Facilitating cheatgrass (Bromus tectorum) fuels reduction: what defines a resistant plant community

Authors: Harmon, Daniel - Dan; Clements, Darin - Charlie; Blank, Robert - Bob

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/26/2018
Publication Date: 2/10/2019
Citation: Harmon, D.N., Clements, D.D., Blank, R.R. 2019. Facilitating cheatgrass (Bromus tectorum) fuels reduction: what defines a resistant plant community. Society for Range Management Meeting Abstracts. 72:111.

Interpretive Summary:

Technical Abstract: The Martin fire near Paradise Nevada burned over 439,000 acres in less than a week during July 2018. This was the single largest fire recorded in Nevada history. The ease to which fires start and spread can largely be attributed to cheatgrass fine fuels. Managing cheatgrass to prevent habitat loss is critical for the survival of native plants, wildlife and domestic animal industries. The best means to suppress cheatgrass is a long-lived perennial grass. This intuitive concept now termed “resistance” involves many questions such as which species exhibit the greatest suppression effect or what environmental factors affect suppression. We present results from three experiments to examine these questions. First experiment focused on establishment potential of native and introduced grasses and cheatgrass “resistance”. Second focused on environmental factors that may affect cheatgrass suppression from year to year. A third experiment measured the ability of grass species to compete for soil resources. Results found that effective cheatgrass control using herbicides was required to establish native grasses compared to introduced grasses. Within 3 years of establishment introduced grasses suppressed cheatgrass fuels by 94% compared to native grasses 72%. Environmental factors found to effect suppression were; increased precipitation and cheatgrass litter which both decreased suppression. We found that four of nine grasses significantly depleted soil moisture and nitrogen. Of the four, two species established during the first experiment crested wheatgrass and blue bunch wheatgrass reduced soil nitrogen by close to 75% and soil moisture by 50%. Resource depletion by perennial grass is a suppression mechanism and differs by species making some species ineffective and some highly effective for fuels reductions. Competition for resources is the means by which resistance can be defined. In order to facilitate resistance perennial plants must have the potential to establish and persist.