Document Detail

Multiple predator effects in an intertidal food web.
MedLine Citation:
PMID:  16903040     Owner:  NLM     Status:  MEDLINE    
1. We examined the effects of multiple predators from an intertidal boulder food web to test whether and how three different predator species affected the survival of a small amphipod species. 2. Predators were chosen because they differ in their foraging mode, two feeding at the bottom and in benthic refuges (nemertean and shrimp) and one in the water-column (juveniles of a fish). 3. Mortality of amphipods was not affected by nemerteans, but was high in the presence of shrimp or fish. Highest mortalities were observed in predator-combinations that contained both shrimp and fish. Amphipods responded to shrimp by escaping into the water column, while they avoided fish by remaining in the refuge. We conclude that predator-specific defence causes conflicts for prey when both shrimp and fish are present. 4. Comparing observed effects of multiple predators with expected effects revealed risk enhancement for the shrimp + fish combination. A comparison of different predictive models revealed that the multiplicative model was most appropriate, although additive models may work well under certain conditions. 5. Based on known consumption-ranges of the predators used, we conclude that nemerteans were saturated with prey while fish were far from their saturation point. A predator's functional response curve (prey consumption in relation to prey abundance) determines its impact on prey populations. This knowledge appears essential in order to predict whether prey organisms face risk enhancement, risk reduction or additive effects of multiple predators.
Thijs Christiaan Van Son; Martin Thiel
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of animal ecology     Volume:  75     ISSN:  0021-8790     ISO Abbreviation:  J Anim Ecol     Publication Date:  2006 Jan 
Date Detail:
Created Date:  2006-08-14     Completed Date:  2007-07-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376574     Medline TA:  J Anim Ecol     Country:  England    
Other Details:
Languages:  eng     Pagination:  25-32     Citation Subset:  IM    
Facultad Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile.
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MeSH Terms
Amphipoda / growth & development*,  physiology
Decapoda (Crustacea) / physiology*
Fishes / physiology*
Food Chain*
Models, Biological
Oceans and Seas
Population Density
Population Dynamics
Population Growth
Predatory Behavior / physiology*

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