A fossil pollen based reconstruction of the late Quaternary history of lodgepole pine (Pinuscontorta ssp. latifolia) in the western interior of Canada

Abstract

Previous reconstructions of the late Quaternary biogeographical history of lodgepole pine (Pinus contorta Dougl.) have been based upon inferences from the modern geographical distribution of morphological and genetic variation. These studies have led to the widely accepted conclusion that relict populations of the Rocky Mountain subspecies of lodgepole pine (ssp. latifolia Engelm.) persisted in glacial refugia located in northwestern Canada. New fossil pollen evidence of the late Pleistocene and Holocene distribution of lodgepole pine in the western interior of Canada contradicts this view. Pinus contorta ssp. latifolia migrated northward into Canada from refugia located south of the continental glacial limits and did not reach its northern range limits in the southern Yukon until the late Holocene.