Related to my post last November about how the biodiversity of Yosemite Valley was mismanaged, author Michael Crichton shared a story at a 2005 talk about how the National Park Service has grossly mismanaged nature at Yellowstone National Park, resulting in less biodiversity, the disappearance of many natural species from the park, and catastrophic fires. Since this anecdote was part of a longer talk, I’ll quote the whole thing from the transcript.
Long recognized as a scene of great natural beauty, in 1872, Ulysses Grant set aside Yellowstone as the first formal nature preserve in the world. More than two million acres, larger than Delaware and Rhode Island combined. John Muir was very pleased when he visited in 1885, noting that under the care of the Department of the Interior, Yellowstone was protected from, quote, “the blind, ruthless destruction that is going on in adjoining regions.”
Theodore Roosevelt was also pleased in 1903, when as President, he went to Yellowstone for a dedication ceremony. Here he is. This was his third visit. Roosevelt saw a thousand antelope, plentiful cougar, mountain sheep, deer, coyote and many thousands of elk. He wrote at that time, “Our people should see to it that this rich heritage is preserved for their children and their children’s children forever, with its majestic beauty all unmarred.”
But in fact, Yellowstone was not preserved. On the contrary, it was altered beyond repair in a matter of years. By 1934, the Park Service acknowledged that whitetail deer, cougar, lynx, wolf, and possibly wolverine and fisher are gone from the Yellowstone.
What they didn’t say was that the Park Service was solely responsible for the disappearances. Park rangers had been shooting the animals for decades, even though that was illegal since the Lacey Act of 1894. But they thought they knew best. They thought their environmental concerns trumped any mere law.
What actually happened at Yellowstone is a cascade of ego and error, but to understand it, we have to go back to the 1890s. Back then, it was believed that elk were becoming extinct, so these animals were fed and encouraged. Over the next few years, the number of elk in the park exploded. Here you can see them feeding them hand to hand.
Roosevelt had seen a few thousand animals on his visit, and he’d noticed that the elk were more numerous than in his previous visit. Nine years later, in 1912, there were 30,000 elk in Yellowstone. By 1914, there were 35,000.
Things were going very well. Rainbow trout had also been introduced, and although they crowded out the native cutthroats, nobody really worried. Fishing was great. Bears were increasing in numbers, and moose and bison as well.
By 1915, Roosevelt realized the elk had become a problem, and he urged scientific management, which meant culling. His advice was ignored. Instead, the Park Service did everything they could to increase the number of elk. The results were predictable. Antelope and deer began to decline. Overgrazing changed the flora. Aspen and willows were being eaten at a furious rate and did not regenerate. Large animals and small began to disappear from the park.
In an effort to stem the loss, the park rangers began to kill predators, which they did without public knowledge. They eliminated the wolf and the cougar, and they were well on their way to getting rid of the coyote. Then a national scandal broke out. New studies showed that it wasn’t predators that were killing the other animals. It was overgrazing from too many elk. The management policy of killing predators therefore had only made things worse.
Actually, the elk had so decimated the aspen that now, where formerly they were plentiful, now they’re quite rare. Without the aspen, the beaver, which use these trees to make dams, began to disappear from the park. Beaver were essential to the water management of Yellowstone, and without dams, the meadows dried hard in summer and still more animals vanished.
The situation worsened further. It became increasingly inconvenient that all the predators had been killed off by 1930, so in the 1960s, there was a sigh of relief when new sightings by rangers suggested that wolves were returning. Of course, there were rumors all during that time, persistent rumors that the rangers were trucking them in. But in any case, the wolves vanished soon afterward. They needed to eat beaver and other small rodents, and the beaver had gone.
Pretty soon, the Park Service initiated a PR campaign to prove that excessive elk were not responsible for the problems in the park, even though they were. The campaign went on for about a decade, during which time the bighorn sheep virtually disappeared.
Now, we’re in the 1970s, and bears were recognized as a growing problem. They used to be considered fun-loving creatures, and their close association with human beings was encouraged in the park. Here’re people coming to watch bear feedings. There’s a show at a certain hour of the day. And here’s one of my favorites. Setting the table for bears at Lake Camp in Yellowstone Park. You see they’re very well behaved.
But that didn’t actually continue-the good behavior, I mean. There were more bears, and certainly there were many more lawyers, and thus the much-increased threat of litigation, so the rangers moved the grizzlies out. The grizzlies promptly became endangered. Their formerly growing numbers shrank. The Park Service refused to let scientists study them, but once they were declared endangered, the scientists could go back in again.
And by now, we’re about ready to reap the rewards of our 40-year policy of fire suppression, Smokey the Bear and all that. The Indians used to burn forests regularly, and lightning causes natural fires every year. But when these are suppressed, branches fall from the trees to the ground and accumulate over the years to make a dense groundcover such that when there’s a fire, it is a very low, very hot fire that sterilizes the soil. In 1988, Yellowstone burned, and all 1.2 million acres were scorched, and 800,000 acres, one third of the park, burned.
Then having killed the wolves, having tried to sneak them back in, they officially brought the wolves back. And now the local ranchers screamed. The newer reports suggested the wolves seemed to be eating enough of the elk that slowly, the ecology of the park was being restored. Or so it is claimed. It’s been claimed before. And on and on.
Update: As Crichton notes above, wolves were reintroduced into Yellowstone in 1995 and their presence started what’s called a trophic cascade. From Wikipedia:
Trophic cascades occur when predators in a food web suppress the abundance or alter traits (e.g., behavior) of their prey, thereby releasing the next lower trophic level from predation (or herbivory if the intermediate trophic level is a herbivore). For example, if the abundance of large piscivorous fish is increased in a lake, the abundance of their prey, zooplanktivorous fish, should decrease, large zooplankton abundance should increase, and phytoplankton biomass should decrease. This theory has stimulated new research in many areas of ecology. Trophic cascades may also be important for understanding the effects of removing top predators from food webs, as humans have done in many places through hunting and fishing activities.
In a TED talk, George Monbiot explains the surprising effects the wolves had on Yellowstone…they even changed the courses of the rivers flowing through the park.
Fascinating. A sort of trickle down ecology. (via @gasperak and several others)