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L'initiative de produire ce guide émane de la Fédération québécoise des coopératives forestières (FQCF). Elle découle de la motivation de la Fédération de mettre en place des passerelles entre le réseau de coopératives qu'elle représente et les communautés autochtones. Elle a obtenu le financement pour le réaliser. La FQCF mise sur la pertinence du modèle coopératif comme moyen d'aider les travailleurs à s'organiser pour créer et partager des richesses provenant du milieu forestier. Elle estime aussi que le partenariat entre les coopératives forestières et les Premières Nations peut être porteur d'occasions de développement mutuel. La Fédération comprend la complexité du dossier forestier pour les communautés autochtones, qui sont souvent partagées entre leur attachement au territoire comme milieu de vie et comme héritage culturel, leur revendication pour la gestion du territoire et leur intérêt pour créer des emplois pour leurs membres. Elle espère humblement que la combinaison de l'aménagement forestier durable avec la coopération peut contribuer à améliorer les conditions de vie dans les communautés. La FQCF compte également sur une démarche de partenariat en construction avec la Commission de développement économique des Premières Nations du Québec et du Labrador (CDEPNQL) pour enrichir ce guide et pour faciliter sa diffusion auprès des Premières Nations. Afin de bénéficier de son expertise auprès des communautés autochtones, la FQCF a aussi sollicité l'aide de la Chaire de leadership en enseignement en foresterie autochtone pour la rédaction de ce guide. La FQCF souhaite que ce guide serve d'outil pour faire connaître la coopération comme mode d'organisation des travailleurs ou des entrepreneurs forestiers issus des communautés autochtones. Ce guide présente le fonctionnement des coopératives en général, les particularités de la coopération en milieu autochtone, les exemples de coopératives forestières autochtones au Québec, ainsi que les conditions gagnantes

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Annabelle a perdu son Lapin Pinpin adoré ! Impossible de l’oublier, mais impossible aussi de le retrouver ! À moins que…Simone joue dans la cour lorsqu’elle fait une surprenante découverte : un doudou abandonné dans la neige ! A priori, impossible de retrouver son ou sa propriétaire. À moins que… Dans cet album (tête-bêche pour la version papier), Janou-Ève LeGuerrier nous livre un récit vécu tendre et touchant, ingénieusement mis en scène grâce aux douces illustrations d’Amélie Dubois.

Annabelle a perdu son Lapin Pinpin adoré ! Impossible de l’oublier, mais impossible aussi de le retrouver ! À moins que…Simone joue dans la cour lorsqu’elle fait une surprenante découverte : un doudou abandonné dans la neige ! A priori, impossible de retrouver son ou sa propriétaire. À moins que… Dans cet album (tête-bêche pour la version papier), Janou-Ève LeGuerrier nous livre un récit vécu tendre et touchant, ingénieusement mis en scène grâce aux douces illustrations d’Amélie Dubois.

Annabelle a perdu son Lapin Pinpin adoré ! Impossible de l’oublier, mais impossible aussi de le retrouver ! À moins que…Simone joue dans la cour lorsqu’elle fait une surprenante découverte : un doudou abandonné dans la neige ! A priori, impossible de retrouver son ou sa propriétaire. À moins que… Dans cet album (tête-bêche pour la version papier), Janou-Ève LeGuerrier nous livre un récit vécu tendre et touchant, ingénieusement mis en scène grâce aux douces illustrations d’Amélie Dubois.

Vies et fictions d’exils certes, mais au risque de la création et des récits qui ne proposent pas une image stéréotypée des réfugiés et des déplacés. Si la « crise » des réfugiés a retenu l'attention des médias au cours des dernières années, l'art et la littérature sont des espaces où l'exil a droit de cité. Les lectures présentées par les auteurs de cet ouvrage collectif témoignent à la fois de cette tradition et du renouvellement des récits littéraires, photographiques et médiatiques où abondent les représentations des exils. À propos de la réalité de la migration forcée, les auteurs font place à la parole subjective du migrant et aux représentations de l'imaginaire collectif qui le déshumanisent.

Background Transcatheter aortic valve replacement (TAVR) has revolutionized management of high-risk patients with severe aortic stenosis. However, survival and the incidence of severe complications have been assessed in relatively small populations and/or with limited follow-up. Objectives This report details late clinical outcome and its determinants in the FRANCE-2 (FRench Aortic National CoreValve and Edwards) registry. Methods The FRANCE-2 registry prospectively included all TAVRs performed in France. Follow-up was scheduled at 30 days, at 6 months, and annually from 1 to 5 years. Standardized VARC (Valve Academic Research Consortium) outcome definitions were used. Results A total of 4,201 patients were enrolled between January 2010 and January 2012 in 34 centers. Approaches were transarterial (transfemoral 73%, transapical 18%, subclavian 6%, and transaortic or transcarotid 3%) or, in 18% of patients, transapical. Median follow-up was 3.8 years. Vital status was available for 97.2% of patients at 3 years. The 3-year all-cause mortality was 42.0% and cardiovascular mortality was 17.5%. In a multivariate model, predictors of 3-year all-cause mortality were male sex (p < 0.001), low body mass index, (p < 0.001), atrial fibrillation (p < 0.001), dialysis (p < 0.001), New York Heart Association functional class III or IV (p < 0.001), higher logistic EuroSCORE (p < 0.001), transapical or subclavian approach (p < 0.001 for both vs. transfemoral approach), need for permanent pacemaker implantation (p = 0.02), and post-implant periprosthetic aortic regurgitation grade ≥2 of 4 (p < 0.001). Severe events according to VARC criteria occurred mainly during the first month and subsequently in <2% of patients/year. Mean gradient, valve area, and residual aortic regurgitation were stable during follow-up. Conclusions The FRANCE-2 registry represents the largest database available on late results of TAVR. Late mortality is largely related to noncardiac

