Range-wide population genetic analysis of Seaside Sparrows (Ammospiza maritima) supports at least five distinct population segments that do not align with current subspecies descriptions

As an obligate salt marsh species, Seaside Sparrows (Ammospiza maritima) are vulnerable to numerous threats including climate change, coastal erosion, sea level rise, and both natural and anthropogenic disasters. Of the nine recognized subspecies, two are extinct and one is endangered. Previous genetic analyses of mitochondrial DNA (mtDNA) and microsatellite loci showed that current taxonomy does not accurately reflect underlying genetic diversity, with possible consequences for the distribution of conservation resources. To further inform Seaside Sparrow management, we comprehensively describe genetic structure among 24 range-wide sampling locations that include all extant subspecies. We inferred population structure from several thousand single-nucleotide polymorphisms collected from 272 individuals via restriction-site associated DNA sequencing. Principal components, pairwise FST values, and clustering approaches suggest that Seaside Sparrows on the Atlantic and Gulf Coasts are disti...