title: Timing and causes of mid-Holocene mammoth extinction on St. Paul Island, Alaska.
abstract: Relict woolly mammoth (Mammuthus primigenius) populations survived on several small Beringian islands for thousands of years after mainland populations went extinct. Here we present multiproxy paleoenvironmental records to investigate the timing, causes, and consequences of mammoth disappearance from St. Paul Island, Alaska. Five independent indicators of extinction show that mammoths survived on St. Paul until 5,600 ± 100 y ago. Vegetation composition remained stable during the extinction window, and there is no evidence of human presence on the island before 1787 CE, suggesting that these factors were not extinction drivers. Instead, the extinction coincided with declining freshwater resources and drier climates between 7,850 and 5,600 y ago, as inferred from sedimentary magnetic susceptibility, oxygen isotopes, and diatom and cladoceran assemblages in a sediment core from a freshwater lake on the island, and stable nitrogen isotopes from mammoth remains. Contrary to other extinction models for the St. Paul mammoth population, this evidence indicates that this mammoth population died out because of the synergistic effects of shrinking island area and freshwater scarcity caused by rising sea levels and regional climate change. Degradation of water quality by intensified mammoth activity around the lake likely exacerbated the situation. The St. Paul mammoth demise is now one of the best-dated prehistoric extinctions, highlighting freshwater limitation as an overlooked extinction driver and underscoring the vulnerability of small island populations to environmental change, even in the absence of human influence.
authors.affiliation: Department of Geosciences, College of Earth and Mineral Sciences, The Pennsylvania State University, University Park, PA 16802; rgraham@ems.psu.edu.
authors.forename: Russell W
authors.initials: RW
authors.lastname: Graham
authors.affiliation: Department of Geosciences, College of Earth and Mineral Sciences, The Pennsylvania State University, University Park, PA 16802; Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ 85721;
authors.forename: Soumaya
authors.initials: S
authors.lastname: Belmecheri
authors.affiliation: Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775;
authors.forename: Kyungcheol
authors.initials: K
authors.lastname: Choy
authors.affiliation: Human Paleoecology and Isotope Geochemistry Laboratory, Department of Anthropology, The Pennsylvania State University, University Park, PA 16802;
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: Culleton
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E3;
authors.forename: Lauren J
authors.initials: LJ
authors.lastname: Davies
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E3;
authors.forename: Duane
authors.identifier: 0000-0003-1032-5944
authors.initials: D
authors.lastname: Froese
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95064;
authors.forename: Peter D
authors.identifier: 0000-0002-6449-0219
authors.initials: PD
authors.lastname: Heintzman
authors.affiliation: AAAS Science and Technology Policy Fellow, National Science Foundation, Arlington, VA 22230;
authors.forename: Carrie
authors.initials: C
authors.lastname: Hritz
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95064;
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Kapp
authors.affiliation: Department of Anthropology, The Pennsylvania State University, University Park, PA 16802; Penn State Institutes of Energy and the Environment, The Pennsylvania State University, University Park, PA 16802;
authors.forename: Lee A
authors.initials: LA
authors.lastname: Newsom
authors.affiliation: Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775;
authors.forename: Ruth
authors.initials: R
authors.lastname: Rawcliffe
authors.affiliation: Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775;
authors.forename: Émilie
authors.initials: É
authors.lastname: Saulnier-Talbot
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95064; UC Santa Cruz Genomics Institute, University of California, Santa Cruz, CA 95064;
authors.forename: Beth
authors.identifier: 0000-0002-2733-7776
authors.initials: B
authors.lastname: Shapiro
authors.affiliation: Department of Geography, University of Wisconsin-Madison, Madison, WI 53706;
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Geography, University of Wisconsin-Madison, Madison, WI 53706; Center for Climatic Research, University of Wisconsin-Madison, Madison, WI 53706;
authors.forename: John W
authors.initials: JW
authors.lastname: Williams
authors.affiliation: Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775; School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Wooller
mesh_terms: D000413:Alaska; D000818:Animals; D053476:Extinction, Biological; D056665:Mammoths / Q000502:physiology*; D013997:Time Factors
keywords: Holocene; St. Paul Island; ancient DNA; extinction; mammoth