title: Climate variables explain neutral and adaptive variation within salmonid metapopulations: the importance of replication in landscape genetics.
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.
authors.affiliation: Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA.
authors.forename: Brian K
authors.identifier: 0000-0003-1152-665X
authors.initials: BK
authors.lastname: Hand
authors.affiliation: Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA.|U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT, 59936, USA.
authors.forename: Clint C
authors.initials: CC
authors.lastname: Muhlfeld
authors.affiliation: Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA.
authors.forename: Alisa A
authors.initials: AA
authors.lastname: Wade
authors.affiliation: U.S. Geological Survey, Northern Rocky Mountain Science Center, Glacier National Park, West Glacier, MT, 59936, USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Kovach
authors.affiliation: Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA.
authors.forename: Diane C
authors.initials: DC
authors.lastname: Whited
authors.affiliation: Columbia River Inter-Tribal Fish Commission, Hagerman Fish Culture Experiment Station, 3059-F National Fish Hatchery Road, Hagerman, ID, 83332, USA.
authors.forename: Shawn R
authors.initials: SR
authors.lastname: Narum
authors.affiliation: Columbia River Inter-Tribal Fish Commission, Hagerman Fish Culture Experiment Station, 3059-F National Fish Hatchery Road, Hagerman, ID, 83332, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Matala
authors.affiliation: Pacific States Marine Fisheries Commission, IDFG Eagle Fish Genetic Laboratory, 1800 Trout Road, Eagle, ID, 83616, USA.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Ackerman
authors.affiliation: Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA.
authors.forename: Brittany A
authors.initials: BA
authors.lastname: Garner
authors.affiliation: College of Forestry & Conservation, The University of Montana, Missoula, MT, 59812, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Kimball
authors.affiliation: Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA.|Division of Biological Sciences, The University of Montana, Missoula, MT, 59812, USA.
authors.forename: Jack A
authors.initials: JA
authors.lastname: Stanford
authors.affiliation: Flathead Lake Biological Station, University of Montana, Polson, MT, 59860, USA.|Division of Biological Sciences, The University of Montana, Missoula, MT, 59812, USA.
authors.forename: Gordon
authors.initials: G
authors.lastname: Luikart
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D001499:Bayes Theorem; D002980:Climate; D017753:Ecosystem; D014644:Genetic Variation; D005828:Genetics, Population; D008957:Models, Genetic; D015205:Northwestern United States; D017686:Oncorhynchus mykiss / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D013696:Temperature; D014872:Water Movements
keywords: adaptive genetic differentiation; conservation genetics; gene flow; landscape genomic modelling; population genomics; riverscape genetics; salmonids