Oregon study confirms that cutting conifers can help sage grouse
I must have looked like an idiot to the folks watching me from the big diesel pickup.
It was a scorching day in July of 2012, and I had been ushered out in front of the rig to toddle down a dusty, high-desert two track behind a line of greater sage grouse hens like a motherless chick, trying to take a photo. Instead, all six of the mottled brown, chicken-sized birds exploded skyward, scaring me witless as they fled like paparazzi-weary movie stars. I paged through the images I had managed to snap as I trotted back: Nothing but rolling scrubby hills and a clear sky marked with the barest hints of distant, retreating sage grouse butts.
“Well, at least now you know we’re not lying about this story,” laughed Patti Bennett as I climbed into the air-conditioned cab. She and her husband Mark Bennett, along with Travis Bloomer and Josh Uriarte of the Natural Resource Conservation Service’s Sage Grouse Initiative (SGI), were taking me on a tour of a federally-funded conifer removal project meant to benefit sage grouse on the Bennetts’ 6,000-acre ranch in Unity, Oregon. The bird’s numbers have plummeted 90 percent across its range over the past century due to habitat loss and fragmentation, among other factors, and it is a candidate for federal endangered species protection, with a decision due from the U.S. Fish and Wildlife Service in 2015. Hoping to help head off the need for such a listing, and the onerous land-use regulations it would come with, the Bennetts and hundreds of other ranchers have signed on with the SGI, which, as I reported for HCN in 2011, relies on
existing conservation incentive programs to fund and facilitate sage grouse conservation on private lands, (home to) some 40 percent of remaining occupied grouse habitat. The program takes a "core areas" approach that sounds a lot like a region-wide version of Wyoming's grouse plan in that it focuses on preventing fragmentation and improving habitat in the approximately 25 percent of occupied grouse range that hosts 75 percent of the remaining population – an area encompassing more than 50 million total acres in 11 Western states.
As we drove, my hosts pointed out the skeletons of juniper trees they had cut and left scattered over the sagebrush-covered hilltops. In some areas where juniper had grown into full forests – places perhaps beyond restoration -- they showed me how the trees had outcompeted other vegetation, leaving the ground beneath them bare of the sagebrush, forbs and grasses that grouse rely on for food and cover.
Based on such changes and anecdotal observations of where the birds are and aren’t, wildlife experts and ranchers have long thought sage grouse avoid conifers, which have encroached on their prime habitat over the past 150 years (juniper, for example, has expanded its range as much as 600 percent in that timeframe) thanks to factors such as fire suppression, cattle grazing and natural and man-made climate change.
But until now, there hasn’t been landscape-level scientific proof to back up juniper removal as a conservation strategy. Last week, the journal Biological Conservation published a Nature Conservancy and Sage Grouse Initiative-sponsored modeling study based on high-resolution maps and counts of male sage grouse visiting leks, or breeding sites, within an approximately 6 million-acre east-Oregon study area. It showed that even a small number of trees were enough to drive sage grouse from leks in areas. Four percent tree cover or more was enough to inspire the birds to abandon these ancestral areas.
That’s important on a population scale, the study says, because 95 percent of sage grouse nests are found within 10 kilometers of leks, and because sage grouse are long-lived birds that produce few young per year, meaning nest success is an important influence on overall numbers.
“This gives us confidence going forward that if we get onto this before a particular sagebrush ecosystem becomes a forest, there’s a high likelihood of keeping birds on that landscape,” says Jeremy Maestas, the SGI’s technical lead in Redmond, Oregon. The SGI has accelerated its annual rate of tree removal 10-fold since the program began, Maestas adds, spending $14 million on clearing 150,000 acres on private land in Oregon alone. The Bureau of Land Management is doing the same on some of its holdings.
Along these lines, the study suggests that all of Oregon’s sage grouse breeding habitat in the early stages of conifer colonization could be treated in the next decade for $9 million a year, which seems within the realm of the possible given that the SGI is putting in about $4 million annually already. Beyond the possible benefits to sage grouse, removing junipers is a clear boon for ranchers; conversion from early-stage conifer encroachment to a conifer forest leads to a significant reduction in grazing capacity, Maestas says.
Of course, the study doesn’t prove that actively removing conifers will bump the birds’ numbers, only that it improves habitat that they occupy or could reoccupy. That’s why the SGI is in the fourth year of a long-term monitoring study of how sage grouse, collared with transmitters, fare in areas where trees are being cleared out. Depending on the results, the agencies and landowners involved will correct and adjust as necessary.
“This is a species that’s going to take constant investment to recover,” Maestas says. “But we have the opportunity here for a win-win across a lot of different fronts. And now, we’ve finally got the scientific validation we need to put the pedal to the floor.”
Sarah Gilman is associate editor of High Country News. Photos courtesy of the author.