Transcatheter aortic-valve implantation (TAVI) is an emerging intervention for the treatment of high-risk patients with severe aortic stenosis and coexisting illnesses. We report the results of a prospective multicenter study of the French national transcatheter aortic-valve implantation registry, FRANCE 2.

Objectives We evaluated a large multicenter series of patients operated on for low-flow/low-gradient aortic stenosis (LF/ LGAS) to stratify the operative risk, assess whether perioperative mortality has decreased over recent years, and analyze the post-operative outcome. Background Although LF/LGAS is classically associated with a high operative risk, few data are available concerning the results of surgery in this setting. Methods A total of 217 consecutive patients (168 men, 77%) with severe aortic stenosis (area <1 cm(2)), low ejection fraction (EF) (<= 35%), and low mean gradient (MG) (<= 30 mm Hg) who underwent aortic valve replacement (AVR) between 1990 and 2005 were included. Results Perioperative mortality was 16% and decreased dramatically from 20% in the 1990 to 1999 period to 10% in the 2000 to 2005 period. Higher European System for Cardiac Operative Risk Evaluation score (EuroSCORE), very low MG and EF, New York Heart Association functional class III or IV, history of congestive heart failure, and multivessel coronary artery disease (MVD) were associated with perioperative mortality. On multivariate analysis, very low preoperative MG and MVD were predictors of excess perioperative mortality. In the subgroup of patients with dobutamine stress echocardiography, the absence of contractile reserve was a strong predictor of perioperative mortality. Overall 5-year survival rate was 49 +/- 4%. Lower MG, higher EuroSCORE, prior atrial fibrillation, and MVD were identified as independent predictors of overall long-term mortality. Conclusions In view of the very poor prognosis of unoperated patients, the current operative risk, and the long-term outcome after surgery, AVR is the treatment of choice in the majority of cases of LF/LGAS.

Network analysis was used to analyse steady-state models of the food webs of two intertidat mudflat ecosystems: Aiguillon Cove and Brouage Mudflat, on the South-Western Atlantic Coast of France. The aim was to highlight emergent properties of food-web functioning in these two ecosystems and to compare these properties with other coastal ecosystems. Both ecosystems imported detritus in parallel to a high benthic primary production. They were characterised by a high diversity of resources. Both also exported living material, leading to a high quality production, quantified as export of Exergy. This export was mainly composed of cultivated bivalves during the cold season for Brouage Mudflat, and of the migration of grazing fish in Aiguillon Cove during the warm season. Their internal organization was characterised by short pathways, high recycling, high redundancy and low net ecosystem production, compared to the other systems selected. These characteristics, encountered in many estuaries, presented less extreme values. (c) 2007 Elsevier Ltd. All rights reserved.

Network analysis was used to analyse steady-state models of the food webs of two intertidat mudflat ecosystems: Aiguillon Cove and Brouage Mudflat, on the South-Western Atlantic Coast of France. The aim was to highlight emergent properties of food-web functioning in these two ecosystems and to compare these properties with other coastal ecosystems. Both ecosystems imported detritus in parallel to a high benthic primary production. They were characterised by a high diversity of resources. Both also exported living material, leading to a high quality production, quantified as export of Exergy. This export was mainly composed of cultivated bivalves during the cold season for Brouage Mudflat, and of the migration of grazing fish in Aiguillon Cove during the warm season. Their internal organization was characterised by short pathways, high recycling, high redundancy and low net ecosystem production, compared to the other systems selected. These characteristics, encountered in many estuaries, presented less extreme values. (c) 2007 Elsevier Ltd. All rights reserved.

Network analysis was used to analyse steady-state models of the food webs of two intertidat mudflat ecosystems: Aiguillon Cove and Brouage Mudflat, on the South-Western Atlantic Coast of France. The aim was to highlight emergent properties of food-web functioning in these two ecosystems and to compare these properties with other coastal ecosystems. Both ecosystems imported detritus in parallel to a high benthic primary production. They were characterised by a high diversity of resources. Both also exported living material, leading to a high quality production, quantified as export of Exergy. This export was mainly composed of cultivated bivalves during the cold season for Brouage Mudflat, and of the migration of grazing fish in Aiguillon Cove during the warm season. Their internal organization was characterised by short pathways, high recycling, high redundancy and low net ecosystem production, compared to the other systems selected. These characteristics, encountered in many estuaries, presented less extreme values. (c) 2007 Elsevier Ltd. All rights reserved.

