According to Derek Bailey, New Mexico State University (NMSU) rangeland specialist, 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 In some areas, the grasses that fueled normal and periodic low-intensity surface fires in the past have been replaced by densely packed trees and brush that fuel the raging prairie and forest fires seen in recent years, including record-setting 2011 fires in the Southwest.
Bailey, a professor in the Department of Animal and Range Sciences and the director of NMSU's Chihuahuan Desert Rangeland Research Center north of Las Cruces, is among researchers engaged in a three-year study investigating the benefits of targeted grazing by range cattle to significantly reduce the risk of catastrophic wildfires. The project is funded by a $363,000 grant from the USDA Agriculture and Food Research Initiative (AFRI).
Titled "Integrated Approaches for Targeting Cattle Grazing to Improve Ecosystem Services," the project also includes NMSU professor and ag economist Allen Torell; Larry D. Howery, a University of Arizona Extension rangeland specialist; and Maria Fernandez-Gimenez, Colorado State University specialist in the ecological and social dimensions of rangelands.
Their 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 material 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,'" Bailey says. "Our assumption is that moderate levels of grazing can 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."
The targeted grazing approach employed by the researchers at four locations in New Mexico and Arizona involves manually herding cattle into the more rugged and remote areas of fine fuel build-up 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 source.
GPS collars are being used to monitor where the cattle in both the control group situation and the experimental group situation spend their time.
Where the cattle graze and wander is only one element in evaluating the targeted grazing strategy. Researchers must also determine the extent to which the fine fuels are being consumed by cattle and incorporate that data into a computer model.
Bailey says preliminary results suggest the combination of herding and strategic supplement placement can effectively reduce biomass of fine fuels.
"In Arizona, we were able to reduce the abundance of fine fuels in the desired target area by half, even though the site was located in steep, rugged terrain and was almost two miles from water," he says. The research will continue over the next two years at all four study sites to determine if the successes observed thus far can be repeated, he adds.
Torell's role in the project is to examine the economic feasibility of using targeted cattle grazing to manage fine fuels and other potential ecosystem services. He will develop a cost/benefit analysis on whether the costs of herding cattle and providing supplements are offset by the potential benefits of reducing the intensity and rate of spread of wildfires.
Assuming the answer is "yes," the next question is who should bear those additional herding and supplement costs the grazing strategy would entail.
Torell points out that a good portion of the recent economic loss from catastrophic wildfires has been from the destruction of homes owned by people other than ranchers. "This means some type of cost share and incentive program will be needed to promote adoption of the targeted grazing practice if the practice is found to have economic potential," he says.
If targeted grazing is shown to be effective and cost-effective in managing wildfires and their damage, effective communication will be needed to change the behaviors of individuals and organizations responsible for management policy and practices, the researchers say.
Fernandez-Gimenez is assessing how familiar ranchers and public land managers are with the concept of targeted grazing and their level of willingness to incorporate it into their management plans. The information will eventually be used to develop the outreach and Extension portion of the project under the terms of the AFRI grant.