# Deciphering Cryptic Population Structure in Western Sandhill Crane Subspecies (Antigone canadensis) of the Pacific Flyway

## TL;DR

This study finds that Western Sandhill Crane populations in the Pacific Flyway are genetically distinct and should be managed separately to protect their diversity.

## Contribution

The study reveals cryptic genetic differentiation in Sandhill Crane populations, suggesting the need for tailored conservation strategies.

## Key findings

- Geographically separated crane populations show substantial genetic differentiation.
- Divergent diets, flyways, and breeding habitats support genetic separation.
- Small coastal populations require special management to preserve genetic diversity.

## Abstract

Population segregation catalyses genetic differentiation and can lead to speciation. Population genetic structure is also critically important for population management, especially in species characterised 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 analyse microsatellite markers, mitochondrial DNA sequences, and mitochondrial haplogroups derived from 203 individual Sandhill Cranes to elucidate the 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, F
ST, 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.

Sandhill Crane populations of the Pacific Flyway are made up of breeding populations nesting west of the Rocky Mountains, and isolated by intermediate mountain ranges. Here, we analyze microsatellite markers, mitochondrial DNA sequences, and mitochondrial haplogroups to elucidate population genetic structure and found substantial genetic differentiation. The conservation of Sandhill Cranes west of the Rocky Mountains depends on safeguarding the genetic diversity and adaptations within and between populations to protect them from current and future climate scenarios.