An unexpected 'moo'

An unexpected sight in most regional parks, cattle grazing is a natural activity on 1,600-acre Santa Teresa Park in Santa Clara, California. The cattle are a part of conservation efforts to rid the park of non-native grasses and restore its threatened butterfly habitat. Credit: Byrhonda Lyons/USFWS

Cattle grazing helps restore threatened butterfly habitat in Bay Area

By Byrhonda Lyons
October 13, 2017

When people escape San Jose for a 10 mile trip south of the city to Santa Teresa County Park, they expect to see spectacular views, nature and wildlife. What  they  don’t anticipate is coming close to thousand-pound animals that ‘moo.’

But that’s exactly what happens when they visit the park nowadays. Cattle are a part of conservation efforts to rid the park of non-native grasses and restore its threatened butterfly habitat.

Santa Teresa Park covers more than 1,600 acres in Santa Clara County, and many of those acres are filled with native grasses that thrive in serpentine soils. The thin rocky soils are comprised of decayed minerals that don’t have many nutrients, but years of pollution from nearby cities has changed the soil and serpentine grasses.

Santa Teresa Park covers more than 1,600 acres in Santa Clara County. Credit: Byrhonda Lyons/USFWS

“The smog from Silicon Valley is basically fertilizing the grasslands,” said Stuart Weiss, Ph.D., chief scientist at Creekside Center for Earth Observation.

It’s called atmospheric nitrogen deposition. The nitrogen in the atmosphere from pollution fertilizes the serpentine soil, making it difficult for native grasslands.

“[Atmospheric nitrogen deposition] is delivering 10-20 pounds of nitrogen to the [serpentine grasslands] per acre per year,” said Weiss, who has studied the effects of nitrogen deposition for decades. “That makes our nutrient-poor serpentine grasslands not so nutrient-poor anymore.”

“The smog from Silicon Valley is basically fertilizing the grasslands,” said Stuart Weiss, chief scientist at Creekside Center for Earth Observation. Credit: Byrhonda Lyons/USFWS

Serpentine grasslands are critical for many wildlife species that depend on its native grasses for habitat. One of those species is the bay checkerspot butterfly. Over the years, the butterfly’s population has significantly declined, leading to it being listed threatened under the federal Endangered Species Act in 1987. Since then, local scientists have worked to establish conservation methods that will protect the species and improve serpentine grasslands.

“Because of the nutrient deposits, non-native annual grasses grow really thick and strong, and they thatch over,” Weiss said. “So you end up with a layer of thatch that’s smothering all of the [native] wildflowers that the butterfly needs.”

One way to fight back against the non-native grasses choking out serpentine grasslands is through cattle grazing.

Grazing at the Park

Before Santa Teresa County Park was open to the public, the area was privately owned and operated by ranchers.

About 490 acres of serpentine soil grasslands are enhanced with wildflowers due to managed grazing at the park. Credit: Byrhonda Lyons/USFWS

“This [park] was grazed as private ranches,” said Don Rocha, deputy director of Santa Clara Parks. “At that time, we were buying parcels and the parks department was taking cattle off the land. Volunteers were coming in and pulling out the infrastructure, the fence lines and everything that was associated with cattle grazing.”

But around the late-1990s, things began to change. Weiss wrote a scientific article highlighting the benefits of cattle grazing for checkerspot butterfly habitat in 1999. The U.S. Fish and Wildlife Service designated the Santa Teresa County Park as critical habitat for the butterfly. The park’s serpentine soils, which produce native grasslands, require special management considerations, such as grazing, in order for the butterfly to survive.

“It took a while for us to get the momentum to bring the cows back and identify the funds to construct the infrastructure to manage the cattle in a way that is compatible with public access and park operations,” Rocha said.

After years of thinking about it and educating the public to the idea of having cattle in the park, “the plans started to align,” Rocha added. Both the Service and the Bureau of Reclamation awarded Santa Clara Parks almost $800,000 to reestablish grazing infrastructure in the park. The funding is through the Central Valley Project Improvement Act Habitat Restoration Program and the Central Valley Project Conservation Program. Both programs protect and restore native habitats and stabilize and improve native species populations that were impacted by the Central Valley Project. Projects are selected through a competitive solicitation process.

“We’ve worked with ranchers, and their goals are pretty much the same as ours; removing the non-native grass every year,” said Dr. Stuart Weiss. Credit: Byrhonda Lyons/USFWS

“Our grants provided funds to install fencing, water troughs, water tanks and corrals,” said Caroline Prose, the U.S. Fish and Wildlife Service's co-program manager for the restoration program. “Having the cattle out there grazing will also control invasive grasses, increase biodiversity and reduce the risk of fire from thatch build-up.”

About 490 acres of serpentine soil grasslands are enhanced because of managed grazing at the park.

“It took a while for us to get the momentum to bring the cows back and identify the funds to construct the infrastructure to manage the cattle in a way that is compatible with public access and park operations,” said Don Rocha, deputy director of Santa Clara Parks. Credit: Byrhonda Lyons/USFWS

“We’ve worked with ranchers, and their goals are pretty much the same as ours; removing the non-native grass every year,” said Weiss.

The infrastructure was installed at the park in 2016, and the cattle have been grazing there ever since. Park visitors are bound to see cattle from a distance or even spot cow pies near some of the trails, but even if people don’t see evidence of cattle, it’s difficult to miss the huge signs that let folks know the cows are nearby.

“There aren’t inherent conflicts between cattle and park operations,” said Rocha. “Cattle grazing provides a much-needed conservation benefit for all of us, and an enhanced recreational experience due to the resulting wildflower displays and return of serpentine flora and fauna. “The parks department will be increasing its outreach to added conservation benefits for all of us.”

Park visitors are bound to see cattle from a distance, but even if people don’t see them, it’s difficult to miss the signs that cows are nearby. Credit: Byrhonda Lyons/USFWS

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Byrhonda Lyons

About the author...

Byrhonda Lyons is a public affairs specialist and social media coordinator for the Pacific Southwest Region's external affairs office located in Sacramento, California.

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