The presence of herbicides in the run-off water coming over Brouage mudflat (Marennes-Oleron Bay, France) is suspected to cause a loss of primary production by benthic diatom biofilm. Microphytobenthos being the main primary producer of this ecosystem, it was questioned about what could be the effect of such a modification of primary production on the entire food web that depends on it. The probable impacts were investigated through a sensitivity analysis conducted on the steady-state model of the Brouage mudflat, coupling two seasons and trophic-hydrodynamic flows. The loss of benthic primary production had an effect on compartments at a low trophic level, but was buffered at higher levels because of the compensation of herbivory by other pathways and especially detritivory. The consequences seemed more important on physical flows through resuspension and export by advection, but this should be apprehended through dynamic modeling coupling physics and biology.

The presence of herbicides in the run-off water coming over Brouage mudflat (Marennes-Oleron Bay, France) is suspected to cause a loss of primary production by benthic diatom biofilm. Microphytobenthos being the main primary producer of this ecosystem, it was questioned about what could be the effect of such a modification of primary production on the entire food web that depends on it. The probable impacts were investigated through a sensitivity analysis conducted on the steady-state model of the Brouage mudflat, coupling two seasons and trophic-hydrodynamic flows. The loss of benthic primary production had an effect on compartments at a low trophic level, but was buffered at higher levels because of the compensation of herbivory by other pathways and especially detritivory. The consequences seemed more important on physical flows through resuspension and export by advection, but this should be apprehended through dynamic modeling coupling physics and biology.

We used Markov chains to assess residence time, first passage time, rare of transfers between compartments, recycling index with a general mathematical formalism. Such a description applies to any flow-balanced system that can be modelled as a series of discrete stages or compartments through which matter flows. We derived a general set of equations from a probabilistic approach and applied them to a food web and a physical system derived from the literature. We therefore analysed preferential pathways of matter and behaviour of these systems and showed how it was possible to build up and exploit indices on the basis of a transition probability matrix describing the network, and to characterize with a generic algorithm: (1) the total indirect relationships between two compartments, (2) (he residence time of one compartment and (3) the general recycling pathways including the amount of matter recycling and the implication of each compartment in recycling. (C) 2005 Elsevier B.V. All rights reserved.

Inverse analysis was used to model the food webs of two intertidal mudflat ecosystems: Aiguillon Cove (AC) and Brouage Mudflat (BM) (south-western Atlantic coast, France). The aim of the present study is to describe and compare the functioning of these two ecosystems. The method of inverse analysis has been adapted in order to take into account, in a single calculation, two seasons: spring/summer (mid-March to mid-October) and autumn/winter (the rest of the year). Gathering all available data on the two sites, the most important gaps in knowledge were identified with the help of sensitivity analyses: they concerned mainly the exports of material by grazing fish (such as mullet Liza ramada), resuspension of microphytobenthos, and fluxes linked to microfauna which is poorly known for the two systems. The two sites presented the same overall type of functioning (net import of detritus, export of living organic material and higher faunal activity during spring/summer). In both ecosystems, primary production was dominated by the microphytobenthic production, of which a great part was exported via water-column advection and biotic vectors (grazing fish), while many secondary producers also used detritus as a food resource. Each system also had its own characteristics, one BM being much more seasonally driven than the other AC. It appeared essential to take the seasons into account, as variations in microphytobenthos production and in meiofauna, macrofauna and biotic vectors led to great differences in the food-web organisation. (c) 2006 Elsevier Ltd. All rights reserved.

The presence of herbicides in the run-off water coming over Brouage mudflat (Marennes-Oleron Bay, France) is suspected to cause a loss of primary production by benthic diatom biofilm. Microphytobenthos being the main primary producer of this ecosystem, it was questioned about what could be the effect of such a modification of primary production on the entire food web that depends on it. The probable impacts were investigated through a sensitivity analysis conducted on the steady-state model of the Brouage mudflat, coupling two seasons and trophic-hydrodynamic flows. The loss of benthic primary production had an effect on compartments at a low trophic level, but was buffered at higher levels because of the compensation of herbivory by other pathways and especially detritivory. The consequences seemed more important on physical flows through resuspension and export by advection, but this should be apprehended through dynamic modeling coupling physics and biology.

We used Markov chains to assess residence time, first passage time, rare of transfers between compartments, recycling index with a general mathematical formalism. Such a description applies to any flow-balanced system that can be modelled as a series of discrete stages or compartments through which matter flows. We derived a general set of equations from a probabilistic approach and applied them to a food web and a physical system derived from the literature. We therefore analysed preferential pathways of matter and behaviour of these systems and showed how it was possible to build up and exploit indices on the basis of a transition probability matrix describing the network, and to characterize with a generic algorithm: (1) the total indirect relationships between two compartments, (2) (he residence time of one compartment and (3) the general recycling pathways including the amount of matter recycling and the implication of each compartment in recycling. (C) 2005 Elsevier B.V. All rights reserved.

