Oregon study shows taking out juniper trees benefits sage grouse
A study by Idaho and Oregon researchers showed that when intrusive Western juniper trees go down, r sage grouse populations go up.
Working primarily in Southeast Oregon from 2010 to 2014, researchers compared sage grouse populations in areas where juniper and other conifers had been cut or burned to bird populations in control areas where trees weren’t removed.
Juniper tree removal increased the sage grouse population growth rate by 25 percent compared to the control areas, concluded the study, whimsically named “Better Living Through Conifer Removal: A Demographic Analysis of Sage-grouse Vital Rates.”
More seriously, the work reinforces what rangeland and wildlife scientists have maintained for years: Cutting down junipers has widespread benefit for the sagebrush ecosystem and especially for sage grouse, which at one point teetered on the edge of Endangered Species Act listing.
The study is among the first to link sage grouse demographic rates to conifer removal, primarily juniper. On a landscape scale, the work showed the potential to increase female sage grouse survival and nest survival, “two of the most important demographic parameters affecting population growth,” according to the study.
An Oregon State University researcher who co-wrote the study said the early results are promising, but cautioned that “We’re in this for the long haul.”
“We hope to carry this 10 years out,” said Christian Hagen, a research faculty member with OSU’s Department of Fisheries and Wildlife. “Sage grouse is still an upland bird, it’s susceptible to the mood swings of Mother Nature.”
Hagen co-wrote the study with John Severson, who conducted the research for his doctoral dissertation at the University of Idaho. He now works for U.S. Geological Survey.
Taking out junipers primarily helps sage grouse because it deprives predators of perches from which to attack adults, chicks or eggs. Hawks, crows, ravens and jays prey on sage grouse.
Junipers are notorious for taking up water and crowding out other plants, including native sage and grasses. Removing them “preserves basic sagebrush ecosystem function” by extending water availability. Grazing cattle are among the beneficiaries, leading some ranchers to take up the motto, “What’s good for the bird is good for the herd.”
“From an agricultural producer standpoint, what we’re seeing is that maintaining rangeland and forage production for livestock can be compatible with sage grouse,” Hagen said. While the work may not necessarily increase forage, measured by the Animal Unit Month, it can make the land more resilient when the next fire or drought comes, he said.
“I know it’s cliche, but it is win-win,” Hagen said. “You’re providing sustainable rangeland, water quality and habitat for this bird. If you’re doing that, then our concerns over the species become alleviated over time.”
For the study, researchers collected data on 219 female sage-grouse and 225 nests from 2010 to 2014. The worked in an area in Southeast Oregon where western juniper was being removed and an area with no removal in Southeast Oregon, Northeast California and Northwest Nevada. Both areas involved both public and private lands.
Greater sage grouse use range in 11 Western states and was a candidate for protection under the Endangered Species Act as its numbers declined. Producers warned that habitat restrictions accompanying a listing would hamper or shut down ranching, farming, mining or energy development in wide expanses of the West. At one point, producer groups referred to the potential impact as “the Spotted Owl on steroids.”
However, ranchers, federal agencies and local organizations such as Soil and Water Conservation Districts spearheaded an effort that reversed the situation. Ranchers signed voluntary habitat conservation agreements on private land that protected them from additional regulation in return for such things as marking fences to reduce bird strikes and removing juniper trees. Meanwhile, federal agencies prepared management plans for BLM and Forest Service land.
In September 2015, then-U.S. Interior Secretary Sally Jewell announced an endangered species listing for sage grouse was not warranted.
“The truth is, we’ve never done anything like this before,” Jewell said at the time. She called it the “largest, most complex land conservation effort ever in the history of the United States of America, perhaps the world.”