Patterns of Genetic Structure in the American Kestrel (\u3cem\u3eFalco sparverius\u3c/em\u3e): Influence of Distance and Migration and Implications for Monitoring and Management

Genetic structure is useful for inferring patterns of selection, gene flow and connectivity, and can define management units that aid in interpretation of spatially-specific trends and species management. American kestrels (Falco sparverius) are a widespread, generalist species with fully migratory, partial migrant, and resident populations. In many parts of their range, kestrels show evidence of declining population trends; however, it has been difficult to identify threats to kestrels because of differences in regional trends. We used a genome-wide sequencing approach to investigate the genetic structure of American kestrels, test hypotheses about the processes that influence genetic structuring of populations by affecting dispersal and gene flow and suggest new approaches for kestrel management based on genetic information. Specifically, we sequenced the first American kestrel genome and used restriction site associated DNA (RAD) sequencing to assess population structure at 72,263 SNP markers screened in 12 populations from across the migratory and non-migratory range of two subspecies of the American kestrel (F. s. sparverius and F. s. paulus ) in North America. We revealed previously unrecognized amounts of population genetic structure in American kestrels. We found the highest amount of genetic differentiation between resident populations, followed by moderate levels of differentiation between migratory and resident populations, and the lowest amount of genetic differentiation between long-distance migrants. These results suggest that migratory behavior facilitates dispersal, increases gene flow, and therefore reduces the amount of genetic differentiation and structuring between populations. Further, we suggest that genetically distinct groups of kestrels be monitored and managed separately to identify limiting factors that may affect these groups differently. This information increases our understanding of migrant ecology and evolution and has important implications for management of American kestrels