Another Self Serving Livestock Study Championing Targeted Grazing To Reduce Wildfire

Livestock grazing in the Great Basin has increased cheatgrass, a highly flammable annual grass. Livestock advocates allege targeted grazing can reduce large wildfires. Photo George Wuerthner

A recent publication in the Journal of Rangeland Ecology and Management, “Evaluating the efficacy of targeted cattle grazing for fuel break creation and maintenance,” perpetuates the myth that livestock grazing effectively reduces large wildfires.

Cheatgrass invasion promotes wildfire that is destroying sagebrush steppe ecosystems of the West. Photo George Wuerhner 

Due primarily to climate change and the invasion of the highly flammable alien annual cheatgrass, rangeland In the Great Basin between 2001 and 2021 experienced 40 mega fires that burned across over 3.3 million ha. This change in community structure poses a threat to sagebrush dependent species like sage grouse, pygmy rabbit, and sage sparrow.

The livestock industry continues to ballyhoo grazing as a cost-effective means of containing range fires. Still, as with many self-serving claims by the livestock industry, these assertions ignore many problematic aspects of grazing, its impacts on the ecosystem, and the overall failure of such strategies as an effectual fire control agent.

PROBLEMS WITH THIS STUDY

First, the study compared targeted grazed sites with “nominally grazed controls.” The authors concluded that targeted grazing produced “no consistent adverse effects or trends in ecosystem health within the fuel break treatments.”

In other words, there were no ungrazed control sites for comparison. Livestock grazing has been shown to have numerous impacts on rangelands. So finding no “adverse effects” to ecosystems that are adversely impacted by grazing, in general, is not reassuring.

After four years of study, the treatment areas showed little statistical difference from control sites in their ability to slow or halt wildfire. Cheatgrass’s  height, cover, and soil coverage were similar in both treatments and control sites.

Three small fires did encounter the targeted grazing sites. These fires were suppressed with fire-fighters and air support. Firefighters’ positive anecdotal reports were “evidence” for the effectiveness of targeted grazing. That is hardly “unbiased” science.

The paper also outlines many of the problematic aspects of targeted grazing. It is expensive for the agency and  and few ranchers will commit to it even if the forage is “free.”

A few years ago, I attended a BLM field trip in Idaho to look at targeted grazing and fire breaks. The BLM officials asked the ranchers in attendance if they would be willing to participate in targeted grazing, and without hesitation, all declined. The cost of transporting cows to a specific treatment area and confining cattle to the targeted area, either with electric fencing or cowboys, did not make economic sense to all ranching participants.

Another area for improvement with targeted grazing is that livestock tends to select perennial grasses for consumption over cheatgrass. As a result, if there are desirable native grasses, these tend to be consumed and eliminated first, growing over time to eliminate native plants and increase annual grass cover. All of the treatment areas in this study were heavily infested with cheatgrass.

EFFECTIVENESS OF FUEL BREAKS AND TARGETED GRAZING QUESTIONED

Fuel break in southern Idaho. A review found fuel breaks had many negative impacts on rangeland ecosystems including serving as vectors for cheatgrass invasion. Photo George Wuerthner 

One review of fuel breaks concluded that they (1) directly alter ecosystems, (2) create edges and edge effects, (3) serve as vectors for wildlife movement and plant invasions, (4) fragment otherwise contiguous sagebrush landscapes, thus have questionable utility if all ecological impacts are considered.

Targeted grazing advocates ignore that high winds are responsible for most large fires, and wind-blown embers regularly fly over or around any fuel treatment areas.

In other words, the very fires fuel treatments seek to reduce are the ones that extreme fire weather with its high winds cannot influence. A frequently cited paper about targeted grazing in Arizona admitted as much in the second to last paragraph, where it admitted that targeted grazing failed under extreme fire weather conditions.

Quoting from the paper:

“Targeted grazing treatment did influence fire behavior in grass/shrub communities, but its effects were limited. Although it is a promising tool for altering fire behavior, targeted grazing will be most effective in grass communities under moderate weather conditions.”

WHY CHEATGRASS IS A CONCERN

Relict perrenial grass among nearly continuous cheatgrass. Such situations favor the spread of wildfire. Photo George Wuerhner

The plant in this study targeted for reduction was cheatgrass.

