Yellowstone's wolf recovery program has brought stability to the park's ecosystem/NPS, Jacob W. Frank
It was cold, right around 20 degrees below zero at Old Faithful, but that didn’t keep the excitement from bubbling up from the two women I met on the boardwalk near the famous geyser.
“Did you see the wolf? It loped right through the geyser basin!” they said, their words emphasized by the small clouds of condensation created by the temperature. It was if they were anxious to share the experience with others as if to verbally pinch themselves that it actually occurred.
Unfortunately, I had missed that sighting, but I’ve enjoyed other moments of wolf ecstasy in the park. There was the time in the Lamar Valley near Soda Butte Creek when two wolves, drawn by the squeals of an elk calf tackled by a grizzly, appeared on a rise just above the road that runs to Silver Gate at Yellowstone’s northeast entrance. Then there was the predawn howl that sliced through the backcountry quiet deep down the South Arm of Yellowstone Lake.
Going on a quarter-century since wolves were returned to the park in an ambitious gambit to make Yellowstone’s ecosystem whole and balanced once again, Canis lupus has definitely added a measure of wildness to the landscape.
"I think they’re restored. The population has been stable for about 10 years, which indicates that the kind of the up and down and the recolonization things that were necessary, have taken place. And wolves are a natural part of the ecosystem now,” said Doug Smith, who heads the park’s Wolf Project.
In some aspects there have been fits and starts to the wolf’s return. There were the initial “soft releases” back in 1995 and 1996, when wolves brought from Canada were placed in fenced in areas and fed elk meat in a bid to get them used to the setting, rather than simply freeing the predators from a truck and hoping they’d stick around.
There were the bouts of mange (2007) and canine distemper virus (1999, 2005 and 2008), and there were wolves lost to hunters beyond the park’s borders. There were the livestock depredations attributed to Yellowstone wolves that roamed far, as well.
Through it all, the wolves not only endured, but they thrived in the park. And they exhibited some behavior that some might not have expected.
“Like every living creature, there’s always a to and fro, a back and forth, and those territory boundaries are always in flux,” Smith replied when asked whether the original territories staked out back in the early years of the recovery program have held fast. “But, having said that, the location of the primary wolf territories is amazingly stable. In other words, where wolves settled in Yellowstone say the first eight, ten years, is primarily where they are now. And the wolves have divided up the landscape to be in different territories, and those territories year to year are stable.”
Through the years there have been notable white wolves, such as this alpha female from the Canyon Pack that Neal Herbert snapped in 2006/NPS, Neal Herbert
In other words, they’re not unlike a human family that holds onto a favored homestead through the generations.
“Wolf packs are a family, and these families get a toehold in a certain area and they’re lineages kind of keep to those certain areas on the landscape,” the wildlife biologist explained. “And so it’s in one way amazingly stable. Where wolves have settled in Yellowstone is where they are year after year.”
What has been particularly surprising, perhaps, has been the longevity of Mollie’s Pack, which was spun off from one of the original recovery packs and named for the late Mollie Beattie, who was director of the U.S. Fish and Wildlife Service during the early days of the recovery program.
“We’ve studied the average lifespan of wolves and we’re evening getting into, because few people have looked at it, the average lifespan of a pack,” said Smith. “And the average is about 10-12 years, a short one could be just two or three. But Mollie’s is the outlier for the longest running pack.
“That used to be the Crystal Creek Pack that we introduced in northern Yellowstone in 1995. They lost a territorial battle, the next year, in 1996, with the Druid Peak Pack killing the alpha male, wounding the alpha female, sending (the survivors) south into Pelican Valley, and they have been there ever since in a continuous lineage that we’ve documented.
“And so this next year will be 25 years, and that’s one of the longest running wolf packs known to people.”
Along with finding the Pelican Valley empty of other wolves and to their liking, Mollie’s Pack became adept at killing bison that spent the entire year in the valley. The pack also had some pretty good alpha females through the years, believes Smith.
