Weak interactions, omnivory and emergent food-web properties.

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Serval ID
serval:BIB_AB438BAA36C2
Type
Article: article from journal or magazin.
Collection
Publications
Title
Weak interactions, omnivory and emergent food-web properties.
Journal
Proceedings. Biological Sciences / The Royal Society
Author(s)
Emmerson M., Yearsley J.M.
ISSN
0962-8452
Publication state
Published
Issued date
2004
Peer-reviewed
Oui
Volume
271
Number
1537
Pages
397-405
Language
english
Abstract
Empirical studies have shown that, in real ecosystems, species-interaction strengths are generally skewed in their distribution towards weak interactions. Some theoretical work also suggests that weak interactions, especially in omnivorous links, are important for the local stability of a community at equilibrium. However, the majority of theoretical studies use uniform distributions of interaction strengths to generate artificial communities for study. We investigate the effects of the underlying interaction-strength distribution upon the return time, permanence and feasibility of simple Lotka-Volterra equilibrium communities. We show that a skew towards weak interactions promotes local and global stability only when omnivory is present. It is found that skewed interaction strengths are an emergent property of stable omnivorous communities, and that this skew towards weak interactions creates a dynamic constraint maintaining omnivory. Omnivory is more likely to occur when omnivorous interactions are skewed towards weak interactions. However, a skew towards weak interactions increases the return time to equilibrium, delays the recovery of ecosystems and hence decreases the stability of a community. When no skew is imposed, the set of stable omnivorous communities shows an emergent distribution of skewed interaction strengths. Our results apply to both local and global concepts of stability and are robust to the definition of a feasible community. These results are discussed in the light of empirical data and other theoretical studies, in conjunction with their broader implications for community assembly.
Keywords
Computer Simulation, Ecosystem, Food Chain, Models, Biological
Pubmed
Web of science
Create date
19/11/2007 10:44
Last modification date
20/08/2019 15:15
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