EGU21-10391
https://doi.org/10.5194/egusphere-egu21-10391
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Patterns of postglacial vegetation establishment clarified by lacustrine sedaDNA from Baffin Island, Arctic Canada

Sarah E. Crump1,2, Matthew Power3, Bianca Fréchette4, Gregory de Wet5, Martha K. Raynolds6, Jonathan H. Raberg2, Morten Allentoft3, Michael Bunce7, and Gifford H. Miller2
Sarah E. Crump et al.
  • 1Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA (secrump@ucsc.edu)
  • 2Institute of Arctic and Alpine Research and Department of Geological Sciences, University of Colorado Boulder, Boulder, CO, USA
  • 3Trace and Environmental DNA Laboratory, Curtin University, Perth, Australia
  • 4Geotop, Université du Québec à Montréal, Montréal, Quebec, Canada
  • 5Department of Geosciences, Smith College, Northampton, MA, USA
  • 6Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA
  • 7New Zealand Environment Protection Authority, Wellington, New Zealand

The colonization of recently deglaciated landscapes by tundra vegetation during the early Holocene is an important case study for understanding possible rates and patterns of plant migration in a rapidly warming world. Fossil pollen in lake sediment has traditionally served as the primary tool for reconstructing paleovegetation and understanding postglacial biogeography. However, because pollen can be wind-transported long distances and, in some cases, reworked from older deposits on the landscape, pollen-based vegetation histories can sometimes obscure the true history of plant colonization. In contrast, lacustrine sedimentary ancient DNA (sedaDNA) is sourced locally and is less likely to be adequately preserved through reworking events, thus making it a more reliable proxy for determining the precise timing of plant colonization. Here, we present three sedaDNA records from Holocene lake sediment across southern Baffin Island, Arctic Canada, that clarify the timing of postglacial vegetation changes. In particular, DNA from the subarctic shrub Betula (dwarf birch) first appears thousands of years after deglaciation in all three lake catchments, suggesting delayed colonization despite its strong pollen signal in early postglacial sediments. While moderate levels of Alnus (alder) pollen characterize early to mid-Holocene lake sediments from the region, sedaDNA suggests that Alnus was likely not present in any of the three lake catchments during the Holocene. In addition, aquatic plant community changes indicated by sedaDNA faithfully reflect the timing of early Holocene warmth in the region, highlighting the potential utility of aquatic plant DNA as a qualitative temperature proxy. We suggest that ancient plant DNA in lake sediment provides key paleoecological information that is distinct from traditional proxy records, particularly during periods of relatively rapid ecological change like the early Holocene. 

How to cite: Crump, S. E., Power, M., Fréchette, B., de Wet, G., Raynolds, M. K., Raberg, J. H., Allentoft, M., Bunce, M., and Miller, G. H.: Patterns of postglacial vegetation establishment clarified by lacustrine sedaDNA from Baffin Island, Arctic Canada, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10391, https://doi.org/10.5194/egusphere-egu21-10391, 2021.

Displays

Display file