Observer file The Zumwalt Prairie is home to 3,500 head of elk. The population has grown from 500 head of elk to the large number of today over 13 years.
The Nature Conservancy manages growing elk numbers on the Zumwalt Prairie
ENTERPRISE — Over the last 13 years the elk population on the Zumwalt Prairie has ballooned from 500 head to 3,500. For the managers of The Nature Conservancy’s Zumwalt Prairie Preserve, keeping elk in balance with the rest of the ecosystem is a multi-level task.
Justin Jones of the Preserve said the elk population isn’t only huge, but there is a distribution problem with higher numbers transitioning to the grasslands.
“The elk population has not only grown, but all indications are that it will remain healthy,” said Jones. “If you look at the number of cows and number of calves, the ratio describes how productive the herd is. The current ratio is 30 or 40 calves to 100 cows.
“An estimate of 23 calves per 100 cows would provide a stable population with the current level of hunter harvest and human influence.”
The Preserve owns 33,000 acres of prairie. Most of its neighbors are cattle ranchers whose cattle compete with the elk for forage. Ranching is Wallowa County’s main industry with approximately 27,000 head of cattle.
The bunchgrass prairie drew settlers here to raise livestock in the 1800s and today it’s still prime real estate for grazing.
“The elk numbers create difficulty in managing grazing pressure on grass,” said Jones. “Any rancher will tell you he is managing grass not just cows — grass is what’s going to allow you to graze cattle. Since you can’t predict where these huge herds are going to be it makes it hard to manage the level of utilization on your pasture lands.”
Besides competition for forage, elk are hard on fences, said Jones.
Repairing and replacing fence is expensive, so the Preserve decides where they need fencing and how to construct it so it’s both elk friendly and not easily destroyed.
“We know we are going to want fences along public roads and property boundaries,” said Jones.
As for construction of fence, he said the most important thing is to have the top wire down to 40 inches or lower, making it easier for the elk to jump over, while having the bottom wire up to 18 inches or higher so the calves can crawl under.
Jones said another way to ease stress on fences is installing pole crossings.
“We put them in where we see heavy elk use,” Jones said. “We see places that look like elk highways, often in swales, where they can travel easily. Another good place for pole crossings is where they go to cross a canyon. Often, their path leads to a watering spot or shelter. We want to put in pole crossings because they are easier to cross than a wildlife-friendly fence and they are better than any sort of barbed wire because they can easily see it.”
Jones said pole crossings may even be better than an open wire gate.
“If they become habituated to seeing a pole crossing, when they are stressed and running and getting pushed, they might head for it. An open wire gate might not be as visible. So far, we can see that the elk are using them.”
Keeping all things in balance is the overarching philosophy of the Preserve and protecting shrub and aspen is another piece of the puzzle. Though elk love the bunchgrass, in the winter, browsing on trees and shrubs supplements their diet.
“We are concerned with the elk impact on aspen and shrub communities. We see them as an important component of the upland prairie ecosystem. They provide nesting habitat for birds and are important food source for a wide variety of wildlife,” said Jones.
He said aspen and shrubs give the prairie structural variation. “All this grassland and then all these isolated spots of shrubs and trees create structural difference and offer different habitat for a variety of wildlife and plants that only occur in those habitats. All of this increases biological diversity.”
Jones said through monitoring it’s been determined that cattle don’t browse on aspen and shrubs like deer and elk do. “We certainly want elk to be a component of the prairie ecology, but the numbers are so high they are currently negatively impacting habitat quality.”
Besides good forage, Jones said the elk may prefer the prairie over the forest because of the numerous stock ponds created over the last 70 years. Before the ponds, there wasn’t much year-round water.
“If you stand on Harsin Butte at dusk you can see the light hitting off dozens of ponds,” said Jones.
Another guess at the elk’s preference for prairie life is warmer winters which Jones said may allow elk to spend more time there browsing on shrubs and aspen.
And yet another assumption is that there may be differences in the canyons that make it less desirable winter habitat. “A higher percentage used to winter in Joseph Creek and Cherry Creek,” said Jones. “Maybe something has changed – predators or motorized vehicles on the national forest?” said Jones.
Keeping an ecosystem in balance includes human influences like ranching and hunting, said Jones.
“There is an intersection of how humans can make a living while being respectful of other living beings across the Zumwalt Prairie. Ranching and bunchgrass prairie are compatible at maintaining an economy along with conserving habitat. In the same vein we see hunting as a human activity that is compatible with a healthy ecological system on the Zumwalt Prairie,” said Jones.
He said hunting is human predation, which not only decreases the population size but it also creates a disturbance that influences the elk’s distribution and therefore reduces their negative impacts.
“It is a tool which allows us to decrease the population, better manage grazing pressure on grass forage for cattle and it provides an opportunity for people to be outside, experience the prairie and have a connection with a beautiful landscape. Hunters have profound respect for both wildlife and landscapes,” said Jones.