Local adaptation in Trinidadian guppies alters stream ecosystem structure at landscape scales despite high environmental variability

Copeia
By: , and 

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Abstract

While previous studies have shown that evolutionary divergence alters ecological processes in small-scale experiments, a major challenge is to assess whether such evolutionary effects are important in natural ecosystems at larger spatial scales. At the landscape scale, across eight streams in the Caroni drainage, we found that the presence of locally adapted populations of guppies (Poecilia reticulata) is associated with reduced algal biomass and increased invertebrate biomass, while the opposite trends were true in streams with experimentally introduced populations of non-locally adapted guppies. Exclusion experiments conducted in two separate reaches of a single stream showed that guppies with locally adapted phenotypes significantly reduced algae with no effect on invertebrates, while non-adapted guppies had no effect on algae but significantly reduced invertebrates. These divergent effects of phenotype on stream ecosystems are comparable in strength to the effects of abiotic factors (e.g., light) known to be important drivers of ecosystem condition. They also corroborate the results of previous experiments conducted in artificial streams. Our results demonstrate that local adaptation can produce phenotypes with significantly different effects in natural ecosystems at a landscape scale, within a tropical watershed, despite high variability in abiotic factors: five of the seven physical and chemical parameters measured across the eight study streams varied by more than one order of magnitude. Our findings suggest that ecosystem structure is, in part, an evolutionary product and not simply an ecological pattern.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Local adaptation in Trinidadian guppies alters stream ecosystem structure at landscape scales despite high environmental variability
Series title Copeia
DOI 10.1643/CE-16-517
Volume 105
Issue 3
Year Published 2017
Language English
Publisher The American Society of Ichthyologists and Herpetologists
Contributing office(s) Patuxent Wildlife Research Center
Description 10 p.
First page 504
Last page 513
Country Trinidad