ABSTRACT: Paleoecological analyses of lake sediments from Hippa Island, Haida Gwaii (Queen Charlotte Islands), British Columbia.

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Abstract

The vegetation history of the past 14,000 cal yr was reconstructed for Hippa Island, located on the exposed west coast of Haida Gwaii (Queen Charlotte Islands) on the northern British Columbia coast. Pollen analysis was conducted on a 3.55 m sediment core extracted from the island's only lake and five radiocarbon ages obtained on organic-rich sediment were used to develop an age-depth model based on linear interpolation. Hippa Island's vegetation history shares broad similarities to other pollen records from Haida Gwaii and the North Pacific Coast, but the moderating influence of the Pacific Ocean appears to have lessened climate-driven vegetation changes on the island. The vegetation history begins at 14,000 cal yr BP with diverse herb and shrub communities, dominated by Cyperaceae, Artemisia, and Salix. Pinus contorta woodland was present by 13,250 cal yr BP. A decrease in Pinus contorta and minor increases in ferns and herbs coincide with the Younger Dryas cold period; however, these changes are limited in magnitude compared to other sites along the North Pacific Coast. After 11,000 cal yr BP, Pinus contorta woodland is replaced by Picea and Tsuga heterophylla forest with Lysichiton americanum. Stable proportions of most taxa suggest a mild early Holocene on Hippa Island in contrast to research from throughout North America that indicates that the early Holocene was warmer and drier than present. Cupressaceae is present by 6000 cal yr BP, joining Picea and Tsuga heterophylla to form modern mixed forest by 4500 cal yr BP.

Bibliography of Canadian Geomorphology