All that work restoring grizzly bear populations, and now this: A major source of fat for their hibernation, the whitebark pine nut, is disappearing. Warming temps have allowed the mountain pine beetle, usually frozen out of the trees’ terrain, to thrive. In some areas, like Avalanche Ridge, the pests have started eradicating entire forests. And tree species with higher resistance to climate change–like the lodgepole pine–are displacing whitebarks. There’s also the ever-present threat of massive wildfires, à la 1988; long-term Western drought, early runoff, and hot summers all increase the chances of park-altering conflagrations.
12. ISLE ROYALE
Species exist in a delicate balance in this 45-mile-long island park, and that balance is increasingly out of whack. Scientists at the Isle Royale Institute have been studying wolves and moose for 50 years, and their latest findings are grim: In 2002, more than 1,000 moose lived here; now there are 385. As deciduous trees replace conifers like balsam firs–a common phenomenon in the Midwest as rising temps push out boreal forests–the moose lose their food supply. With milder springs, ticks multiply to such levels that they lead to anemia and hair loss in moose. With hotter summers, moose lose their appetites and thus their strength for winter. When their numbers drop, wolves hunt the hares on which red foxes depend, and eventually both predators run out of food. University of Michigan researchers forecast that if the mercury keeps rising, the moose population will crash between 2025 and 2040–with wolves following suit in the two ensuing decades.
13. CHANNEL ISLANDS
Comprising five islands off the coast of Santa Barbara, CA, this park is threatened both above and below the waterline. Up on terra firma, trees such as the bishop pine can’t tolerate higher temperatures, and other vegetation–which holds dunes in place, keeps soil from drying, and prevents eroding drainages called arroyos from forming–could die off. If the dunes become active, “the islands could look like a bloody desert,” says Daniel Muhs, a USGS geologist. As ocean temps spike, marine invertebrates may begin migrating north, and the rich, upwelling currents off California’s coast could become less productive, with fewer organisms at the bottom of the food chain. Of course, sea-level rise could have a huge effect on land: As beaches erode, seals and sea lions lose their habitat; sea cliffs would get undercut, and thus retreat; and sea caves will flood.
14. MESA VERDE
In 2000, fires burned more than a third of this Colorado archeological wonder, closing it for three weeks. In 2002, another 2,600 acres burned, destroying staff housing and shuttering the park for two more weeks. Counting three other big blazes, more than half of this park has burned in the last seven years. The piñon-and-juniper forests take three centuries to regenerate. And because it’s small (52,000 acres), surrounded by development, and situated atop a self-contained plateau, its tree species–like the piñon pine–have nowhere to migrate when temperatures rise. A study by the Rocky Mountain Climate Organization found that high temps and drought could eventually eliminate Mesa Verde’s forests.
15. Wrangell-St. Elias
In a June 2007 report by the NPCA, Mark Wenzler describes flying over hundreds of acres of what looked like charred spruce trees in this Alaska park. “The grayish brown skeletons,” he discovered, “were the remains of a spruce bark beetle invasion.” Millions of Alaska trees have been killed because the bug is suddenly thriving in a changing climate. As in Glacier Bay, tundra is disappearing, taking caribou herds with it. Wrangell-St. Elias is also home to famed Copper River salmon, which might not withstand warmer water–or the loss of closed-basin tundra ponds, which have decreased by half in the Copper River Basin.