WWETAC Projects

Project Title: A pilot application of ecological risk assessment to the management of landscape change in the Interior Landscape Analysis System (INLAS) project area site, upper Grande Ronde River watershed

Principal Investigators: Wayne G. Landis, Professor; April J. Markiewicz, Assistant Director; Suzanne Anderson and Kimberley Kolb Ayre, Institute of Environmental Toxicology, Huxley College of the Environment, Western Washington University

wayne.landis [at] wwu.edu

Key Issues/Problems Addressed:

The ability to integrate a wide-variety of data into a threat analysis or risk assessment across a broad landscape is an ongoing challenge in forest management. Pilot studies were completed to evaluate the use of risk assessments as a tool to incorporate an array of data and analyze various management scenarios across a broad landscape.

Setting and Approach:

The Relative Risk Model (RRM), and a derivative Bayesian network model using the framework of an ecological risk assessment, were developed and used to evaluate the potential ecological impacts to the habitats and ecological resources resulting from wildfire, grazing, forest management activities and insect outbreaks in a forested landscape in northeastern Oregon.  The study area encompassed 178,000 ha of forest and rangelands in the upper Grande Ronde sub-basin (Interior Northwest Landscape Analysis System, or INLAS).  The model had three tiers of nodes: landscape disturbances, habitats, and the ecological resources or endpoints of interest to land managers.

Key Findings:

  • The model reliably predicted probable risk to habitats and the ecological endpoints from natural and anthropogenic disturbances.
  • Forest management and wildfire were the sources of landscape disturbance that were most likely to transform habitats and impact ecological resources.
  • Of the six habitats, the moist forest (characterized by Douglas fir and grand fir) was found to be at greatest risk of ecological changes from landscape disturbances.
  • The management endpoints or goals with the highest likelihood of impact were maintenance of salmon habitat, hunting opportunities for native ungulates), and restoration of natural fire at historic frequencies.
  • When compared to the Wallowa-Whitman National Forest prioritization of watershed restoration (POWR) analysis, the RRM assessment demonstrated similar results, but with a better accounting for uncertainty. 


Risk assessments were shown to be a viable tool for evaluating/prioritizing management activities by assessing the relative risk and uncertainty of a variety of disturbances across a broad landscape or region. Risk assessments may also be useful for highlighting how management goals may be impacted by disturbances such as wildfires, floods, or active forest management.


Ayre K.K., and W.G. Landis. In press October 2012.  A Bayesian approach to landscape ecological risk assessment applied to the Upper Grande Ronde watershed, Oregon.  Human and Ecological Risk Assessment.

Anderson,  S.A., and W.G. Landis. In press August 2012. A pilot application of regional scale risk assessment to the forestry management of the Upper Grande Ronde watershed, Oregon. Human and Ecological Risk Assessment.