Mountain pine beetle and climate change

Conference Paper

Justification

The mountain pine beetle (MPB) (Dendroctonus ponderosae ) is a native insect of pine forests in western North America. While it has a broad geographical distribution, it has been historically confined to the western side of the continent, in the U.S. by the distribution of its pine hosts and in the northern half of British Columbia in western Canada by the geoclimatic barrier of the Rockies. Since the early to mid-1990s, an outbreak of MPB has reached unprecedented levels in terms of acreages and numbers of pine trees, in particular lodgepole pine, killed throughout its range, most notably in Colorado and British Columbia. The MPB is also causing very high mortality among whitebark and limber pines at high elevations. Historical records from the past 100 years suggest these ecosystems have had pulses of MPB-caused mortality but not at levels currently being observed. Since 2006, MPB has extended its range into the Peace River area of north-central Alberta. Climate change may well be involved in this recent northeastward and upward range expansion. There is ample and mounting evidence of similar latitudinal and altitudinal shifts in insect distributions throughout the world, many convincingly linked to climate change. The main concern at this time is the likelihood that this insect will continue spreading east into the pines of Canada’s boreal forest, eventually reaching the eastern provinces and threatening the pines growing on the Atlantic side of the continent all the way into the Southern U.S. Because of this recent incursion at the gates of the Canadian boreal forest, MPB is being viewed as a potential invading species in eastern pine ecosystems. It could be viewed as an invader into the high-elevation whitebark pine ecosystems as well.