HIK, D.S.; Biological Sciences, University of Alberta, Edmonton: The future of biology in the Canadian Arctic: the view from the St. Elias Mountains, Yukon.

For the past decade it has been apparent that ecosystems in northern Canada are changing in response to a variety of disturbances, including climate warming, bioaccumulation of pollutants, and increased industrial activity. There is still uncertainty about the magnitude of these effects, and the scientific capacity within Canada to properly understand northern ecosystems through research and monitoring efforts is largely insufficient. I will discuss several options for rebuilding this capacity, using examples from long-term research programs in the St. Elias Mountains, Yukon. The St. Elias Mountains are the major topographic divide between the Pacific and Arctic Ocean basins, and provide a useful model for discussing the future of biology in the Canadian Arctic. Specifically, I will focus on the dynamics of plant-herbivore-climate interactions in alpine ecosystems in the southwest Yukon, with emphasis on three mammalian herbivores: Dall sheep, collared pikas, and hoary marmots. Population dynamics, reproduction and growth of all three species are largely correlated with variation in climate conditions that influence availability and quality of summer forage. Sheep horn growth in particular shows regular periodic variation consistent with known �11-year cycles� in precipitation. Herbivores living in northern alpine environments appear to be well adapted for cold conditions, but consequences of climate warming appear to be lethal for pikas and juvenile marmots, and sublethal for adult marmots and Dall sheep. A better understanding of the consequences of the rapid rate of change in these mountain environments and other parts of the Canadian Arctic requires a renewed commitment to support research in the north.