Cryptic population structure in sandhill cranes (Antigone canadensis) of the Pacific Flyway

Population segregation catalyzes genetic differentiation and can lead to
speciation. Population genetic structure is also critically important for
population management, especially in species characterized by small,
isolated populations. Sandhill Crane (Antigone canadensis) populations of
the Pacific Flyway are made up of breeding populations nesting west of the
Rocky Mountains, and isolated by intermediate mountain ranges. Current
management policy in British Columbia treats all Sandhill Cranes as a
single population, whereas in the western United States subpopulations are
subject to population specific management. Here, we analyze microsatellite
markers, mitochondrial DNA sequences, and mitochondrial haplogroups,
derived from 203 individual Sandhill Cranes to elucidate population
genetic structure of cranes migrating along the Pacific Flyway to summer
breeding habitat on the North and Central Coast of British Columbia and
southeast Alaska. STRUCTURE, AMOVA, FST, DAPC, and phylogenetic analyses
reveal that geographically separated crane populations along the west
coast of North America show substantial genetic differentiation in the
Pacific Flyway. These findings are consistent with behavioural and
ecological evidence - divergent diets, flyways and breeding habitats. We
conclude that the relatively small coastal Sandhill Crane populations
deserve special management consideration to safeguard their genetic
diversity and adaptations, and to mitigate deleterious impacts of current
and future climate change scenarios.