, we also evidenced that pastoral values (forage quality) exhibited poor spatial heterogeneity in these grasslands in relation to the fine grained spatial variability of species and plant traits in grazed areas. These results suggest the expression of a low selective grazing promoted by sheep herds grazing and low productivity of subalpine communities and the predominance of the abiotic filter in the determination of spatial assemblages of species and traits. Pronounced spatial patterns in response to grazing may be expected in more productive environments where competitive interactions between species are more intense and species regrowth promoted. Therefore, the consideration of the spatial variability in addition to the mean response of community components appeared to be essential in the analysis of subalpine grassland community dynamics in response to land use changes. One of the strong perspective following this work is to analyse the association between spatial responses of vegetation components and those of belowground components (root traits, microbial diversity...)
Fonctionnement des communautés végétales et stocks de carbone en prairies bas-normandes by Caroline Kohler( Book )

2 editions published in 2015 in French and held by 2 WorldCat member libraries worldwide

Grasslands are recognized for their high potential to mitigate the increase in atmospheric CO2 concentrations through carbon (C) storage in soils. At the interface between the soil and the atmosphere, plant communities constitute a key component driving C inputs and C outputs in the ecosystem. This work aims to determine the impact of the functional composition of plant communities on C stocks and C distribution in grasslands, and to assess the underlying mechanisms. We studied in situ the C stocks in the plant-soil system of seven grasslands in an experimental farm in Normandy, and characterized the functional composition of the plant communities. This study shows that the functioning of plant communities affects soil C stocks. The LDMC (leaf dry matter content) community-weighted mean trait, proved to be the best indicator of soil C stocks. Overall, the results highlight the importance of the grassland age: the oldest and least productive grasslands have a higher soil C stock than the most recent and productive ones. The oldest grasslands are also characterized by a high root C amount, which is positively correlated with the soil organic C stock. The positive correlation between the stubble carbohydrate contents and the soluble soil C contents in spring suggests an impact of root carbohydrate exudation on the quality of soil organic matter and soil microbes C. Overall, our results highlight the need for a compromise between forage production and soil C storage
Effets de l'introduction du pois dans une succession de cultures sur certaines communautés végétales et bactériennes et leurs fonctions écosystémiques associées by Nicolas Romillac( )

1 edition published in 2015 in French and held by 1 WorldCat member library worldwide

Les plantes cultivées peuvent modifier la disponibilité en ressources et les perturbations perçues par les communautés d'organismes présentes dans les agroécosystèmes et en conséquence, influencer les fonctions écosystémiques utiles à la production agricole telles que la minéralisation de N et de S ou la compétition culture-adventices. Notre objectif était d'évaluer l'effet du pois (Pisum sativum L.), introduit dans une succession de cultures, sur les communautés d'adventices et les communautés microbiennes impliquées dans la minéralisation de N et S. Pour ce faire, nous avons mené des expérimentations en conditions contrôlées et utilisé les données d'une expérimentation au champ conduite pendant 5 ans. En conditions contrôlées, nous avons montré que le pois influence via ses traits racinaires certaines activités enzymatiques liées à la minéralisation de N. En revanche au champ, les variables climatiques influencent principalement le fonctionnement des communautés microbiennes impliquées dans la minéralisation de N et S. Par ailleurs, nous avons observé que le pois sélectionnait des communautés d'adventices fonctionnellement différentes de celles d'autres cultures, comme le colza, mais cet effet du pois ne persistait pas sous la culture suivante. En conclusion, les effets du pois sur les communautés microbiennes impliquées dans la minéralisation de N et S sont faibles comparés à ceux d'autres facteurs comme les conditions climatiques. En revanche l'effet du pois sur les communautés d'adventices est fort mais limité dans le temps. Ces résultats montrent la nécessité de mener les expérimentations au champ sur plusieurs années afin de prendre en compte la variabilité climatique
Développement racinaire du hêtre (Fagus sylvatica) en interaction avec d'autres espèces forestières et en fonction de la disponibilité en eau : conséquences sur la croissance et le fonctionnement hydrique et carboné by Alexandre Fruleux( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

