Plant environmental DNA extracted from lacustrine sediments (sedimentary DNA, sedDNA) has been increasingly used to investigate past vegetation changes and human impacts at a high taxonomic resolution. However, the representation of vegetation communities surrounding the lake is still unclear. In this study, we compared plant sedDNA metabarcoding and pollen assemblages from 27 lake surface-sediment samples collected from alpine meadow on the central-eastern Tibetan Plateau to investigate the representation of sedDNA data. In general, the identified components of sedDNA are consistent with the counted pollen taxa and local plant communities. Relative to pollen identification, sedDNA data have higher taxonomic resolution, thus providing a potential approach for reconstructing past plant diversity. The sedDNA signal is strongly influenced by local plants while rarely affected by exogenous plants. Because of the overrepresentation of local plants and PCR bias, the abundance of sedDNA sequence types is very variable among sites, and should be treated with caution when investigating past vegetation cover and climate based on sedDNA data. Our finding suggests that sedDNA analysis can be a complementary approach for investigating the presence/absence of past plants and history of human land-use with higher taxonomic resolution.

从湖泊沉积物中提取的植物环境 DNA（沉积 DNA、sedDNA）已越来越多地用于以高分类分辨率研究过去的植被变化和人类影响。然而，湖泊周围植被群落的代表性仍不清楚。在本研究中，我们比较了从青藏高原中东部高寒草甸采集的 27 个湖泊表面沉积物样本的植物 sedDNA 元条形码和花粉组合，以研究 sedDNA 数据的表征。总体而言，已鉴定的 sedDNA 成分与计数的花粉类群和当地植物群落一致。相对于花粉鉴定，sedDNA数据具有更高的分类分辨率，从而为重建过去的植物多样性提供了潜在的方法。sedDNA信号受本地植物的影响强烈，而很少受外源植物的影响。由于当地植物过多和 PCR 偏差，sedDNA 序列类型的丰度在不同地点之间差异很大，在根据 sedDNA 数据调查过去的植被覆盖和气候时应谨慎对待。我们的研究结果表明，sedDNA 分析可以作为一种补充方法，以更高的分类分辨率调查过去植物的存在/不存在和人类土地利用的历史。