Researchers measured the changes in the Yellowstone meadow plant community from 1997 to 2007, including a period of extended drought, and found that shrubs (such as sagebrush) that grow in the drier meadows increased, while flowering plants decreased in number.
The USFWS said wolf populations have exceeded biological recovery goals and are now thriving.
While it was feared the elk population would be at risk upon reintroduction, wolf numbers on Yellowstone’s northern range has grown to 84 and elk numbers have not declined appreciably.
The study conducted by forestry researchers supports a “trophic cascade” theory of ecological interdependence — extending to plants, animals, food chains and ecological zones.
It is believed that about 640,000 years ago (during the Pleistocene epoch), a massive volcano erupted, creating a caldera in the center of what is now Yellowstone National Park.
The coalition groups filing the lawsuit argued that snowmobiles endanger the health of the Yellowstone staff that work at the park entrances, where large numbers of snowmobiles enter the park during the winter and spring snowmobile season.
This is the fifth time in less than 10 years that the U.S. government is requesting public comment on snowmobile use in Yellowstone and Grand Teton National Parks.
The latest round of public comment represents the fourth time in two years that the public has delivered this message about future winter use in Yellowstone.
The U.S. District Court for Wyoming on December 12, 1997 held that the U.S. Fish and Wildlife Service’s final rules establishing a nonessential experimental population of gray wolves in Yellowstone National Park and central Idaho and southwestern Montana are unlawful and ordered the Service to remove all of the reintroduced wolves and their offspring from the Yellowstone and central Idaho areas.
The central part of Yellowstone has been uplifting and subsiding or “breathing” about five times during the last 9,000 years.