pine, and to a lesser degree the lodgepole pine, are considered at risk. In the case of the whitebark pine, an invasive species of fungus known as white pine blister rust weakens the tree, making it more susceptible to destruction from endemic mountain pine beetles. Whitebark pines generally thrive at elevations above and produce large seeds that are high in fat content and an important food source for various species such as the grizzly bear, red squirrel and Clark's nutcracker. The species is considered to be a keystone and a foundation species; keystone in that its "ecological role (is) disproportionately large relative to its abundance" and foundation in that it has a paramount role that "defines ecosystem structure, function, and process". Whitebark pine has generally had a lower incidence of blister rust infection throughout the Greater Yellowstone Ecosystem than in other regions such as Glacier National Park and the Cascade Range. The incidence of blister rust on whitebark pines in Yellowstone National Park is slightly lower than in Grand Teton. Though blister rust is not in itself the cause of increased mortality, its weakening effect on trees allows native pine beetles to have more easily infest the trees, increasing mortality. While general practice in national parks is to allow nature to take its course, the alarming trend of increased disease and mortality of the vital whitebark pine trees has sparked a collaborative effort amongst various government entities to intervene to protect the species. Fauna Sixty-one species of mammals have been recorded in Grand Teton National Park. This includes the gray wolf, which had been extirpated from the region by the early 1900s but migrated into the Grand Teton National Park from adjacent Yellowstone National Park after the species had been reintroduced there. The re-establishment of the wolves has ensured that every indigenous mammal species now exists in the park. In addition to gray wolves, another 17 species of carnivores reside within Grand Teton National Park including grizzlies and the more commonly seen American black bear. Relatively common sightings of coyote, river otter, marten and badger and occasional sightings of cougar, lynx and wolverine are reported annually. A number of rodent species exist including yellow-bellied marmot, least chipmunk, muskrat, beaver, Uinta ground squirrel, pika, snowshoe hare, porcupine, and six species of bats. Of the larger mammals, the most common are elk, which exist in the thousands. Their migration route between the