Heading to Yellowstone myself in a few days [June 2013], I was very interested to learn that blaming the wolves for the huge decrease in elk numbers in Yellowstone is a big over-simplification. The numbers are unquestionably way down since I began taking notice in the mid 1990s.
When I was researching for Yellowstone Treasures’ first edition (2002), I found that about 35,000 elk were summering in the park. The new fourth edition (August, 2013) will say that on the order of 4,000 elk can be found on the northern Yellowstone range, and there are a few more in the rest of the park. This is a reduction of more than 80 percent.
A majority of the park’s wolf packs since reintroduction in 1995 have primarily preyed on elk. Thus, it has been easy to assume that wolves are to blame for this huge reduction in numbers. But a recent article in the latest issue of the journal Ecology reveals that the situation is much more complicated.
Migratory elk are struggling, while their resident counterparts thrive in the foothills, recent studies have found. The 4,500-member Clarks Fork elk herd, which migrates between the Absaroka Mountains and the upper Lamar River area, finds less forage because of extended drought.
In contrast, another researcher found that those elk living northwest of Cody, WY who do not migrate produce more calves, and more of them survive. They stay in the area because they find irrigated croplands. In addition, in settled areas many preying wolves and bears are removed by hunters and ranchers.
Grizzly bears and poor summer forage conditions caused by several years of drought have a bigger effect on elk health than do wolves, the researchers concluded.