Ancient DNA and osteological analyses of a unique paleo-archive reveal Early Holocene faunal expansion into the Scandinavian Arctic

Paleo-archives are essential for our understanding of species responses to climate warming, yet such archives are extremely rare in the Arctic. Here, we combine morphological analyses and bulk-bone metabarcoding to investigate a unique chronology of bone deposits sealed in the high-latitude Storsteinhola cave system (68°50’ N 16°22’ E) in Norway. This deposit dates to a period of climate warming from the end of the Late Glacial to the Holocene Thermal Maximum. A combination of comparative morphology and paleogenetic analyses allowed us to exploit the deposit to its full potential, with ancient DNA providing taxonomical identification to the 1000s of morphologically unidentifiable bone fragments. Our results show a high-resolution sequence of fish, mammal, and bird species, including species not previously discovered in the region, and providing fundamental insights in the ecosystem-wide responses that are ongoing today.