The link between species diversity and ecosystem productivity is a central issue in ecology. Numerous studies have shown a positive relationship between forest diversity and productivity, as well as a greater resistance to various stresses such as droughts. On the other hand, few studies demonstrated the mechanisms behind the benefits observed in multi-species forests compared to monospecific ones. In particular, the role of belowground interactions among species in explaining the origin of positive effects of species diversity on ecosystem functioning is unknown. The aim of my PhD work was to study the influence of tree species interactions on the root development of beech (Fagus sylvatica) under different levels of water conditions. We showed that at the seedling stage, underground competition between beech, oak and pine was strong and that mixing these species could influence the growth of the beech. Water availability had a strong impact on the growth of beech seedlings, but the presence of seedlings of other species competing with beech did not particularly improve its response to drought. At the adult stage, in a forest plantation, we showed that maple trees competing with beech did not strongly modify the mean depth of soil water extraction of beech trees or the vertical distribution of beech roots. We conclude that (i) there was no separation of the underground ecological niches of these two species, both spatially and functionally (with respect to water acquisition), and (ii) that the mechanisms of belowground interaction between these two species do not seem to explain the origin of the higher productivity in the mixture than in the monoculture zone. Finally, the richest fungal communities were found in the mixed species zone: we hypothesize that greater fungal community richness in the mixture may improve water and nutrient acquisition and then contribute to higher productivity in the mixed species zone. My work suggests that underground interactions between beech and other forest species are probably not the main mechanism explaining beneficial effects of mixtures on productivity
Production de biomasse et quantification des flux d'azote dans une plantation mixte d'Eucalyptus urophylla x grandis et d'Acacia mangium au Congo by Sogni Viviane Tchichellé( )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

Les plantations forestières représentent 5% de la surface forestière mondiale mais assurent plus du tiers de l'approvisionnement en bois de la planète. La durabilité de ces systèmes de production repose sur le maintien à long terme de leur fertilité, sans recourir à la fertilisation. L'introduction d'une espèce fixatrice d'azote (N) dans les plantations forestières est une des solutions envisagées pour relever ce défi. L'objectif de la thèse était d'évaluer l'effet de l'introduction de l'Acacia mangium dans une plantation pure d'eucalyptus sur la croissance des arbres, la production de biomasse et la dynamique de N dans le sol. Pour atteindre cet objectif, des inventaires destructifs combinés à une collecte des chutes de litière ainsi qu'un suivi annuel de la minéralisation de N dans le sol, ont été réalisés. Ils ont été associés à l'étude de la fixation symbiotique de N et de l'enrichissement en N de la matière organique particulaire. Cette étude a permis de mettre en évidence un effet positif de l'acacia sur la croissance des eucalyptus à travers une modification des relations interspécifiques. La relation de facilitation engendrée par la fixation symbiotique de N a été à l'origine d'une augmentation de la croissance des eucalyptus et de la production primaire nette aérienne. Cette augmentation de croissance était liée à l'amélioration du contenu azoté du sol, en particulier dans la fraction grossière de la matière organique particulaire. Une augmentation de la production de N par minéralisation a révélé un recyclage beaucoup plus rapide du N du sol. Ces travaux ouvrent des perspectives pour une intensification écologique de la sylviculture des plantations tropicales
Influences de l'organisation du paysage sur l'abondance des abeilles sauvages, leur diversité et le service de pollinisation en prairie permanente by Colin Van Reeth( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

Wild bees (20 000 species worldwide) contribute to the pollination of 87.5% of angiosperm species. The decline of wild bees in Europe jeopardizes the sustainability of the pollination service. Among the causes of this decline, the diminution of the surface of semi-natural habitats (e.g. permanent grasslands), providing diverse floristic resources, plays an important role. While the surface of semi-natural habitats has reduced since the second half of the 20th century, the surface of oilseed rape has considerably increased in Europe. Oilseed rape offers a large amount of nectar and pollen during its flowering. The main objective of this study was to evaluate the influence of the spatial organization of semi-natural habitats and oilseed rape fields on the abundance of wild bees, their diversity and the pollination service in permanent grasslands. To achieve this objective, we implemented several experiments in permanent grasslands of the “Parc Naturel Régional de Lorraine”, during and after oilseed rape flowering. Firstly, we showed that the areas covered by flowering oilseed rape fields and semi-natural habitats influence the abundance and species richness of bees in permanent grasslands (different influences according to their sociality) as well as the body size intra-specific distribution of Andrena cineraria. Effects of oilseed rape disappear few weeks after oilseed rape flowering. Secondly, we found that the abundance in grasslands of Andrena cineraria (a species whose peak activity and larval feeding coincide with oilseed rape flowering period), during year N is positively related to the area covered by oilseed rape during the year N-1. Finally, a last experiment was conducted to detect potential effects of flowering oilseed rape on the pollination service in permanent grasslands. Our results showed that increasing areas of flowering oilseed rape in the landscape lead to a reduction of the reproductive success of Cardamine pratensis, a co-flowering wild plant in permanent grasslands. This study highlights the influence of oilseed rape on several trophic levels (pollinators and wild plants) and levels of organization of life (community and population) in permanent grasslands
DYNAMIQUE VEGETALE D'UN ECOSYSTEME PRAIRIAL SOUMIS A DIFFERENTES MODALITES DE PATURAGE EXEMPLE DES COMMUNAUX DU MARAIS POITEVIN by Bernard Amiaud( Book )

