Trajectories of Change: How Climate, Wildfire, and Management Drive Shrubland Ecosystem Transitions

A change in wildfire regimes and the expansion of invasive grasses are degrading sagebrush ecosystems, altering wildlife habitats, and threatening property and human livelihoods. In response, land managers often treat large areas of land with fuel reduction or post-fire seeding treatments in an attempt to reduce these risks. However, the trajectories of ecosystem change following treatment are inconsistent across the sagebrush steppe. In some places, treatments are successful, leading to a decrease in invasive grasses which allows native plants to recover. In other places, treatments either have no effect or they facilitate the spread of invasive grasses. Under some climate conditions, native grasses and forbs do well following a fire while sagebrush has difficulty establishing. As the climate becomes warmer and drier, there is an urgent need to understand the drivers of invasive species establishment and sagebrush repopulation, so that management efforts can focus on the most vulnerable areas and the types of treatment that are likely to have the most success.

This project will use data from field studies and satellite imagery to identify vegetation transitions and pair them with on-site information about disturbances, management treatments, and climate drivers. This analysis will determine which climate drivers (i.e., drought, precipitation, temperatures, etc.), disturbances (wildfire), and management treatments (fuels reduction and seeding) will result in the most favorable ecosystem conditions to reestablish sagebrush communities. The researchers will also model landscape changes under projected climate scenarios to identify areas most vulnerable in the future. The results from this research will inform land managers and decision-makers in prioritizing their efforts for today’s climate, as well as develop adaptation strategies for future climate conditions. Understanding the combined impacts of climate drivers, disturbances, and management on sagebrush steppe ecosystems will strengthen our ability to ensure they continue to provide important ecosystem services, such as maintaining water resources, creating wildlife habitat, and enhancing human social and economic well-being.