WWETAC Projects

Project Title: Rapid threat assessment of climate change effects on western bark beetles.

Principal Investigator: Barbara Bentz, , Western Bark Beetle Research Group and USDA Forest Service, Rocky Mountain Research Station (RMRS)

Collaborators: C. Fettig, S. Seybold, J. L. Hayes, (Pacific Southwest Research Station, USDA Forest Service); R. Kelsey, J. Lundquist (Pacific Northwest Research Station);; M. Hansen, A. Lynch, and J. Negron (Rocky Mountain Research Station); J. Hicke, University of Idaho; J. Powell, Utah State University; J. Regniere, Canadian Forest Service

Key Issues/Problems Addressed:

Native bark beetles (Coleoptera: Curculionidae, Scolytinae) have significantly contributed to mortality in billions of trees across millions of forest acres from Alaska to Mexico.  Bark beetle populations are influenced directly and indirectly by the effects of climate change. This project comprehensively reviewed the effects of climate change on western bark beetles.

Setting and Approach:

This project used available beetle information, population models, and climate forecasts to explore responses of two eruptive bark beetle species Dendroctonus rufipennis (Kirby) and Dendroctonus ponderosae (Hopkins). Available knowledge of beetle population ecology was used to describe potential impacts of climate change when little or no data were available on population response to temperature.

Key Findings:

  • Predictions suggest greater success for mountain pine beetle populations than spruce beetles in the short term, however, long-term beetle affects on spruce forests may be greater overall.
  • Using the Intergovernmental Panel on Climate Change A2 emissions scenario and the Canadian Regional Climate Model, results suggest that the probability of mountain pine beetle surviving low temperature induced mortality will increase dramatically by 2030, predominately at high elevations and in forests that previously experienced cool temperatures.
  • The likelihood of mountain pine beetle range expansion across Canada and into eastern and central U.S. forests is predicted to be low based on the combination of several models,


Understanding potential temperature effects on bark beetle population success are instrumental in the development/application of future forest resource management practices.


Bentz, B.J., J. Regniere, C. J. Fettig, E. M. Hansen, J. L. Hayes, J. A. Hicke, R. G. Kelsey, J. F. Negron, and S. J. Seybold. 2010. Climate Change and Bark Beetles of the Western United States and Canada: Direct and Indirect Effects BioScience 60(8): 602-613. (PDF, 690KB)

WWETAC Project ID: FY07JB21