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dc.contributor.authorClarke, Charlotte L.
dc.contributor.authorHeintzman, Peter D.
dc.contributor.authorLammers, Youri
dc.contributor.authorMonteath, Alistair J.
dc.contributor.authorBigelow, Nancy H.
dc.contributor.authorReuther, Joshua D.
dc.contributor.authorPotter, Ben A.
dc.contributor.authorHughes, Paul D.M.
dc.contributor.authorAlsos, Inger Greve
dc.contributor.authorEdwards, Mary Elizabeth
dc.date.accessioned2024-08-21T07:44:59Z
dc.date.available2024-08-21T07:44:59Z
dc.date.issued2024-05-16
dc.description.abstractWhen tracing vegetation dynamics over long timescales, obtaining enough floristic information to gain a detailed understanding of past communities and their transitions can be challenging. The first high-resolution sedimentary DNA (sedaDNA) metabarcoding record from lake sediments in Alaska—reported here—covers nearly 15,000 years of change. It shows in unprecedented detail the composition of late-Pleistocene “steppe-tundra” vegetation of ice-free Alaska, part of an intriguing late-Quaternary “no-analogue” biome, and it covers the subsequent changes that led to the development of modern spruce-dominated boreal forest. The site (Chisholm Lake) lies close to key archaeological sites, and the record throws new light on the landscape and resources available to early humans. Initially, vegetation was dominated by forbs found in modern tundra and/or subarctic steppe vegetation (e.g., <i>Potentilla, Draba, Eritrichium, Anemone patens</i>), and graminoids (e.g., <i>Bromus pumpellianus, Festuca, Calamagrostis, Puccinellia</i>), with <i>Salix</i> the only prominent woody taxon. Predominantly xeric, warm-to-cold habitats are indicated, and we explain the mixed ecological preferences of the fossil assemblages as a topo-mosaic strongly affected by insolation load. At ca. 14,500 cal yr BP (calendar years before C.E. 1950), about the same time as well documented human arrivals and coincident with an increase in effective moisture, <i>Betula</i> expanded. Graminoids became less abundant, but many open-ground forb taxa persisted. This woody-herbaceous mosaic is compatible with the observed persistence of Pleistocene megafaunal species (animals weighing ≥44 kg)—important resources for early humans. The greatest taxonomic turnover, marking a transition to regional woodland and a further moisture increase, began ca. 11,000 cal yr BP when <i>Populus</i> expanded, along with new shrub taxa (e.g., <i>Shepherdia, Eleagnus, Rubus, Viburnum</i>). <i>Picea</i> then expanded ca. 9500 cal yr BP, along with shrub and forb taxa typical of evergreen boreal woodland (e.g., <i>Spiraea, Cornus, Linnaea</i>). We found no evidence for <i>Picea</i> in the late Pleistocene, however. Most taxa present today were established by ca. 5000 cal yr BP after almost complete taxonomic turnover since the start of the record (though <i>Larix</i> appeared only at ca. 1500 cal yr BP). Prominent fluctuations in aquatic communities ca. 14,000–9,500 cal yr BP are probably related to lake-level fluctuations prior to the lake reaching its high, near-modern depth ca. 8,000 cal yr BP.en_US
dc.identifier.citationClarke, Heintzman, Lammers, Monteath, Bigelow, Reuther, Potter, Hughes, Alsos, Edwards. Steppe-tundra composition and deglacial floristic turnover in interior Alaska revealed by sedimentary ancient DNA (sedaDNA). Quaternary Science Reviews. 2024;334en_US
dc.identifier.cristinIDFRIDAID 2271341
dc.identifier.doi10.1016/j.quascirev.2024.108672
dc.identifier.issn0277-3791
dc.identifier.issn1873-457X
dc.identifier.urihttps://hdl.handle.net/10037/34305
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalQuaternary Science Reviews
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2024 The Author(s)en_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0en_US
dc.rightsAttribution 4.0 International (CC BY 4.0)en_US
dc.titleSteppe-tundra composition and deglacial floristic turnover in interior Alaska revealed by sedimentary ancient DNA (sedaDNA)en_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US


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Attribution 4.0 International (CC BY 4.0)
Med mindre det står noe annet, er denne innførselens lisens beskrevet som Attribution 4.0 International (CC BY 4.0)