Inverse analysis was used to model the food webs of two intertidal mudflat ecosystems: Aiguillon Cove (AC) and Brouage Mudflat (BM) (south-western Atlantic coast, France). The aim of the present study is to describe and compare the functioning of these two ecosystems. The method of inverse analysis has been adapted in order to take into account, in a single calculation, two seasons: spring/summer (mid-March to mid-October) and autumn/winter (the rest of the year). Gathering all available data on the two sites, the most important gaps in knowledge were identified with the help of sensitivity analyses: they concerned mainly the exports of material by grazing fish (such as mullet Liza ramada), resuspension of microphytobenthos, and fluxes linked to microfauna which is poorly known for the two systems. The two sites presented the same overall type of functioning (net import of detritus, export of living organic material and higher faunal activity during spring/summer). In both ecosystems, primary production was dominated by the microphytobenthic production, of which a great part was exported via water-column advection and biotic vectors (grazing fish), while many secondary producers also used detritus as a food resource. Each system also had its own characteristics, one BM being much more seasonally driven than the other AC. It appeared essential to take the seasons into account, as variations in microphytobenthos production and in meiofauna, macrofauna and biotic vectors led to great differences in the food-web organisation. (c) 2006 Elsevier Ltd. All rights reserved.

The presence of herbicides in the run-off water coming over Brouage mudflat (Marennes-Oleron Bay, France) is suspected to cause a loss of primary production by benthic diatom biofilm. Microphytobenthos being the main primary producer of this ecosystem, it was questioned about what could be the effect of such a modification of primary production on the entire food web that depends on it. The probable impacts were investigated through a sensitivity analysis conducted on the steady-state model of the Brouage mudflat, coupling two seasons and trophic-hydrodynamic flows. The loss of benthic primary production had an effect on compartments at a low trophic level, but was buffered at higher levels because of the compensation of herbivory by other pathways and especially detritivory. The consequences seemed more important on physical flows through resuspension and export by advection, but this should be apprehended through dynamic modeling coupling physics and biology.

We used Markov chains to assess residence time, first passage time, rare of transfers between compartments, recycling index with a general mathematical formalism. Such a description applies to any flow-balanced system that can be modelled as a series of discrete stages or compartments through which matter flows. We derived a general set of equations from a probabilistic approach and applied them to a food web and a physical system derived from the literature. We therefore analysed preferential pathways of matter and behaviour of these systems and showed how it was possible to build up and exploit indices on the basis of a transition probability matrix describing the network, and to characterize with a generic algorithm: (1) the total indirect relationships between two compartments, (2) (he residence time of one compartment and (3) the general recycling pathways including the amount of matter recycling and the implication of each compartment in recycling. (C) 2005 Elsevier B.V. All rights reserved.

Inverse analysis was used to model the food webs of two intertidal mudflat ecosystems: Aiguillon Cove (AC) and Brouage Mudflat (BM) (south-western Atlantic coast, France). The aim of the present study is to describe and compare the functioning of these two ecosystems. The method of inverse analysis has been adapted in order to take into account, in a single calculation, two seasons: spring/summer (mid-March to mid-October) and autumn/winter (the rest of the year). Gathering all available data on the two sites, the most important gaps in knowledge were identified with the help of sensitivity analyses: they concerned mainly the exports of material by grazing fish (such as mullet Liza ramada), resuspension of microphytobenthos, and fluxes linked to microfauna which is poorly known for the two systems. The two sites presented the same overall type of functioning (net import of detritus, export of living organic material and higher faunal activity during spring/summer). In both ecosystems, primary production was dominated by the microphytobenthic production, of which a great part was exported via water-column advection and biotic vectors (grazing fish), while many secondary producers also used detritus as a food resource. Each system also had its own characteristics, one BM being much more seasonally driven than the other AC. It appeared essential to take the seasons into account, as variations in microphytobenthos production and in meiofauna, macrofauna and biotic vectors led to great differences in the food-web organisation. (c) 2006 Elsevier Ltd. All rights reserved.

