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Interspecific competition

Ecology Theory:

Interspecific competition

This article has been reviewed by the following Topic Editor: Kevin J. Caley

Introduction

Interspecific competition occurs between members of two, or more, different species. Individuals may compete over a variety of limiting resources including food, water, light, soil resources, or space. Members of different species may compete by exploitative competition or by interference competition. Interspecific competition is an important factor limiting the population size of many species. In addition, interspecific competition can limit the number of species that can coexist in a community and affect the phenotypic characteristics of organisms in an attempt to reduce the effects of competition.

Interspecific competition and population regulation

Interspecific interference competition between lions and hyenas. (Photo by Anup and Manoj Shah) Interspecific interference competition between lions and hyenas. (Photo by Anup and Manoj Shah)

Interspecific competition is an important factor limiting the population size of many species. The growth rate of a species will be limited as the population size of their competitors increases, either because they have access to fewer limiting resources (exploitative competition) or because of the negative effects of the direct interactions of their competitor (interference competition).

Interspecific competition and community structure

Interspecific competition can plan an important role in influencing aspects of community structure such as species richness, species diversity, and patterns of species abundance.

Species richness

Interspecific competition can limit the number of species that can coexist in a community. The competitive exclusion principle suggests that two species with exactly the same niche are not able to coexist.  Thus, when the niches of two competing species are too similar, one of the species will be driven to extinction or be extirpated from the range of the other (competitive exclusion).

Limiting the effects of interspecific competition

Species may respond to the effects of interspecific competition by evolving to fill slightly different niches (niche differentiation). The divergence in phenotype produced by natural selection to reduce the effects of competition are known as character displacement.

Models of interspecific competition

Ecologists have developed mathematical models to study interspecific competition. The Lotka-Volterra model of competition is a phenomenological model whereas Tilman's model of competition for resources is a mechanistic model that explicitly models the influence of exploitative competition between species.

Further reading

  • Campbell, N.A., J.B. Reece, and L.G. Mitchhell. 2006. Biology. Addison Wesley Longman, Inc. Menlo Park, CA. ISBN: 080537146X
  • Raven, P.H., G.B. Johnson, J.B. Losos, K.A. Mason, and S.R. Singer. 2008. Biology, 8th edition. McGraw Hill, New York, NY. ISBN: 0073227390

Citation

Mark McGinley (Lead Author);Kevin J. Caley (Topic Editor) "Interspecific competition". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth January 17, 2008; Last revised Date November 20, 2010; Retrieved May 20, 2013 <http://www.eoearth.org/article/Interspecific_competition?topic=58074>

The Author

Mark McGinleyMark McGinley is an Associate Professor in the Honors College and Department of Biological Sciences at Texas Tech University. He has conducted research in the evolutionary, behavioral, and community ecology of animals and plants. Dr. McGinley’s recent scholarly interests focus on educating the general public about scientific (particularly environmental) issues. He is currently working closely with students in an interdisciplinary degree program, Natural History and Humanities, which combine ... (Full Bio)

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February 11, 2013 | 5:40 pm

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