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Environmental extremes drive population structure at the northern range limit of Atlantic salmon in North America
Author(s) -
Sylvester Emma V. A.,
Beiko Robert G.,
Bentzen Paul,
Paterson Ian,
Horne John B.,
Watson Beth,
Lehnert Sarah,
Duffy Steven,
Clément Marie,
Robertson Martha J.,
Bradbury Ian R.
Publication year - 2018
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.14849
Subject(s) - biology , range (aeronautics) , salmo , population , ecology , genetic structure , population genomics , genetic variation , fishery , genomics , genetics , genome , gene , fish <actinopterygii> , materials science , demography , sociology , composite material
Conservation of exploited species requires an understanding of both genetic diversity and the dominant structuring forces, particularly near range limits, where climatic variation can drive rapid expansions or contractions of geographic range. Here, we examine population structure and landscape associations in Atlantic salmon ( Salmo salar ) across a heterogeneous landscape near the northern range limit in Labrador, Canada. Analysis of two amplicon‐based data sets containing 101 microsatellites and 376 single nucleotide polymorphisms ( SNP s) from 35 locations revealed clear differentiation between populations spawning in rivers flowing into a large marine embayment (Lake Melville) compared to coastal populations. The mechanisms influencing the differentiation of embayment populations were investigated using both multivariate and machine‐learning landscape genetic approaches. We identified temperature as the strongest correlate with genetic structure, particularly warm temperature extremes and wider annual temperature ranges. The genomic basis of this divergence was further explored using a subset of locations ( n = 17) and a 220K SNP array. SNP s associated with spatial structuring and temperature mapped to a diverse set of genes and molecular pathways, including regulation of gene expression, immune response, and cell development and differentiation. The results spanning molecular marker types and both novel and established methods clearly show climate‐associated, fine‐scale population structure across an environmental gradient in Atlantic salmon near its range limit in North America, highlighting valuable approaches for predicting population responses to climate change and managing species sustainability.