SOUTH HILLS — A doe and two fawns walked hesitantly out of the scorched creek. They looked about skittishly for a moment, then scampered across the road and began climbing the black mountainside. The entire canyon appeared colorless and lifeless except for the three mule deer, which gradually faded into small brown dots as they pushed up the mountain in search of food.
“They’re going to have to go a lot farther,” U.S. Forest Service District Wildlife Biologist Scott Soletti said.
The Badger Fire has drastically changed the South Hills for thousands of mule deer and other ungulates — large hooved mammals. The 90,000-acre blaze swept through nearly a third of the entire forest and incinerated some critical habitat. The Badger Fire has changed the landscape for decades, and at the northern end, at low elevation, the land may never recover.
Elk, and perhaps moose, will see their numbers increase.
But mule deer numbers will drop. With their wintering range devastated, next year’s South Hills mule deer population will be determined in large part by weather, which will dictate both the expansion of non-native cheatgrass and the severity of the coming winter. A harsh winter could be devastating for the animals.
“When they come down to their winter range and find that there’s nothing there but charcoal, what are they going to do?” Idaho Department of Fish and Game Regional Wildlife Biologist Jake Powell said. “Where are they going to go at that point?”
Winners and losers
Each of the four undomesticated South Hills ungulate species occupies a separate biological niche.
Pronghorn live in open areas and primarily rely on sagebrush and forbs — think mainly wildflowers that can grow out in the Idaho desert. If forbs bounce back from the Badger Fire somewhat quickly, pronghorn numbers could be OK.
Moose eat a steady diet of willow and aspen. Aspen flourishes after fire, so those trees are likely to boom, much to the benefit of South Hills ungulates. While a fire might kill the trees above the surface, aspen sucker — they grow back from the roots. Willows, primarily found in wet, riparian areas, could take several years to come back, but biologists say the South Hills’ famous and dense moose population could benefit from the Badger Fire overall even if food is harder to find in the immediate future.
Elk are the big winners of the fire. They’re grass grazers.
“There’s going to be so much grass out there,” Idaho Fish and Game Regional Habitat Biologist Brandon Tycz said. “Our elk population — they’re going to be happy for sure.”
Grass will be more plentiful and elk numbers will likely go up after the Badger Fire killed off thousands of acres of shrubs and trees. Elk numbers probably increased after 2012’s Cave Canyon Fire, which burned through nearly 90,000 acres of the South Hills just east of the Badger Fire, removing vast swathes of shrubs and forest.
But mule deer — the South Hills’ most abundant ungulate species — are going to struggle now that the Cave Canyon and Badger fires have burned almost two-thirds of the forest in the last decade.
Mule deer eat some grass, but for the most part, they’re browsers, eating shrubs such as sagebrush and bitterbrush as well as forbs and aspen. In winter, with the higher parts of the South Hills covered in deep snow, mule deer head for the sagebrush steppe on the forest’s lower edges. During the cold months, the animals rely even more heavily on sagebrush and bitterbrush — two species that the Badger Fire removed from roughly 60% of the northern portion of mule deer winter range.
“They’re going to drop down onto winter range and there’s not going to be anything there in areas where they historically wintered,” Soletti said.
Highs and lows
The Badger Fire is a story of two ecosystems: The high elevation, timbered ecosystem and the lower, shrubbier one.
Mule deer spend their summers up high in the South Hills, fattening themselves up so they can make it through the winter. Their summer range, in the long-term, will probably improve because of the Badger Fire. The burn removed old conifers, which have expanded due to long-term fire suppression. Soletti said many subalpine fir stands were due to burn.
Without so many conifers, species beneficial to mule deer will have more room to grow. Forbs could come back quickly, and in time, shrubs and aspen will fill in the upper elevation burn areas. It’ll take a couple of years — decades in many cases — for the sagebrush and shrubs to get established, but biologists predict mule deer will have improved summer habitat.
The fire also didn’t kill everything up top.
“(The Badger Fire) burned in kind of a mosaic,” Tycz said of the higher elevation areas. “When we do see burns, those are the burns that we prefer. This way there’s going to be some litter removed and with that mosaic there’s going to be some seed sources for the future.”
The mosaic burn also ensures ungulates have some islands of habitat remaining in the burn area. A lot of animals are currently living in the islands of vegetation that survived the fire.