In order to better understand the functioning of the Brouage intertidal mudflat (Marennes- Oléron Basin, France), its carbon-based trophic web has been modelled and analyzed. The foodweb building is based on the 4 step method of Inverse Analysis: 1) conceive an a priori model as the graph of compartments (nodes) between which exist fluxes of material (vertices). These vertices are the unknowns for the problem; 2) gather all the existing knowledge about the ecosystem and translate it into linear equations and inequalities involving the fluxes; 3) complete this set of data by common knowledge on the behaviour of the compartments and translate it into inequalities, 4) solve the obtained linear system under the parsimony principle to find a unique solution vector. The food-web analysis is based on. The first purpose of this work was a methodological one: inverse analysis method has been adapted to consider the seasonal and spatial variability of the temperate ecosystem: two seasons have been coupled in the computation and the area has been divided into three geographical zones along a cross-shore gradient. Hence, two types of physical exchanges are involved: the benthicpelagic ones and the advection ones. Statistical results can also be obtained by coupling Monte Carlo methods to Inverse Analysis. To study the obtained networks, new indices based on Markov Chains take delay into account in describing integrative transfers of material between compartments. This lets emerge the systems' properties that are not obvious at first sight and emphasizes the role of peculiar components. The second purpose was to apply such methods to the Brouage mudflat ecosystem in order to better understand its functioning. As the knowledge and methods evolve, various food webs were computed and analyzed with the help such indices and existing ones. Sensitivity analyses allow to point at the most crucial lacks of knowledge, which can orientate future field research. New data would improve the, Un double objectif (méthodologique et appliqué) a été visé par une modélisation du réseau trophique de la vasière de Brouage (Bassin de Marennes Oléron, France) à l'aide de l'analyse inverse, et son étude à l'aide de l'analyse des réseaux. L'Analyse Inverse permet en effet de reconstruire l'ensemble du réseau à partir de données éparses, le problème du manque de données étant récurrent en Ecologie. Au plan méthodologique, l'analyse inverse a été adaptée à la prise en compte des caractères saisonnier et spatialement hétérogène d'un écosystème tempéré de zone intertidale : deux saisons ont ainsi été couplées et la vasière a été considérée le long d'un transect perpendiculaire au rivage et divisé en trois zones spatiales. Deux types de flux physiques interviennent donc : les flux verticaux de dépôt et remise en suspension, et les flux d'advection via la colonne d'eau. Des pistes d'amélioration et de nouvelles méthodes sont proposées. Un résultat sous forme statistique peut être obtenu en couplant l'utilisation de méthodes de Monte Carlo à l'analyse inverse pour la construction des réseaux trophiques. Les moyens d'étude des modèles ont été enrichis par la mise au point d'indices issus de la construction de chaînes de Markov et prenant en compte le caractère temporel des transferts de matière entre compartiments. Enfin, la transformation mathématique du modèle statique pour une étude dynamique de la stabilité de l'équilibre décrit est abordée. Plusieurs modèles ont été construits au cours de l'évolution des méthodes et de l'acquisition de connaissances sur le site. Des méthodes d'analyses existantes et d'autres mises au point dans le cadre de cet ouvrage ont été appliquées aux réseaux obtenus afin de faire émerger les propriétés du fonctionnement de la vasière et de souligner le rôle de certains compartiments. Des analyses de sensibilité permettent d'évaluer la robustesse des résultats et d'orienter les recherches futures en mettant en évidence les manques les plus cruci

In order to better understand the functioning of the Brouage intertidal mudflat (Marennes- Oléron Basin, France), its carbon-based trophic web has been modelled and analyzed. The foodweb building is based on the 4 step method of Inverse Analysis: 1) conceive an a priori model as the graph of compartments (nodes) between which exist fluxes of material (vertices). These vertices are the unknowns for the problem; 2) gather all the existing knowledge about the ecosystem and translate it into linear equations and inequalities involving the fluxes; 3) complete this set of data by common knowledge on the behaviour of the compartments and translate it into inequalities, 4) solve the obtained linear system under the parsimony principle to find a unique solution vector. The food-web analysis is based on. The first purpose of this work was a methodological one: inverse analysis method has been adapted to consider the seasonal and spatial variability of the temperate ecosystem: two seasons have been coupled in the computation and the area has been divided into three geographical zones along a cross-shore gradient. Hence, two types of physical exchanges are involved: the benthicpelagic ones and the advection ones. Statistical results can also be obtained by coupling Monte Carlo methods to Inverse Analysis. To study the obtained networks, new indices based on Markov Chains take delay into account in describing integrative transfers of material between compartments. This lets emerge the systems' properties that are not obvious at first sight and emphasizes the role of peculiar components. The second purpose was to apply such methods to the Brouage mudflat ecosystem in order to better understand its functioning. As the knowledge and methods evolve, various food webs were computed and analyzed with the help such indices and existing ones. Sensitivity analyses allow to point at the most crucial lacks of knowledge, which can orientate future field research. New data would improve the, Un double objectif (méthodologique et appliqué) a été visé par une modélisation du réseau trophique de la vasière de Brouage (Bassin de Marennes Oléron, France) à l'aide de l'analyse inverse, et son étude à l'aide de l'analyse des réseaux. L'Analyse Inverse permet en effet de reconstruire l'ensemble du réseau à partir de données éparses, le problème du manque de données étant récurrent en Ecologie. Au plan méthodologique, l'analyse inverse a été adaptée à la prise en compte des caractères saisonnier et spatialement hétérogène d'un écosystème tempéré de zone intertidale : deux saisons ont ainsi été couplées et la vasière a été considérée le long d'un transect perpendiculaire au rivage et divisé en trois zones spatiales. Deux types de flux physiques interviennent donc : les flux verticaux de dépôt et remise en suspension, et les flux d'advection via la colonne d'eau. Des pistes d'amélioration et de nouvelles méthodes sont proposées. Un résultat sous forme statistique peut être obtenu en couplant l'utilisation de méthodes de Monte Carlo à l'analyse inverse pour la construction des réseaux trophiques. Les moyens d'étude des modèles ont été enrichis par la mise au point d'indices issus de la construction de chaînes de Markov et prenant en compte le caractère temporel des transferts de matière entre compartiments. Enfin, la transformation mathématique du modèle statique pour une étude dynamique de la stabilité de l'équilibre décrit est abordée. Plusieurs modèles ont été construits au cours de l'évolution des méthodes et de l'acquisition de connaissances sur le site. Des méthodes d'analyses existantes et d'autres mises au point dans le cadre de cet ouvrage ont été appliquées aux réseaux obtenus afin de faire émerger les propriétés du fonctionnement de la vasière et de souligner le rôle de certains compartiments. Des analyses de sensibilité permettent d'évaluer la robustesse des résultats et d'orienter les recherches futures en mettant en évidence les manques les plus cruci

