Using Virtual Fencing to Create Fuel Breaks in the Sagebrush Steppe

Wildfires are increasingly impacting ecosystem processes and ecological services provided by sagebrush rangelands in the western United States. Mitigating this problem involves actions taken before, during, and after fire. In recent years, there has been increased emphasis on prefire fuel management, including fuel breaks. Cattle grazing can be used as a tool to manage fine fuel loading within fuel breaks; however, spatially focusing grazing impacts inside a linear fuel break is challenging. We evaluated using virtual fencing (VF) technology for concentrating grazing impacts inside a 200-m wide, 3-km long fuel break within a 410-ha pasture in sagebrush steppe. The fuel break was bounded by four 35-m wide virtual fences, each consisting of boundaries for auditory (10-m wide) and electrical cues (25-m wide), and a traditional 5-strand barbed wire perimeter fence delineated the pasture perimeter. In June 2021 we introduced 16 dry cows and 23 cow/calf pairs into the fuel break following a 5-d VF training period; cattle were removed after 30 d. Cows were fitted with VF collars (calves not collared) that use Global Positioning System positioning to contain cattle inside fuel break boundaries and record animal locations at 5-min intervals. End-of-trial forage utilization was 48.5% +/- 3.7% and 5.5% +/- 0.7% for areas inside and outside of the fuel break, respectively. Daily percentage of cattle locations inside the fuel break was initially > 94% but declined to approximately 75% by the end of the trial. Percentage daily locations of dry cows and cow/calf pairs inside the fuel break was 98.5% +/- 0.5% and 80.6% +/- 1.1%, respectively (P < 0.001). Our data suggest virtual fencing can be a highly effective method of concentrating grazing to reduce herbaceous fuel biomass within linear fuel breaks. Efficacy of this method could be substantially impacted by use of dry versus cow/calf pairs.