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Tracking late-Quaternary extinctions in interior Alaska using megaherbivore bone remains and dung fungal spores

Published online by Cambridge University Press:  28 April 2020

Keziah J. Conroy ,
Ambroise G. Baker Open the ORCID record for Ambroise G. Baker [Opens in a new window] ,
Vivienne J. Jones ,
Maarten van Hardenbroek ,
Emma J. Hopla ,
Robert Collier ,
Adrian M. Lister  and
Mary E. Edwards
Keziah J. Conroy
Affiliation:
Environmental Change Research Center, Department of Geography, University College London, Gower Street, London, WC1E 6BT Leverhulme Centre for Human Evolutionary Studies, Henry Wellcome Building, Fitzwilliam Street, Cambridge, CB2 1QH
Ambroise G. Baker*
Affiliation:
Environmental Change Research Center, Department of Geography, University College London, Gower Street, London, WC1E 6BT School of Health and Life Science, Teesside University, Middlesbrough, TS1 3BX
Vivienne J. Jones*
Affiliation:
Environmental Change Research Center, Department of Geography, University College London, Gower Street, London, WC1E 6BT
Maarten van Hardenbroek
Affiliation:
Geography and Environment, University of Southampton, Southampton, SO17 1BJ Geography Politics and Sociology, Newcastle University, Newcastle upon Tyne, NE1 7RU
Emma J. Hopla
Affiliation:
Geography and Environment, University of Southampton, Southampton, SO17 1BJ
Robert Collier
Affiliation:
Geography and Environment, University of Southampton, Southampton, SO17 1BJ
Adrian M. Lister
Affiliation:
Department of Earth Sciences, Natural History Museum, London, SW7 5BD
Mary E. Edwards
Affiliation:
Geography and Environment, University of Southampton, Southampton, SO17 1BJ
*
*Corresponding authors at: School of Health and Life Science, Teesside University, Middlesbrough, TS1 3BX (A.G. Baker) and Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London, WC1E 6BT (V.J. Jones). Email addresses: a.baker@tees.ac.uk (A.G. Baker), vivienne.jones@ucl.ac.uk (V.J. Jones).
*Corresponding authors at: School of Health and Life Science, Teesside University, Middlesbrough, TS1 3BX (A.G. Baker) and Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London, WC1E 6BT (V.J. Jones). Email addresses: a.baker@tees.ac.uk (A.G. Baker), vivienne.jones@ucl.ac.uk (V.J. Jones).
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Abstract

One major challenge in the study of late-Quaternary extinctions (LQEs) is providing better estimates of past megafauna abundance. To show how megaherbivore population size varied before and after the last extinctions in interior Alaska, we use both a database of radiocarbon-dated bone remains (spanning 25–0 ka) and spores of the obligate dung fungus, Sporormiella, recovered from radiocarbon-dated lake-sediment cores (spanning 17–0 ka). Bone fossils show that the last stage of LQEs in the region occurred at about 13 ka ago, but the number of megaherbivore bones remains high into the Holocene. Sporormiella abundance also remains high into the Holocene and does not decrease with major vegetation changes recorded by arboreal pollen percentages. At two sites, the interpretation of Sporormiella was enhanced by additional dung fungal spore types (e.g., Sordaria). In contrast to many sites where the last stage of LQEs is marked by a sharp decline in Sporormiella abundance, in interior Alaska our results indicate the continuance of megaherbivore abundance, albeit with a major taxonomic turnover (including Mammuthus and Equus extinction) from predominantly grazing to browsing dietary guilds. This new and robust evidence implies that regional LQEs were not systematically associated with crashes of overall megaherbivore abundance.

Keywords

BeringiaPaleoecologyMegafaunaHerbivoreSporormiellaSordariaCoprophilous fungal sporesFossilLast glacial maximumTransition
Type
Research Article
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Quaternary Research , Volume 97 , September 2020 , pp. 99 - 110
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Copyright © University of Washington. Published by Cambridge University Press, 2020

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