In order to better understand the functioning of the Brouage intertidal mudflat (Marennes- Oléron Basin, France), its carbon-based trophic web has been modelled and analyzed. The foodweb building is based on the 4 step method of Inverse Analysis: 1) conceive an a priori model as the graph of compartments (nodes) between which exist fluxes of material (vertices). These vertices are the unknowns for the problem; 2) gather all the existing knowledge about the ecosystem and translate it into linear equations and inequalities involving the fluxes; 3) complete this set of data by common knowledge on the behaviour of the compartments and translate it into inequalities, 4) solve the obtained linear system under the parsimony principle to find a unique solution vector. The food-web analysis is based on. The first purpose of this work was a methodological one: inverse analysis method has been adapted to consider the seasonal and spatial variability of the temperate ecosystem: two seasons have been coupled in the computation and the area has been divided into three geographical zones along a cross-shore gradient. Hence, two types of physical exchanges are involved: the benthicpelagic ones and the advection ones. Statistical results can also be obtained by coupling Monte Carlo methods to Inverse Analysis. To study the obtained networks, new indices based on Markov Chains take delay into account in describing integrative transfers of material between compartments. This lets emerge the systems' properties that are not obvious at first sight and emphasizes the role of peculiar components. The second purpose was to apply such methods to the Brouage mudflat ecosystem in order to better understand its functioning. As the knowledge and methods evolve, various food webs were computed and analyzed with the help such indices and existing ones. Sensitivity analyses allow to point at the most crucial lacks of knowledge, which can orientate future field research. New data would improve the, Un double objectif (méthodologique et appliqué) a été visé par une modélisation du réseau trophique de la vasière de Brouage (Bassin de Marennes Oléron, France) à l'aide de l'analyse inverse, et son étude à l'aide de l'analyse des réseaux. L'Analyse Inverse permet en effet de reconstruire l'ensemble du réseau à partir de données éparses, le problème du manque de données étant récurrent en Ecologie. Au plan méthodologique, l'analyse inverse a été adaptée à la prise en compte des caractères saisonnier et spatialement hétérogène d'un écosystème tempéré de zone intertidale : deux saisons ont ainsi été couplées et la vasière a été considérée le long d'un transect perpendiculaire au rivage et divisé en trois zones spatiales. Deux types de flux physiques interviennent donc : les flux verticaux de dépôt et remise en suspension, et les flux d'advection via la colonne d'eau. Des pistes d'amélioration et de nouvelles méthodes sont proposées. Un résultat sous forme statistique peut être obtenu en couplant l'utilisation de méthodes de Monte Carlo à l'analyse inverse pour la construction des réseaux trophiques. Les moyens d'étude des modèles ont été enrichis par la mise au point d'indices issus de la construction de chaînes de Markov et prenant en compte le caractère temporel des transferts de matière entre compartiments. Enfin, la transformation mathématique du modèle statique pour une étude dynamique de la stabilité de l'équilibre décrit est abordée. Plusieurs modèles ont été construits au cours de l'évolution des méthodes et de l'acquisition de connaissances sur le site. Des méthodes d'analyses existantes et d'autres mises au point dans le cadre de cet ouvrage ont été appliquées aux réseaux obtenus afin de faire émerger les propriétés du fonctionnement de la vasière et de souligner le rôle de certains compartiments. Des analyses de sensibilité permettent d'évaluer la robustesse des résultats et d'orienter les recherches futures en mettant en évidence les manques les plus cruci

