Today I’m thinking about Yellowstone’s animals, the “charismatic megafauna”—an expression that makes me smile. And I’m anticipating being able to present my first-ever guest blog, by my friend Rita Reining. Rita took part in a late season wolf-watching seminar this winter given by the Yellowstone Institute. Their next winter’s classes are not yet listed but will be up by August or September.
Wolf picture from “Yellowstone Treasures,” page 351
Awaiting her article, I’ll pass on some thoughts inspired by a Science Magazine article, “Lessons from the Wild Lab,” March 20, 2015, pages 1302–7.
A video circulating on the Web a few months ago attributed recent changes in Yellowstone’s environment to the reintroduction of gray wolves, beginning in 1995. The video seemed to claim that the observed changes, all the way through the animal and plant kingdoms to the re-channeling of rivers, were due to predation on elk by wolves. However, according to writer Virginia Morell from Yellowstone, scientists disagree as to whether or not the coming of the wolves was the only trigger for observed changes “in species from elk to coyotes to willows to bison to beavers.” She cites cougars, grizzly bears, and drought as partners in the park’s transformation.
Wolves and cougars were both extirpated by the early 1930s. Coyotes, however, have been protected from 1936 on—a discrimination in the ruling that I have never understood, since these smaller canids can also prey on animals as large as deer or (very occasionally) elk and have even been known to attack humans.
In addition to the larger predators, Douglas W. Smith, the Yellowstone Wolf Project leader, who has studied wolves for more than three decades, says that smaller predators and humans should be factored in to the great depletion of the elk herd since wolves came to the park.
Here are a few megafauna statistics from Morell’s article:
Elk:
1994, more than 19,000 in the northern range of Yellowstone
2008, just over 6,000
Cougars (known in the park):
1972, almost none
1995, estimated at 15 to 20
2015, estimated at about 35, a “natural experiment,” according to Morell, “but they are
rarely seen and do not howl”
Bison:
1997 (after slaughter of 1,000), about 1,600
2004, over 4,000
2014, 4,900
Beaver colonies:
2014, 12 (but the
park website) gives 112 beaver colonies in 2011.)*
Wolves:
1994, none
2013, 95 in the park; 34 on the northern range
Human visitors:
2014: 3.6 million.
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*From the NPS Yellowstone website: “The increase [in beavers] has occurred throughout the park and is likely related to the resurgence in willow since the late 1990s, at least on the northern range, and possibly in the park interior.”