Sabiia Seb
PortuguêsEspañolEnglish
Embrapa
        Busca avançada

Botão Atualizar


Botão Atualizar

Ordenar por: RelevânciaAutorTítuloAnoImprime registros no formato resumido
Registros recuperados: 7
Primeira ... 1 ... Última
Imagem não selecionada

Imprime registro no formato completo
Characterising the temporal variability of the spatial distribution of animals: an application to seabirds at sea ArchiMer
Certain, Gregoire; Bellier, E; Planque, Benjamin; Bretagnolle, V.
Understanding the patterns of spatial and temporal variations in animal abundance is a fundamental question in ecology. Here, we propose a method to quantify temporal variations in animal spatial patterns and to determine the spatial scale at which such temporal variability is expressed. The methodology extends from the approach proposed by Taylor (Taylor, L. R. 1961. Aggregation, variance and the mean. Nature 189: 732-735) and relies on models of the relationship between temporal mean and variance in animal abundance. Repeated observations of the spatial distribution of populations are used to construct spatially explicit models of Taylor's power law. The resulting slope parameters of the Taylor power law provide local measures of the temporal variability...
Tipo: Text Palavras-chave: Temporal variability; Taylor's Power Law; Spatio temporal distribution; Seabirds; Scale dependence; Bay of Biscay.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-3523.pdf
Imagem não selecionada

Imprime registro no formato completo
How do MAR(1) models cope with hidden nonlinearities in ecological dynamics? ArchiMer
Certain, Gregoire; Barraquand, Frederic; Gardmark, Anna.
1.Multivariate autoregressive (MAR) models are an increasingly popular technique to infer interaction strengths between species in a community and to predict the community response to environmental change. The most commonly employed MAR(1) models, with one time lag, can be viewed either as multispecies competition models with Gompertz density‐dependence or, more generally, as a linear approximation of more complex, nonlinear dynamics around stable equilibria. This latter interpretation allows for broader applicability, but may come at a cost in terms of interpretation of estimates and reliability of both short‐ and long‐term predictions. 2.We investigate what these costs might be by fitting MAR(1) models to simulated two‐species competition,...
Tipo: Text Palavras-chave: Forecasting; Interaction strength; MARSS; Multivariate autoregressive models; PRESS perturbation.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00439/55085/56521.pdf
Imagem não selecionada

Imprime registro no formato completo
Investigation of spatiotemporal patterns in mean temperature and mean trophic level of MEDITS survey catches in the Mediterranean Sea ArchiMer
Peristeraki, Panagiota; Bitetto, Isabella; Carbonara, Pierluigi; Carlucci, Roberto; Certain, Gregoire; De Carlo, Francesco; Gristina, Michele; Kamidis, Nikos; Pesci, Paola; Stagioni, Marco; Valls, María; Tserpes, George.
Mean temperature (MTC) and mean trophic level (MTL) spatiotemporal patterns of MEDITS survey catches were examined in 13 geographic statistical areas (GSAs) of the Mediterranean between 1994 and 2016. The study aimed to detect changes in the demersal community structure related to anthropogenic impacts. A generalized additive modelling approach was used to examine the effects of year and GSA on the MTC and MTL indexes and on bottom temperature by haul. For the MTC index, the year was significant only in 4 GSAs, while for MTL it was significant in 5. Higher MTC values were observed in central and eastern areas. Bottom temperature increased after 2010, and also from west to east and from north to south. Our results indicate that the recently observed...
Tipo: Text Palavras-chave: Mean temperature of the catch; Trophic level; Bottom temperature; Trends; Mediterranean; Fishing pressure; Sea warming; Climate change.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00489/60054/63332.pdf
Imagem não selecionada