In order to better understand the functioning of the Brouage intertidal mudflat (Marennes- Oléron Basin, France), its carbon-based trophic web has been modelled and analyzed. The foodweb building is based on the 4 step method of Inverse Analysis: 1) conceive an a priori model as the graph of compartments (nodes) between which exist fluxes of material (vertices). These vertices are the unknowns for the problem; 2) gather all the existing knowledge about the ecosystem and translate it into linear equations and inequalities involving the fluxes; 3) complete this set of data by common knowledge on the behaviour of the compartments and translate it into inequalities, 4) solve the obtained linear system under the parsimony principle to find a unique solution vector. The food-web analysis is based on. The first purpose of this work was a methodological one: inverse analysis method has been adapted to consider the seasonal and spatial variability of the temperate ecosystem: two seasons have been coupled in the computation and the area has been divided into three geographical zones along a cross-shore gradient. Hence, two types of physical exchanges are involved: the benthicpelagic ones and the advection ones. Statistical results can also be obtained by coupling Monte Carlo methods to Inverse Analysis. To study the obtained networks, new indices based on Markov Chains take delay into account in describing integrative transfers of material between compartments. This lets emerge the systems' properties that are not obvious at first sight and emphasizes the role of peculiar components. The second purpose was to apply such methods to the Brouage mudflat ecosystem in order to better understand its functioning. As the knowledge and methods evolve, various food webs were computed and analyzed with the help such indices and existing ones. Sensitivity analyses allow to point at the most crucial lacks of knowledge, which can orientate future field research. New data would improve the, Un double objectif (méthodologique et appliqué) a été visé par une modélisation du réseau trophique de la vasière de Brouage (Bassin de Marennes Oléron, France) à l'aide de l'analyse inverse, et son étude à l'aide de l'analyse des réseaux. L'Analyse Inverse permet en effet de reconstruire l'ensemble du réseau à partir de données éparses, le problème du manque de données étant récurrent en Ecologie. Au plan méthodologique, l'analyse inverse a été adaptée à la prise en compte des caractères saisonnier et spatialement hétérogène d'un écosystème tempéré de zone intertidale : deux saisons ont ainsi été couplées et la vasière a été considérée le long d'un transect perpendiculaire au rivage et divisé en trois zones spatiales. Deux types de flux physiques interviennent donc : les flux verticaux de dépôt et remise en suspension, et les flux d'advection via la colonne d'eau. Des pistes d'amélioration et de nouvelles méthodes sont proposées. Un résultat sous forme statistique peut être obtenu en couplant l'utilisation de méthodes de Monte Carlo à l'analyse inverse pour la construction des réseaux trophiques. Les moyens d'étude des modèles ont été enrichis par la mise au point d'indices issus de la construction de chaînes de Markov et prenant en compte le caractère temporel des transferts de matière entre compartiments. Enfin, la transformation mathématique du modèle statique pour une étude dynamique de la stabilité de l'équilibre décrit est abordée. Plusieurs modèles ont été construits au cours de l'évolution des méthodes et de l'acquisition de connaissances sur le site. Des méthodes d'analyses existantes et d'autres mises au point dans le cadre de cet ouvrage ont été appliquées aux réseaux obtenus afin de faire émerger les propriétés du fonctionnement de la vasière et de souligner le rôle de certains compartiments. Des analyses de sensibilité permettent d'évaluer la robustesse des résultats et d'orienter les recherches futures en mettant en évidence les manques les plus cruci

We used a carbon-based food web model to investigate the effects of oyster cultivation on the ecosystem of an intertidal mudflat. A previously published food web model of a mudflat in Marennes-Oleron Bay, France, was updated with revised parameters, and a realistic surface area and density of existing oyster cultures on the mudflat. We developed 2 hypothetical scenarios to estimate the impact of oyster cultivation on the food web structure of the ecosystem: one with no oysters, the other with a doubled area devoted to cultivated oysters in the bay. Oysters are direct trophic competitors of other filter feeders, and their presence modifies benthic-pelagic coupling by forcing a shift from pelagic consumers to benthic consumers. Increasing the surface area of cultivated oysters caused secondary production to increase, providing food for top predators (in particular juvenile nekton), reinforcing the nursery role of the mudflat in the ecosystem, and altering the species composition available to the top predators.

We used a carbon-based food web model to investigate the effects of oyster cultivation on the ecosystem of an intertidal mudflat. A previously published food web model of a mudflat in Marennes-Oleron Bay, France, was updated with revised parameters, and a realistic surface area and density of existing oyster cultures on the mudflat. We developed 2 hypothetical scenarios to estimate the impact of oyster cultivation on the food web structure of the ecosystem: one with no oysters, the other with a doubled area devoted to cultivated oysters in the bay. Oysters are direct trophic competitors of other filter feeders, and their presence modifies benthic-pelagic coupling by forcing a shift from pelagic consumers to benthic consumers. Increasing the surface area of cultivated oysters caused secondary production to increase, providing food for top predators (in particular juvenile nekton), reinforcing the nursery role of the mudflat in the ecosystem, and altering the species composition available to the top predators.

We used a carbon-based food web model to investigate the effects of oyster cultivation on the ecosystem of an intertidal mudflat. A previously published food web model of a mudflat in Marennes-Oleron Bay, France, was updated with revised parameters, and a realistic surface area and density of existing oyster cultures on the mudflat. We developed 2 hypothetical scenarios to estimate the impact of oyster cultivation on the food web structure of the ecosystem: one with no oysters, the other with a doubled area devoted to cultivated oysters in the bay. Oysters are direct trophic competitors of other filter feeders, and their presence modifies benthic-pelagic coupling by forcing a shift from pelagic consumers to benthic consumers. Increasing the surface area of cultivated oysters caused secondary production to increase, providing food for top predators (in particular juvenile nekton), reinforcing the nursery role of the mudflat in the ecosystem, and altering the species composition available to the top predators.

We used a carbon-based food web model to investigate the effects of oyster cultivation on the ecosystem of an intertidal mudflat. A previously published food web model of a mudflat in Marennes-Oleron Bay, France, was updated with revised parameters, and a realistic surface area and density of existing oyster cultures on the mudflat. We developed 2 hypothetical scenarios to estimate the impact of oyster cultivation on the food web structure of the ecosystem: one with no oysters, the other with a doubled area devoted to cultivated oysters in the bay. Oysters are direct trophic competitors of other filter feeders, and their presence modifies benthic-pelagic coupling by forcing a shift from pelagic consumers to benthic consumers. Increasing the surface area of cultivated oysters caused secondary production to increase, providing food for top predators (in particular juvenile nekton), reinforcing the nursery role of the mudflat in the ecosystem, and altering the species composition available to the top predators.

