Can interspecific competition lead to an increase in niche width?

[Amaru]

In spite of the classical notion that interspecific competition constrains niche width it is possible to envision circumstances under which it could cause niche width to increase.

 

For example, reducing the availability of a valuable resource forces an animal to compensate in some fashion: through increased exploitation of the other resources it currently consumes (as classical theory would dictate), or potentially, through exploiting new resources which can mitigate the loss. If more than one alternative resource is incorporated, an animal will have widened their niche as a direct result of interspecific competition.

 

Does anyone know of any studies which have shown such effects? Or any papers in which this or other possible ways interspecific competition could widen niche are discussed?

 

[Harold Squared]

Only example I can think of is raccoons feasting on suburban garbage, more like exploiting vacant niche, one not too different from natural opportunistic omnivore behavior. Tough proposition, sorry not to be more helpful.

[H.sapiens]

Nature. 2001 Mar 22;410(6827):463-6.

Intraspecific competition favours niche width expansion in Drosophila melanogaster.

Bolnick DI¹.

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Abstract

Ecologists have proposed that when interspecific competition is reduced, competition within a species becomes a potent evolutionary force leading to rapid diversification. This view reflects the observation that populations invading species-poor communities frequently evolve broader niches. Niche expansion can be associated with an increase in phenotypic variance (known as character release), with the evolution of polymorphisms, or with divergence into many species using distinct resources (adaptive radiation). The relationship between intraspecific competition and diversification is known from theory, and has been used as the foundation for some models of speciation. However, there has been little empirical proof that niches evolve in response to intraspecific competition. To test this hypothesis, I introduced cadmium-intolerant Drosophila melanogaster populations to environments containing both cadmium-free and cadmium-laced resources. Here I show that populations experiencing high competition adapted to cadmium more rapidly than low competition populations. This provides experimental confirmation that competition in a population can drive niche expansion onto new resources for which competition is less severe.

 

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Ecological release from interspecific competition leads to decoupled changes in population and individual niche width

Daniel I. Bolnick, Travis Ingram, William E. Stutz, Lisa K. Snowberg, On Lee Lau, Jeff S. Paull

Published 17 February 2010.DOI: 10.1098/rspb.2010.0018

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Abstract

A species's niche width reflects a balance between the diversifying effects of intraspecific competition and the constraining effects of interspecific competition. This balance shifts when a species from a competitive environment invades a depauperate habitat where interspecific competition is reduced. The resulting ecological release permits population niche expansion, via increased individual niche widths and/or increased among-individual variation. We report an experimental test of the theory of ecological release in three-spine stickleback (Gasterosteus aculeatus). We factorially manipulated the presence or absence of two interspecific competitors: juvenile cut-throat trout (Oncorhynchus clarki) and prickly sculpin (Cottus asper). Consistent with the classic niche variation hypothesis, release from trout competition increased stickleback population niche width via increased among-individual variation, while individual niche widths remained unchanged. In contrast, release from sculpin competition had no effect on population niche width, because increased individual niche widths were offset by decreased between-individual variation. Our results confirm that ecological release from interspecific competition can lead to increases in niche width, and that these changes can occur on behavioural time scales. Importantly, we find that changes in population niche width are decoupled from changes in the niche widths of individuals within the population.

Edited June 20, 2015 by H.sapiens