Columbia subject headings:
Ecological assessment (Biology)--Yellowstone National Park Region.
Environmental indicators--Yellowstone National Park Region.
Environmental monitoring--Yellowstone National Park Region.
Harvard subject headings:
American bison--Ecology--Yellowstone National Park.
Ecological assessment (Biology)--Yellowstone National Park Region.
Elk--Ecology--Yellowstone National Park.
Environmental indicators--Yellowstone National Park Region.
Environmental monitoring--Yellowstone National Park Region.
Ungulates--Ecology--Yellowstone National Park.
Wildlife management--Yellowstone National Park.
Princeton subject headings:
American bison--Ecology--Yellowstone National Park.
Elk--Ecology--Yellowstone National Park.
Ungulates--Ecology--Yellowstone National Park.
Wildlife management--Yellowstone National Park.