Food web modelling is an ideal way to describe ecosystems, because it accounts for the totality of the relationships between its various components. One difficulty of such an approach, however, lies in the lack of data and information about some ecological relationships, resulting in under-defined systems. Inverse analysis can serve to complete steady-state food webs where the number of direct flow measurements is insufficient relative to the actual number of flows. We applied this method to the intertidal mudflat ecosystem of Brouage (eastern Marennes-Oleron Bay, SW France) and estimated the annual average carbon flows between the compartments of a coupled benthic and pelagic trophic food web from primary producers (microphytobenthos and phytoplankton) to top predators (fish and birds). The resulting network was very sensitive to the primary production of the microphytobenthos which was the most important flow in the system. Sensitivity analyses demonstrated the need for additional data on the nekton, pelagic protozoa, and bacterial compartments. The resulting network showed high bacterial activity, but indices resulting from network analysis showed low cycling in comparison with other ecosystems. The meiofauna had a small biomass, but constituted a very active compartment compared to the macrofauna. Bird production was limited by macrofaunal production. Macrofaunal production reached the maximum allowed by the analysis. The intertidal mudflat ecosystem at Brouage is dominated by benthic production (including benthic primary producers, secondary producers, and predators) with an input of phytoplankton primary production.

Food web modelling is an ideal way to describe ecosystems, because it accounts for the totality of the relationships between its various components. One difficulty of such an approach, however, lies in the lack of data and information about some ecological relationships, resulting in under-defined systems. Inverse analysis can serve to complete steady-state food webs where the number of direct flow measurements is insufficient relative to the actual number of flows. We applied this method to the intertidal mudflat ecosystem of Brouage (eastern Marennes-Oleron Bay, SW France) and estimated the annual average carbon flows between the compartments of a coupled benthic and pelagic trophic food web from primary producers (microphytobenthos and phytoplankton) to top predators (fish and birds). The resulting network was very sensitive to the primary production of the microphytobenthos which was the most important flow in the system. Sensitivity analyses demonstrated the need for additional data on the nekton, pelagic protozoa, and bacterial compartments. The resulting network showed high bacterial activity, but indices resulting from network analysis showed low cycling in comparison with other ecosystems. The meiofauna had a small biomass, but constituted a very active compartment compared to the macrofauna. Bird production was limited by macrofaunal production. Macrofaunal production reached the maximum allowed by the analysis. The intertidal mudflat ecosystem at Brouage is dominated by benthic production (including benthic primary producers, secondary producers, and predators) with an input of phytoplankton primary production.

Food web modelling is an ideal way to describe ecosystems, because it accounts for the totality of the relationships between its various components. One difficulty of such an approach, however, lies in the lack of data and information about some ecological relationships, resulting in under-defined systems. Inverse analysis can serve to complete steady-state food webs where the number of direct flow measurements is insufficient relative to the actual number of flows. We applied this method to the intertidal mudflat ecosystem of Brouage (eastern Marennes-Oleron Bay, SW France) and estimated the annual average carbon flows between the compartments of a coupled benthic and pelagic trophic food web from primary producers (microphytobenthos and phytoplankton) to top predators (fish and birds). The resulting network was very sensitive to the primary production of the microphytobenthos which was the most important flow in the system. Sensitivity analyses demonstrated the need for additional data on the nekton, pelagic protozoa, and bacterial compartments. The resulting network showed high bacterial activity, but indices resulting from network analysis showed low cycling in comparison with other ecosystems. The meiofauna had a small biomass, but constituted a very active compartment compared to the macrofauna. Bird production was limited by macrofaunal production. Macrofaunal production reached the maximum allowed by the analysis. The intertidal mudflat ecosystem at Brouage is dominated by benthic production (including benthic primary producers, secondary producers, and predators) with an input of phytoplankton primary production.

Food web modelling is an ideal way to describe ecosystems, because it accounts for the totality of the relationships between its various components. One difficulty of such an approach, however, lies in the lack of data and information about some ecological relationships, resulting in under-defined systems. Inverse analysis can serve to complete steady-state food webs where the number of direct flow measurements is insufficient relative to the actual number of flows. We applied this method to the intertidal mudflat ecosystem of Brouage (eastern Marennes-Oleron Bay, SW France) and estimated the annual average carbon flows between the compartments of a coupled benthic and pelagic trophic food web from primary producers (microphytobenthos and phytoplankton) to top predators (fish and birds). The resulting network was very sensitive to the primary production of the microphytobenthos which was the most important flow in the system. Sensitivity analyses demonstrated the need for additional data on the nekton, pelagic protozoa, and bacterial compartments. The resulting network showed high bacterial activity, but indices resulting from network analysis showed low cycling in comparison with other ecosystems. The meiofauna had a small biomass, but constituted a very active compartment compared to the macrofauna. Bird production was limited by macrofaunal production. Macrofaunal production reached the maximum allowed by the analysis. The intertidal mudflat ecosystem at Brouage is dominated by benthic production (including benthic primary producers, secondary producers, and predators) with an input of phytoplankton primary production.