Jun
19

Sheep VS Sheep – The Next Chapter

We’ve had the conversation before; that one about die-offs of bighorn sheep across much of bighorn habitat in America. Causes of the die-offs are now quite well understood. The challenge lies in finding – and implementing – prevention measures. That is the next chapter in looking after these “icons of the Mountain West.” If you doubt this “icon” business, think about the last time you drove down Central Washington’s  Yakima River Canyon – or anywhere else in the West – and spotted wild sheep. Odds are that others were already stopped, or stopping, to momentarily immerse themselves in the beauty, grace – the majesty – of these animals.

Recall that there are three primary subspecies, of bighorns: Rocky Mountain bighorns (most of the West), desert bighorns (desert mountains of our southwest and down into Mexico) and California bighorns (occupying the mountains and steep country of our West Coast states). Our local sheep are California sheep (there are a few Rocky Mountain bighorns in the easternmost wild places of Washington). There are 18 herds of bighorns in Washington – somewhere around 1,500 sheep, of which more than half are along the Yakima River.

At the range-wide scale, the fair numbers of bighorns from Mexico to Canada live a rather precarious existence. While there have likely been bighorn die-offs through history, regular die-offs in wild sheep herds became a fact of life when European settlers moved into their various habitats…bringing domestic sheep and goats with them.

Countless die-offs have occurred over the past 150 years. Our most recent regional losses were in 2009-10, and again in 2015. Those losses were largely a mirror image of the problems across most of bighorn country, caused by one or another form of pneumonia – with lingering after-effects. In the last three decades, pneumonia has almost wiped out bighorn herds in the Blue Mountains and in portions of the Hells Canyon area of Idaho and Oregon along the Snake River. For up to a decade after a die-off, surviving ewes may not produce lambs that live more than a year. Thus, herd recovery can take decades, if it even happens. This is a big deal.

The pneumonia outbreaks are all apparently related to various Mycoplasma and Pasteurella bacteria. Recent study confirms that the Mycoplasma bacteria sufficiently weaken bighorn immune defenses for Pasteurella (and several other genetically-identified relatives) to trigger the pneumonia. Each of the various bacteria-caused pneumonias may lead to different outcomes. (For example, sheep may survive one type, develop antibodies which last for only a year or two, and be re-infected. Or, some strains may kill so quickly that little evidence remains of the bacteria responsible.)

A great deal is now known about the specifics of how the illnesses spread through a sheep herd. Wildlife managers are learning more about how much – or little – patience needs to be practiced when wild sheep start dying. Most urgent, now, are growing efforts to keep domestic sheep from sharing any given habitat with bighorn herds.

Through much of bighorn habitat the various bacteria are transmitted from unaffected domestic sheep to wild sheep through nose-to-nose greetings, and spread very rapidly. Significant research has centered on antibiotics and vaccines (and ways to get them into bighorns), but those solutions are still well down the road. Domestic sheep are also being developed which are free of the Mycoplasma bacteria – some happening at the Washington State Prison in Walla Walla – but they are unlikely to be viable in the large sheep flocks using the vast grazing allotments scattered across bighorn country, but they will be highly prized in some smaller areas.

We have discussed before the efforts among groups like the Wild Sheep Foundation and the National Wildlife Federation to actually pay sheep grazers to not use allotments that pose a risk to bighorns. In addition, current state and federal environmental impact studies prior to bidding on grazing allotments are putting high value on the presence of, or proximity to, wild sheep.

That brings us to the next chapter for our state’s wild sheep. The Okanogan-Wenatchee National Forest (OWNF) is now underway with its Sheep Project, in partnership with the Washington Department of Fish and Wildlife and the USDA Agricultural Research Service. This begins an environmental analysis (NEPA) process intended to update forest plans for managing domestic sheep/goat grazing allotments to meet its mandate to protect and maintain healthy bighorn sheep populations. It seems that a number of those allotments are within the OWNF, and many overlap nearly three-quarters of our state’s wild sheep, in or along the forest. An open house held in Cle Elum the evening of June 12 was the second step in kicking off the process.

We will return to this process in the next few weeks, but you can begin your own learning now. Find the overview to the Sheep Project at www.fs.usda.gov/project/?project=53257 – just follow any interesting link, particularly those in the “Get Connected” box. A video of that 6/12 open house will be found at facebook.com/OkaWenNF (scroll down to “videos”). For some great interactive maps of the forest and project areas of interest, take an online trip to arcg.is/0DbDbD.

This is just a next chapter as we work for the future of our wild sheep. Next time you’re in the Yakima River Canyon, say hello to ours.

Written by Jim Huckabay. Posted in Uncategorized

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