| 1. |
- Johnson, Ernst, 1995-, et al.
(författare)
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The potential of lacustrine sedimentary ancient DNA for revealing human postglacial recolonization patterns in northern Sweden – a review
- 2024
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Ingår i: Boreas. - 0300-9483 .- 1502-3885.
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Forskningsöversikt (refereegranskat)abstract
- The postglacial recolonization of Fennoscandian flora and fauna was initiated when the land became accessible as the last ice sheet retreated. In northern Sweden, plants are represented in pollen and macrofossil records, but there is no genetic evidence from the first plants, animals or humans in the region, mainly owing to an absence of osteological finds. The questions of who the first postglacial peoples, or pioneers, were and where they came from therefore remain unanswered. Previous palaeogenomic analyses from remains from adjacent regions have suggested that two main routes into Sweden could have been taken by the pioneers, one from the SW through modern-day Denmark and Norway, and one from the east via Finland. However, no direct genetic evidence from the pioneers of northern Sweden exists. Modern technology has provided the ancient DNA field with an updated toolbox that could allow for novel approaches for revealing the origin and genetic profiles of the first Scandinavians, of which sedimentary ancient DNA (sedaDNA) is well placed. Lake sediments are now a routine source of sedaDNA that have been used to record environmental changes and detect species that lived in the surrounding lake catchment. This review will provide context and background, a summary of the ground-breaking studies within the field of lacustrine sedaDNA, and relevant methodology to address the scientific questions at hand. We conclude that the field is mature enough to provide insight into the origins and arrival times of the first postglacial humans that migrated into northern Sweden.
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| 2. |
- Salonen, J. Sakari, et al.
(författare)
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Uncovering Holocene climate fluctuations and ancient conifer populations : Insights from a high-resolution multi-proxy record from Northern Finland
- 2024
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Ingår i: Global and Planetary Change. - 0921-8181 .- 1872-6364. ; 237
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Tidskriftsartikel (refereegranskat)abstract
- A series of abrupt climate events linked to circum-North Atlantic meltwater forcing have been recognised in Holocene paleoclimate data. To address the paucity of proxy records able to characterise robustly the regional impacts of these events, we retrieved a sub-centennial resolution, well-dated core sequence from Lake Kuutsjarvi, northeast Finland. By analysing a range of paleo-environmental proxies (pollen, plant sedimentary ancient DNA, plant macrofossils, conifer stomata, and non-pollen palynomorphs), and supported with proxy-based paleotemperature and moisture reconstructions, we unravel a well-defined sequence of vegetation and climate dynamics over the early-to-middle Holocene. The birch-dominated pioneer vegetation stage was intersected by two transient tree-cover decrease events at 10.4 and 10.1 thousand years ago (ka), likely representing a two-pronged signal of the 10.3 ka climate event. Our data also show a clear signal of the 8.2 ka climate event, previously not well recorded in the European Arctic, with a collapse of the pine-birch forest and replacement by juniper developing in tight synchrony with Greenland isotopic proxies over 8.4-8.0 ka. Supported by climate modelling, severe winter cooling rather than summer might have been driving vegetation disruptions in the early Holocene. The Kuutsjarvi data indicate an early arrival of Norway spruce (Picea abies) by 9.2 ka (pollen, DNA, and stoma finds), as well as the first evidence for Holocene presence of larch (Larix) in Finland, with pollen finds dating to 9.6-5.9 ka.
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