The role of cheatgrass (bromus tectorum) in Great Basin rangeland rehabilitation

Authors: Clements, Darin; Harmon, Daniel

Submitted to: Society for Range Management Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/2/2022
Publication Date: 2/15/2023
Citation: Clements, D.D., Harmon, D.N. 2023. The role of cheatgrass (bromus tectorum) in Great Basin rangeland rehabilitation. Society for Range Management Meeting Proceedings. 76:64.

Interpretive Summary:

Technical Abstract: Invasion of alien plant species influences many phases of wildland research in the Great Basin. The accidental introduction and subsequent invasion of cheatgrass throughout the Great Basin has led to the conversion of former big sagebrush/bunchgrass communities to cheatgrass dominance. Cheatgrass has revolutionized secondary succession in more arid big sagebrush plant communities by providing a fine-textured, early maturing fuel that increases the chance, rate, spread and season of wildfires. This invasive annual grass truncates secondary succession by largely inhibiting the establishment of perennial seedlings through competition for moisture. Cheatgrass produces many more seeds than are required to sustain the population, while at the same time exhibiting the ability to acquire seed dormancy and build persistent seed banks. As little as 40 cheatgrass seedlings/m² outcompete perennial grass seedlings. Cheatgrass has been a challenge to range research for nearly a century. Predicting the cheatgrass competition using soil seedbank bioassays can dictate if cheatgrass control is required prior to a seeding effort. The best means to manage cheatgrass is by biologically suppressing it with established competitive perennial grasses. Species used in rehabilitation efforts must have the inherent potential to germinate, emerge and establish in these arid environments in the face of cheatgrass competition. Rehabilitation effort must first establish sufficient densities of perennial grasses to achieve cheatgrass suppression, reduce wildfire frequency and allow succession to occur. The degree of cheatgrass control along with climate will dictate the level of perennial grasses establishment and persistence to suppress cheatgrass in the long-term. We will review, through decades of research and experience, effective weed control practices aimed at reducing cheatgrass competition along with plant material testing of perennial grasses and seed mixes aimed at reducing cheatgrass densities and associated fuels to provide sustainable grazing and wildlife resources.