Genetic structure and adaptation at a dynamic range margin

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We are currently in a period of global warming that is having dramatic effects on species distributions worldwide. Geographic expansions of northern range boundaries are occurring for many species, while the range margins at their southern peripheral distribution are impacted by less suitable habitat and increased isolation resulting from anthropogenic activities and increased biotic stress. These distributional changes will have profound effects on biodiversity and ecological processes and require a detailed understanding of the causes and consequences of range shifts at the population level. This project will study flying squirrels (Glaucomys sp.) that have undergone an important "natural experiment" in Ontario. Southern flying squirrels expanded their range by approximately 200 km over a 10-year period, however, in 2003-04, the combined effects of a cold winter and low food caused the population to contract by an equivalent distance in one year. This project will survey any surviving southern flying squirrel populations or hybrid northern x southern flyers that may have been adapted to the acute local climatic event. Candidate adaptive genes potentially involved in thermoregulation that promoted local adaptation to the colder winter at the range front or in any surviving pockets will be characterized. We will also examine the synergistic effects of warming trends and habitat fragmentation on flying squirrels as they expand through the developed Ontario landscape. It will be important over the next few decades to increase our understanding the combined effects of climatic warming and increasingly random harsh weather conditions, such as the 2003-04 Ontario winter, on range expansions and local adaptation in wildlife populations.