| Apparent competition with an exotic plant reduces native plant establishment. | |
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MedLine Citation:
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PMID: 18481540 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Biological invasions can change ecosystem function, have tremendous economic costs, and impact human health; understanding the forces that cause and maintain biological invasions is thus of immediate importance. A mechanism by which exotic plants might displace native plants is by increasing the pressure of native consumers on native plants, a form of indirect interaction termed "apparent competition." Using experimental exclosures, seed addition, and monitoring of small mammals in a California grassland, we examined whether exotic Brassica nigra increases the pressure of native consumers on a native bunchgrass, Nassella pulchra. Experimental plots were weeded to focus entirely on indirect effects via consumers. We demonstrate that B. nigra alters the activity of native small-mammal consumers, creating a gradient of consumption that dramatically reduces N. pulchra establishment. Previous work has shown that N. pulchra is a strong competitor, but that it is heavily seed limited. By demonstrating that consumer pressure is sufficient to curtail establishment, our work provides a mechanism for this seed limitation and suggests that, despite being a good competitor, N. pulchra cannot reestablish close to B. nigra within its old habitats because exotic-mediated consumption preempts direct competitive exclusion. Moreover, we find that apparent competition has a spatial extent, suggesting that consumers may dictate the rate of invasion and the area available for restoration, and that nonspatial studies of apparent competition may miss important dynamics. |
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Authors:
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John L Orrock; Martha S Witter; O J Reichman |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: Ecology Volume: 89 ISSN: 0012-9658 ISO Abbreviation: Ecology Publication Date: 2008 Apr |
Date Detail:
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Created Date: 2008-05-16 Completed Date: 2008-10-28 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0043541 Medline TA: Ecology Country: United States |
Other Details:
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Languages: eng Pagination: 1168-74 Citation Subset: IM |
Affiliation:
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National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, California 93101, USA. orrock@wustl.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals California Ecosystem* Feeding Behavior Mammals Mustard Plant / physiology* Poaceae / physiology* Population Dynamics Species Specificity Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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