Climate variables explain neutral and adaptive variation within salmonid metapopulations: The importance of replication in landscape genetics

Molecular Ecology
By: , and 

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Abstract

Understanding how environmental variation influences population genetic structure is important for conservation management because it can reveal how human stressors influence population connectivity, genetic diversity and persistence. We used riverscape genetics modelling to assess whether climatic and habitat variables were related to neutral and adaptive patterns of genetic differentiation (population-specific and pairwise FST) within five metapopulations (79 populations, 4583 individuals) of steelhead trout (Oncorhynchus mykiss) in the Columbia River Basin, USA. Using 151 putatively neutral and 29 candidate adaptive SNP loci, we found that climate-related variables (winter precipitation, summer maximum temperature, winter highest 5% flow events and summer mean flow) best explained neutral and adaptive patterns of genetic differentiation within metapopulations, suggesting that climatic variation likely influences both demography (neutral variation) and local adaptation (adaptive variation). However, we did not observe consistent relationships between climate variables and FST across all metapopulations, underscoring the need for replication when extrapolating results from one scale to another (e.g. basin-wide to the metapopulation scale). Sensitivity analysis (leave-one-population-out) revealed consistent relationships between climate variables and FST within three metapopulations; however, these patterns were not consistent in two metapopulations likely due to small sample sizes (N = 10). These results provide correlative evidence that climatic variation has shaped the genetic structure of steelhead populations and highlight the need for replication and sensitivity analyses in land and riverscape genetics.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Climate variables explain neutral and adaptive variation within salmonid metapopulations: The importance of replication in landscape genetics
Series title Molecular Ecology
DOI 10.1111/mec.13517
Volume 25
Issue 3
Year Published 2016
Language English
Publisher Blackwell Science
Publisher location Oxford
Contributing office(s) Northern Rocky Mountain Science Center
Description 17 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Molecular Ecology
First page 689
Last page 705
Country United States
Other Geospatial Columbia River Basin
Online Only (Y/N) N
Additional Online Files (Y/N) N