Postglacial vegetation community change over an elevational gradient on the western Kenai Peninsula, Alaska: pollen records from Sunken Island and Choquette Lakes

Scott R Anderson, Edward Berg, Chris Williams, Tami Clark

Research output: Contribution to journalArticle

Abstract

The Kenai Peninsula of south-central Alaska is a region of high topographic diversity with a complex glacial history. The sedimentary record of two small lakes [Sunken Island (SIL; 76 m a.s.l.) in the Kenai Lowlands; Choquette (CL; 527 m a.s.l.) in the Caribou Hills upland] exemplifies the postglacial development of the conifer–hardwood forest over an elevational range there. A herb–shrub tundra was established at both sites after deglaciation. By ~10.7 ka, poplar (Populus sp.) and alder (Alnus) dominated the lowland forest, while alder with minor poplar occurred at the upland site. Lake levels lower than today occurred during the early Holocene until ~8 ka. Subsequently at SIL, the near-modern Kenai birch (Betula kenaica) – white spruce (Picea glauca) forest maintained prominence throughout the Holocene. However, at CL, alder dominated with dwarf birch and other subshrubs; small amounts of white spruce arrived ~5.2 ka. Black spruce (Picea mariana) grew around SIL by ~4 ka, but never gained prominence at CL. Fire, a prominent agent of disturbance in the Kenai Lowlands since ~8 ka, was essentially absent at the hardwood-dominated upland site before ~6 ka, and rare thereafter. This suggests an important link between fire and spruce in Kenai forests.

Original languageEnglish (US)
Pages (from-to)309-322
Number of pages14
JournalJournal of Quaternary Science
Volume34
Issue number4-5
DOIs
StatePublished - Jan 1 2019

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Keywords

  • Alaska biogeography
  • fire history
  • Kenai Peninsula
  • paleoecology
  • pollen analysis

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Earth and Planetary Sciences (miscellaneous)
  • Palaeontology

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