Understanding patterns and processes in models of trophic cascades
MetadataShow full item record
KeywordBottom-up; Density dependence; Food chain; Food web; Harvesting; Model; Predator–prey; Simulation; Top-down
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.
© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecology Letters 17 (2014): 101-114, doi:10.1111/ele.12200.
Suggested CitationEcology Letters 17 (2014): 101-114
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234) Sherwood, Christopher R.; Aretxabaleta, Alfredo L.; Harris, Courtney K.; Rinehimer, J. Paul; Verney, Romaric; Ferré, Bénédicte (Copernicus Publications on behalf of the European Geosciences Union, 2018-05-14)We describe and demonstrate algorithms for treating cohesive and mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in the Coupled Ocean–Atmosphere–Wave–Sediment ...
Short-term dispersal of Fukushima-derived radionuclides off Japan : modeling efforts and model-data intercomparison Rypina, Irina I.; Jayne, Steven R.; Yoshida, Sachiko; Macdonald, Alison M.; Douglass, Elizabeth M.; Buesseler, Ken O. (Copernicus Publications on behalf of the European Geosciences Union, 2013-07-24)The Great East Japan Earthquake and tsunami that caused a loss of power at the Fukushima nuclear power plants (FNPP) resulted in emission of radioactive isotopes into the atmosphere and the ocean. In June of 2011, an ...
Sediment transport model including short-lived radioisotopes: Model description and idealized test cases Birchler, Justin J.; Harris, Courtney K.; Sherwood, Christopher R.; Kniskern, Tara A. (American Meteorological Society, 2018-11-27)Geochronologies derived from sediment cores in coastal locations are often used to infer event bed characteristics such as deposit thicknesses and accumulation rates. Such studies commonly use naturally occurring, short-lived ...