Phylogenomic Barcoding of Soil Seed Bank–Persistent and Wind‐Dispersed Non‐Native Plant Species in South Georgia.

Climate change and invasive species are leading drivers of biodiversity loss, with island ecosystems being especially vulnerable.South Georgia, a remote sub-Antarctic island, is 170 km long with approximately 30,000 ha of vegetated coastal areas, as snowand ice dominate the inland regions. Human activities on the island have historically introduced non-native species, resultingin 41 introduced vascular plant species compared with only 24 native ones. To address this imbalance, the South Georgia Non-Native Plant Management Strategy was implemented (2016–2020) to control non-native plant populations. We assessed emergentseedlings from South Georgia soil samples and wind-dispersed seeds to determine which species persist in the soil seed bankand contribute to dispersal. Using a molecular barcoding approach, we evaluated traditional markers (rbcL and matK) and op-timized a high-throughput Angiosperms353 sequencing pipeline for accurate seedling identification. We generated a referencelibrary covering all native and non-native species and applied this to 1,498 emergent seedlings and 737 trapped seeds. Molecularbarcoding identified 21 species, including 10 non-natives and 11 natives. Strikingly, 84% of emergent seedlings were non-native,with Class III invasive species (Cerastium fontanum, Poa annua, Taraxacum officinale) dominating across most sites and in allwind traps. By contrast, Class I and II species occurred rarely and only at a few sites, indicating that management efforts havesubstantially reduced their spread, though viable seeds persist in the soil. These findings highlight both the continued threatfrom persistent seed banks of dominant invaders and the value of molecular barcoding for long-term monitoring. Our approachprovides a framework for biosecurity and restoration management in South Georgia and other vulnerable ecosystems underclimate change pressures