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”.

尽管学界普遍认为北极植物区系（arctic flora）是地球上最年轻、多样性最低的类群之一，但其形成过程却鲜为人知。我们在此呈现基于首个环北极植物多样性大规模古DNA元条形码测序（metabarcoding）研究得到的5万年（kyr）北极植被演化历史。在此时间区间内，我们还探究了线虫多样性，将其作为模拟植被覆盖、土壤质量以及植食性巨型哺乳动物食谱的代用指标——这类哺乳动物中的多数在约10千年BP（before present）走向灭绝。在本次研究覆盖的大部分时段，北极植被以干草原苔原为主，优势类群为非禾本科草本植物（forbs）。在末次冰盛期（Last Glacial Maximum，25~15 kyr BP），植被多样性显著下降，但非禾本科草本植物仍占据优势。10千年BP之后，植被格局发生巨变：以木本植物和禾草类植物（graminoids）为优势的湿草甸苔原出现。我们的分析显示，禾草类植物与非禾本科草本植物均曾出现在巨型哺乳动物的食谱中。据此，我们的研究结果对晚第四纪北极以禾草类为主导的“猛犸草原”主流认知提出了质疑。