Earthquake Swarm, Wildlife Counts, and Decline in Whitebark Pine Infestation Detailed in Annual Report on Yellowstone's Ecological HealthIn 2010, Yellowstone National Park experienced more than 3,200 earthquakes, the grizzly bear population in the Greater Yellowstone Ecosystem reached 602, and 7 percent of Yellowstone's 281,700 acres of whitebark pine were infested with beetles, down from 15 percent in 2009, according to the 2011 Yellowstone National Park Natural Resource Vital Signs report, released by the Yellowstone Center for Resources last month. The report details influences in and outside the park that affect its overall ecological and environmental stability.
The report outlines the current and historical status of 25 Yellowstone vital signs. They fall into four categories: ecosystem drivers, such as climate, fire, and geothermal activity; environmental quality, including air and water quality; native species, including bald eagles, wolves, grizzlies, bison, elk, western cutthroat and Yellowstone cutthroat trout, and amphibians; and stressors, including nonnative plants and animals, disease, park visitation, and land use.
The report noted that the 2010 growing season was 118 days, up from an average of 88 days from 1985 to 1996; half the park's bison population approached park boundaries during last winter's heavy snow, with 800 being fenced and hundreds more allowed outside the park until spring; the northern range elk count was 4,635 in early 2011, the lowest since the 1960s, attributed to wolf and bear predation and possible drought-related effects; the park wolf population dropped to 97 but numbers increased beyond the park; reproduction of westslope cutthroat trout was documented in High Lake; and the invasive lake trout population in Yellowstone Lake likely has increased faster than the fish are being removed, though new efforts continue to change that.