Ecological Disturbance

  • Donald McKenzie


Disturbances are the chief cause of ecosystem change across much of the West. The important disturbances on the mountain landscape are wildfire, insect outbreaks, windstorms, and avalanches and landslides. I define disturbance a “relatively discrete event in space and time”, and discuss how different disturbances may change in a warming West. Much has been made of predicted increases in wildfire extent and severity, but strong negative feedbacks, such as diminishing available vegetation (fuel), may offset the projected increases. Warmer and drier is better for most insects, and some of our most widespread, e.g., bark beetles, could be big winners in that outbreaks may be more extensive. Projecting changes in avalanches is uncertain because snow dynamics are complex and local changes in layer formation could increase or decrease stability. The principal driver of landslides is precipitation, so in regions in which precipitation is projected to increase, landslides may also. Air pollution, in the form of haze and visibility reduction at regional scales and toxic effects of smoke at local scales, is associated with both wildfire and prescribed fire, so changes in air quality will track changes in wildfire.


Fire regime Flammability-limited Fuel-limited Mountain pine beetle Regional haze Landscape disturbance models 

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© Springer Nature Switzerland AG 2020

Authors and Affiliations

  • Donald McKenzie
    • 1
  1. 1.School of Environmental and Forest SciencesUniversity of WashingtonSeattleUSA

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