Date(s) - 01/05/2019
4:15 pm - 5:30 pm
By Charlotte Clarke, University of Southampton
Ancient DNA recovered from sediments (sedaDNA) in the Arctic and Subarctic has proved a useful new tool for studying change in terrestrial ecosystems over time. The cold and relatively dry conditions of the Arctic and Subarctic appear to be ideal for the preservation of extra-cellular (i.e. “environmental”) DNA, particularly within permafrost and/or lake sediments.
Here, Dr Clarke provides an overview of the sedaDNA metabarcoding method and evaluates its potential for reconstructing plant community dynamics and changes in floristic diversity, based on late Quaternary sediments from the Eurasian Arctic. In particular, she will present two sedaDNA records from lakes in northern Norway and the Polar Ural Mountains in northern Russia, which differ greatly in terms of their catchment size, sedimentary characteristics and glacial histories. The floristically rich sedaDNA signal at both lakes includes representatives from all important plant functional groups and provides insights into species persistence and/or floristic diversity changes over the past 24,000 years. Both records demonstrate how reconstructions of vegetation history and floristic richness based on pollen can be improved by using sedaDNA, with sedaDNA being less sensitive to “swamping” by woody anemophilous taxa. Moreover, the sedaDNA record from the Polar Urals shows several features that the pollen stratigraphy failed to detect, including a turnover in grass genera at the Pleistocene-Holocene transition, an individualistic response of arctic-alpine plants to Holocene warming, and a diverse and variable bryophyte flora through time.