Imprime registro no formato completo
Lower trophic levels and detrital biomass control the Bay of Biscay continental shelf food web: Implications for ecosystem management ArchiMer
Lassalle, G.; Lobry, J.; Le Loc'H, F.; Bustamante, Paco; Certain, Gregoire; Delmas, Daniel; Dupuy, C.; Hily, Christian; Labry, Claire; Le Pape, O.; Marquis, Elise; Petitgas, Pierre; Pusineri, Claire; Ridoux, Vincent; Spitz, J.; Niquil, Nathalie.
The Bay of Biscay (North-East Atlantic) has long been subjected to intense direct and indirect human activities that lead to the excessive degradation and sometimes overexploitation of natural resources. Fisheries management is gradually moving away from single-species assessments to more holistic, multi-species approaches that better respond to the reality of ecosystem processes. Quantitative modelling methods such as Ecopath with Ecosim can be useful tools for planning, implementing and evaluating ecosystem-based fisheries management strategies. The aim of this study was therefore to model the energy fluxes within the food web of this highly pressured ecosystem and to extract practical information required in the diagnosis of ecosystem state/health. A...
Tipo: Text
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00057/16851/14329.pdf
Imagem não selecionada

Imprime registro no formato completo
Modelling spatio-temporal patterns of fish community size structure across the northern Mediterranean Sea: an analysis combining MEDITS survey data with environmental and anthropogenic drivers ArchiMer
Bitetto, Isabella; Romagnoni, Giovanni; Adamidou, Angeliki; Certain, Gregoire; Di Lorenzo, Manfredi; Donnaloia, Marilena; Lembo, Giuseppe; Maiorano, Porzia; Milisenda, Giacomo; Musumeci, Claudia; Ordines, Francesc; Pesci, Paola; Peristeraki, Panagiota; Pesic, Ana; Sartor, Paolo; Spedicato, Maria Teresa.
The state of marine systems subject to natural or anthropogenic impacts can be generally summarized by suites of ecological indicators carefully selected to avoid redundancy. Length-based indicators capture the status of fish community structure, fulfilling the Marine Strategy Framework Directive (MSFD) requirement for Descriptor 3 (status of commercial fish species). Although the MSFD recommends the development of regional indicators, a comparison among alternative length-based indicators is so far missing for the Mediterranean Sea. Using principal component analysis and dynamic factor analysis, we identified the most effective subset of length-based indicators, whether or not based on maximum length. Indicator trends and time series of fishing effort and...
Tipo: Text Palavras-chave: Demersal fish community; Size structure indicators; Geographical sub-area; Marine Strategy Framework Directive; Dynamic factor analysis; Redundancy analysis.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00599/71148/69466.pdf
Imagem não selecionada

Imprime registro no formato completo
Poissons, céphalopodes et crustacés du Golfe du Lion. Courbes de croissance. Taille et poids. Maturité sexuelle. ArchiMer
Bensebaini, Cyria Meriem; Billet, Norbert; Certain, Gregoire; Jadaud, Angelique; Le Roy, Emilie.
Tipo: Text
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00505/61688/65656.pdf
Imagem não selecionada

Imprime registro no formato completo
Suitable habitats of fish species in the Barents Sea ArchiMer
Husson, Berengere; Certain, Gregoire; Filin, Anatoly; Planque, Benjamin.
Many marine species are shifting their distribution poleward in response to climate change. The Barents Sea, as a doorstep to the fast-warming Arctic, is experiencing large scale changes in its environment and its communities. This paper aims at understanding what environmental predictors limit fish species habitats in the Barents Sea and discuss their possible evolution in response to the warming of the Arctic. Species distribution models usually aim at predicting the probability of presence or the average abundance of a species, conditional on environmental drivers. A complementary approach is to determine suitable habitats by modelling the upper limit of a species’ response to environmental factors. Using quantile regressions, we model the upper limit...
Tipo: Text Palavras-chave: Quantile regression; Habitat suitability models; Climate change; Species distribution; Species shifts; Environmental drivers.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00605/71682/70120.pdf
Registros recuperados: 7
Primeira ... 1 ... Última
 

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Embrapa
Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco

Valid HTML 4.01 Transitional