Understanding patterns and processes in models of trophic cascades
Heath, Michael R.
Speirs, Douglas C.
Steele, John H.
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.
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
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 ...
Historical and idealized climate model experiments : an intercomparison of Earth system models of intermediate complexity Eby, Michael; Weaver, Andrew J.; Alexander, K.; Zickfeld, K.; Abe-Ouchi, A.; Cimatoribus, A. A.; Crespin, E.; Drijfhout, S. S.; Edwards, N. R.; Eliseev, A. V.; Feulner, G.; Fichefet, T.; Forest, C. E.; Goosse, H.; Holden, P. B.; Joos, Fortunat; Kawamiya, M.; Kicklighter, David W.; Kienert, H.; Matsumoto, K.; Mokhov, I. I.; Monier, Erwan; Olsen, S. M.; Pedersen, J. O. P.; Perrette, M.; Philippon-Berthier, G.; Ridgwell, Andy; Schlosser, A.; Schneider von Deimling, T.; Shaffer, G.; Smith, R. S.; Spahni, R.; Sokolov, Andrei P.; Steinacher, M.; Tachiiri, K.; Tokos, K.; Yoshimori, M.; Zeng, Ning; Zhao, F. (Copernicus Publications on behalf of the European Geosciences Union, 2013-05-16)Both historical and idealized climate model experiments are performed with a variety of Earth system models of intermediate complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate ...
Incorporating ‘recruitment’ in matrix projection models : estimation, parameters, and the influence of model structure Cooch, Evan G.; Cam, Emmanuelle; Caswell, Hal (2010-07)Advances in the estimation of population parameters using encounter data from marked individuals have made it possible to include estimates of the probability of recruitment in population projection models. However, ...