By Sylvia Kantor, College of Agricultural, Human & Natural Resource Sciences
OLYMPIA, Wash. – Carefully managed cattle grazing can improve weed control, plant health and plant diversity on native prairies, according to anecdotal evidence. However, no systematic study has attempted to track the impacts of managed grazing on native prairie plant communities in western Washington – until now.
Scientists at Washington State University, in partnership with the U.S. Department of Defense (DoD) and the nonprofit Center for Natural Lands Management, will study how “working landscapes” might support habitat conservation goals.
Much of Washington’s remaining native prairie lands are in southern Puget Sound, including on Joint Base Lewis-McChord (JBLM ) in Thurston County. These prairies support a diverse array of plant and animal species at risk of extinction. These include native golden paintbrush, Taylor’s checkerspot butterfly and the Mazama pocket gopher, which was recently listed as threatened under the federal Endangered Species Act.
These prairies are the focus of the Sentinel Landscape pilot project, a federal, local and private collaboration intended to preserve agricultural lands while restoring and protecting more than 2,600 acres of public and private prairies and wildlife habitat.
At the same time, the $12.6 million project – funded by the DoD, the U.S. Natural Resources Conservation Service and the U.S. Fish and Wildlife Service – will reduce restrictions to military training activities on JBLM land.
“This is a unique partnership between agricultural and conservation professionals looking to improve productivity and conserve species,” said Lucas Patzek, director and agriculture faculty for WSU Thurston County Extension. “It’s part field research to study how we might be able to integrate native plant species into working livestock operations … and it’s part outreach.”
The three-year study includes plots on Fred Colvin’s 550-acre black and red Angus cattle ranch. Fencing and research plots were set up last fall to measure differences between excluding cattle and allowing them to graze.
Certain fields are managed to improve native plant diversity and cover, while others are managed for a mixture of non-native species such as orchardgrass and tall fescue.
“They’re trying to figure out whether cattle can be part of a commercial operation plus help as far as the prairies are concerned,” Colvin said. “Frankly, if you don’t have ag on these prairies, you might as well write the prairies off. Because what’s the other alternative use? Forestry? That won’t work. Pavement? I’ll tell you the pocket gopher can’t live under pavement.”
As the Sentinel Landscape project moves forward, Colvin wants to be sure the needs of the landowner — the ability to have a productive and profitable farming operation — are given priority.
Managing intensive grazing
To introduce producers to the concept of integrating livestock with prairie habitat conservation, Patzek developed a unique three-part managed intensive grazing course.
Colvin and more than 60 other participants who took the course this summer learned about the importance of designating areas for livestock to graze when native plant pastures are dormant and deferring grazing during critical growth periods of the native species.
It’s too early for results, but Patzek expects to find that, through prescribed management, cattle will selectively graze non-native perennial grasses that limit establishment and growth of native species. He also expects cattle hoof action will more readily return organic matter to the soil and promote seed contact with soil for improved rates of germination of native plants like golden paintbrush.
It can take a couple of years for native plants to get established, so Patzek expects the research will continue as part of a long-term restoration and management project.
In the meantime, he will continue to offer workshops for private landowners to better manage agricultural endeavors in western Washington prairie ecosystems. A series of fall workshops will teach agricultural producers how to conduct ecological site assessments.