Holocene Vegetation and Plant Diversity Changes in the North-Eastern Siberian Treeline Region From Pollen and Sedimentary Ancient DNA

• Published in: Frontiers in Ecology and Evolution
• Main Authors: Sisi Liu, Kathleen R. Stoof-Leichsenring, Stefan Kruse, Luidmila A. Pestryakova, Ulrike Herzschuh
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2020
• Subjects: sedimentary ancient DNA; metabarcoding; pollen; Siberia; palaeovegetation; plant diversity; Evolution; QH359-425; Ecology; QH540-549.5; Arctic; Tundra
• Online Access: https://doi.org/10.3389/fevo.2020.560243; https://doaj.org/article/06acc42218904833a96eed1c15bcc5a2

Although sedimentary ancient DNA (sedaDNA) has been increasingly used to study paleoecological dynamics (Schulte et al., 2020), the approach has rarely been compared with the traditional method of pollen analysis for investigating past changes in the vegetation composition and diversity of Arctic treeline areas. Here, we provide a history of latitudinal floristic composition and species diversity based on a comparison of sedaDNA and pollen data archived in three Siberian lake sediment cores spanning the mid-Holocene to the present (7.6–0 cal ka BP), from northern typical tundra to southern open larch forest in the Omoloy region. Our results show that the sedaDNA approach identifies more plant taxa found in the local vegetation communities, while the corresponding pollen analysis mainly captures the regional vegetation development and has its limitations for plant diversity reconstruction. Measures of alpha diversity were calculated based on sedaDNA data recovered from along a tundra to forest tundra to open larch forest gradient. Across all sites, sedaDNA archives provide a complementary record of the vegetation transition within each lake’s catchment, tracking a distinct latitudinal vegetation type range from larch tree/alder shrub (open larch forest site) to dwarf shrub-steppe (forest tundra) to wet sedge tundra (typical tundra site). By contrast, the pollen data reveal an open landscape, which cannot distinguish the temporal changes in compositional vegetation for the open larch forest site and forest-tundra site. Increasing Larix pollen percentages were recorded in the forest-tundra site in the last millenium although no Larix DNA was detected, suggesting that the sedaDNA approach performs better for tracking the local establishment of Larix. Highest species richness and diversity are found in the mid-Holocene (before 4.4 ka) at the typical tundra site with a diverse range of vegetational habitats, while lowest species richness is recorded for the forest tundra where dwarf-willow habitats dominated the ...