Rattus population genomics across the Haida Gwaii archipelago provides a framework for guiding invasive species management

Invasive species have led to precipitous declines in biodiversity, especially in island systems, with brown (Rattus norvegicus) and black rats (R. rattus) leading the way. Combining sampling of black (n=291) and brown (n=287) rats across the Haida Gwaii archipelago (British Columbia, Canada) with genotyping-by-sequencing (10,770-27,686 SNPs), we reconstructed distinct clusters of populations regionally, determined that reinvasion was the cause of past failed eradication attempts, and defined six eradication units constituting single or clusters of islands that would limit the potential for re-invasion in the future. Overall, our results highlight the importance of targeted research prior to conducting eradications and demonstrates a framework for applying population genomics for guiding invasive species management in island systems.