Document Detail

Food chains in freshwaters.
MedLine Citation:
PMID:  19432649     Owner:  NLM     Status:  MEDLINE    
There are three hypothesized controls on food-chain length (FCL): energy supply (or "resource availability"), ecosystem size and disturbance (or "environmental variation"). In this article, the evidence for controls on FCL in freshwater ecosystems is evaluated. First, the various ways FCL can be measured are defined. Food-chain length typically is estimated as (1) connectance-based FCL--an average connectance between basal resources and top consumers, (2) functional FCL--by experimental determination of functionally significant effects of a top predator on lower trophic-level biomass patterns, and (3) realized FCL--an average connectance measure weighted by energy flow between basal consumers and the consumer occupying the maximum trophic position in the food web. Second, all evidence for relationships between the three hypothetical controls and FCL in freshwater ecosystems are evaluated. The review includes studies from streams, lakes, ponds, wetlands, phytotelmata, and experimental containers. Surprisingly, few studies of FCL in freshwaters that test the same suite of controls using the same methods are found. Equally compelling results arise from case studies based on functional, realized, and connectance-based measures of FCL. Third, 10 rules of thumb that could increase similarity of future studies, thereby facilitating synthesis across systems, are suggested. Fourth, it is discussed how FCL influences the concentration of contaminants in large-bodied animals (many of which are consumed by humans) as well as the efficacy of biocontrol applications in agriculture. Finally, there is a discussion of the potential relationships between global climate change, hydrology, and FCL in freshwaters.
John L Sabo; Jacques C Finlay; David M Post
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Review    
Journal Detail:
Title:  Annals of the New York Academy of Sciences     Volume:  1162     ISSN:  1749-6632     ISO Abbreviation:  Ann. N. Y. Acad. Sci.     Publication Date:  2009 Apr 
Date Detail:
Created Date:  2009-05-12     Completed Date:  2009-05-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7506858     Medline TA:  Ann N Y Acad Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  187-220     Citation Subset:  IM    
School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501, USA.
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MeSH Terms
Food Chain*
Fresh Water*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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