2 editions published in 1998 in French and held by 1 WorldCat member library worldwide

AU SEIN DES MARAIS DE L'OUEST DE LA FRANCE, LA CREATION DE POLDERS GERES EN PATURAGE COLLECTIF DEPUIS LE XIEME SIECLE A ENTRAINE LA GENESE D'UN ECOSYSTEME PRAIRIAL SAUMATRE. L'ORGANISATION SPATIALE DE CET AGROECOSYSTEME EST BASEE SUR UN MODELE MICRO-TOPOGRAPHIQUE HERITE DES VASIERES INITIALES ET CONSTITUE DE DEPRESSIONS INONDABLES, DE PENTES INTERMEDIAIRES ET DE REPLATS SUPERIEURS. LA SUPRESSION DU PATURAGE ENTRAINE UNE DYNAMIQUE VEGETALE SE TRADUISANT PAR UNE HOMOGENEISATION DU COUVERT VEGETAL DUE A LA DOMINANCE DE DEUX ESPECES COMPETITIVES (AGROSTIS STOLONIFERA ET ELYMUS REPENS). MALGRE CETTE DOMINANCE, LES ESPECES APPARUES DES LES PREMIERES PHASES DE POLDERISATION PERSISTENT ET PARTICIPENT AU MAINTIEN DE LA MATRICE PRAIRIALE. D'AUTRES ESPECES, QUI ENTRENT DANS LA COMPOSITION DES COMMUNAUTES PRAIRIALES, DISPARAISSENT : ELLES SONT QUALIFIEES D'ESPECES SATELLITES. LES DIFFERENTES MODALITES DE PATURAGE (CHARGEMENT ANIMAL ET NATURE DE L'HERBIVORE) TESTEES EXPERIMENTALEMENT ENGENDRENT EGALEMENT DES VARIATIONS DE L'ORGANISATION SPATIALE DU COUVERT VEGETAL. LA DYNAMIQUE VEGETALE DEPEND A LA FOIS DE LA NATURE DE L'HERBIVORE ET DE L'INTENSITE DE FREQUENTATION ANIMALE DES COMMUNAUTES. QUEL QUE SOIT LE CHARGEMENT, LES EQUINS PATURENT PREFERENTIELLEMENT LES DEPRESSIONS ET LES PENTES. LA DYNAMIQUE S'ACCOMPAGNE DU DEVELOPPEMENT D'ELYMUS REPENS ET D'ESPECES RUDERALES SENSU GRIME (1979) AU NIVEAU DES REPLATS PEU FREQUENTES, ET DE L'EXTENSION DES SUB-HALOPHYTES ET DES HEMICRYPTOPHYTES A ROSETTES SUR LES PENTES TRES PATUREES. DANS LES DEPRESSIONS, L'IMPACT DU PATURAGE SEMBLE LIMITE PAR LE FACTEUR HYDRIQUE. LES BOVINS EXERCENT UN PATURAGE PLUS HOMOGENE SUR L'ENSEMBLE DU SYSTEME ET L'INTENSITE DES REPONSES DYNAMIQUES EVOQUEES EST ETROITEMENT DEPENDANTE DU CHARGEMENT. L'APPARITION DES ESPECES RUDERALES EST LIEE A LA CREATION DE MICRO-PERTURBATIONS DUE A L'ACTIVITE DES MICRO-MAMMIFERES ET AUX DEPOTS D'EXCREMENTS. CES OUVERTURES DANS LE TAPIS VEGETAL FAVORISENT LEUR RECRUTEMENT ET FACILITENT LEUR DYNAMIQUE D'OCCUPATION SPATIALE. LE DEVELOPPEMENT DES SUB-HALOPHYTES ET DES HEMICRYPTOPHYTES A ROSETTES EST DEPENDANT DU PIETINEMENT ANIMAL ET EST VRAISEMBLABLEMENT INFLUENCE PAR LE DEGRE DE SALINITE DU SOL
Valorisation des activités biologiques de certaines espèces végétales sahariennes nord-africaines by Ionut-Florin Palici( )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

