Objectives

Wildland fire combines with other factors to maintain — and at times transform — sagebrush steppe ecosystems in western North America.  Changes in livestock management in the area where the Murphy Complex burned had prompted questions about possible relationships between livestock grazing practices and the extent and intensity of wildfires.  Specifically, could grazing be used to reduce the amount of wildfire fuel in an area, and thereby reduce the extent or intensity of fires while still maintaining other resource values?

The research team formulated three objectives in answering this question:

• Formulate preliminary observations about the effects, if any, that the vegetation mixes and grazing management in place before the fires had on how the fires behaved and spread.

• Recommend further studies and research needed to address remaining questions about the potential for using livestock to reduce fuels while also maintaining other resource values.

• Discuss how the study's findings might be applied in other areas.

The team also considered what kinds of vegetation were present on the lands burned in the fires and were therefore available as fuels at the time of ignition.   Vegetation in the Complex area included sagebrush with a native grass understory, grasslands seeded with introduced grasses (crested wheatgrass), and various shrublands and woodlands. Less than five percent (<5%) of the burned area was dominated by invasive non-native vegetation such as cheatgrass or medusahead.

Findings

§  Under the extreme weather and fuel conditions in the Murphy Complex, grazing levels probably had little effect on the fires' behavior.

§   Modeling suggests that in more moderate conditions, grazing can reduce the rate of spread and the intensity of fires (more so in grasslands than in shrublands).

§   Livestock grazing that reduces annual carry-over of dead herbaceous fuels in grasslands can reduce rate of spread and fireline intensity.

§   Contrast lines observed in the Complex were mostly due to distinct changes in the types or amounts of pre-fire vegetation, as shown at left, where a distinct contrast is visible between an area dominated by big sagebrush and an adjacent area previously seeded with crested wheatgrass.  In a few cases, grazing was the distinct variable across a contrast line.

Recommendations for Resource Management

The report recommends that a team of specialists and scientists create one or more carefully planned, targeted, intensively monitored pilot projects large enough (i.e., landscape scale) to evaluate management opportunities and ecological implications.

A general technical guide should be developed based on existing research and field examples of how livestock grazing influences, the extent, severity and intensity of wildland fires.  This guide would be a platform for creating pilot projects and other opportunities for targeted grazing, for considering possible changes to existing grazing plans, and for evaluating the effects of grazing on recent and future fires.

Finally, the team recommends continued research and monitoring of the ecosystem effects of the Murphy Complex fires to gain additional insights to guide future management decisions in this ecosystem and others like it.

Recommendations for Further Research

Addtional research tools are needed to analyze more thoroughly the interactions among grazing, vegetation and fire behavior in sagebrush steppe ecosystems.

The concept of burn severity as developed for forests has somewhat limited values for shrublands and grasslands, and should be refined for evaluating fire behavior in non-forested environments.

New fire behavior models are needed to better reflect actual behavior in multi-layered sagebrush steppe and in more-extreme conditions.

Remote sensing technology to assess fuels in sage steppe and to detect the influence of grazing at landscape scales is needed to support further use of grazing as a fuel management tool.