Deciphering cryptic population structure in Western Sandhill Crane
subspecies (Antigone canadensis) of the Pacific Flyway
Abstract
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 BC and southeast Alaska. STRUCTURE, AMOVA, FST, DAPC, and
phylogenetic analyses reveal 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 the unique characteristics of coastal
Sandhill Crane populations deserve special management consideration
relative to interior and southwestern Alaskan crane populations. The
conservation of Pacific Flyway Sandhill Cranes depends on safeguarding
the genetic diversity and adaptations within and between populations to
protect these cranes from current and future climate scenarios, and by
protecting the breeding, staging and wintering habitats of each
population.