丁香园AV

Although no pollen was preserved at Charlie Lake Cave, two palynological studies in nearby regions document a post- glacial sequence leading from open to forested environments. To the northeast, MacDonald's (1987) study of two lakes in the Clear Hills suggests a sparse post-glacial vegetation consisting of deciuous trees and shrubs such as aspen, birch and willow in association with herbs and grasses. Spruce arrived by 10,000 B.P. and was a dominant species by 9800 B.P., and was a major component of a boreal forest somewhat similar to today's northern boreal forest, although with a different species composition. To the southeast, White's (1983) study of the Saddle Hills records a similar early post-glacial vegetation, but both spruce and pine appear as early as 10400 B.P. (White 1983 : 116). Coniferous forests seem to have been established earlier to the south and east of Charlie Lake Cave and at about the same time to the northeast. This would fit the model of spruce forest development lagging behind deglaciation and the draining of glacial lakes.

In fact, most palynological sequences in once glaciated areas situated long a 500 km wide area east of the Rockies show a similar post-glacial sequence of pioneering, colonizing non-coniferous vegetation succeeded by a coniferous forest. It was into this early open environment that the first large mammals and humans migrated at the end of the Pleistocene.