The recent article, “Disease die-offs continue to ravage bighorn sheep,” (Herald, Jan. 15), highlighting the failure of federal land management agencies to address risks to native bighorn sheep, underscores the challenges faced by Durango’s local Weminuche bighorn sheep herd.
The U.S. Forest Service decision to continue grazing domestic sheep in the largest wilderness area in Colorado has resulted in the marked decline of a highly valued bighorn sheep population, now in jeopardy of complete extirpation.
In 2011, the San Juan National Forest began to analyze the risk posed to bighorn sheep by grazing domestic sheep in the wilderness, as they considered renewal of grazing on several active allotments in the Columbine Ranger District. At the time, Colorado Parks and Wildlife estimated the Weminuche bighorn sheep herd to total 460 animals, and noted that the herd population objective, based on the quantity and quality of available habitat, was upward of 1,000 animals.
A bighorn sheep risk assessment and viability analysis completed by the SJNF in 2010 noted, “There is increased recognition that an incompatibility exists between bighorn sheep and domestic sheep and goats. The incompatibility stems from a risk of disease transmitted from domestic sheep and goats to bighorn sheep, potentially resulting in substantial mortality of bighorn sheep.”
The risk of bighorn sheep respiratory disease caused by bacteria from domestic sheep is not speculative. Dozens of devastating bighorn sheep die-offs have been documented in Colorado and across the West in the last few decades. They occur somewhere nearly every year. Genetic research has concluded that the source of the disease-causing bacteria is domestic sheep and goats. Although most bighorn herds have been exposed to these bacteria in the past, the existence of dozens of different strains of bacteria ensure that any bighorn herd is just one exposure to a particularly virulent strain away from another catastrophic die-off.
The Columbine Ranger District undertook an Environmental Assessment process for renewing the grazing allotments in 2012 but pivoted to a more robust analysis, a full Environmental Impact Statement in 2014. The final EIS and associated Risk Assessment in 2016 determined that the rate at which bighorns were expected to contact the active grazing allotments was more frequent than the levels thought necessary to maintain bighorn sheep herd persistence for the long term, and that a subsequent bighorn sheep respiratory disease event could result in the loss of viability of the species on the SJNF. Yet, the agency chose to shelve the analysis and make no changes to grazing management on the forest that would protect bighorn sheep.
Today, the prediction made in the 2016 Risk Assessment is coming to pass. Bighorn sheep in the Weminuche Wilderness have steadily declined from the CPW estimate of 460 in 2011 to just 290 today, a loss of 37% of the population.
The Forest Service continues to renew grazing permits without incorporating the results of their own environmental analysis that predicted a potential total loss of bighorn sheep in the area. The agency says it has no plans to renew the Weminuche grazing analysis, which means the remaining bighorn sheep continue to be threatened with extirpation.
The neighboring Pagosa Ranger District on the SJNF long ago recognized the risk that domestic sheep grazing posed to the Weminuche bighorn sheep herd and closed their active domestic sheep grazing allotments in 2010.
It is inexcusable that the Columbine Ranger District continues to jeopardize the health of the herd to accommodate grazing domestic sheep on just three allotments in the Weminuche.
There are options available that protect bighorn sheep and maintain multiple use of federal lands. The citizens and our Colorado state animal deserve better than the unsustainable management taking place currently on our national forests.
Terry Meyers is executive director of the nonprofit Rocky Mountain Bighorn Society. He lives in Grand Junction.
