Courtesy of the Bureau of Land Management
HAMMETT, Idaho — The Bureau of Land Management and a local ranching family have completed the first three-year cycle of a planned nine-year collaborative study using management-intensive grazing to restore native perennial plants to landscapes where they’ve been choked out by invasive weeds.
The terrain along Interstate 84 from Twin Falls to Mountain Home is covered by invasive annual cheatgrass and medusahead, which overwhelm native plants and burn readily. Wildfires often force ranchers off of important pasture for a couple of years until vegetation regrows.
Several years ago, local ranchers Bob Howard, John McGrew and Steve Damele started a long-term demonstration project on their private land, hoping to convince the BLM of the merits of increasing grazing densities on public allotments to improve rangeland health, thereby decreasing the prevalence of fires.
In 2012, the ranchers hired range specialists with Wilder-based Intermountain Rangeland Consultants to document their progress with data and scientific analysis.
Their consultant, Dan Ogle, explained the ranchers have been grazing land at higher densities in the winter and spring for short durations, feeding on annual invasive plants when they’re green and provide good forage, but before native perennials have emerged.
Ogle regularly checks improvements in range health by evaluating “transects,” encompassing three 100-foot lines stretching in different directions. The lines include 50 points, at which Ogle records the species composition throughout the plant canopy.
“They do have some improvements in perennials at many of the sites they were monitoring,” Ogle said.
On Damele’s land, Ogle has noticed growth in populations of a native “species of concern” called slickspot peppergrass. Though he acknowledges increased precipitation during recent years could account for some of the plant’s gains, he said it’s clear intensive grazing hasn’t caused damage. Ogle also has data from a transect on Howard’s private land showing perennials increased from 16 percent of the biomass in 2013 to 20 percent in 2017. He’s been especially pleased by the spreading of native Sandberg bluegrass.
In 2014, the BLM and the Howard family partnered on a more in-depth version of the study on the BLM’s Rattlesnake Seeding Allotment.
The public study encompasses 48 transects. BLM staff have been recording data from half of the sites, and the Howards have paid Ogle to monitor the remaining transects.
Howard’s daughter, Jessica Oldham, said fields are fenced into small pastures, which are intensively grazed early during the first year, at a middle timing during the second year and late during the third year. Cattle rotate pastures every 10 to 20 days. Oldham said progress toward reducing annual invasive plants has been slow, due to their high densities, but she’s optimistic the data will ultimately convince BLM managers that they’d be wise to step up grazing pressure, with the timing and density based on actual fuel loads rather than rigid policies. She believes her family’s investment will help generate data to base improved regulations.
“(BLM managers) all seem to want change, but they’re so terrified of being sued that they won’t implement it,” Oldham said.
BLM Ecologist Joe Sirotnak said the partners in the project have scheduled a meeting for Dec. 6 to evaluate data from the first full three-year rotation of the Rattlesnake project.
“I think ultimately cooperating with ranchers is the best way to do this (research),” Sirotnak said. “I think it would be really wise to expand this type of thing to different habitats.”