Greater Yellowstone Ecosystem

[1] It is located within the northern Rocky Mountains, in areas of northwestern Wyoming, southwestern Montana, and eastern Idaho, and is about 22 million acres (89,000 km2).

In 1932, President Hoover issued an executive order that added more than 7,000 acres (2,800 ha) between the north boundary and the Yellowstone River, west of Gardiner.

[4] By the 1970s, the grizzly bear's (Ursus arctos) range in and near the park became the first informal minimum boundary of a theoretical "Greater Yellowstone Ecosystem" that included at least 4,000,000 acres (16,000 km2).

Grizzly bears (Ursus arctos horribilis) and gray wolves (Canis lupus) are apex predators[7] that play crucial roles in regulating prey populations.

Though 20 or 30 or even 50 years of information on a population may be considered long-term by some, one of the important lessons of Greater Yellowstone management is that even half a century is not long enough to give a full idea of how a species may vary in its occupation of a wild ecosystem.

Among native plants of the GYE, whitebark pine (Pinus albicaulis) is a species of special interest, in large part because of its seasonal importance to grizzly bears,[20] but also because its distribution could be dramatically reduced by relatively minor global warming.

In this case, researchers do not have a good long-term data set on the species, but they understand its ecology well enough to project declining future conservation status.

[citation needed] The decline has been linked to multiple stressors, such as defoliation by the forest tent caterpillar (Malacosoma disstria), aspen bark beetles (Trypophloeus populi and Procryphalus mucronatus), wood-boring beetles such as the poplar borer (Saperda calcarata) and the bronze poplar borer (Agrilus liragus), fungal disturbances such as those by the Cytospora canker (Valsa sordida), and Climate change related stressors.

[citation needed] Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) have suffered considerable declines since European settlement, but recently began flourishing in some areas.

Especially in Yellowstone Lake itself, long-term records indicate an almost remarkable restoration of robust populations from only three decades ago when the numbers of this fish were depleted because of excessive harvest.

Early accounts of pronghorn (Antilocapra americana) in Greater Yellowstone described herds of hundreds seen ranging through most major river valleys.

Elk, the primary prey of the gray wolf, became less abundant and changed their behavior, freeing riparian zones from constant grazing.