The role of competition – colonization tradeoffs and spatial heterogeneity in promoting trematode coexistence

By: , and 



Competition – colonization tradeoffs occur in many systems, and theory predicts that they can strongly promote species coexistence. However, there is little empirical evidence that observed competition – colonization tradeoffs are strong enough to maintain diversity in natural systems. This is due in part to a mismatch between theoretical assumptions and biological reality in some systems. We tested whether a competition – colonization tradeoff explains how a diverse trematode guild coexists in California horn snail populations, a system that meets the requisite criteria for the tradeoff to promote coexistence. A field experiment showed that subordinate trematode species tended to have higher colonization rates than dominant species. This tradeoff promoted coexistence in parameterized models but did not fully explain trematode diversity and abundance, suggesting a role of additional diversity maintenance mechanisms. Spatial heterogeneity is an alternative way to promote coexistence if it isolates competing species. We used scale transition theory to expand the competition – colonization tradeoff model to include spatial variation. The parameterized model showed that spatial variation in trematode prevalence did not isolate most species sufficiently to explain the overall high diversity, but could benefit some rare species. Together, the results suggest that several mechanisms combine to maintain diversity, even when a competition – colonization tradeoff occurs.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The role of competition – colonization tradeoffs and spatial heterogeneity in promoting trematode coexistence
Series title Ecology
DOI 10.1890/15-0753.1
Volume 97
Issue 6
Year Published 2016
Language English
Publisher The Ecological Society of America
Contributing office(s) Western Ecological Research Center
Description 13 p.
First page 1484
Last page 1496
Online Only (Y/N) N
Additional Online Files (Y/N) N
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