Lessons from 1988
fires in Yellowstone

Game Range Ramblin's


Game Range Articles
by Mike Thompson,
FW&P wildlife biologist,
writing for the Pathfinder

 

 


August 31, 2000
Seeley Swan Pathfinder
Seeley Lake, Montana


by Mike Thompson

Last Friday, I fielded a call from a family in the upper Bitterroot Valley, south of Conner, where no one has escaped the Fires of 2000 without a direct, personal cost.

This family was among the lucky. They lost their barn full of hay, but were able to save their house. Otherwise, their ranch of several hundred acres was burned. With winter coming on, they're buying hay to feed their livestock, and were asking for assistance from Fish, Wildlife & Parks to help protect the stacks from the elk and deer that have already found the small, green oasis around their house.

As the son described the skeletal remains of two wild animals (he thought they were probably deer) that burned on his property, and the incidents of deer that survived the fire, but were burned so badly they had to be destroyed, I grew increasingly dissatisfied with the amount of information I've been able to find so far on the effects of fire on wildlife.

So, I searched for more data on the fires of 1988 in Yellowstone National Park. I dug a little deeper in the library and found a very useful article by Francis J. Singer and others that was published in the November 1989 issue of Bioscience, entitled "Drought, Fires, and Large Mammals."

Why the fascination with Yellowstone in this column, week after week? The explanation is simple. The Yellowstone incident gives us a glimpse at a "worst case" fire scenario in a place where the effects were studied and chronicled. It was in Yellowstone where the nation first came to grips with the possibility that modern fire-fighting techniques may be useless against a true firestorm. I'm guessing that some of the extreme fire phenomena witnessed in Yellowstone in 1988 may apply to this summer's Bitterroot fires. But, as I understand it, our local Spread Ridge-Upper Monture fires are burning at lower intensity, so direct effects on wildlife there would be expected to be less severe.

Let me quote directly from the Bioscience article:

"Immediately after the [Yellowstone] fires began to subside, we surveyed fire-caused large mammal deaths in 15 burned areas where wide, fast-moving fire fronts occurred. Helicopters were used to survey transects 0.4 to 0.6 kilometers apart, and in six of the burned areas an additional 694 kilometers [430 miles] were surveyed by foot and horseback. Trachea and muscle samples were collected to determine whether the animals had died of smoke inhalation."

"A total of 261 large mammals were found dead in the areas of four of the 1988 fires within Yellowstone National Park: 246 elk, 2 moose, 4 mule deer, and 9 bison. This count represents approximately 1 percent of the 31,000 elk summering within YNP and an even lower fraction of the other animals. None of the 68 radio-collared park elk died in the fires. Two radio-collared grizzly bears in the park are believed to have been killed by the fires; the proportion of the grizzly bear population possibly killed is estimated at 0.5-1 percent. An additional 137 large mammals were killed just outside of the park (89 elk, 10 moose, 6 black bear, and 32 mule deer)."

"We suspect the count includes all the large groups of carcasses in the park. The more than 10,000 fire fighters, who accumulated 18,000 flight hours and more than [620 miles] of foot travel reported carcasses. In addition, the large carcass piles were especially noticeable as they were visited by hundreds of scavenger birds and animals. Small groups of one to three carcasses may have gone undetected."

"Groups of carcasses contained 1 to 146 dead elk. Generally, the sizes, sex and age composition, and locations of dead elk were suggestive of typical rutting group aggregations of cows, calves and yearling bulls, with a central harem and several competing large bulls in satellite positions. The only exception was a large group of 146 elk, found clustered in a 20-meter [66-foot] circle, which we speculate consisted of several harem groups that had bunched together in panic."

"Sex and age ratios of the fire-killed elk were 36 calves, 11 yearling bulls, and 63 adult bulls per 100 cows. The calf and yearling bull-to-cow ratios did not depart significantly from the herd ratios as a whole; however, more adult bulls died in the fires than expected based on the herd ratio. Cow-calf groups tend to use more open habitats than bulls do. Therefore, the greater preference for cooler, mature forests on north and east slopes where fires burned faster, and perhaps the solitary nature of mature bull elk in summer, may have made bulls more vulnerable than cow-calf-yearling groups."

"Trachea evidence suggests smoke inhalation killed all or nearly all the fire-killed elk before they were burned by the flames. . . Dense, low-lying smoke was observed in front of several fires at the approximate time of the elk deaths. One group of elk south of the park was killed when caught between the Mink fire and a man-started back burn. Flames burned or singed most of the elk carcasses, especially ears, hooves, teeth, hides, and shattered antlers. The bodies of some suffocated elk in small wet sites, however, were unburned."

"The dead large mammals were all found in sites where sustained wind speeds of [6-12 miles per hour] with gusts to [37 miles per hour] were documented during the fires and where the estimated rates of fire spread were [2.5-4.3 miles per hour]. No large mammal mortality was observed in fires where slower rates of fire spread were estimated and the animals could move out of the way. Fire fronts exceeding [1.24 miles] in width and total fire runs of [4-13 miles] in a day were characteristic of the sites where large mammal mortality occurred."

In my opinion, this information from the Yellowstone fires of 1988 puts our observations from the summer of 2000 in perspective. Although we would not expect to lose a high proportion of our wildlife populations to fire, reports of wildlife burned in the volatile Bitterroot fires would appear to be in line with the Yellowstone experience. We would not expect to lose as many individual animals to the slower moving fires in the Monture Creek drainage.

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