How Wild Herbivores Are Becoming Our Latest Firefighting Allies
As climate change intensifies, scientists are turning to grazing animals as unexpected allies in the fight against wildfires.
As climate change intensifies, transforming landscapes into tinderboxes, scientists are turning to an unexpected ally in the fight against wildfires: large grazing animals. From the hardy Sorraia horses of Portugal to the cattle and goats roaming American rangelands, herbivores are being recognized not just as passive inhabitants of ecosystems, but as active managers that can reshape fire dynamics.
Research has confirmed that catastrophic wildfires with both high economic costs and loss of human life are happening more frequently 2 .
"We live on a flammable planet, and that flammability is increasing."
When we think about wildfire management, our minds typically turn to water bombers, firebreaks, and crews of firefighters. But for millennia, nature has maintained its own fire suppression system in the form of large herbivores.
Herbivores consume the grasses and shrubs that serve as primary fuels for wildfires.
Their movement patterns create natural firebreaks that can slow or stop fire spread.
This ecological interaction creates a self-reinforcing cycle where grazing and fire work together 7 .
Ecosystems were populated by numerous species of megaherbivores—plant-eaters weighing over 2,000 pounds, such as woolly mammoths, ground sloths, and giant rhinoceroses 3 .
With the extinction of most megaherbivores, their ecological roles were partially filled by smaller surviving herbivores and domestic livestock.
Without natural grazing pressure, vegetation patterns changed dramatically, leading to more continuous fuel beds that allowed fires to spread more easily 3 .
To understand how grazing intensity affects fire behavior, researchers conducted a carefully designed experiment in Oregon's native shrub steppe during peak wildfire season 9 .
The researchers established experimental plots with varying grazing intensities:
They measured key fuel characteristics including vegetation cover, height, moisture content, and biomass across these different treatments.
| Grazing Intensity | Effect on Fuel Load | Impact on Ignition Probability | Influence on Fire Spread |
|---|---|---|---|
| Light Grazing | Minimal reduction | Similar to ungrazed areas | No significant reduction |
| Moderate Grazing | Substantial reduction | Significantly reduced | Notably decreased |
| High Grazing | Maximum reduction | Most significantly reduced | Most substantially decreased |
Visual representation of how different grazing intensities affect fire behavior parameters
Implementing grazing as a fire management strategy requires understanding the different roles that various herbivore species can play. Not all grazing is equal—different animals have distinct feeding preferences and ecological impacts.
| Herbivore Type | Primary Feeding Strategy | Key Role in Fire Management | Example Ecosystems |
|---|---|---|---|
| Cattle | Grazers (grasses) | Reduce fine grass fuels | Rangelands, Savannas |
| Goats | Browsers (woody plants) | Reduce shrubby vegetation | Shrublands, Woodlands |
| Horses | Grazers (grasses) | Maintain open grasslands | Grasslands, Valleys |
| European Bison | Mixed feeding | Create habitat heterogeneity | Forests, Woodlands |
| White Rhinos | Grazers (grasses) | Maintain short grass communities | Savannahs |
This approach is defined as "the use of livestock grazing to accomplish defined vegetation or landscape goals" 5 . It involves strategically deploying animals to specific areas at specific times to achieve precise fuel reduction objectives.
"Introducing species for rewilding or other management objectives is complex... The outcomes may not be as simple as the expectation that returning the lost species will restore conditions to what they were."
In northern Portugal, the organization Rewilding Portugal has introduced herds of Sorraia horses and Tauros cattle to the Côa Valley 3 .
"Instead of using machinery to cut vegetation and control fires, we use large herbivores to do that work year-round, for free."
In the Western United States, researchers are taking a more measured approach, conducting detailed studies on how grazing practices affect fire behavior in different ecosystems.
Comparison of fire incidents before and after implementing herbivore grazing programs in different regions
The relationship between grazing and fire risk is not always straightforward.
"If [herbivores'] feeding reduces highly flammable species or overall vegetation, fire risk can decrease—but if grazing encourages the growth of more fire-prone plants, the risk can just as easily increase" 3 .
Implementing widespread grazing programs faces practical hurdles:
Successful rewilding initiatives require not just herbivores, but complete ecosystems including predators.
"When the deer come back, so do the predators... Our work is to promote the conditions to allow them to settle and actually act as a top predator for the whole circle of life" 3 .
As research into herbivore-fire interactions advances, scientists are working to incorporate these natural processes into high-tech fire management tools.
The Fire-BGCv2 model is an ecosystem process model that researchers are developing to simulate how grazing regimes influence fuel dynamics and fire behavior 1 .
This represents a significant advance beyond current Landscape Fire Succession Models (LFSMs), which "are not able to account for influences that large grazing herbivores have on succession and fuel dynamics" 1 .
This integrated approach will help land managers understand how grazing interacts with other disturbance agents like fire suppression and fuels management under different climate warming scenarios 1 .
The research aims to "articulate interactions between grazing regimes and the regimes of other agents, and clarify the extent to which variance in grazing should modify strategic LFSM projections" for fuel dynamics and fire regimes 1 .
| Research Area | Current Status | Future Needs |
|---|---|---|
| Grazing in Fire Models | Limited incorporation of grazing effects | Integration into next-generation models like Fire-BGCv2 |
| Multiple Herbivore Systems | Understanding of single-species effects | Research on mixed-species grazing impacts |
| Climate Interactions | Recognition of climate as a factor | Detailed projections under various warming scenarios |
| Economic Analysis | Anecdotal cost-benefit accounts | Rigorous analysis of cost-effectiveness compared to conventional methods |
"We've predisposed fire to occur under the most extreme conditions, where there's lots of fuel, on the worst possible days. That leads to catastrophic, uncontrollable fires."
The emerging science of herbivore-driven fire management represents more than just a new tool—it signifies a fundamental shift in how we relate to both fire and the natural world.
For decades, the dominant approach has been fire suppression, attempting to eliminate fire from landscapes entirely. The recognition that this approach has often worsened fire risk by allowing fuels to accumulate has led to a more nuanced understanding of fire as a natural ecological process.
Now, we're beginning to see herbivores not simply as agricultural commodities or wildlife to be conserved, but as active partners in landscape management. As we face a future where climate change is amplifying wildland fire activity , and where catastrophic wildfires are becoming more frequent and costly 2 , we need to employ every available strategy.
The path forward won't be simple. It will require continued research, adaptive management, and collaboration across disciplines and stakeholders. But by learning from both modern science and prehistoric ecosystems, we may discover that some of our most powerful allies in creating fire-resilient landscapes have been waiting in plain sight all along—grazing peacefully in fields and forests, their quiet movements shaping the land in ways that make it safer for all.