A nearly pure stand of cheatgrass surrounds native sagebrush in northern Nevada. Frequent fires promoted by cheatgrass eliminates sagebrush from the landscape. Photo George Wuerthner 

Cheatgrass, a highly flammable annual grass, has converted much of the West’s rangelands from perennial native plant communities into monocultures of annual grass. A paper looking at long term trends on BLM rangelands “found widespread increases in cover and production of annual grasses and forbs, declines in herbaceous perennial cover.” This is particularly true of the Great Basin regions of Nevada, southeast Oregon, southern Idaho, eastern California, and many parts of Utah.

This has numerous impacts on the ecological stability of rangeland ecosystems. Annual grasses, as the name implies, vary significantly in their yearly biomass production. In wet years they produce lots of grass but in drought years, only some. By contrast, native perennial grasses remain far more constant in overall forage production.

Cheatgrass is also less palatable to native wildlife, insects, and even “fungi,” which decompose grasses.

Cheatgrass tends to “green up” earlier in the season, robbing the native plants of moisture and nutrients.

However, the biggest problem with cheatgrass is that it is highly flammable. It dries out earlier in the summer than native grasses, providing a significant source of readily combustible fuel.

Because it is an annual, and its seeds are somewhat protected from fire impacts in the soil, cheatgrass can burn and revegetate the site the following year.

By contrast, most native plants, including native grasses and sagebrush, historically burned at much longer intervals. Native bunchgrasses may require ten years to recover from a fire, and all species of sagebrush need decades to centuries to achieve complete restoration after a major fire.

Consequently, cheatgrass fires are the biggest threat to the sagebrush steppe across the West. The idea that fuel breaks are effective has been questioned. For instance, a review of fuel breaks concluded: “Fuel breaks were least successful in areas classified as having low resilience to disturbance and low resistance to invasion, in areas composed of primarily woody fuels, and when operating in high temperature and low precipitation conditions.” In short, places favorable to colonization and dominance by cheatgrass are unlikely to benefit from fuel reductions.

HOW CATTLE PROMOTE CHEATGRASS ESTABLISHMENT AND PERSISTENCE

One of the problems that cattle grazing advocates never mention is that cattle use promotes cheatgrass establishment and persistence.

Cattle selectively consume native grasses, ignoring cheatgrass unless no other forage is available. Over time, native grasses must use scarce resources to replace the loss of photosynthetic material (leaves) by transferring energy from roots to new leaves. Over time this reduces the root system of native grasses, so in times of drought, they are less competitive.

Cattle also trample biocrusts. Biocrust, including algae, lichens, moss, and other soil coverings, inhibit the establishment of cheatgrass. However, in places with significant cattle use, biocrust coverage is reduced, enabling cheatgrass to become established.

For instance, a study of cheatgrass found that the “probability of a community transitioning to a cheatgrass state was (1) strongly and positively related to the initial (2007) cover of cheatgrass in hotspots where initial cheatgrass cover was >20%, and (2) negatively related to biocrust cover where the initial biocrust cover was >4% of ground area.

Biocrusts in this ungrazed site cover the soil inbetween sagebrush. Photo George Wuerthner

Another study found: “evidence that biocrusts increase site resistance to invasion at a landscape scale and mediate the effects of disturbance. Biocrust species richness, which is reduced by livestock grazing, also appears to promote native perennial grasses.”

The same thing is true of the creation of “fuel breaks,” which often eliminate all plant cover and soil disturbance, making an ideal medium for cheatgrass colonization.

The paper admits numerous other problems with targeted livestock grazing: “targeted grazing involves concentrated herbivory, trampling, and other intensive actions that could adversely impact rangeland ecosystems.”

Livestock grazing in general, has numerous other negative ecological impacts, including displacing of naïve herbivores, destruction of riparian areas, soil compaction, disease transmission from livestock to wildlife, water pollution, justification for the killing of native predators, and the previously mentioned destruction of biocrust, among many other adverse influences.

SUMMARY

A proposal by the BLM to create 11,000 miles of fuel breaks across the Great Basin, especially when the actual effectiveness of these fuel reductions created by targeted grazing is questionable and poses a significant threat to sagebrush ecosystems.

The study “Evaluating the efficacy of targeted cattle grazing for fuel break creation and maintenance” appears to be another pro-grazing publication using the fear of wildfire to justify the ongoing destruction of rangelands by domestic cattle.

Furthermore, the study ignores the collateral damage from livestock grazing, the nuances of fire ecology, and the inability of limited fuel reductions to influence wildfire during extreme fire weather conditions of drought, high temperature, low humidity, and high winds. Under such conditions, fuel reductions fail; thus, the “cure” of targeted grazing, which promotes disturbance and increase in cheatgrass, is another failed strategy perpetuated by the livestock industry.