Cattle grazing – along with forest thinning and prescribed burning – has been an effective way to help manage and reduce invasive weeds south of the National Center for Atmospheric Research.

The City of Boulder today worked with local ranchers to return cattle on open space south of the National Center for Atmospheric Research. Their return to open space is part of long-term city work to support diverse and healthy native plant communities and help reduce wildfire risks on open space.

This year will mark the 10th year that City of Boulder Open Space and Mountain Parks (OSMP) staff has worked with local ranchers who lease open space agricultural land to conduct cattle grazing south of Boulder. Long-term monitoring of cattle grazing, which is the most cost-effective tool to manage vegetation in the rocky open space area, has shown it is an effective way to reduce invasive weeds that can fuel wildfires.

More recent observations have indicated the land management practice – when combined with fast actions from first responders and other city work to address wildfire risks, such as prescribed burning and forest thinning – helped slow the March 2022 NCAR Fire and kept it from becoming a more intense fire.

Cattle grazing south of Boulder also helps to support ecosystems by removing tall oatgrass, a highly invasive weed species. Tall oatgrass is a non-native and invasive weed that quickly forms dense spreading stands that prevent native vegetation from receiving essential light, moisture and nutrients. Its spread:

  • Creates additional fuel for wildfires, increasing fire risks for Boulder neighborhoods.
  • Threatens rare and uncommon native grassland plant communities, including globally imperiled tallgrass prairie.
  • Can impact a wide range of wildlife species – such as grassland birds, mule deer and wild turkey – that depend on OSMP’s more diverse native plant communities.

City of Boulder Open Space and Mountain Parks staff will rotate cattle in five different areas south of Boulder through the end of June. OSMP reminds open space visitors to be mindful of cattle when recreating south of Boulder. Cattle can be aggressive, particularly if there are calves present. Remember:

  • Do not approach cattle.
  • Do not damage/remove a gate.
  • Never get between a cow and her calf.
  • Leash dogs in areas where cattle are present.
  • Maintain a safe distance.
  • Always close gates behind you!

OSMP anticipates rotating cattle through these five pastures from May 15 through July 1.

Map showing where cattle grazing will occur on Shanahan Ridge south of Boulder