Sagebrush steppe ecosystems dominate low-elevation, arid lands east of the Cascade Range and the Northern Great Basin. They are ecologically, culturally and economically important to human communities living within these systems. Fire is an important and natural part of this ecosystem that maintains a mosaic of diverse habitat types that in turn support more biological diversity, including native perennial grasses. Modern stressors, especially climate change, invasive annual grasses, human land use, and their interactions, have altered the fire regime such that fire is now one of the greatest threats to sagebrush steppe. These changes have reduced the natural sagebrush steppe distribution by almost half and continue to threaten what remains. As a result, over 300 species of plants and animals are at risk in the sagebrush ecosystem, as are important ecosystem processes. 

Land managers may use prescribed burning and other management treatments to decrease the probability of large, catastrophic wildfires and to insure a diversity of habitat types. As these actions have the potential to cause further degradation, understanding when and where they can be beneficial is essential for conserving this ecosystem’s biodiversity and ecological functions. In addition to fire impacts in sagebrush steppe landscapes, long-term monitoring in some unburned sites has revealed changes in sagebrush steppe vegetation similar to, but independent of fire, and are likely due to a warming climate.

To lend insight into the contexts in which prescribed burning is beneficial, and to understand the relative impacts of fire versus climate change on native plant communities, Susan is working with the Bureau of Land Management, U. S. Geological Survey and U. S. Department of Agriculture to understand local and regional mechanisms driving change in burned and unburned sagebrush shrublands. They are using a long-term data set from experimental burns that was replicated across the region and allows comparisons of effects such as relative aridity, plant community and soil differences within sites and between sites. They will analyze data on climate variability, site differences, and the interactions of these factors to understand which attributes are most important for determining post-fire plant communities.

This work builds on existing models of vegetation change by providing a quantitative understanding of drivers of change and the important local and regional factors affecting outcomes. Land managers will have access to this information through an open-source journal publication and digital outreach products to inform decisions and predictions related to prescribed burning, post-fire restoration and conservation of this important, endangered ecosystem.