Consulta: subjectFacets:"Ecopath"
Registros recuperados: 10
Data/hora: 01/06/2024 07:25:25

Complexity in trophic structure and stability in a modelled West African estuary
Provedor de dados: 5
Autores: Villanueva, Ching-maria; Diouf, P.s.; Albaret, J.-j.; Moreau, J.
Un modèle Ecopath de l'estuaire du Sine-Saloum (Sénégal) comportant au total 37 groupes fonctionnels a été appliqué dans la présente étude en vue de déterminer les faits essentiels de ce système aquatique. La grande biodiversité spécifique des poissons de l'écosystème peut y jouer un rôle en assurant son intégrité, spécialement en présence de facteurs de stress, bien qu'il ait été observé que ce n'est pas entièrement le cas. Les résultats montrent qu'un autre facteur de mitigation est le niveau des forces d'interaction entre les groupes fonctionnels. La stabilité est accrue par des relations plus faibles et des pyramides plus courtes et plus larges. Bien que différentes questions se posent concernant les facteurs conduisant à la stabilité d'un système, les...
Tipo: Text
Palavras-chave: Stabilité des systèmes; Sénégal; Omnivorie; Estuaire; Ecosystème côtier; Ecopath; Biodiversité; Afrique de l'Ouest; West Africa; System Stability; Senegal; Omnivory; Estuary; Ecopath; Coastal Ecosystem; Biodiversity.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-2554.pdf

Comparative analysis of trophic structure and interactions of two tropical lagoons
Provedor de dados: 5
Autores: Villanueva, Ching-maria; Laleye, P; Albaret, J; Lae, Raymond; Tito De Morais, Luis; Moreau, J.
A comparative study of the Ebrie lagoon (Ivory Coast) and Lake Nokoue (Benin) was made based on ecotrophic model outputs that describe each system's structure and functioning. Two models were constructed using the Ecopath software to differentiate main biomass flows in the systems.   Results indicate that biomasses and productions in both ecosystems are concentrated in trophic levels (TL) 2 and 3. Higher TL biomasses and productions in Lake Nokoue compared to Ebrie lagoon may be explained by the presence of acadjas. High production per biomass (P/B) and food consumption per biomass (Q/B) values indicate the high productivity of these systems and the abundance of juveniles in most groups which utilize these systems as refuge zones and nurseries. The...
Tipo: Text
Palavras-chave: Ecopath; System maturity; Transfer efficiency; West Africa; Tropical lagoons.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2009.pdf

Biodiversité et relations trophiques dans quelques milieux estuariens et lagunaires de l’Afrique de l’Ouest : Adaptations aux pressions environnementales
Provedor de dados: 5
Autores: Villanueva, Ching-maria.
This work is the result of a research on West African estuaries and lagoon ecosystems: estuaries of Sine-Saloum (Senegal) and the Gambia, (The Gambia), as well as the lagoons Ébrié (Ivory Coast) and Lake Nokoué (Benin). Estuaries and lagoons are highly productive and economically important ecosystems and are among those threatened as their biodiversity and productivity are constant exposed to various disturbances. These disturbances can weaken the stability and durability of these ecosystems. This led to the problematic raised in the thesis: To approach the African western ecosystems and the environmental pressures that they undergo that eventually affect the biodiversity and the trophic relations of their aquatic living resources.    This work seeks to...
Tipo: Text
Palavras-chave: Milieux estuariennes et lagunaires; Relations trophiques; Adaptation; Ecopath; Reseaux neurones artificiels; Stress environnementaux; Maturité des écosystèmes.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/00180/29122/29305.pdf

Trophic flow structure of a neotropical estuary in northeastern Brazil and the comparison of ecosystem model indicators of estuaries
Provedor de dados: 5
Autores: Lira, Alex; Angelini, Ronaldo; Le Loc'H, Francois; Menard, Frederic; Lacerda, Carlos; Fredou, Thierry; Fredou, Flavia Lucena.
We developed an Ecopath model in the Estuary of Sirinhaém River (SIR), a small-sized system surrounded by mangroves, subject to high impact, mainly by sugar cane industry and other farming industries in order to describe the food web structure and trophic interactions. In addition, we compared our findings with those of 20 available Ecopath estuarine models for tropical, subtropical and temperate regions, aiming to synthesize the knowledge on trophic dynamics and provide a comprehensive analysis of the structures and functioning of estuaries. Our model consisted of 25 compartments and its indicators were within the expected range for estuarine areas around the world. The average trophic transfer efficiency for the entire system was 11.8%, similar to the...
Tipo: Text
Palavras-chave: Tropical estuary; Ecopath; Food web; Global comparison of ecological indicators.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00428/53929/55061.pdf

An ecosystem approach for the assessment of fisheries impacts on marine top predators: the Bay of Biscay case study
Provedor de dados: 5
Autores: Lassalle, Geraldine; Gascuel, Didier; Le Loch, Francois; Lobry, Jeremy; Pierce, Graham John; Ridoux, Vincent; Santos, Maria Begona; Spitz, Jerome; Niquil, Nathalie.
A number of marine mammal populations is currently threatened by their interactions with fisheries. The present study aimed to provide insights into the severity of potential impacts of operational and biological interactions between top predators and fisheries, in the Bay of Biscay region. Our approach was to modify an Ecopath with Ecosim (EwE) model describing the overall structure and function of the ecosystem by including landings and discards of exploited stocks and estimations of the bycatch of non-target compartments. Second, a set of ecological indices and a trophic level (TL)-based model (EcoTroph, ET) were derived from the EwE model. ET was used to simulate the effects of increasing fishing pressure on the ecosystem and, more particularly, on top...
Tipo: Text
Palavras-chave: Ecopath; Ecosystem modelling; EcoTroph; Fisheries impacts; Marine mammals; Trophic level.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00087/19855/17541.pdf

