The Impacts of Dam Construction and Removal on the Genetics of Recovering Steelhead ( Oncorhynchus mykiss ) Populations across the Elwha River Watershed
Dam construction and longitudinal river habitat fragmentation disrupt important life histories and movement of aquatic species. This is especially true for that exhibits both migratory (steelhead) and non-migratory (resident rainbow) forms. While the negative effects of dams on salmonids have been e...
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Published in | Genes Vol. 12; no. 1; p. 89 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Switzerland
MDPI AG
13.01.2021
MDPI |
Subjects | |
Online Access | Get full text |
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Summary: | Dam construction and longitudinal river habitat fragmentation disrupt important life histories and movement of aquatic species. This is especially true for
that exhibits both migratory (steelhead) and non-migratory (resident rainbow) forms. While the negative effects of dams on salmonids have been extensively documented, few studies have had the opportunity to compare population genetic diversity and structure prior to and following dam removal. Here we examine the impacts of the removal of two dams on the Elwha River on the population genetics of
Genetic data were produced from >1200 samples collected prior to dam removal from both life history forms, and post-dam removal from steelhead. We identified three genetic clusters prior to dam removal primarily explained by isolation due to dams and natural barriers. Following dam removal, genetic structure decreased and admixture increased. Despite large
population declines after dam construction, we did not detect shifts in population genetic diversity or allele frequencies of loci putatively involved in migratory phenotypic variation. Steelhead descendants from formerly below and above dammed populations recolonized the river rapidly after dam removal, suggesting that dam construction did not significantly reduce genetic diversity underlying
life history strategies. These results have significant evolutionary implications for the conservation of migratory adaptive potential in
populations above current anthropogenic barriers. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2073-4425 2073-4425 |
DOI: | 10.3390/genes12010089 |