Global Warming Endangers the Lives of Grizzly Bears

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Global Warming Endangers the Lives of Grizzly Bears There are less then 1000 grizzly bears left in the lower 48 United States, around 400 of them live in Yellowstone National Park. These endangered, and beautiful bears, are threatened by many factors, most significantly the fragmentation of their habitat by roads. The latest threat to this species is the Global Warming trend that is threatening the White Bark Pine Tree, which is very important to the grizzly bear diet. Grizzly bears need to eat a great deal of fat in the fall in order to prepare for hibernation. Female grizzlies who don't get enough fat may develop fertility problems. White Bark Pine trees produce pine nuts that are considered to be the grizzly bears favorite food and provide up to 40% of the fat they need. Global Warming threatens the White Bark Pine in two ways. First it reduces the area in which the trees can grow. They depend on a cool, alpine habitat, so as the climate warms they are forced to grow higher on the mountains. Since mountains are conical the higher they go, the less space there is for them to grow. Second, the warming climate creates fog banks in which European Blister Rust thrives. European Blister Rust is a plant disease that was accidentally introduced into the Pacific Northwest in 1906. Blister Rust girdles the infected tree, eventually killing it. Since the introduction of this disease more than 98% of White Bark Pine stands in the northwest have been destroyed. In recent years Blister Rust has been noted getting closer and closer to Yellowstone Park. White Bark Pine stands in Waterton Lakes National Park, Alberta and Blackfoot Reservation, Montana have suffered serious declines. Nearly 30% of the White Bark Pines in these areas have been killed and more than 70% of the remaining, living trees are infected. In the past five years Blister Rust has been seen in Gallatin National Forest, just south of Yellowstone, where Yellowstone grizzlies often forage for food. How does this threat to the White Bark Pine Tree also threaten Grizzly Bears? In two ways. First since the White Bark Pine Tree provides as much as 40% of the fat requirement of grizzlies, the loss of the White Bark Pine directly threatens the fertility of female grizzlies. With only 400 grizzlies living in an isolated pocket around Yellowstone Park, a threat to their fertility is a grave threat to their very existence.

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