Жоғарғы Йеллоустоун Экосистемасы: Табиғат және Қорғау

Ecosystem in the Rocky Mountains

The Greater Yellowstone Ecosystem (GYE) is one of the last remaining large, nearly intact ecosystems in the northern temperate zone of the Earth. It is located within the northern Rocky Mountains, in areas of northwestern Wyoming, southwestern Montana, and eastern Idaho, and is about 22 million acres (8,903,092 km2). Yellowstone National Park and the Yellowstone Caldera 'hotspot' are within it. The area is a flagship site among conservation groups that promote ecosystem management. The Greater Yellowstone Ecosystem (GYE) is one of the world's foremost natural laboratories in landscape ecology and Holocene geology, and is a world renowned recreational destination. It is also home to the diverse native plants and animals of Yellowstone.

Yellowstone National Park boundaries were drawn in 1872 with the intent to include all the known geothermal basins in the region. As landscape ecology considerations were not incorporated into original boundary, revisions were suggested to conform more closely to natural topographic features, such as the ridgeline of the Absaroka Range along the east boundary. In 1929, President Hoover signed the first bill changing the park's boundaries: The northwest corner now included a significant area of petrified trees; the northeast corner was defined by the watershed of Pebble Creek; the eastern boundary included the headwaters of the Lamar River and part of the watershed of the Yellowstone River. In 1932, President Hoover issued an executive order that added more than between the north boundary and the Yellowstone River, west of Gardiner. These lands provided winter range for elk and other ungulates. 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 Since then, definitions of the greater ecosystem's size have steadily grown larger. A 1994 study listed the size as , while a 1994 speech by a Greater Yellowstone Coalition leader enlarged that to
In 1985 the United States House of Representatives Subcommittees on Public Lands and National Parks and Recreation held a joint subcommittee hearing on Greater Yellowstone, resulting in a 1986 report by the Congressional Research Service outlining shortcomings in inter agency coordination and concluding that the area's essential values were at risk.

The park is a commonly cited example of apex predators affecting an ecosystem through a trophic cascade. After the reintroduction of the gray wolf in 1995, researchers noticed drastic changes occurring. Elk, the primary prey of the gray wolf, became less abundant and changed their behavior, freeing riparian zones from constant grazing. The respite allowed willows and aspens to grow, creating habitat for beaver, moose, and scores of other species. In addition to the effects on prey species, the gray wolf's presence also affected the park's grizzly bear population. The bears, emerging from hibernation, chose to scavenge off wolf kills to gain needed energy and fatten up after fasting for months. Dozens of other species have been documented scavenging from wolf kills.