Modern and ancient DNA in lacustrine sediments – Vegetation signals unraveled


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bastian.niemeyer [ at ] awi.de

Abstract

Current climatic changes, mostly triggered by global warming, influence broad parts of the northern latitudes all over the world, and reliable assessments of present and past vegetation are highly relevant to predict the future development of Arctic ecosystems. The northernmost Siberian arcto-boreal treeline areas in the Taymyr lowlands may be particularly affected by climatic changes, with latitudinal shifts of the treeline ecotone and resulting vegetation changes from tundra to taiga. Obtaining reliable information about present vegetation composition in such remote arctic locations is difficult, as vegetation surveys in the field can typically only be carried out during brief visits, and the flowering season is short. Although these techniques are time consuming, methods like vegetation assessment by ground surveys or palynological analyses are common tools to evaluate floral composition and provide valuable, complimentary information. While vegetation surveys mainly provide information about the status quo, pollen analyses also allow investigation of vegetation back in time. In recent years, sedimentary DNA has emerged as an additional and effective tool to improve knowledge about past vegetation. DNA metabarcoding of lake sediments and sediment cores has become more and more relevant as a tool for such research, but an explicit assessment of lake sediment DNA data in comparison to data obtained from pollen and vegetation surveys is still lacking. Here, we present a study comparing these three vegetation assessment methods for 31 lakes within a 300 km transect in arctic Siberia, reaching from Tundra, through the treeline area, to the light Taiga. Surface sediments of lakes were taken, subsampled for DNA and pollen analyses and processed in the respective laboratories. Together with six representative vegetation surveys, we present results of this comparative study. Our results show that taxa assigned by DNA sequence analyses are comparable to those found in the pollen and vegetation analyses. Overall, the DNA provides a higher taxonomical level of identification, while the pollen grains mainly identify to genus level. Compared to the vegetation survey, pollen and DNA provide more information, as they are able to track vegetation elements, which could not been surveyed at the time of the year the surveys were carried out. The results show that the combination and comparison of pollen, DNA and vegetation seems to serve as a calibration set for future investigations of such remote and highly dynamic ecosystems. Our investigation draws a multidisciplinary, comprehensive image of the current composition of the Siberian lowland vegetation by combining well established and promising, newly emerging methods.



Item Type
Conference (Poster)
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Not peer-reviewed
Publication Status
Published
Event Details
11th International Conference on Permafrost (ICOP), 20 Jun 2016 - 24 Jun 2016.
Eprint ID
41409
Cite as
Niemeyer, B. , Stoof-Leichsenring, K. , Epp, L. and Herzschuh, U. (2016): Modern and ancient DNA in lacustrine sediments – Vegetation signals unraveled , 11th International Conference on Permafrost (ICOP), 20 June 2016 - 24 June 2016 .


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