Replanting to Aid Glacier's Grizzlies
Scientists plant whitebark pine to provide future bear food.
GLACIER N. P., MONT.— Grizzlies love seeds. And Glacier ecologist Tara Williams plans to produce enough seed-bearing trees to augment food supplies for the region's grizzly bears for at least the next hundred years.
Williams and her crew have begun planting whitebark pine saplings in patches of recently burned subalpine forest in hopes of providing a sustainable food source for grizzlies. The intent is to keep the animals in the high country, away from human garbage cans and campsites where they seek food in lean years and are often destroyed as a result.
The whitebark pine's seeds are a favorite and valuable food source for the grizzlies, and the bears will feed exclusively on the fatty, high protein seeds from August to autumn if they are available, said Kate Kendall, a grizzly bear researcher for the U.S. Geological Survey. Unfortunately, the pine population has declined severely in the last several decades because of fire suppression and white pine blister rust, a fungus introduced in 1910 on a load of lumber from France.
The disease has killed nearly 45 percent of the whitebark pine trees in Glacier, and it's estimated that of the remaining trees, 85 percent are infected with the disease and unlikely to survive. Fire suppression has exacerbated the decline because the trees—which can live more than 1,000 years and grow so gradually as to be almost unnoticeable—need intense sunlight. Without fire to burn away large shrubs and trees, whitebark pine saplings are shaded, and their seeds are robbed of the newly enriched soil needed to germinate.
Other species—squirrels and Clark's nutcrackers—play an integral role between grizzly bears and whitebark pine. Red squirrels cut the cones and drop the seeds to the ground, caching the cones in large middens that bears eagerly raid. Forgotten or unused nutcracker caches of up to 20 seeds can germinate into new trees.
Three years ago, researchers began collecting seeds by placing protective coverings on the tops of the trees and gathering them at a later time. They chose healthy trees in the midst of dying trees, hoping that the living trees had survived because of a natural resistance to the disease.
Of the 1,500 saplings that Williams planted last spring, nearly one-third were lost.
"We were grateful we didn't lose more during the severe drought conditions we had this summer, and it has made us think that it would be better to plant them in the fall."
When planted in autumn, the trees go into dormancy immediately and are spared risking the difficulties of surviving through drought conditions. The group planted an additional 1,500 this fall and will need to wait until next spring to see the results.
