Sagebrush Study to Improve Native Grasses, Sage Grouse Habitat

Friday, August 30 2013

MOSCOW, Idaho –– Thinning old sagebrush stands may give sage grouse more high-quality habitat to spread their wings and prosper.

University of Idaho Extension faculty members plan to test that idea, and whether younger, sparser sagebrush stands can help restore populations of the iconic Western bird.

The study will test two mechanical treatments to remove sagebrush, with the possibility of a third chemical treatment, on approximately 640 acres of private land located in the Medicine Lodge area near Dubois, Idaho. The Lawson Aerator and Dixie Harrow mechanical treatments are designed to crush the sagebrush and reduce cover.

“A lot of people often have the misconception that all sagebrush is good sage grouse habitat, and in reality that’s not always true,” said Amanda Gearhart, UI Extension rangeland specialist.

While sagebrush is valuable habitat for sage grouse, a candidate species under the Endangered Species Act, if the sagebrush is too dense, around 35 to 40 percent cover, there isn’t much else growing, Gearhart said.

UI Extension faculty received an $8,000 grant from the David Little Endowment for a sagebrush canopy reduction study that will look into the economic and biological impacts of sagebrush removal.

The project team includes Gearhart, John Hogge, UI Extension educator, and Neil Rimbey, UI Extension range economist.

“The sagebrush that is in the project site is really at its peak age. It’s 20 to 30 years old, and it’s not very productive sagebrush,” Hogge said.

Removing the sagebrush will allow younger sagebrush, native grasses and forbs to grow, Hogge said. The team is optimistic these habitat changes will attract more birds.

“There are a lot of insects that are in the area when there are lots of grasses and forbs,” Hogge said. “Sage grouse need those during late brood rearing.”

Sagebrush reduction could also provide more forage for domestic livestock.

Not only does the project study the biological effects of sagebrush removal, but the costs associated with the treatments, too.

“Some studies have started to look at these mechanical treatments but most do not include the economic aspect, which is why we wanted Neil Rimbey to join us,” Gearhart said.

As the team’s range economist, Rimbey will estimate the costs of applying each treatment, which will be of particular use to landowners and livestock producers who want to use these treatments to improve their land.

The data from the study will be used by federal and state land management agencies.

“Our primary objective is to improve sage grouse habitat, and we want to provide landowners with useful economic and ecological information about how to treat large tracts of sagebrush that are dense in cover,” Gearhart said.

Pre-treatment data will be collected this summer, with the treatments applied in the fall and post-treatment data collected next spring.