“They had a few key individuals that lived a long time, and I think they were the glue that held the pack together,” he said. “We don’t have solid research on this yet, but it looks like it’s females. You get a good female leader, she can hold things together. Average lifespan of a wolf is five or six years, but they can live 8, 9, 10, and we had a female live that long in Mollie’s, and so that can be the reason that a pack will subsist a long time.”
Today there are about 80 wolves in Yellowstone, a number that’s not quite half of the population highs seen in the early to mid-2000s. Why the decline? The answer, said Smith, is simple.
“Elk. We had then an overpopulated elk situation,” he said.
Early in Yellowstone’s history as a national park the management strategy was to kill off the predators, the wolves and cougars, primarily. That led to unrestrained elk population growth. While managers tried to deal with the large number of elk and the impact they were having on vegetation by shipping elk off to other locations “all over North America and even Mexico to re-establish elk populations where they had been lost,” noted Smith, that practice ended in 1968 and the population boomed again.
In 1995 when the first wolves were returned to Yellowstone the elk population numbered at least 19,000.
“It’s well known that when you count elk you miss a lot, and the average number you miss is roughly 30 percent, but it can be up to 50 percent,” Smith pointed out. “So that true elk population was well over 20,000.”
The wolves feasted on that population, and today it’s closer to 6,000-8,000, he said.
“That decline has occurred, and it’s probably more in fit for the environment. Again, elk hunters don’t like this because hunter success rates around the park have declined. Big issue,” said Smith. “But that was built on Yellowstone being an ‘elk farm.’ Essentially you’re growing elk in the summer and sending them out in the hunting season. Hunters liked it, but the ecosystem probably didn’t.
“And if you’re a park visitor that was looking for a well-balanced ecosystem with lots of biodiversity, you probably didn’t like it either. It’s the story of human society. Some like things, some don’t. But we do feel, ecologically, that we’re at a better point now. And wolves have declined, to a degree cougars have.”
While wolves at Isle Royale National Park ran into an inbreeding problem that prompted the National Park Service to perform a genetic rescue program of sorts by importing wolves from Canada and Michigan to the island park, Smith doesn’t foresee any genetic problems for the Yellowstone wolves for at least a century.
“We’ve looked at genetic diversity of Yellowstone wolves, and they’re equal to wolves living in northern Canada, which is largely undeveloped and a large population of wolves that has a lot of intermixing in terms of breeding,” he said. “The genetic diversity of Yellowstone right now is similar to those wolves.”
While some have questioned the wisdom of the Park Service bringing wolves into Isle Royale, saying nature should have been allowed to run its course, Smith maintains it was the only choice the agency had to prevent the park’s moose population from soaring and over-browsing the forests.
“The decline of wolves there was human-caused. So we meddled with it. I actually don’t mean to be so strong worded, because some great friends and great groups opposed that, saying it’s not natural to do this and stop meddling with nature and we’re always better off leaving things alone,” he said. “Well, in that case it will be a lot worse off ecologically and ecosystem wise if you leave things alone. And if that’s in the cards, so be it. But the issue there is the population declined because of genetic depression.”
The genetic depression, the biologist said, was human caused because anthropogenic climate change has altered the natural cycle of ice bridges between Isle Royale and the U.S. and Canadian mainlands that allowed wolves to reach the island somewhat regularly.
“Wolves couldn’t get out there any more because the ice bridge used to form every eight out of ten years. Now it forms every two, three years out of every ten,” he explained. “So the transfer of wolves from the mainland to the island has been cut dramatically due to climate change. And secondly, there was human-introduced disease (parvovirus) there that caused the wolf population to decline that created a bottleneck. So there were two different human impacts there that caused wolves to decline.”
Spend time in Yellowstone’s Lamar Valley in late spring and early summer, and again during the winter months, preferably during the day’s early and late light, and the odds of spotting one or more wolves will go up. Pitch your tent at the Slough Creek Campground and, if you’re lucky, you just might catch a howl or two from the Junction Butte or Lamar Canyon packs.