The Saharan desert is one of the most unfavorable areas, to the plant life. However, a small number of plants possesses both morphological and ecophysiological mechanisms ensuring their survival in the arid soil and on the sand dunes.It can be estimated that the secondary metabolism biosynthesizes considerable amounts of bioactive compounds, meant to ensure the development and the continuity of these species.The pharmacological properties of saharan plant extracts may bring benefits in the healing of certain microbial or proliferative diseases or contributes to the supply of antioxidants activities.The study of toxic properties is meant to enrich the knowledge of Saharan plants'bioactive potential.The biological activities of Anthyllis henoniana Coss., Centropodia forskalii (Vahl)Cope, Cornulaca monacantha Delile, Ephedra alata var. alenda (Stapf.) Trabut,Euphorbia guyoniana Boiss & Reut., Henophyton deserti Coss. & Durieu, Helianthemum confertum Dunal, Moltkiopsis ciliata (Forssk.) I.M.Johnst. and Spartidium saharae (Coss.& Durieu) Pomel have been studied. It can be seen that these species possess interesting properties, capitalized in the treatment of some human diseases. But, on the other hand in certain concentrations, extracts from these species may exhibit toxic effects onorganisms.Despite the extreme conditions, the Saharan desert represents the area of development for some valuable plant species, whose scientific knowledge is necessary
Les communautés végétales des interfaces forêt-prairie et leur environnement face aux cas d'afforestation et de déforestation by Maxime Burst( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

In temperate Europe, landscapes are dominated by a mosaic of forests, grasslands and crops since several centuries. This long period of time allowed the specialization of species within the habitats and their interfaces thanks to strong environmental contrasts. However, there have been frequent land-use changes in the past, which have accelerated in recent decades, challenging the stability of plant communities and their environment. The afforestation of former grasslands and the extension of grasslands by deforestation, mostly resulting from the progression and regression of the edges, have been poorly studied. In the forest-grassland interfaces, in addition to an edge effect induced in each habitat by the proximity to the adjacent habitat, a history effect can be added in recent habitats, i.e. an environmental and/or floristic legacy (extinction debt, colonization credit). In the recent habitat edges, an interaction between edge effect and history effect can also be encountered. In this thesis, the objectives were to evaluate the relative abundance of the edge effect and the history effect along forest-grassland interfaces stable, from afforestation process and from deforestation process, by studying (i) environmental conditions, (ii) the richness and floristic composition of plant communities, and (iii) trait values within communities. Our results showed increasing gradients of light intensity and soil nutrients ranging from grassland edges to grassland cores. In response to these gradients, a strong edge effect on the composition of plant communities was found in grasslands. These floristic differences between grassland edges and grassland cores are explained by the presence of a large number of transgressive species among the forest specialist species, which have trait values favoring their transgression in grasslands. Besides this, an extinction debt of grassland specialist species has been found in recent forests, which is responsible for a higher vegetative height compared to ancient forests. These results can be explained by the fact that light intensity remained higher in recent forests, even after several decades. An extinction debt of forest specialist species has also been demonstrated in the recent grassland edges, which is the result of an interaction between edge effect and history effect. In recent grasslands, the edge effect favors the maintenance of forest species. According to our findings, forest and grassland edges, most of which have been displaced over the past two centuries, are home to many plant species that are habitat specialists, sometimes in extinction debt. A re-evaluation of the distribution of species within forest and grassland plant communities then seems necessary, taking into account the history of habitats. In a context of increasing forests and grasslands instability, the identification of species in extinction debt represents an opportunity for the conservation and restoration of plant biodiversity
Dynamique végatale d'un écosystème prairial soumis à différentes modalités de pâturages : exemple des communaux du marais poitevin by Bernard Amiaud( Book )

1 edition published in 1998 in French and held by 0 WorldCat member libraries worldwide

 
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Languages
French (14)

English (4)