Sedimentary ancient DNA offers new insights into the vegetation history of western Beringia since the Eemian

• Main Authors: Zimmermann, Heike, Epp, Laura, Stoof-Leichsenring, Kathleen, Schwamborn, Georg, Schirrmeister, Lutz, Herzschuh, Ulrike
• Format: Conference Object
• Language: unknown
• Published: 2017
• Subjects: laptev; Laptev Sea; permafrost; taiga; Tundra; Beringia
• Online Access: https://epic.awi.de/id/eprint/44534/; https://hdl.handle.net/10013/epic.50845

Past climatic changes led to the migration of plant species and even whole plant communities, e.g. the replacement of arctic tundra by boreal taiga and vice versa. Sedimentary ancient DNA from natural archives is a valuable proxy to track such changes. Bol’shoy Lyakhovsky is an island within the Laptev Sea but it was part of Western Beringia during the last glacial due to the marine regression. There deposits can be found dating back to the Eemian (Krest Yuryakh Suite, ~125 kyr BP). Paleobotanical records based on macrofossils and pollen are available, but limited in their temporal resolution. Since sedimentary ancient DNA has proven to reveal complementary information not captured by traditional paleobotanical proxies, our aim was to provide a paleobotanical record in high resolution spanning from the Eemian to the present. We collected four terrestrial permafrost sediment cores from dated coastal localities and applied a DNA metabarcoding approach using the universal plant barcode of the trnL P6 loop. In total we recovered 325 taxa of which 244 (75%) were identified to species or genus level. The dataset is dominated by Saliceae, Anthemidae and Agrostidinae. In twelve samples from three different cores we detected sequences of Larix, which has not been detected before by macrofossil analyses and only sporadically by pollen analyses of coastal outcrops at the island. This suggests that the northern extent of the Siberian treeline was further north than previously assumed, and that Larix was indeed present at Bol’shoy Lyakhovsky Island.