Data from: Population genomics of invasive fallow deer supports feasibility of island eradication and ecosystem restoration

Island biodiversity is especially vulnerable to the negative impacts of
invasive species. Myriad examples over the past few decades have
demonstrated the effectiveness of invasive species eradication as an
effective conservation and restoration strategy on islands. Population
genomics can support management planning by delineating eradication units
(i.e., genetically distinct populations) and identifying potential sources
of reinvasion. Here, we conducted population genomic analyses to guide the
management of invasive European fallow deer (Dama dama) on Sidney Island
in British Columbia, Canada. Specifically, we aimed to determine whether
deer on Sidney Island were genetically isolated from deer on two nearby
islands, James and Mayne, which represented potential sources of
reinvasion. To that end, we genotyped 44 individuals across the three
islands at 8,528 genome-wide single-nucleotide polymorphisms, revealing
strong pairwise genetic differentiation, with no evidence of gene flow
among islands. The contemporary population of Sidney Island also exhibited
extremely low genetic diversity, likely reflecting low propagule pressure,
founder effects, and/or the cumulative impacts of genetic drift due to
decades of culling. Taken together, these results suggest that Sidney
fallow deer are genetically isolated and that a successful eradication is
unlikely to be undermined by natural reinvasion from nearby islands,
providing an opportunity for ecosystem restoration. This work more broadly
demonstrates the ability of population genomics to guide the management of
invasive species on islands by assessing invasion history, dispersal
capacity, and reinvasion risk, ultimately improving opportunities for
successful and sustainable conservation outcomes.