While the flora of Grand Teton National Park is generally healthy, the whitebark 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 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.