Population assignment reveals low migratory connectivity in a weakly structured songbird.

Area of Science:

• Ecology and Evolutionary Biology
• Genomics
• Conservation Science

Background:

• Understanding migratory connectivity is crucial for population dynamics and conservation of migratory species.
• Genetic markers are useful but can be uninformative for species with weak population structure.
• The prothonotary warbler (Protonotaria citrea) is a Neotropical songbird of conservation concern.

Purpose of the Study:

• To develop and apply a genomic approach to describe migratory connectivity in the prothonotary warbler.
• To assess the effectiveness of different numbers of genetic markers for population assignment.
• To quantify migratory connectivity for a weakly structured species.

Main Methods:

• Utilized 26,189 single nucleotide polymorphisms (SNPs) to analyze genetic structure.
• Employed population assignment models with varying numbers of informative SNPs.
• Assigned individuals from nonbreeding sites to breeding regions.

Main Results:

• Revealed weak genetic differentiation among populations (FST = 0.0055).
• Genetic variation was more associated with geographic (14.5%) than environmental (8.2%) factors.
• Maximum assignment accuracy (94.3% to region) was achieved using 600 highly differentiated SNPs, indicating low migratory connectivity.

Conclusions:

• Filtering genetic markers is essential for accurate population assignment models, especially in weakly structured species.
• This genomic approach can be applied to a wider range of migratory species.
• Quantifying migratory connectivity aids understanding of migratory strategies and conservation.