The Greater Yellowstone Ecosystem - Mountains and Plains: The Ecology of Wyoming Landscapes - page 252

Fig. 15.7. Meadows and wetlands cover much of Hayden
Valley in Yellowstone national Park. the high point in the
distance is Mount Washburn, on the northern rim of the Yel-
lowstone caldera. the valley is in the caldera and is underlain
by lake-bottom sediments deposited early in the Pinedale
glacial period. Moist meadows support mountain silver

sagebrush and shrubby cinquefoil; on drier sites, idaho fescue
and Wyoming big sagebrush are common. Where the soil is
flooded during much of the summer, water sedge and beaked
sedge are common. the trees in the foreground are lodgepole
pine. elevation 7,400 feet.

water, primarily for idaho farmers, a dam on the Snake
River was completed in 1906, thereby enlarging Jackson
Lake . 29 P erennial concerns about possible dam failure,
triggered by the 1976 failure of the teton Dam 30 miles
west (in idaho), led to reinforcements on the Jackson
Lake dam (completed in 1989).
the abundant wildlife and spectacular scenery south
of YnP increased in popularity, and some began to
think that a second national park should be established.
Pierce cunningham, a rancher near Spread creek, cir-
culated a petition in 1925 asking the state of Wyoming
or the federal government to set aside the valley “for
the education and enjoyment of the nation as a whole.”
Four years later, congress created Grand teton national
Park. Predictably, the park boundaries encompassed
most of the rugged and uninhabitable parts of the
tetons but almost none of the valley lying east of the
mountain front—yet it was the valley that needed pro-
tection from development. John D. Rockefeller, Jr., took

on the mission of enlarging the park by buying as much
land in Jackson Hole as possible and then donating it
to the federal government. 30 this was accomplished in
1950, though not without criticism by many local land-
owners. As a compromise to enable park enlargement,
provisions were made for continued livestock grazing
and hunting. in 1972, the land along the highway con-
necting YnP and Grand teton national Park was trans-
ferred to the national Park Service by the U.S. Forest
Service and named the John D. Rockefeller Jr. Memorial
Parkway, thereby acknowledging his vision.

Vegetation of Jackson Hole and the Tetons

Jackson Hole is surrounded by mountains that extend
above treeline. Fifty-eight percent of Grand teton
national Park is nonforested (alpine tundra, boulder
fields, meadows, grasslands, and shrublands), 28 per-
cent is lodgepole pine forest, 7 percent engelmann