September 24, 2015
It’s been a bad year for wildfires in the Western United States. The drought conditions and high temperatures across much of the region have combined to bring fires that arrived earlier and burned larger than most years.
While the impact on humans is dramatic, many folks are concerned about the impact of these fires on wildlife.
Thanks to the Disney classic Bambi, many Americans carry a distinct image with them of the way animals react to wildfires: thousands of terrified creatures dashing madly for a river as a wall of flames approaches. Unfortunately, this image is hardly accurate.
The truth is that while some animals die—more often as a result of suffocation than from immolation—most wild creatures possess survival skills that help them avoid the fatal consequences of fires.
It’s Best To Fly
Birds have the most obvious advantage—the ability to fly to safe locations when flames appear. The fact that most fires strike during late summer or fall, after breeding season, means that few species of birds still have flightless young or nests to protect.
Unfortunately, some of this year’s fires were so early in the season they were an exception. Because some occurred as early as mid-May, many nests with eggs or young birds were lost.
But Walking Can Keep An Animal Safe Too
Large mammals can usually stay ahead of fires by walking. Even huge blazes seldom move faster than two miles per hour, so these animals can safely flee the advancing flames.
Also, most fires don’t burn evenly across a landscape, and animals can seek refuge in the areas of unburned terrain.
In the 1988 fire that swept across Yellowstone National Park, the confirmed count of large mammals killed, according to one report, was five Bison, one Black Bear, two Moose, four deer, and two hundred forty-five Elk—a surprisingly low body count when you consider the fact that the fire involved almost 1.5 million acres.
It’s Tougher If You’re Not Mobile
Small animals, by contrast, most often seek refuge below ground in burrows or other cavities. Even flightless insects dig their way into the upper soil or humus as the flames pass. The fire may be burning out of control, but the temperature just a few inches below the surface remains unchanged.
One small mammal that doesn’t fare well is the Wood Rat. In forested areas these rodents live in nests made of sticks and other dry vegetation placed just above ground level or low in trees, and these sites are extremely vulnerable to understory fires.
What About Insects?
Invertebrate populations tend to decrease after a fire because eggs, food supplies, and shelter are destroyed. Flying insects are especially vulnerable because they are attracted to fire by heat or smoke and are incinerated in great numbers.
Surface insect populations, such as grasshoppers, also tend to decrease. Other insect populations, especially bark beetles, increase after a fire, as trees damaged or killed provide large amounts of suitable habitat.
Sadly, some of the worst damage associated with fires is caused by human efforts aimed at fire control. Firebreaks created by bulldozers result in more long-term habitat degradation and associated impact on wildlife than the fires themselves. Likewise, fire retardant dropped by aircraft can poison fish and other aquatic creatures.
To make matters worse, the presence of low-flying helicopters, droning bulldozers, and fire crews often confound the efforts of animals trying to escape.
In fact, one report on the Yellowstone fire states that about a hundred of the large mammals listed as killed during the fire died as a result of collisions with fire-fighting vehicles.
Not All The News Is Bad
Yet plants and animals are more resilient and resourceful than most people think. Not only do many creatures survive wildfires, some even thrive in the wake of conflagrations.
In natural conditions, fires burn away tree and shrub seedlings on prairies and other open grasslands. In woodlands and large forests, periodic fires keep sapling trees and shrubs from overcrowding the understory and thereby fueling major conflagrations.
Fires also release necessary minerals into the soil, open the cones on Lodgepole Pines, Giant Sequoias, and several other evergreens, and generally promote good health to the environment.
Image above: Forest fires that reach above the ground and low-lying vegetation to the crowns of trees are among the most destructive of fires.
McKenzie River Reflections