As of September of 2012, 8.7 million acres have burned in the western United States; 2.6 million acres were in the Great Basin alone. Much of the burned acres were federally managed by the Bureau of Land Management or Forest Service. Many permittees that graze livestock on these public lands will lose their ability to graze for at least the next two years, under the premise that bunchgrasses need rest from grazing to survive and recover after fire.
Rangelands that have been invaded by cheatgrass may have little perennial bunchgrass returning due to subsequent competition with annual invasive weeds. However, cheatgrass will continue to grow each year and increase fine fuel loads; which after two years could easily prime these burned and rested lands for another catastrophic wildfire.
Great Basin ranchers have already experienced this burn-rest phenomenon where allotments have not been grazed for several years, due to the mandates of the BLM or FS, and then burn in years subsequent to rest from grazing.
A new concept, building upon state-and-transition model theory is Disturbance Response Groups (DRGs). DRGs are groups of ecological sites that respond similarly to disturbance with varying rates of responses, but with the same end point. DRGs are important to land managers because they allow management decisions to be applied over a large area, simplifying the complex decision making process in the wake of large fire events.
The objective of this study is to measure plant community responses to no grazing and three different defoliation/grazing treatments after wildfire. By measuring the DRGs scale rather than the ecological site scale, this project will determine the utility and value of DRGs for land management decisions.
Additionally, this project will assess the plant community’s response for a variety of threshold values. Being able to identify threshold triggers will enable managers to make better pre- and post-disturbance decisions.
Understanding the role of grazing after fire in bunchgrass recovery and cheatgrass management will provide land managers with knowledge to promote post-fire recovery, fuels management and subsequently smaller and fewer fires.