Hanging on the night air, the sound is of wildness thriving in Yellowstone.
Traveler postscript: Listen to the entire interview with Doug Smith in National Parks Traveler Podcast #39.
Comments
I was very happy to see this article anticipating the 25th anniversity of wolf reintroduction. Bringing this species back into Yellowstone has yielded tremendous benefits that go far beyond just entertaining humans who long for a taste of what they had before it was cleared, farmed, grazed, mined, or paved. There have also been significant and profound benefits to the science of conservation biology. But, the greatest benefits have actually been benefits to the ecosystem itself. I believe Doug Smith's comments on Isle Royale, as quoted in the article, demonstrate that broader ecosystem dynamics are and must have always been at the core of his thinking. And, day by day and in countless subtle ways, wolves are completing, rebalancing, complicating, and enriching the natural community and broader ecology of Yellowstone, evolution written large on the landscape right before our eyes. They have and will do the same on Isle Royale. Doug Smith fully deserves the place he has earned among the great biologists who have historically graced the National Park Service.
With that said, the article indicates, "Smith doesn't foresee any genetic problems for the Yellowstone wolves for at least a century." Doug Smith is quoted confirming, "We've looked at genetic diversity of Yellowstone wolves, and they're equal to wolves living in northern Canada, which is largely undeveloped and a large population of wolves that has a lot of intermixing in terms of breeding... the genetic diversity of Yellowstone right now is similar to those wolves." Doug Smith is absolutely correct. Across the full spectrum of their genetics, Yellowstone's wolves are in good shape. However, I spent many years looking for and often guarding against unanticipated factors, which taught me to focus on the complete picture while still analyzing every detail. In that context, I believe that, if we look a little bit deeper, even Yellowstone's wolves can still give us a realtime glimpse of what the process of "genetic drift" can look like, again right before our eyes.
As Doug Smith indicates, the founding members of Yellowstone's wolf population were collected from northern Canada and were a typical cross-section of wolves from that remote region. Commonly known as "gray" wolves, most wolves in those isolated areas are gray, often with tan or darker saddles, because this color scheme provides camouflage for hunting in every season. Very few wolves up there are all black because all black wolves are highlighted against winter snow. Very few wolves up there are all white because all white wolves are highlighted in wooded areas and during longer warm seasons below the Arctic Circle. As a result, very few all black or all white wolves were reintroduced into Yellowstone.
Doug Smith is also correct that northern Canada is "largely undeveloped" with only sparse and widely scattered human settlements. In that remote and wild region, domestic dogs either stay close to those settlements or don't last very long. As a result, wolves in those isolated areas don't have much contact with either humans or their dogs, which is good because domestic dogs, vaccinated or not, generally carry some residual level of the canine distemper virus. A full course of vaccination will provide an animal with an immune response that enables it to cull the distemper virus from its system well enough to avoid symptoms; but, not every animal reliably receives a full course of vaccination and those that do are still not reliably completely free of the virus, especially given the high dog populations in human communities. If the vaccine completely eliminated the virus from all its potential hosts, the virus would be eliminated and there would be no further need for the vaccine, which is certainly not the case.
So, with exposure to humans and our dogs, Yellowstone's wolves have suffered repeated outbreaks of distemper that have caused major mortality events; but, the original reintroduced population included a tiny fraction of all black wolves, which, although still within the same species, are actually ancient hybrids that carry an inherited immunity to distemper. As a result, black pups disproportionately survived these outbreaks while the disease selectively and lethally culled a far greater proportion of "gray" pups. After only 25 years, closer to half of Yellowstone's wolves are now all black.
The point here is neither about wolves nor their coloration. The point is the ease with which exposure to a single disruptive factor has been able to so quickly and dramatically remake this species' population structure and genetic mix in Yellowstone, alter its survival dynamics, and potentially eliminate traits that might be needed in the future. This very rapid "genetic drift" is also not likely to slow down with domestic dogs still being allowed into the Park. ...just sayin'.