Publication Date:
2016-03-22
Description:
Reconstructing past vegetation and species diversity from arctic lake sediments can be challenging because of low pollen and plant macrofossil concentrations. Information may be enhanced by metabarcoding of sedimentary ancient DNA ( sed aDNA). We developed a Holocene record from Lake Skartjørna, Svalbard, using sed aDNA, plant macrofossils and sediment properties, and compared it with published records. All but two genera of vascular plants identified as macrofossils in this or a previous study were identified with sed aDNA. Six additional vascular taxa were found, plus two algal and 12 bryophyte taxa, by sed aDNA analysis, which also detected more species per sample than macrofossil analysis. A shift from Salix polaris -dominated vegetation, with Koenigia islandica , Ranunculaceae and the relatively thermophilic species Arabis alpina and Betula , to Dryas octopetala -dominated vegetation ~6600–5500 cal. BP suggests a transition from moist conditions 1–2°C warmer than today to colder/drier conditions. This coincides with a decrease in runoff, inferred from core lithology, and an independent record of declining lacustrine productivity. This mid-Holocene change in terrestrial vegetation is broadly coincident with changes in records from marine sediments off the west coast of Svalbard. Over the Holocene sed aDNA records little floristic change, and it clearly shows species persisted near the lake during time intervals when they are not detected as macrofossils. The flora has shown resilience in the presence of a changing climate, and, if future warming is limited to 2°C or less, we might expect only minor floristic changes in this region. However, the Holocene record provides no analogues for greater warming.
Print ISSN:
0959-6836
Electronic ISSN:
1477-0911
Topics:
Geography
,
Geosciences
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