Genomics-informed conservation units reveal spatial variation in climate vulnerability in a migratory bird

Area of Science:

• Conservation genetics
• Avian ecology
• Genomics

Background:

• Delineating genetic conservation units (CUs) is vital for threatened species, especially highly mobile ones like the Canada Warbler (Cardellina canadensis).
• Challenges include high gene flow and isolation by distance, often resulting in CUs lacking crucial conservation need data.
• Existing methods struggle to integrate adaptive variation and climate vulnerability for effective management.

Purpose of the Study:

• To implement a framework for identifying CUs in the Canada Warbler.
• To integrate demographic modeling and genomic offset for conservation decision-making.
• To identify populations with the greatest conservation need based on current and future threats.

Main Methods:

• Whole genome sequencing to analyze genetic variation in Canada Warblers.
• Identification of evolutionarily significant units (ESUs) and adaptive units (AUs) across the breeding range.
• Quantification of genomic offset to assess climate vulnerability and demographic modeling for population trends.

Main Results:

• Canada Warbler genetic variation is primarily driven by adaptive variation.
• Two ESUs and three AUs (South, East, Northwest) were identified.
• The Northwestern AU shows high climate vulnerability, while the Eastern AU exhibits the steepest population declines.

Conclusions:

• Genomics-informed CUs provide a robust framework for identifying regional threats in highly mobile species.
• Understanding adaptive units and genomic offset is critical for guiding conservation strategies under climate change.
• This approach aids in prioritizing management actions for species like the Canada Warbler facing rapid environmental shifts.