How will a Changing Climate Affect the Landscape-scale Competition between Perennial Grass, Exotic Annual Grass and Sagebrush after Fire?

Sagebrush along the Columbia River

Widespread exotic annual grass invasion of western sage-steppe communities has resulted in increased fire, intensity, size and frequency. Regeneration of landscapes post-fire involves competition among sagebrush, exotic annual grass and perennial bunchgrasses (which are often seeded to prevent invasion/reinvasion of exotic annual grass), and these interactions are moderated by seasonal weather patterns. Climate change may shift future weather patterns, particularly winter precipitation and growing season temperature, in ways that have the potential to alter the species interactions in post-fire systems. Previous projections of sagebrush or exotic annual grass distributions under climate change scenarios have failed to consider species interactions, potentially rendering these projections inaccurate.

This research will seek to quantify how variability in temperature and precipitation influences the landscape-scale post-fire interactions among sagebrush, exotic annual grass and perennial bunchgrass and will project changes anticipated under future climate scenarios. The results will help land managers anticipate the likelihood of success for rehabilitation treatments given changing climate.