The U.S. Forest Service (USFS) has proposed an update to its existing plan to control noxious weeds in the Bighorn National Forest to include aerial spraying, which conservationists say shouldn’t destroy native species for the benefit of livestock grazing.
Bighorn National Forest (BNF) is located in north central Wyoming and comprises 1.1 million acres within the Bighorn Mountain range. BNF stretches 80 miles from the Montana border to south of state Highway 16 and encompasses portions of Sheridan, Washakie, Big Horn and Johnson counties.
USFS states that invasive grasses such as cheatgrass, medusahead and ventenata are threatening or dominating “desired native plant communities, big game winter ranges, sage-grouse habitat, soil and watershed resources, recreation, domestic livestock forage availability and aesthetic values on the BNF.” Additionally, USFS proposed reducing the habitat range of mountain big sagebrush and larkspur to meet desired conditions for wildlife and livestock forage.
The draft environmental impact statement (DEIS) proposes using a combination of control methods, including mechanical methods, prescribed burning, revegetation, livestock grazing and herbicide application using ground-based and aerial applications.
The draft study was conducted to add aerial spraying and is proposed under the preferred alternative under the DEIS. USFS is also considering a “no action” alternative of controlling up to 3,110 acres using current methods and treating up to 5,100 acres without aerial spraying.
Mountain big sagebrush comprises 15 percent of BNF, or 163,000 acres,and the DEIS calls for treating 68,000 total acres—5,100 acres annually—under the preferred alternative. Currently, USFS is treating approximately 591 acres of sagebrush annually using prescribed burns, but the DEIS would also use the herbicide tebuthiuron.
The goal is to “mimic the sagebrush-to-grass/forb historical pre-fire suppression conditions,” the DEIS reads. The DEIS also states some counties have declared larkspur a weed due to its toxicity to livestock.
Another 5,310 acres of invasive grasses would be treated, of which 1,000 acres would be treated by aerial spraying with the herbicides imazapic and indaziflam. The DEIS states, “Northeast Wyoming, specifically Sheridan, Johnson, and Campbell Counties, is the only known location in the northern Great Plains eco-region with medusahead and ventenata. The BNF would be unable to effectively perform its shared stewardship responsibilities if unable to aerially treat them.”
Opposition
During the comment period, conservationists opposed the proposal to spray larkspur and mountain big sagebrush; they also opposed the proposal to spray aerially.
The Bighorn Audubon Society wrote that USFS acknowledges “more than 90 bird species have a facultative relationship with big sagebrush ecosystems,” and “the importance of sagebrush in the diet of adult sage-grouse is impossible to overstate.”
The group said they are not opposed to controlling invasive species through prescribed burning and increasing livestock grazing. However, they wrote, “The BNF preferred plan to treat up to 5,100 acres annually of the 163,000 acres of mountain big sage[brush] for years to come, and by aerial spraying of chemicals, is a very unreasonable plan that purposely further reduces bird and other wildlife habitat, therefore populations, in the forest.”
Western Watersheds Project (WWP) called the use of herbicides for sagebrush control “Neanderthalic.” WWP stated that current livestock grazing rates are “far beyond what the ecosystem could support,” using a 2006 current condition report showing that most grasslands, sagebrush habitat and riparian areas are in poor condition. WWP also asserts the DEIS is a “fictional understanding of sagebrush ecology,” and sagebrush is not a “pest.”
Forest Service Employees for Environmental Ethics (FSEEE) also opposes the proposal to control larkspur, stating the fact that “some Wyoming counties have declared larkspur a ‘weed’ is irrelevant. Counties have no legal jurisdiction over our national forests.”
FSEEE stated that larkspur is a valuable forage for wild herbivores. The group also opposed using tebuthiuron to kill sagebrush, as it poses a threat to groundwater, and the “DEIS fails to disclose that tebuthiuron is already present in Wyoming domestic and municipal water wells.” FSEEE proposes using drones for aerial spraying to combat drift and leaching into groundwater.
Support
The Wyoming Department of Agriculture (WDA) supports the use of biological controls of mountain big sagebrush and invasive grasses using “reformulated” herbicides and targeted grazing to “support rangeland vegetation health goals.” WDA recommends the DEIS include the authority to make temporary changes to livestock grazing permits “to address specific invasive weed infestations.”
WDA challenged the section of the DEIS on “cumulative effects” of livestock grazing, stating that grazing has no negative effect and recommends that cumulative effects be changed to “improper livestock grazing.”
Jim Magagna, executive vice president of the Wyoming Stock Growers Association (WSGA), wrote that success in controlling invasive grasses would require timely action and the use of available tools. WSGA also stated that the management of mountain big sagebrush “is essential in meeting desired resource conditions and maximizing available forage for both livestock and wildlife.”
Magagna wrote that aerial spraying is a necessary tool in rugged areas, and “properly managed” grazing can also be used. “The value of this tool will be enhanced if forest managers are given the authority to work with grazing permittees to provide the flexibility that can maximize this opportunity,” Magagna wrote.
The DEIS states it will support 118,000 animal unit months of grazing as part of the plan to control invasive grasses and mountain big sagebrush. — Charles Wallace, WLJ editor
