Abstract: Mountain pine beetle (Dendroctonus ponderosae) have spread well beyond their historical range in Canada, across the Rocky Mountains and into Alberta. They now threaten further expansion into the boreal forest and across Canada. At the edge of their range in Alberta, mountain pine beetle has shifted from lodgepole pine (Pinus contorta) hosts to genetically distinct lodgepole x jack pine hybrid and jack pine (Pinus banksiana) hosts. These forests represent a change in host quality for mountain pine beetle, and their success in these novel hosts is uncertain. Together with the impacts of climate change on forest health, this changing host resilience causes major uncertainty in predicting long-term dynamics of mountain pine beetle and the risk of further eastward spread in Canada. In this talk, I will present results from a model coupling mountain pine beetle population dynamics with an age-structured model for forest growth. This combination allows us to study long term mountain pine beetle dynamics under different forest resilience scenarios. I will discuss boom-bust scenarios as well as endemic equilibria, driven by a small fraction of low resilience trees, which then seed future outbreaks under climate change. By extending the model to be spatially explicit I will show how the spatiotemporal beetle outbreak dynamics change as they move from lodgepole to jack pine. Overall, the model and its extensions presented here allow us to study long term risks and management consequences as mountain pine beetle spreads across Canada.
