Some dog owners upset over sheep grazing on hill
The most controversial method of weed control in Missoula commenced Tuesday on the city's open-space land on Mount Jumbo with the release of about 150 sheep.
The presence of the sheep on the mountain is virtually guaranteed to engender public opposition, said Marilyn Marler, noxious weed coordinator for Missoula and the University of Montana.
"It's been my experience," said Marler, "that sheep are the most controversial" of various weed-control methods in the city's vegetation management plan for open-space land. That includes the notoriously contentious issue of herbicides, she said.
"Most of the unhappy people I hear from are people who like to hike on Mount Jumbo with their dogs," Marler added. "They like to have them off the leash. But when we have the sheep up there, we ask people to keep their dogs on a leash."
Actually, a city ordinance requires dog owners to leash their pets while walking on Mount Jumbo when sheep are grazing, according to Kate Supplee, Missoula's open space program manager.
"A lot of people think their dogs are not going to chase sheep," Marler said. "But you don't really know if your dog's going to chase sheep until they're around sheep. We've had lots of dogs chase sheep. Two years ago dogs killed four of the sheep we had on Mount Jumbo. It was really brutal."
This year, she said, the sheep will be confined at night inside protective electric fencing. During the day, they will be able to roam freely. However, the city will have two full-time shepherds attending to the animals.
Marler secured a grant from the state's Noxious Weed Trust Fund to pay the salary of one of the shepherds, who earn $7 an hour. The city pays for the other shepherd. Besides guarding the sheep, shepherds also will be available to talk to the public and explain the mission of the sheep on the mountain, Marler said.
"Last year," she said, "we could only afford to pay for one full-time shepherd. And we had several volunteers. So this will be a huge improvement."
The sheep will graze in the saddle area of Mount Jumbo for about six weeks, Marler said. They were provided for free by John Stahl, who farms west of Missoula, and has loaned his sheep to the city and UM for weed control in past years.
The sheep have done a good job in the past, munching knapweed and leafy spurge infestations on Mount Jumbo and Mount Sentinel, Marler said.
"Actually, there's been so much research done about the effectiveness of grazing, it would be silly to eliminate grazing as a tool," she added.
But the controversy points out the fact that there are pros and cons to any weed-control method, she said, that no single method can be successful by itself, and that the most effective strategy is an integrated approach that uses a variety of methods.
The cons of grazing as a weed-control method on Mount Jumbo don't end with the animosity of dog owners.
Last summer, Marler said, two wild Rocky Mountain bighorn sheep yearlings, apparently from the Bonner herd, joined the domestic sheep grazing on Mount Jumbo.
Domestic sheep pose a serious threat of passing disease to wild bighorn sheep, she said.
"It can devastate a wild sheep herd," said Marler. "So Montana Fish, Wildlife and Parks ended up having to shoot the two bighorns. Usually, they don't come over on Jumbo. That hadn't occurred to us. This year we'll make sure the shepherds have cell phones so they can report any bighorns to Fish, Wildlife and Parks. And they can also chase them off. They carry slingshots for the dogs. They can use those."
If it appears that the bighorn herd's patterns are changing, and the animals begin visiting Mount Jumbo routinely, city officials will have to reassess their policy of grazing domestic sheep there, Marler said.
Yet another controversial aspect of using sheep to control weeds on the area's foothills involves a threat to another geological landmark the "beach lines" of Glacial Lake Missoula that are clearly visible on Mount Jumbo and Mount Sentinel.
Some geology professors at UM have expressed concern that sheep grazing can cause erosion that could destroy those unique geological features, said Marler.
David Alt, a UM geology professor who has written a book about Glacial Lake Missoula, has said he doesn't believe that having the sheep on the mountain for a few weeks a year would cause a problem, according to Marler.
But as a precaution, she added, "We won't graze them in the area of Jumbo where there are the most prominent beach lines. And that's why there are no sheep grazing on Mount Sentinel this year."
Many people often are too simplistic in advocating one weed-control method over another, said Marler.
"Some people think spraying herbicides is the worst ecological choice you could make," she said. "But you have to keep in mind, that if you're going to have sheep, and if they're not managed properly, they can cause erosion that's not good for the land. Then there's the disease transmission problem with wild sheep. There's problems with domestic dogs and the pain and suffering they cause sheep. And the social problems with dog owners.
"So when you take all those into consideration, there's some advantages to using herbicides. It doesn't interfere with recreation or cause erosion."
Figuring in the cost of shepherds, Marler said, grazing also becomes an expensive option, although not quite as expensive as herbicides.
But the sheep have an important place in the city's weed-management plan, said Marler. They will gobble up the tops of knapweed and leafy spurge before they go to seed, preventing further spread.
"So," Marler said, "it would be nice if people could support the sheep grazing up there. It's only for five or six weeks."