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Whitebark pine is a foundation species, and barometer of the health of high elevation forests ecosystems in the West. It provides food and cover for numerous wildlife species, including the Clark’s nutcracker, crossbill, grosbeak, red squirrel and chipmunk. Whitebark pine is particularly important in the Greater Yellowstone Ecosystem (GYE), where it provides an essential food source for the imperiled Yellowstone grizzly bear. We will review the current scientific knowledge about the relationship between Yellowstone grizzlies and whitebark pine seeds, and examine the implications of the collapse of whitebark pine. High-fat whitebark pine seeds are important for female reproductive success: females produce larger litters after abundant whitebark pine seed crop years. And, by growing at high elevations in remote country, whitebark pine helps keep grizzlies out of harmís way, reducing human-grizzly conflicts and mortality rates. After poor whitebark seed crop years, grizzly bear mortality in the GYE occurs at more than twice the rate than after good pine seed years. The collapse of whitebark pine in the GYE bodes ill for the future of the Yellowstone grizzly bear population. We will demonstrate the connection between recent years of excessive human-caused grizzly bear mortality and declining whitebark pine in the GYE. We will summarize recent analysis of additional suitable grizzly habitat within the GYE and between the GYE and other grizzly populations in the lower 48 states and Canada. Using recent over-flight assessments of whitebark pine mortality from mountain pine beetle, we will identify priority areas for bear conservation in the GYE. We will demonstrate the need for: 1.) improved measures to reduce human-bear conflicts; and, 2.) new policies that allow Yellowstone bears to access additional habitat needed to offset the loss of whitebark pine. |
