Vegetation Changes in Southeastern Siberia During the Late Pleistocene and the Holocene

• Published in: Frontiers in Ecology and Evolution
• Main Authors: Jérémy Courtin, Andrei A. Andreev, Elena Raschke, Sarah Bala, Boris K. Biskaborn, Sisi Liu, Heike Zimmermann, Bernhard Diekmann, Kathleen R. Stoof-Leichsenring, Luidmila A. Pestryakova, Ulrike Herzschuh
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2021
• Subjects: last glacial; Holocene; Lake Bolshoe Toko; paleoenvironments; sedimentary ancient DNA; metabarcoding; Evolution; QH359-425; Ecology; QH540-549.5; Tundra; Yakutia; Siberia
• Online Access: https://doi.org/10.3389/fevo.2021.625096; https://doaj.org/article/ad9e0216c24b459390640e226d47c78b

Relationships between climate, species composition, and species richness are of particular importance for understanding how boreal ecosystems will respond to ongoing climate change. This study aims to reconstruct changes in terrestrial vegetation composition and taxa richness during the glacial Late Pleistocene and the interglacial Holocene in the sparsely studied southeastern Yakutia (Siberia) by using pollen and sedimentary ancient DNA (sedaDNA) records. Pollen and sedaDNA metabarcoding data using the trnL g and h markers were obtained from a sediment core from Lake Bolshoe Toko. Both proxies were used to reconstruct the vegetation composition, while metabarcoding data were also used to investigate changes in plant taxa richness. The combination of pollen and sedaDNA approaches allows a robust estimation of regional and local past terrestrial vegetation composition around Bolshoe Toko during the last ∼35,000 years. Both proxies suggest that during the Late Pleistocene, southeastern Siberia was covered by open steppe-tundra dominated by graminoids and forbs with patches of shrubs, confirming that steppe-tundra extended far south in Siberia. Both proxies show disturbance at the transition between the Late Pleistocene and the Holocene suggesting a period with scarce vegetation, changes in the hydrochemical conditions in the lake, and in sedimentation rates. Both proxies document drastic changes in vegetation composition in the early Holocene with an increased number of trees and shrubs and the appearance of new tree taxa in the lake’s vicinity. The sedaDNA method suggests that the Late Pleistocene steppe-tundra vegetation supported a higher number of terrestrial plant taxa than the forested Holocene. This could be explained, for example, by the “keystone herbivore” hypothesis, which suggests that Late Pleistocene megaherbivores were able to maintain a high plant diversity. This is discussed in the light of the data with the broadly accepted species-area hypothesis as steppe-tundra covered such an extensive area ...