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Provedor de dados:  ArchiMer
País:  France
Título:  Understanding patterns and processes in models of trophic cascades
Autores:  Heath, Michael R.
Speirs, Douglas C.
Steele, John H.
Data:  2014-01
Ano:  2014
Palavras-chave:  Bottom-up
Density dependence
Food chain
Food web
Resumo:  Climate fluctuations and human exploitation are causing global changes in nutrient enrichment of terrestrial and aquatic ecosystems and declining abundances of apex predators. The resulting trophic cascades have had profound effects on food webs, leading to significant economic and societal consequences. However, the strength of cascades-that is the extent to which a disturbance is diminished as it propagates through a food web-varies widely between ecosystems, and there is no formal theory as to why this should be so. Some food chain models reproduce cascade effects seen in nature, but to what extent is this dependent on their formulation? We show that inclusion of processes represented mathematically as density-dependent regulation of either consumer uptake or mortality rates is necessary for the generation of realistic top-down' cascades in simple food chain models. Realistically modelled bottom-up' cascades, caused by changing nutrient input, are also dependent on the inclusion of density dependence, but especially on mortality regulation as a caricature of, e.g. disease and parasite dynamics or intraguild predation. We show that our conclusions, based on simple food chains, transfer to a more complex marine food web model in which cascades are induced by varying river nutrient inputs or fish harvesting rates.
Tipo:  Text
Idioma:  Inglês

Editor:  Wiley-blackwell
Relação:  info:eu-repo/grantAgreement/EC/FP7/264933/EU//EURO-BASIN
Formato:  application/pdf
Fonte:  Ecology Letters (1461-023X) (Wiley-blackwell), 2014-01 , Vol. 17 , N. 1 , P. 101-114
Direitos:  info:eu-repo/semantics/openAccess

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