“Riverscape” genetics: river characteristics influence the genetic structure and diversity of anadromous and freshwater Atlantic salmon (Salmo salar) populations in northwest Russia

Abstract

Combining population genetic and landscape ecology approaches provides an understanding of how environmental factors affect individual dispersal, population size, and structure. We first generated a set of predictions of the expected effect of “riverscape” characteristics on salmonid genetic diversity and divergence, based on the results of earlier research on this topic in salmonid fishes. We then tested these predictions in a data set consisting of the microsatellite data and riverscape characteristics of 39 Atlantic salmon ( Salmo salar ) populations from northwest Russia. The carrying capacity of the river was an important factor shaping the genetic diversity and differentiation of Atlantic salmon populations in the region: salmon in rivers with a larger carrying capacity tended to have higher genetic diversity and lower genetic differentiation. The importance of other riverscape characteristics often varied between anadromous and freshwater populations. Taken together, these associations demonstrate a high and complex level of river landscape influence on the genetic diversity and structure of Atlantic salmon populations and highlight the importance of spawning and nursery area maintenance for the conservation of salmonids.