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Bay Checkerspot Butterflies thrive in areas managed with cattle grazing.

UC Cooperative Extension helps bring cattle grazing back to Bay Area grassland

To conservationists, it seemed like a good idea. Pull lumbering, voracious cattle from grasslands acquired for preservation, and the land will return to its primeval glory.

However, natural California has changed in the last 200 years – changes that have given non-native plants an edge over native species when there are no cattle grazing the land.

University of California Cooperative Extension (UCCE) natural resources farm advisor Sheila Barry has researched the modern evolution of California grassland and low-impact rangeland management techniques. She works closely with land managers in the Bay Area, which is now witnessing a resurgence of managed grazing on open land.

A major benefit of grazing open grassland is fire fuel management, Barry said. However, she believes an even more important driver is improving the habitat for threatened and endangered species, such as the red-legged frog, the California tiger salamander, the Western burrowing owl and the golden eagle.

Even insects profit from grazing. Barry considers the Bay Checkerspot Butterfly to be the “poster child of grazing benefits.”

“It’s a classic story,” she said. “The only remaining populations of this butterfly are on grazed lands. In areas that were specifically set up for conservation and where cattle grazing was eliminated, the butterfly populations have disappeared.”

Grazing has a long history in California

In ancient California, ground sloth, bison, camels, mammoths, mastodons and oxen survived on a diet of native flora. When these large herbivores became extinct about 10,000 years ago, pronghorn antelope, black-tailed deer, tule elk, grizzly bear and small mammals continued to impact California grasslands.

The discovery of gold in 1848 caused a population explosion in the state, a population that brought with it a hunger for meat. The ranch industry boomed. Under more intensive grazing, and with long-distance travel becoming commonplace, non-native plant species, mostly from Europe, became the dominant plant species on California grassland. Today, only 5 percent of plants on grassland are native species.

“The European plants are very prolific and very competitive,” Barry said. “Removing domestic grazers does not make them go away.”

Early ranchers, perhaps instinctively, began managing their cattle using a combination of fencing, water trough placement and salt licks to disperse the livestock over the range. That helped control the most problematic exotic plant species.

“We don’t know if the ranchers really understood all the benefits of these common practices, but we now recognize what can be achieved when grazing is carefully managed using these and other techniques,” Barry said.

Conservation organizations and environmental groups, like the Midpenisula Open Space District and the Committee for Green Foothills, became alarmed by poorly managed overgrazed pastures, trampled plants and eroded hillsides in the 1990s. They pushed to acquire grassland and remove the cattle. However, a landscape of unsightly coyote brush, poison oak and pampas grass – generating abundant fuel for potential fires – wasn’t the outcome they were looking for. Working with UCCE, the California Farm Bureau Federation, U.S. Department of Agriculture, Natural Resource Conservation Service and consultants, the groups began to develop a plan for reintroduction of grazing. The Midpenisula Open Space District is expected to open its 5,000 acres of San Mateo County grasslands to grazing this spring.

Bay Area public lands already being managed by cattle grazing

This is not the first example of public lands being managed by grazing. Barry said the East Bay Parks District owns and manages 100,000 acres. They graze 7,000 cattle on 60,000 acres of the land. Cattle also graze the San Francisco Bay National Wildlife Refuge in Fremont and land around the San Antonio and Calaveras reservoirs owned by the San Francisco Public Utilities Commission.

Grazing is managed by controlling season of use and intensity, especially in sensitive areas. Livestock water, supplemental feed and salt are used to control grazing distribution. Barry has been collaborating on a USDA-funded research project with other advisors and UC range specialist Mel George to further understand the effectiveness of livestock distribution in working towards resource management objectives. The project, known as “Cows in Space,” uses global positioning collars to monitor the location of livestock on rangeland pastures at the Sierra Foothill Research and Extension Center in Browns Valley, Yuba County.

Barry credits ranchers’ efforts over the years to implement conservation-minded management practices for illustrating the benefits of grazing to control vegetation and preserve wildlife habitat on public land.

“These land management agencies are conscientious about the total ecosystem impact from grazing,” Barry said, “just as ranchers have been for decades.”

(February 2007)

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