Moooove over conservation corps, the cows are here to help!
Cows are being put to work to help conserve native prairies! A group of ranchers, land managers, and ecologists are working together to explore a creative option for preserving native prairie habitat in the Willamette Valley: prescribed cattle grazing.
What’s so special about native prairies?
Prairies are a unique and important habitat in the Tualatin River watershed. They support a diversity of plant and animal species, many of which are state species of concern.
Periodic burning by Native Americans and grazing by elk helped prairies thrive for centuries, by preventing woody species from moving in while increasing the diversity and productivity of wildflowers and grasses. Prairie, and the related oak savanna, were once common throughout the Willamette Valley. But today, less than 10% of its original extent remains due to urban development, conversion to agricultural lands, fire suppression, and invasion by non-native weeds.
Prescribed burning to restore native prairies:
Land managers and partners are working to restore remnant patches of this habitat to ensure it remains on the landscape. This is a challenging task because prairies are disturbance-dependent, meaning the ecosystem thrives on occasional natural disturbance. While prescribed burning is a management option in some areas, this practice is difficult to implement in populated areas like Washington County.
How can cattle help?
That’s the question TSWCD Conservation Specialist Nicole Ruggiero has set out to answer by experimenting with prescribed cattle grazing. If cows are allowed to graze the prairies at certain times of year, they may create the type of disturbance the prairies depend on to maintain native biodiversity and prevent infestations of invasive species—giving land managers an alternative to prescribed burns. Prescribed grazing is already being used in other habitats that were once occupied by large grazers. The key is to figure out the best practices for applying this technique in Willamette Valley native prairies.
Science in action!
In a study at two sites in Washington County, Nicole and her collaborators at Ash Creek Forest Management, LLC observed that the grazing cattle are, in fact, creating enough disturbance to alter the plant community. For example, only a few weeks of grazing reduced the amount of unwanted plant material and cleared space for many small, annual plant species.
Now that we know cattle are creating a disturbance, further understanding the plant community’s response is needed. The Tualatin SWCD Board approved funding to extend the monitoring of this research project for several more years, and extended its scope to two additional sites. The hope is to determine whether grazing cattle in native prairies can create benefits similar to those resulting from a natural disturbance.