The detailed palaeoecology of a mid‐Wisconsinan interstadial (ca. 32 000 14C a BP) vegetation surface from interior Alaska |
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| Authors: | Matthew J Wooller Grant D Zazula Misha Blinnikov Benjamin V Gaglioti Nancy H Bigelow Paul Sanborn Svetlana Kuzmina Catherine La Farge |
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| Institution: | 1. Alaska Stable Isotope Facility, Water and Environmental Research Center and School of Fisheries and Ocean Sciences, University of Alaska, Fairbanks, Alaska, USA;2. Yukon Government Department of Tourism and Culture, Yukon Palaeontology Program, Whitehorse, Yukon Territory, Canada;3. Department of Geography, St Cloud State University, Minnesota, USA;4. Department of Biology and Wildlife, University of Alaska, Fairbanks, Alaska, USA;5. Alaska Quaternary Center, University of Alaska, Fairbanks, Fairbanks, Alaska USA;6. Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, British Columbia, Canada;7. Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada;8. Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada |
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| Abstract: | We present a multi‐proxy reconstruction from a well‐preserved vegetation surface (ca. 32 000 14C a BP) from the Fox Permafrost tunnel near Fairbanks, Alaska. A thick litter layer of plant material on the vegetation surface is consistent with the vegetation lacking evidence of disturbance. Plant macrofossils and graminoid cuticle analysis show the presence of a graminoid assemblage consistent with phytolith data. The pollen data indicate that trees were not local to the site and that Artemisia sp. was present in the region. The insect and bryophyte reconstructions are consistent with the vascular plant reconstruction, indicating the site was at least periodically wet. δ13C values from the graminoids present show a large range encompassing both the wet and dry range displayed by modern graminoids in Alaska. Sequential δ13C analyses conducted along the length of leaves attached to the vegetation surface indicate a seasonal shift towards relatively higher water use efficiency. The lower water use efficiency earlier in the growing season may have stemmed from the use of winter season meltwater by plants at the site – a scenario consistent with the site's cryostratigraphy. Our multi‐proxy reconstruction contributes to the limited palaeoecological data available for graminoid‐dominated vegetation present in Eastern Beringia and particularly the interior of Alaska during the mid‐Wisconsinan interstadial. Copyright © 2011 John Wiley & Sons, Ltd. |
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| Keywords: | grass cuticles carbon isotopes Beringia |
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