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The value of sagebrush: West’s old growth offers habitat for unique species, moisture for the landscape

Research assistants Chelsea Merriman, standing, and Adrian Rus place markers that can be seen from the air in a research plot of sagebrush. Three subspecies of sagebrush, grown from seeds from a variety of places in the west, were planted to see which would survive best, and researchers are hoping that aerial views with multi-spectral and thermal imaging will help simplify identification.
Research assistants Chelsea Merriman, standing, and Adrian Rus place markers that can be seen from the air in a research plot of sagebrush. Three subspecies of sagebrush, grown from seeds from a variety of places in the west, were planted to see which would survive best, and researchers are hoping that aerial views with multi-spectral and thermal imaging will help simplify identification. kjones@idahostatesman.com

Driving from Utah to run Idaho’s whitewater rivers a decade ago, Jennifer Forbey dismissed the sagebrush that lined Interstate 84 as ugly.

Since then, however, the Boise State University biology professor has fallen in love with an ecosystem that is iconic to the West.

“The way I see sagebrush is as a rugged survivor,” said Forbey, while leading a reporter through a thick stand in Boise’s Foothills.

Forbey has gotten to know sagebrush well through her studies of the sage grouse and pygmy rabbit, which actually feed on the bitter-tasting, toxic plant. Her research shows that these two species are completely dependent on sagebrush during the winter and have the ability to find the plants that are least toxic and have more protein and other nutrients.

“Sagebrush survives partially through chemistry,” Forbey said. “Chemistry protects it from heat, ultraviolet light and those animals that would eat it.”

But its chemistry has not protected it from human development over the past 150 years. When settlers arrived, nearly 300 million acres of what is now 11 states was a largely contiguous sagebrush ecosystem. Today nearly half of the complex landscape that evolved since the Pleistocene is gone, turned into farms, converted into grasslands or fragmented by roads to mines, ranches, and oil and gas rigs.

MORE THAN ONE BIRD

Biologist Kathleen Hendricks of the U.S. Fish and Wildlife Service in Boise points out that of the more than 300 species that live in and depend on the sagebrush habitat, about 50 — including sage grouse and pygmy rabbits — couldn’t survive without it. It provides winter range for mule deer and elk, habitat for pronghorn antelope and homes for the small prey that raptors, including golden eagles, feed on.

That brings people to the sagebrush country, including hunters, wildlife watchers, campers, mountain bikers, hikers, motorcyclists and even anglers. A study by EcoNorthwest done for the Western Values Project and the Pew Charitable Trust found that 13.8 million visitors spent $623 million in 2013 in communities within 50 miles of sagebrush recreation sites. Those figures don’t include the money spent on recreation outside the zone, such as guns, ammunition, campers and other equipment.

But the ecological services that the sagebrush steppe provide to society might exceed these other values.

Mike Pellant, a BLM ecologist from Boise, said sagebrush has evolved in the arid West to provide watershed protection, much the way trees do in forests with far more precipitation. Its vast root system holds moisture and sends it deep into the ground.

Sagebrush grows as high as 6 feet also captures snow like a fence, allowing it to melt slowly and sink deep into the ground. The shrubs prevent the floods and erosion that occur when fire removes the sagebrush and allows invasive cheatgrass to gain a foothold.

“Where we have bare ground, we have more erosion,” Pellant said.

Cheatgrass not only doesn’t hold the soil like the shrubs when flooding occurs, but it also doesn’t hold the moisture. The grass quickly dries out, along with the soil and its bacteria, fungi and other tiny organisms.

“Our soil fertility is declining over time with cheatgrass,” Pellant said. “We’re losing the ability to get back our native plants.”

The sagebrush ecosystem also stores more carbon than the cheatgrass that replaces it. One study near Boise showed that carbon sequestration dropped to a fourth when cheatgrass took over from sagebrush, Pellant said.

“The sagebrush ecosystem is very productive,” Pellant said. “It has evolved over thousands of years to support a very diverse community, including pollinators that are critical for our crops.”

Comparing the sagebrush sea to a rainforest is not a reach, Pellant said.

“Given the amount of rain we have, the diversity and productivity of the sagebrush steppe is remarkable,” he said.

NATURE’S ‘NOTEBOOK’

The more we learn about sagebrush and the other species of the steppe, said Forbey, the more we’re learning about its value.

“This is our old growth,” Forbey said. “This is our resource.”

There are many species of sagebrush species, and great diversity among individual species, Forbey said. That complexity applies as well to its chemistry.

“Each leaf has 300 to 400 unique compounds,” Forbey said.

Forbey is working with others, including Carolyn Dadabay, an associate professor of chemistry at The College of Idaho in Caldwell, on potential medical uses of sagebrush.



Since some of the chemicals it produces prevent animals from getting rid of the toxics they ingest when they eat it, researchers are studying whether those compounds might help cancer patients in chemotherapy.

When cancer becomes more aggressive, cancer cells develop the ability to reject medications. If the researchers can find the chemicals that keep the toxins in the sagebrush-eaters, they hope they might work the same way on cancer cells. Forbey said there are other possible medical uses as well.

“We are only beginning to understand sagebrush,” Forbey said. “This is a living notebook. ... When we lose it, all that information is gone.”



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