Late pleistocene and holocene paleoecology and biogeography of high elevation flora and glaciation of western Canada

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British Columbia's (BC) rich flora and diverse ecosytems are ascribed to contemporary landscape and climate diversity. This study investigates the possibility that the biotic richness of high-elevation plants originates in part from an incomplete Cordilleran ice sheet at the end of the Pleistocene Epoch. It also examines the character and rates of change in species distributions and high elevation ecosystems during rapid climatic changes, especially warming, from glacial to non-glacial times about 10,000 years ago. Lake and wetland sediment cores and geological exposures will be dated and studied by pollen, macrofossil and charcoal analyses to reconstruct environmental history on Vancouver Island and in north central BC. Vancouver Island has geological evidence that portions of it escaped the last glaciation. North-central BC has strong evidence from the chloroplast DNA of alpine plants for a long ice-free interval. DNA studies will be carried out on alpine species to complement paleoecological studies and link modern plant distributions with glacial history. The results will shed light on the extent and timing of the last ice sheet in western Canada, provide insight into the response of high altitude species to climate warming, and perhaps explain why diverse chloroplast DNA types occur in some BC alpine plant species.