Evaluating the Efficacy of Targeted Cattle Grazing for Fuel Break Creation and Maintenance

Abstract

Invasive and highly flammable annual grasses continue to alter wildfire regimes across rangelands of the western United States. These hazardous fuels have contributed to the increasing prevalence of western megafires in recent decades. It is clear that existing rangeland fuel management strategies are challenged to keep pace with this growing threat. Targeted livestock grazing, however, might serve as a novel and effective fuels management tool that could be wielded at a scale commensurate with the annual grass–wildfire problem. Unfortunately, this practice has lacked a rigorous scientific foundation to support broad-scale application and decision making. We evaluated the efficacy of targeted beef cattle grazing, applied during the spring, for reducing herbaceous fuel heights, loads, and continuity while maintaining ecosystem health in fuel breaks strategically positioned between invaded, fire-prone landscapes and wildland-urban interface, greater sage-grouse (Centrocercus urophasianus) habitat, and other critical resources threatened by wildfire damage. Our broad-scale experiment was conducted during 2017–2021 as three replicate research projects distributed across the northern Great Basin of Idaho, Nevada, and Oregon. We found targeted grazing in spring reduced total herbaceous and cheatgrass fuel heights and, in some cases, total 1-h and cheatgrass fuels loads and fuel continuity, while producing no consistent adverse effects or trends in ecosystem health within the fuel break treatments relative to nominally grazed controls. One targeted grazed fuel break in this research successfully intercepted three wildfires in 4 yr conserving sage-grouse habitat downwind. Although additional research is required, these findings suggest targeted grazing provides an effective means of reducing fine fuels while avoiding adverse ecosystem impacts. Some expected outcomes from the use of this tool would be improved wildland firefighting safety and efficacy, reduced wildfire size, and enhanced protection of human lives, property, and critical natural and cultural resources within the broad scope of annual grass-wildfire problem.