The positive impacts of the Badger Fire on mule deer essentially end there.
In the South Hills, mule deer make a relatively short migration down to lower elevation. Large numbers of the animals winter on the north end of the South Hills in the sagebrush steppe. When the snow starts to fly, many of the deer will head north, Tycz said.
There isn’t much mule deer food — sagebrush and bitterbrush — to the north anymore after the Badger Fire.
“The further north you go, man, it nuked it,” Tycz said. “It burned very hot and there are no little islands of sagebrush or grasses or trees. It pretty much is black like asphalt.”
Mule deer have high fidelity to their winter ranges. The animals won’t simply leave the South Hills to find better habitat.
Plus, the fire itself didn’t kill many, or any, mule deer, so this winter the same number of animals are going to be competing for the same finite resource.
“To have the same amount of animals on half as much winter range … yeah, we could have issues,” Powell said.
More mule deer than usual will starve. How many make it through the winter will depend largely on the weather. If it’s a long, cold, harsh winter, mortality will be higher. The weather this fall also plays a role. If there’s enough moisture and some plants start growing, that will provide some forage for mule deer.
The hunt for greenery
With so much of their wintering range destroyed, mule deer are going to search desperately for food.
And they’ll find it.
“One of the issues that we’re kind of worried about is how these animals are going to impact private agriculture around the edge,” Powell said. “The South Hills is essentially an island, it’s surrounded by agriculture.”
With their island devoid of food, mule deer will wander onto ag land. They’ll try to survive on pasture, hay bales, alfalfa and other crops. Because of that, Fish and Game is working with farmers on the South Hills’ edge to come up with a plan to compensate landowners for crop and hay losses. That will ensure more mule deer will make it through the winter.
There will be other conflicts, too.
The South Hills’ road system is notorious. People love driving dirt bikes, ATVs and side-by-sides all throughout the forest. It’s the reason people call the South Hills the Magic Valley’s playground. But all of those roads come with a cost.
“The South Hills … is one of the most highly roaded forests in the maybe the state or the nation,” Powell explained. “Roads and trails impact big game in a variety of ways. They push elk and deer away from those trails into less favorable habitats.”
Ungulates don’t usually tolerate human disturbance well. For instance, if there’s a patch of pristine mule deer habitat, but a road cuts right through it, mule deer will typically avoid that area. They’ll opt for a spot with worse food and inferior hiding places if it means they don’t have to be repeatedly startled by loud engines throughout the day.
Heavy motorized vehicle use can reduce mule deer populations. That’s because traffic can cost mule deer valuable energy.
Mule deer often run for cover when vehicles roar past. Each individual interaction doesn’t necessarily hurt the deer much, but over the course of the year, they could be bumped around hundreds of times. All of that extra running and stress means the deer burn precious calories.
“There are very few large chunks of non-motorized ground in the South Hills,” Powell said. “In places where there are lots of roads, lots of trails, animals have larger home ranges, increased daily movements and oftentimes they are pushed into less favorable habitat. A combination of those things increases the energy expenditure.”
When you’re a wild animal, your ability to survive is often directly correlated to your energy reserves. If people are harassing the deer all year, forcing them into worse habitat and making them burn more energy, the animals are going to be skinnier on average. For a mule deer, being fat is the best way to survive the winter.
Successfully fattening up in the summer is especially important for the younger generations.
“For a fawn mule deer to make it through winter, the most important thing is the weight of that fawn,” Powell said, noting that a fawn’s survival probability is correlated with the health of its mother. “Bigger fawns can survive winter better than smaller fawns.”
Human disturbance has always affected South Hills mule deer, but after the Badger Fire, human activity could have an even greater impact. The fire took out trees and shrubs, which means less food in the nearterm, but it also means the deer are going to have fewer hiding places (as well as fewer places to rest and find shelter). That could potentially make them even jumpier when motorized vehicles pass through.
The animals will already be in poor shape before summer.
“These mule deer, when they come out of winter, are going to be in poor body condition and stress,” Soletti said. “There’s going to be a lack of food because a lot of it’s burned up. They’re going to have to work harder to find food.”
Because of those new stresses, the Forest Service will consider additional road closures, Soletti said. Even small road closures in the South Hills have been met with intense public opposition in the past.
