Understanding the relationships between native bunchgrass species and invasive cheatgrass is critical for managing sagebrush steppe landscapes post-wildfire. These relationships can vary with environmental factors like weather and elevation, which may favor one species over another.
Does Post-Fire Recovery of Native Grasses in Sagebrush Steppe Match Theoretical Predictions?
USGS researchers used vegetation monitoring data collected after the 2015 Soda wildfire in southern Idaho and Oregon to determine if natural recovery patterns support two concepts: the stress-gradient hypothesis, or SGH, and the resistance and resilience concept, or RRC. Both concepts predict that favorable environmental conditions will help bunchgrasses outcompete cheatgrass, while stressful conditions will accommodate the spread of cheatgrass. Consistent with the SGH, bunchgrasses were generally more abundant than cheatgrass at higher elevations and lower temperatures, conditions that are favorable for native species. Sandberg bluegrass was unique: it appeared to outcompete cheatgrass even in dry conditions. The authors hypothesize that restoration seeding mixes containing both Sandberg bluegrass and bluebunch wheatgrass could provide the best resistance to cheatgrass under a broad range of environmental conditions.
Anthony, C.R., and Germino, M.J., 2023, Does post-fire recovery of native grasses across abiotic-stress and invasive-grass gradients match theoretical predictions, in sagebrush steppe?: Global Ecology & Conservation, v. 42, e02410. https://doi.org/10.1016/j.gecco.2023.e02410