Flyway structure in the circumpolar greater white-fronted goose

Abstract

Dispersal and migratory behavior are influential factors in determining how geneticdiversity is distributed across the landscape. In migratory species, genetic structurecan be promoted via several mechanisms including fidelity to distinct migratoryroutes. Particularly within North America, waterfowl management units have beendelineated according to distinct longitudinal migratory flyways supported by bandingdata and other direct evidence. The greater white-fronted goose (Anser albifrons) is amigratory waterfowl species with a largely circumpolar distribution consisting of upto six subspecies roughly corresponding to phenotypic variation. We examined therangewide population genetic structure of greater white-fronted geese using mtDNAcontrol region sequence data and microsatellite loci from 23 locales across NorthAmerica and Eurasia. We found significant differentiation in mtDNA between sampling locales with flyway delineation explaining a significant portion of the observedgenetic variation (∼12%). This is concordant with band recovery data which showslittle interflyway or intercontinental movements. However, microsatellite loci revealed little genetic structure suggesting a panmictic population across most of theArctic. As with many high-latitude species, Beringia appears to have played a role inthe diversification of this species. A common Beringian origin of North America andAsian populations and a recent divergence could at least partly explain the generallack of structure at nuclear markers. Further, our results do not provide strong support for the various taxonomic proposals for this species except for supporting thedistinctness of two isolated breeding populations within Cook Inlet, Alaska (A. a. elgasi) and Greenland (A. a. flavirostris), consistent with their subspecies status.