Without road closures, it’s possible Fish and Game might have to scale back mule deer hunting.
“If we can’t provide those chunks of roadless ground, then our only option is to reduce opportunity and that’s cutting tags,” Powell said.
The Forest Service, Bureau of Land Management and Fish and Game are up against one of the West’s biggest environmental nemeses as they try to prevent South Hills mule deer and pronghorn populations from tanking: cheatgrass.
Cheatgrass is a non-native invasive species that starts growing in the fall, giving it a jumpstart on native grass species that start growing in the spring. That advantage allows cheatgrass to cheat native species out of nutrients and moisture.
The invasive is virtually omnipresent in the southern Idaho desert, often taking over the landscape and blanketing the ground in a monoculture of purplish gold. It’s also a prolific seed producer, which helps it reproduce more quickly, and it thrives in disturbed environments.
When a fire comes through and disturbs the ground, cheatgrass is the best prepared to get a foothold. The same is true if an area is disturbed by heavy grazing — cheatgrass gets an advantage.
Cheatgrass doesn’t do native wildlife species much good. For one, few native species like to eat it. And it also burns more readily than native species, partly because it dries out earlier in the year. Cheatgrass means more fire, and every time a fire comes through, the percentage of cheatgrass increases, making another fire even more likely. It’s an unnatural, vicious, environmentally disastrous cycle.
“Maybe there was 30% (cheatgrass in the lower parts of the South Hills) and now we just doubled it or tripled it,” Tycz said. “That is going to be a fight for us.”
At higher elevations, native species can outcompete cheatgrass. The invasive is present up high in the South Hills, but it’s not dominant. Biologists said they’re not worried about cheatgrass expansion up top.
But Soletti and other biologists say of all the biological impacts of the Badger Fire, cheatgrass encroachment is their greatest concern.
Fire is a natural part of the South Hills ecosystem. It isn’t inherently bad. The forest needs fire to be healthy, and over time, the upper elevation areas could grow back.
The same might not be true down low where the timber gives way to steppe and invasive cheatgrass.
“Fire on these lower elevations, it’s bad,” Powell said. “Some of those lower elevations may never recover.”
Soletti explained that the timing of the Badger Fire is rough, from a cheatgrass prevention perspective. The burn area needs to be reseeded, and if the Badger Fire had swept through in July, there would have been ample time this fall for the land management agencies to reseed native grasses and forbs in the burn area. An earlier fire would have meant more time for rainfall, which the seeds need to germinate and get ahead of cheatgrass. Sagebrush will be seeded this winter because the shrub has better success that way.
With the late-season Badger Fire, the Forest Service and BLM have been hustling to get seed on the ground, applying it by plane before snowfall. Ideally, those freshly applied native seeds will have a chance to start growing before they get covered in snow. There’s been some precipitation on those seeds so far, but not spectacular rain.
“We can do everything right,” BLM Burley Field Manager Ken Crane said, “but if Mother Nature doesn’t help us out with a little timely rain (this fall), it’s going to be pretty tough.”
Spring weather conditions and timing will also play a huge role in the success of reseeding efforts. Biologists can’t control the weather, so the effectiveness of reseeding depends on luck. If all goes well this year, cheatgrass won’t infiltrate the South Hills as much. If the weather doesn’t cooperate, cheatgrass could expand much more dramatically.
“Really we’re looking for precipitation late enough or snowmelt that’s late enough that after cheatgrass is on the late stages of its life cycle and it’s setting seed, there’s still soil moisture present for perennial grasses to grow and store carbohydrates in their roots,” Soletti explained.
There are ways to help South Hills mule deer without relying on luck, though. People can make decisions that reduce the amount of stress placed on the animals.
South Hills visitors sometimes illegally drive off-road or ignore seasonal closures. Soletti noted that the Minidoka Ranger District issues more citations for motor vehicle violations than any other district in the Forest Service’s Intermountain Region, which covers Utah, Nevada, southern Idaho, western Wyoming and a portion of eastern California.
Now, with many trees and shrubs gone, it’ll be physically easier for people to illegally drive off-road. That could mean more stress on mule deer, which will need as much quiet, high-quality habitat as they can get.
“Right now, more than ever, it’s going to be important that people abide by the travel management plan and don’t drive cross country,” Soletti said. “That’s something that everyone can do to help mule deer.”
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