To preserve the landscape of the Salmon River Valley in Idaho for future generations, it’s important to control winter annual grasses and noxious weeds. A coordinated effort between federal, state and local agencies is having success controlling and preventing invasive weeds, helping ensure that the land will be viable for big game, ranchers and their livestock, as well as for recreation enthusiasts for years to come.
The area surrounding Idaho’s Salmon River is the largest wildlife landscape in the lower 48 states, and it requires a large, coordinated effort to protect the land from invasive weeds.
Dennis Newman, Regional Wildlife Manager, Salmon Region of Idaho Department of Fish and Game said, “Ours is a unique region. We have nearly every species of big game, and the bulk of the back country in the state. Everything from whitetail and mule deer, elk, moose, mountain goats, pronghorn antelope, bighorn sheep, woodland furbearers, anadromous fish and even wolverines. We have roughly five big game animals per person living in our area.” In addition to this animal life, the area is home to the longest undammed river in the 48 contiguous states, which is filled with numerous fish species. Newman says that this undeveloped landscape and the wildlife it contains is highly sought after by recreationists.
“In Lemhi County, Idaho, 92% to 93% of the public land is held by BLM [Bureau of Land Management] or the Forest Service,” said Katie Baumann, Assistant Program Manager, Botany Invasive Species and Pollinator Program, Salmon Challis National Forest. “It’s high desert, dry, steep and difficult to access. And we see a lot of invasive species there, plus it’s prone to large wildfires.” Diane Schuldt, Program Manager, Botany Invasive Species and Pollinator Program, Salmon Challis National Forest, added, “It’s also a refuge for all kinds of species that are struggling elsewhere. So, our work is conducted with an eye toward how to maintain, enhance and restore all these myriad species.”
“Wildlife populations are cyclical in nature, they ebb and flow,” Newman added. “But populations are highly linked to their habitat, so if something affects one species, it likely affects the rest.” He gives the example of declines in bighorn sheep. “We’ve experienced the majority of the statewide population since the early 1900s and within the region, roughly half of what remained was lost in the last 30 to 40 years,” Newman said. “There are multiple drivers of that, the main ones being disease and habitat. But then you look at elk, and there were hardly any here in the 1800s when Lewis and Clark arrived. Elk populations have since climbed to the current all-time highs. However, deer have experienced the inverse, with large population declines over the last 40 to 50 years. Each of these species has unique habitat needs and the landscape changes are reflected in their population levels.” One factor that has profound impact on animal populations is the availability of healthy forage, a problem that has been compounded by the increasing presence of invasive weed species.
Noxious weeds have been brought into the landscape by human activity. Newman says this was unintentional — weed seeds got carried in on shoes or ATVs — but a lot of the expansion has been caused by fire. This is a fire-prone area, and once the fire burns the vegetation, it’s easier for the weeds to expand.
One of the most problematic weeds he deals with is cheatgrass. Surprisingly, says Newman, cheatgrass isn’t on the noxious weed list because it is no longer economically feasible for most areas to deal with cheatgrass on their own. “At lower elevations, cheatgrass is causing an ecotype conversion of sagebrush habitats that is largely responsible for the decline in sagebrush-obligate species, like sage-grouse. We’re trying to stay ahead of it.”
Newman says they’ve known that weed control is an issue for decades, but they didn’t have quite the right policies or people to handle it until around 2018, when Schuldt got involved and the Forest Service and Idaho Fish and Game began to work together. They looked for solutions to control the cheatgrass while gaining habitat quality.
In the past, Newman says, tools to fight cheatgrass were not user friendly from a habitat perspective. Older options were devastating to forbs, which are important for wildlife, as well as insects, sage-grouse and more. “So, we could kill the cheatgrass, but it would wipe out desirable species,” he said. “There would be no cheatgrass, but we were left with a much less desirable landscape and habitat.
“Where we are now is a lot more exciting,” added Newman. “These treatments are more targeted, more flexible, with minimal negative impact. So, we’re leaving a landscape that is far better. We can do 15,000 acres on one treatment, but the impact is probably more like 750,000 acres because of where the wildlife range. We can move the needle and then we’re not always playing catch-up.”
“The short-term goal is to secure the frontline against cheatgrass, then get to the heart of the infestation and continue to revisit and maintain control action, so it doesn’t recreate itself,” Newman said. “Personally, my end goal is to create a large enough impact to grow more deer, elk and bighorn sheep for my kids and their kids to see.”
“We have learned that community buy-in and education is mission critical,” Newman said about achieving this goal. “We’re treating our public landscape. It’s a public resource.” Schuldt agrees. “You can’t carry a landscape-level program like this without partners. It’s an incredible amount of work, but it’s all worth it.” Baumann also noted the challenge of collaborating. “We can’t win all the hearts and minds,” she said. “In doing new things and working in big groups, you’re not going to please everybody. But our partners rock our world. They have different strengths and can do different things. It’s rewarding to work in a partnership.”
Newman says any opposition they have received has mostly come from a lack of understanding about some of the tactics, such as the need to use herbicides on the land or the use of helicopters. According to Newman, landowners may say, “Why does the government have a helicopter on my landscape? I don’t know what’s going on, I’m not involved, I don’t like it.” He says that’s why you have to involve them in the process. Treatment timing overlaps with hunting seasons here, and that raises concerns about the impact on wildlife. So, you need to involve the hunters and recreationists and get their buy-in.
“Be open and transparent, make sure constituents understand the bigger picture,” he said. “Everyone wants to see more animals and less fire.”