A toolbox to evaluate data reliability for whole-ecosystem models: Application on the Bay of Biscay continental shelf food-web model
Provedor de dados: 5
Autores: Lassalle, Geraldine; Bourdaud, Pierre; Saint-beat, Blanche; Rochette, Sebastien; Niquil, Nathalie.
Ecosystem models are always simplifications of reality and as such their application for ecosystem-based management requires standard validation. Here, the “DataReli” toolbox is proposed to evaluate the quality of the data used during the construction of ecosystem models, their coherence across trophic levels, and whether data limitations prevent the model long-term applications. This toolbox is the combination of three operational and complementary analyses: (i) the pedigree index to determine to what extent a model was calibrated on data of local origin; (ii) the graphical analysis known as PREBAL to assess whether a model respects some basic ecological and fisheries principles; and (iii) a sensitivity analysis to evaluate the robustness of model...
Tipo: Text
Palavras-chave: Food-web model; Ecopath; Model evaluation; Parameter uncertainty; Ecosystem-based management; Bay of Biscay.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00188/29969/28484.pdf

Diversity and stability of an estuarine trophic network
Provedor de dados: 5
Autores: Lobry, Jeremy; David, V; Pasquaud, S; Lepage, M; Sautour, B; Rochard, E.
Estuarine areas provide highly valuable ecosystem benefits for human populations, despite being under intense demographic, economic and ecological pressures. Hence, an understanding of the structure and function of estuarine ecosystems is essential for understanding the persistence and stability of these ecosystems and their response to perturbations. This study synthesises available data and knowledge about the Gironde estuary (SW France) in a mass-balanced trophic model to illustrate potential key patterns in the functioning of the estuarine ecosystem and key elements of its stability. In order to evaluate the total direct and indirect impact on the whole community of the 2 main sources of anthropogenic perturbations in the estuarine area, mortalities...
Tipo: Text
Palavras-chave: Gironde estuary; Ecopath; Diversity; Stability; Network analysis; Food web; Estuarine ecosystem.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4290.pdf

Interactions between a natural food web, shellfish farming and exotic species: The case of the Bay of Mont Saint Michel (France)
Provedor de dados: 5
Autores: Arbach Leloup, F.; Desroy, Nicolas; Le Mao, Patrick; Pauly, D.; Le Pape, Olivier.
To ensure sustainable uses of the coastal zone, an integrated ecosystemic approach and ecosystem models are required to frame ecological processes and evaluate environmental impacts. Here, a mass-balance trophic (Ecopath) model of the Mont Saint Michel Bay (MSMB) was developed, to analyze the bay's functioning as an ecosystem. This bay, intensively exploited by fishing and for shellfish farming, is also suffering from the proliferation of the gastropod Crepidula fornicata, an exotic species.  The MSMB model has 18 compartments, from the primary producers to top predators, and emphasizes the large biomass of filter feeders. The model identified the MSMB as a highly productive ecosystem controlled largely from the bottom-up, and strongly impacted by huge...
Tipo: Text
Palavras-chave: Mont Saint Michel Bay; Crepidula fornicata; Invasive species; Shellfish farming; Trophic model; Ecopath.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2007/publication-2605.pdf

EcoTroph: a simple model to assess fishery interactions and their impacts on ecosystems
Provedor de dados: 5
Autores: Gasche, Loic; Gascuel, Didier.
The EcoTroph model leaves aside the notion of species, and models the functioning of marine ecosystems as flows of biomass from low to high trophic levels, so as to quantify easily the impacts of fishing at an ecosystem scale. In this paper, based on two case studies we present a new development of the EcoTroph model that is devoted to the analysis of fishery interactions and impacts of fleet segments on ecosystems. First, deriving an EcoTroph model from an Ecopath model of the Guinea ecosystem, the impacts of the artisanal fishery are distinguished from those of the industrial fishery. It appears that these fisheries do not always compete for the same fish groups but that they both strongly impact the ecosystem and moderately impact one another. Then, an...
Tipo: Text
Palavras-chave: Ecopath; Ecosystem modelling; EcoTroph; Fishery interactions; Fishing impact; Guinea; Management scenario; Small pelagics; Southern Benguela.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00138/24970/23123.pdf

Modeling energy flow in a large Neotropical reservoir: a tool do evaluate fishing and stability
Provedor de dados: 83
Autores: Angelini,Ronaldo; Agostinho,Angelo Antonio; Gomes,Luiz Carlos.
Recently, there is an increasing perception that the ecosystem approach gives important insights to support fisheries stock assessment and management. This paper aims to quantify energy flows in the Itaipu Reservoir (Brazil) and to simulate increase of the fishing effort of some species, using Ecopath with Ecosim software, which could allow inferences on stability. Therefore, two steady-state Itaipu models were built (1983-87 and 1988-92). Results showed that: a) there are no differences between models, and results on aging trends do not vary over time indicating that fishery does not alter the ecosystem as a whole; b) results of fisheries simulations are approximate to mono-specific stock assessment for the same species and periods; c) many authors...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ecopath; Food web; Fisheries; Ecosystem; Simulation.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252006000200011