Dispersal and selection mediate hybridization between a native and invasive species

Proceedings of the Royal Society B
By: , and 

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Abstract

Hybridization between native and non-native species has serious biological consequences, but our understanding of how dispersal and selection interact to influence invasive hybridization is limited. Here, we document the spread of genetic introgression between a native (Oncorhynchus clarkii) and invasive (Oncorhynchus mykiss) trout, and identify the mechanisms influencing genetic admixture. In two populations inhabiting contrasting environments, non-native admixture increased rapidly from 1984 to 2007 and was driven by surprisingly consistent processes. Individual admixture was related to two phenotypic traits associated with fitness: size at spawning and age of juvenile emigration. Fish with higher non-native admixture were larger and tended to emigrate at a younger age—relationships that are expected to confer fitness advantages to hybrid individuals. However, strong selection against non-native admixture was evident across streams and cohorts (mean selection coefficient against genotypes with non-native alleles (s) ¼ 0.60; s.e. ¼ 0.10). Nevertheless, hybridization was promoted in both streams by the continuous immigration of individuals with high levels of non-native admixture from other hybrid source populations. Thus, antagonistic relationships between dispersal and selection are mediating invasive hybridization between these fish, emphasizing that data on dispersal and natural selection are needed to fully understand the dynamics of introgression between native and non-native species. .

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Dispersal and selection mediate hybridization between a native and invasive species
Series title Proceedings of the Royal Society B
DOI 10.1098/rspb.2014.2454
Volume 282
Year Published 2015
Language English
Publisher The Royal Society
Contributing office(s) Northern Rocky Mountain Science Center
Description 9 p.; 20142454
Online Only (Y/N) N
Additional Online Files (Y/N) N