Data from: Fifty thousand years of arctic vegetation and megafaunal diet

Although it is generally agreed that the arctic flora is among the
youngest and least diverse on Earth, the processes that shaped it are
poorly understood. Here we present 50 thousand years (kyr) of arctic
vegetation history, derived from the first large-scale ancient DNA
metabarcoding study of circumpolar plant diversity. For this interval we
additionally explore nematode diversity as a proxy for modelling
vegetation cover and soil quality, and diets of herbivorous megafaunal
mammals, many of which became extinct around 10 kyr BP (before present).
For much of the period investigated, arctic vegetation consisted of dry
steppe tundra dominated by forbs (non-graminoid herbaceous vascular
plants). During the Last Glacial Maximum (25–15 kyr BP), diversity
declined markedly, although forbs remained dominant. Much changed after 10
kyr BP, with the appearance of moist tundra dominated by woody plants and
graminoids. Our analyses indicate that both graminoids and forbs would
have featured in megafaunal diets. As such our findings question the
predominance of a late Quaternary graminoid-dominated arctic “mammoth
steppe”.