Sedimentary Metagenomics Reveal Cold-Adapted Chickens' Dominance during
the Last Glacial and Holocene Avian Diversification
Abstract
The transition from the Last Glacial to the Holocene was marked by
significant warming. This forced a compositional turnover of terrestrial
plant and mammal communities discovered by diverse palaeoecological
techniques. In this study, we analysed ancient environmental DNA from
eight lake sediment cores, collected in northern Eurasia and Alaska, to
elucidate the relationship of past bird communities and vegetation
structure across the last 21,000 years. We leveraged all DNA reads
assigned to the class “Aves” to characterise the compositional changes
of the bird community. The dominance of chicken birds (mainly
ptarmigans) during the Last Glacial Maximum turned into a higher
taxonomic bird diversity along with the late glacial loss of the
steppe-tundra and the increase of shrub and tree cover. This was
accompanied by an increased relative abundance of songbirds, raptors and
waterfowl. Compared to the northern boreal areas, vegetation and bird
communities were more stable in the northern tundra sites, where open
landscapes prevailed throughout. Reconstruction of past avian community
changes support the predictions of distribution changes in the course of
future ecosystem change.