Late Pleistocene palaeoenvironments and a possible glacial refugium on northern Vancouver Island, Canada: Evidence for the viability of early human settlement on the northwest coast of North America
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Multi-proxy palaeoecological analyses of lake cores from two sites on northern Vancouver Island reveal previously undocumented non-arboreal environments in the region during the late Pleistocene. Radiocarbon, pollen, sedimentary ancient DNA (sedaDNA), diatom, and grain size analyses indicate that Topknot Lake on the west coast of northern Vancouver Island was not glaciated in the last 18,500 years, extending into the hypothesized regional glacial maximum. A cold herb-shrub coastal tundra existed at the site from ca. 17,500–16,000 cal BP with species including willows (Salix), grasses (Poaceae), sedges (Cyperaceae), heathers (Ericaceae), and sagebrush (Artemisia). SedaDNA analysis also supports the presence of rare non-arboreal taxa at Topknot Lake during this interval including Jacob's-ladder (Polemonium), bistort (Bistorta), and wild berries (Rubus). After ca. 16,000 cal BP and through the terminal Pleistocene, pine (Pinus), alder (Alnus), and ferns formed open forests under cool and dry conditions. At Little Woss Lake in the mountains of north-central Vancouver Island, fir (Abies) stands dominated from ca. 14,200–14,100 cal BP, then were replaced by open pine woodland with alder and ferns from ca. 14,100–12,000 cal BP. SedaDNA corroborates these plant taxa as well as indicating grizzly bear (Ursus arctos horribilis) and Chinook salmon (Oncorhynchus tshawytscha) in and around the basin by ca. 14,100 cal BP. Mixed conifer forests of pine, western hemlock (Tsuga heterophylla), and alder spread into the island's interior ca. 12,000–11,100 cal BP during the Pleistocene-Holocene transition. The records from these two lakes demonstrate the diachronous development of postglacial ecosystems on northern Vancouver Island. Furthermore, these data provide key evidence for environments that could have supported human populations on the northwest coast of North America for several millennia during the terminal Pleistocene.
|Quaternary Science Reviews
|Udgivet - 2022
Funding for this research was provided by a SSHRC CGS-M scholarship to C. Hebda and by grants from the Tula Foundation and the University of Victoria to D. McLaren and C. Hebda.
Funding for this research was provided by a SSHRC CGS-M scholarship to C. Hebda and by grants from the Tula Foundation and the University of Victoria to D. McLaren and C. Hebda.The authors of this study would like to acknowledge the Kwakwa? ka? ?wakw peoples, including the Quatsino and the ?Namgis, on whose territories this research was conducted and without whose interest and support it would not have been possible. Financial and logistical support were provided by the Tula Foundation/Hakai Institute and the anthropology department at the University of Victoria. Additional laboratory facilities were provided by Natural Resources Canada at the Pacific Forestry Centre in Victoria, Canada, and by the Lundbeck Foundation GeoGenetics Centre at the University of Copenhagen, Denmark. In particular, we would like to thank E. Peterson and C. Munck at the Tula Foundation; J. Belanger, C. Rzeplinski, U. Muller, and V. Pospelova at the University of Victoria; N. Conder and T. Holmes at the Pacific Forestry Centre; R. W. Mathewes at Simon Fraser University; and J. Stafford, J. Maxwell, J. White, A. Dyck, C. Abbott, A. Gauvreau, L. Dixon, J. McSporran, T. Wallas, and D. Wall for assistance with fieldwork, labwork, and helpful discussions. We would also like to thank Alwynne B. Beaudoin and one anonymous reviewer for their thoughts and suggestions which have helped to improve this manuscript.
© 2022 The Authors
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