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Marine Ecology Progress Series

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MEPS 512:89-98 (2014)  -  DOI:

Strong asymmetrical inter-specific relationships in food web simulations

Ferenc Jordán1,2,*, Marco Scotti1,3, Ágnes Mike4, Marco Ortiz

1The Microsoft Research - University of Trento Centre for Computational and Systems Biology, Piazza Manifattura 1,
38068 Rovereto, TN, Italy
2MTA Centre for Ecological Research, Balaton Limnological Institute, Tihany, Hungary
3GEOMAR Helmholtz-Zentrum für Ozeanforschung, Duesternbrooker Weg 20, 24105 Kiel, Germany
4Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
5Instituto Antofagasta, Instituto de Ciencias Naturales AvH, Facultad de Ciencias del Mar & Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
*Corresponding author:

ABSTRACT: In complex ecosystem models, relationships between species include a large number of direct interactions and indirect effects. In order to unveil some simple and better understandable relationships, it is useful to study the asymmetry of inter-specific effects. We present a simple approach for this based on stochastic food web simulations from previous studies. We refer to the Prince William Sound (Gulf of Alaska) marine ecosystem model for illustration. Real data were used to parameterize a dynamical food web model. Through simulations and sensitivity analysis, we determined the strength of the effects between all species. We calculated the asymmetry between the mutual effects species have on each other, and selected the top 5% most asymmetrical interactions. The set of these highly asymmetrical relationships is illustrated by a separate graph in which we calculated the positional importance of the species and correlated this to other independent properties such as population size and trophic position. Results suggest that halibut is the key species dominating this system of asymmetrical interactions, but sablefish and adult arrowtooth flounder also seem to be of high importance. Nearshore demersals display the highest number of connections in the graph of asymmetrical links, suggesting that this trophic group regulates the dynamics of many species in the food web. This approach identifies key interactions and most asymmetrical relationships, potentially increasing the efficiency of management efforts and aiding conservation efforts.

KEY WORDS: Food web · Stochastic simulation · Asymmetrical effects · Prince William Sound · Eco-dynamics

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Cite this article as: Jordán F, Scotti M, Mike Á, Ortiz M (2014) Strong asymmetrical inter-specific relationships in food web simulations. Mar Ecol Prog Ser 512:89-98.

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