Targeted grazing of range cattle may reduce the risk of wildfires like the record-setting 2011 fires in the Southwest, says Derek Bailey, a New Mexico State University (NMSU) range scientist.
Bailey says overgrazing and 20th century fire-suppression strategies have laid the groundwork for some of today's "catastrophic" wildfires. In some areas, the grasses that fueled periodic low-intensity surface fires in the past have been replaced by densely packed trees and brush that fuel bigger fires, he says.
He and other researchers are halfway through a three-year study on the effectiveness and economics of using targeted grazing to reduce fire risks in certain ecosystems. The study is based on the premise that cattle tend to graze unevenly. Their natural tendency is to stay close to water sources, which can lead to deterioration of riparian plant life while leaving an abundance of forage in more rugged areas or areas away from water. In some cases, the neglected forage exacerbates fire danger.
"Behavior of wildfires is affected by the abundance of what we call fine fuels," says Bailey. "Our assumption is that moderate levels of grazing can be used to strategically reduce the levels of fine fuels and correspondingly limit impacts and economic losses of wildfire by reducing fire risk and rates of fire spread and allowing for the establishment of fire barriers."
Targeted grazing is being tested by Bailey and his colleagues at four locations in New Mexico and Arizona. It involves manually herding cattle into the more rugged and remote areas of fine fuel buildup and determining if the availability of forage, along with the strategic positioning of protein supplement blocks, encourages the animals to spend a higher percentage of their time away from the overgrazed areas around their water sources.
GPS collars are being used to monitor where the cattle spend their time. The researchers also need to determine the extent to which the fine fuels are actually being consumed.
To date, the project has been implemented at NMSU's Corona Range and Livestock Research Center in central New Mexico and on a U.S. Forest Service grazing allotment in the Santa Rita Mountains of Arizona. According to Bailey, preliminary results suggest that the combination of herding and strategic supplement placement can effectively reduce biomass of fine fuels. In Arizona, the amount of fine fuels in the target area was reduced by half, even though the site was in steep, rugged terrain and was almost two miles from water.
"We will continue to evaluate targeted grazing over the next two years in all four study sites to determine if the successes observed thus far can be repeated," he says.