Ancient plant DNA reveals High Arctic greening during the Last Interglacial

Summer warming is driving a greening trend across the Arctic, with the potential for large-scale amplification of climate change due to vegetation-related feedbacks [Pearson et al., Nat. Clim. Chang. (3), 673–677 (2013)]. Because observational records are sparse and temporally limited, past episodes...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences
Main Authors: Crump, Sarah E., Fréchette, Bianca, Power, Matthew, Cutler, Sam, de Wet, Gregory, Raynolds, Martha K., Raberg, Jonathan H., Briner, Jason P., Thomas, Elizabeth K., Sepúlveda, Julio, Shapiro, Beth, Bunce, Michael, Miller, Gifford H.
Format: Text
Language:English
Published: National Academy of Sciences 2021
Subjects:
Physical Sciences
Arctic
Baffin Island
Canada
Arctic Greening
Baffin
Climate change
Dwarf birch
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020792/
http://www.ncbi.nlm.nih.gov/pubmed/33723011
https://doi.org/10.1073/pnas.2019069118
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Summary:Summer warming is driving a greening trend across the Arctic, with the potential for large-scale amplification of climate change due to vegetation-related feedbacks [Pearson et al., Nat. Clim. Chang. (3), 673–677 (2013)]. Because observational records are sparse and temporally limited, past episodes of Arctic warming can help elucidate the magnitude of vegetation response to temperature change. The Last Interglacial ([LIG], 129,000 to 116,000 y ago) was the most recent episode of Arctic warming on par with predicted 21st century temperature change [Otto-Bliesner et al., Philos. Trans. A Math. Phys. Eng. Sci. (371), 20130097 (2013) and Post et al., Sci. Adv. (5), eaaw9883 (2019)]. However, high-latitude terrestrial records from this period are rare, so LIG vegetation distributions are incompletely known. Pollen-based vegetation reconstructions can be biased by long-distance pollen transport, further obscuring the paleoenvironmental record. Here, we present a LIG vegetation record based on ancient DNA in lake sediment and compare it with fossil pollen. Comprehensive plant community reconstructions through the last and current interglacial (the Holocene) on Baffin Island, Arctic Canada, reveal coherent climate-driven community shifts across both interglacials. Peak LIG warmth featured a ∼400-km northward range shift of dwarf birch, a key woody shrub that is again expanding northward. Greening of the High Arctic—documented here by multiple proxies—likely represented a strong positive feedback on high-latitude LIG warming. Authenticated ancient DNA from this lake sediment also extends the useful preservation window for the technique and highlights the utility of combining traditional and molecular approaches for gleaning paleoenvironmental insights to better anticipate a warmer future.

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