<p>The eastern Tibetan Plateau, particularly the Hengduan Mountains and Sanjiangyuan region, is a biodiversity hotspot also known for its sensitivity to climate change. How these vegetation communities assembled since the Last Glacial Maximum is still unclear. Here we present new results from plant metabarcoding of sediments from Lake Ximencuo (Nianbaoyeze Mountains, Sanjiangyuan region) covering the last 18 ka and compare them with records from Lake Naleng (Hengduan Mountains). &#160;We investigate temporal changes of within-site and between-site alpha and beta diversities. Both sites show the highest richness between 14 and 10 ka when alpine meadows covered the areas while richness was rather low in forested periods during the early Holocene. Ordination results support that the vegetation composition was relatively low between-site beta-diversities indicate that the vegetation composition was relatively similar in the two study areas before the Holocene, particularly during the early late-glacial when alpine steppes dominated. The maximal between-site beta-diversity occurred between 10 and 8 ka when environmental filtering was most relevant, as suggested by the dominating turnover component. The nestedness component of beta-diversity reached a maximum during the middle Holocene indicating that between-site differences during this period possibly originated from e.g., dispersal limitation.</p>
Long-Distance Dispersal after the Last Glacial Maximum (LGM) Led to the Disjunctive Distribution of Pedicularis kansuensis (Orobanchaceae) between the Qinghai-Tibetan Plateau and Tianshan Region