Education is also important. “Most people see cheatgrass and think that’s good for wildlife — it’s grass, but it’s not truly feed for most wildlife. It’s highly unpalatable,” Newman said. “People don’t understand how rangeland landscapes function and how wildlife functions on them. They see the cheatgrass dying and think, ‘Oh, no,’ but then we have bunchgrass and forbs. To an untrained eye, it looks like a decline, but it’s actually an improvement.”
In this area that has been treated with herbicides, you can see the distinct spray line six months after treatment, with untreated cheatgrass (tan) below and the treated area with recovering native bunchgrasses (pale green) above. Photo courtesy of Katie Baumann.
Schuldt says that building a collaborative group helps with funding as well as tactics. “We started looking for multi-agency opportunities to deal with the cheatgrass challenge,” she said. “We’ve had a very active cooperative weed management area for more than 20 years, so they were already active partners, and because we were already cooperating loosely, we got a first chance at a lot of funding opportunities.”
She points to a project they did in 2023 with multiple groups working together, including private landowners. “Some have been partners from the beginning, while others see the benefits and after a few years, they want to be part of it too,” she said. “We’re gaining more of those private landowner partners by the year.” Schuldt says they work by consensus, sitting down every year to determine priorities. They currently have a five-year plan and are working on a ten-year plan.
Cheatgrass is just one of the threats the working group is trying to manage. “Cheatgrass invasion post fire is a big problem, along with spotted knapweed and rush skeletonweed,” Schuldt said. This reduces the diversity of the plant community, which becomes a problem for animal populations like deer and bighorn sheep. Humans introduced invasive plant species like cheatgrass over a century ago, but today, species are invading faster and establishing across the landscape in a wider area. “These threats are building on one another,” Schuldt added. “And when we lose species, we lose resiliency in the landscape and ecosystem, as well as the ability to recover after a fire or landslide.”
It’s important to maintain the resiliency of the landscape not just for plant life, but for animals as well. “We’ve got one of the last genetically original bighorn sheep populations right here where we live,” said Schuldt. “They are struggling to hold on. We want to conserve that population. It matters to people.
“We also lose the integral sense of place with these species,” she added. “People have cultural ties to the land, from Native Americans to those with pioneer ancestry. It impoverishes us as we lose species. People are willing to put money and effort into trying to conserve these herds.”
A number of the nation’s largest wildfires have occurred in the area, and post fire, cheatgrass can become pervasive across the landscape. “It’s like its own wildfire spreading across the landscape,” said Schuldt. “The science has been clear for more than thirty years that non-native invasive species totally change the way fire behaves on these landscapes and it gets increasingly worse until the native species can no longer persist.”
A few years ago, Schuldt and the Forest Service got permission to use newer herbicide active ingredients and helicopters for aerial applications, which has opened the doors to treating more areas. “We asked partners if they’d like to join a working group to try something new, and we did a 1,000-acre pilot project using Milestone on cheatgrass in 2018,” she said.
Baumann says they later used a combination of Milestone® herbicide and imazapic to battle knapweed in addition to cheatgrass. She noted that some partners were worried. “We still have intact native plant communities we wanted to protect. We were worried about putting a helicopter up there. We were concerned about nontarget damage and afraid we’d create more problems than we were solving, and we didn’t want to set the plant community further back.” But Baumann says they need not have worried. “We were blown away by response of the native plant community to the Milestone and imazapic combination,” she said. “It was even better than in the trials. I said, ‘Glory be! It works!’”
“We saw a combined effect nobody was talking about. It worked better together, and we don’t have to use as high of rate because of how well the herbicides work together.”
Baumann says that the very first spring, they saw flowering and the setting of viable seeds from native forbs they didn’t even know were still present in the landscape. She said, “We expected to see a lot of non-target damage and that wasn’t the case. The native community responded strongly within six months post treatment. We thought that would take years to recover. Each place we’ve treated, we see that same positive response. It’s like the native plant community is just waiting to be released.”
Schuldt says the group continues to adapt their weed-control strategies. “We’re changing approaches as we learn. Information from our research stations is changing how we prioritize treatment areas,” she said. “For example, even when cheatgrass only covers five percent in the plant community, that’s enough to cause fire frequency to increase significantly. So, we’re dedicating more resources to treating low levels of cheatgrass.”
Their efforts are paying off, according to Baumann. “Every time we’ve treated, I think we’re gaining a little bit. You’re bringing in healthier native plants and some shrub species are filling in post fire. When native plants are more robust, they do a pretty good job of being resilient to further invasion.” Schuldt added, “Viable seeds were in the soil, and as soon as they had a chance, they were blooming and putting more seeds into the seedbank.”
Native plants, like this cactus, are flourishing six months post treatment. Photo courtesy of Katie Baumann.
Newman is pleased at the progress the agencies and landowners are making together. “This is exciting! We’re creating a more resilient landscape for domestic livestock, a more robust landscape for wildlife and we’re decreasing the risk of wildfire in an area where that’s prevalent. We’re doing all three of those things with one treatment.
“And bringing a multitude of players together where everyone is benefitting — ranchers, land managers, hunters, fishermen. Logistically it’s difficult, but it’s been really wonderful,” he added.
Milestone® has no grazing or haying restrictions for any class of livestock. When treating areas in and around roadside or utility rights-of-way that are or will be grazed, hayed or planted to forage, important label precautions apply regarding harvesting hay from treated sites, using manure from animals grazing on treated areas or rotating the treated area to sensitive crops. See the product label for details. Not all products are registered for use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.
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