A tiny bug threatens the Tetons

Tall pines at the base of the Grand Tetons in Wyoming, where climate change is threatening the ecosystem (Beveridge photo)

By Scott Beveridge

GRAND TETON NATIONAL PARK, Wyo. – The story of the mountain pine bark beetle can best define how climate change is harming the ecosystem at the majestic Grand Teton National Park.

Warmer temperatures in recent years have been allowing that tiny native bug to breed faster and destroy more tall pine trees whose pine nuts support the diets of grizzly bears and even a  breed of small bird at this mountain range.

"The large pine nuts are a good source of protein and fat," explains National Park Ranger Karen Kanes while giving a climate change lecture today at the visitor center in Moose, Wyo.

The average temperature has risen in recent years by 1.6 degrees from those recorded over the past 1,300 years. That might not sound like much, but it's a number just 9 degrees warmer than it was during the Ice Age, Kanes said.

The beetle bores into the trees to feed and reproduce, killing pines and turning them red and purple before they fall over. The bug used to hatch eggs every two years while nature allowed some pines to find ways to resist it, while new trees sprouted.

So the beetle wasn't of much concern until the warmer weather allowed it to begin hatching new eggs every year. This year, it hatched twice, Kane said.

"They dryer conditions enabled it to go higher and kill whitebark pines, which produce the large pine nuts," she said. This development threatens to devastate the forest, along with the diet of the Clark's nutcracker, a member of the crow family.

The bird has a large beak, which allows it to pick open the pine cones during warm weather, collect large numbers of the seeds and bury them for its winter food supply. The reproduction of the whitebark pine depends entirely on the bird to forget the locations of some of the seeds it buried.

Meanwhile, the park staff is testing ways to slow the spread of the beetle, which emits pheromones to alert others there is nothing left to feed on in a pine tree. The park is attempting to stash the pheromones on healthy trees to ward off the beetle in what would be an expensive measure to slow the tree damage given the size of the forest, Kanes said.

The U.S. Forest Service also will spend $40 million to slow the spread of the bug in the Rocky Mountains where it has destroyed more than 2 million acres of trees, the Associated Press reported this year.

This story would not be told, though, had it not been for a dramatic climate change thousands of years ago, which melted glaciers covering the United States and left it with many of  National Park landscapes, she said.