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UC Davis Magazine

Volume 29 · Number 4 · Summer 2012

Common ground

Ranchers, environmentalists and policymakers unite to protect water quality on California rangeland.

Portrait photo: the doctor, smiling, and wearing dress shirt and tie

Robinson Creek flows through a meadow where cattle graze in Mono County's Bridgeport Valley.

(Ken Tate/UC Davis)

Plymouth, Amador County — Chris Gansberg's jeep bounces like a stagecoach along this rambling, rangy land — land green as clover, wide as the blue Western sky. "Hang on now, it gets a little bumpy," Gansberg says, turning his four-wheeler as if it were a mare, all grace, power and dare.

Chris '66 and his wife, Faye, who also attended UC Davis in the '60s, are giving a tour of their 3,000-acre ranch near the Amador County town of Plymouth, where cattle graze and wildlife roam on ground still damp from a needed spring rain. "We have all sorts of animals out here — kit fox, coyote, bull frogs, hawks," Faye says. "My sister is a bird-watcher and she says we have 50 species of birds."

Chris brakes for a covey of quail and the scent of earth rises like mist.

California has 30 million acres of rangeland like this, roughly one third of the state. Most of the land is privately owned and managed for livestock production — and that holds big implications for the food we eat and the water we drink. Some 80 percent of the state's irrigation and drinking water passes through or is stored on rangeland. All the water and all those animals raise a serious concern:

Can microbial pollutants in cow manure be transferred to the water that runs off these ranges, tainting the food we eat and water we drink?

The short answer: Yes, but it takes a herculean effort for a bad bug to survive the journey from cow to human, and there are ways to manage cattle to make the journey highly improbable. Rangelands, in fact, provide some of the state's healthiest watersheds.

The short answer was a long time in the making, a journey that continues to this day. UC Davis researchers and UC Cooperative Extension specialists have been central to the process, helping turn foes into friends committed to a common goal — protecting rangelands in order to meet society's need for open space, habitat for plants and wildlife, and healthy watersheds delivering clean water for us all.

"Rangelands are very, very important ecosystems that support water quality, water storage, native biodiversity, food production, carbon storage and plant and wildlife habitat," says Valerie Calegari, director of landowner stewardship for Audubon California. The environmental group owns and operates a 7,000-acre ranch just outside of Winters where cattle graze and its scientists study the conservation and restoration benefits of a working ranch.

A thirsty state

Since the Gold Rush, Californians have adapted to life in a Mediterranean climate by capturing water and diverting it elsewhere. California has 1,400 dams and reservoirs to store surface water, along with a vast network of pipes, ditches, siphons, aqueducts and pumping stations to deliver it to homes and fields. The state's largest "reservoir" is the Sierra Nevada snowpack, and when that snow melts it runs mostly through California's rangelands, where livestock has been grazing since 1769. Most of the state's other reservoirs and dams are also located on or near rangeland.

"Many of those dams and reservoirs were built for flood control and irrigation," says Mel George, a UC Cooperative Extension rangeland specialist with the UC Davis Department of Plant Sciences. "As populations grew, more of that water was used for drinking water."

People don't like the thought of cow manure near their drinking water. "And in the late 1980s, grazing was already being blamed — wrongly, in many cases — for any number of environmental and wildlife conservation issues," George says. "So we knew it was important to get out in front of grazing and water-quality issues. We wanted to know, what was the risk of pathogens in water runoff from rangeland? Were their ways to mitigate it?"

In the early 1990s, George helped spearhead the UC Cooperative Extension Rangeland Watershed Program, which used education and applied research to answer those questions and more. Collaborating with local water districts, the U.S. Environmental Protection Agency, and several state and federal natural resources agencies and associations, the rangeland watershed team went to work.


Ken Tate, who holds the Russell L. Rustici Endowed Chair in Rangeland Watershed Sciences, is among researchers at UC Davis working with ranchers to protect food and water supplies.

(Aubrey White/UC Davis)

The program really started making headway in 1995, George says, with the birth of a new research partnership. Rangeland ecologist Ken Tate joined the Department of Plant Sciences as a Cooperative Extension rangeland watershed specialist. He joined forces with Rob Atwill, D.V.M. '90, M.P.V.M. '91, a newly hired professor at the School of Veterinary Medicine and an expert on waterborne infectious diseases. The pair created multidisciplinary teams and conducted groundbreaking experiments with "waterborne zoonotic pathogens," bugs that are shed by animals, transmitted by water and can make people sick — and sometimes kill them. Some common culprits include Cryptosporidium parvum, Giardia, E. coli and Salmonella.

"They [Tate and Atwill] saved the day during what I call the Crypto Wars of 1997," says Tim Koopmann, a watershed resource specialist with the San Francisco Public Utilities Commission. Koopmann is also a fourth-generation rancher.

San Franciscans get 15 percent of their water from a watershed along the Alameda/Santa Clara county line, 40,000 acres of grasslands where cattle have grazed since long before the public utilities commission bought the land in 1934.

C. parvum is a water-borne protozoan that causes diarrhea in humans. The parasite is not removed by normal drinking water treatment. In 1997, the city of San Francisco considered a ban on grazing in the watershed.

"Some people were up in arms that cows on that watershed were polluting our water with Cryptosporidium," Koopmann says. "Ken Tate and Rob Atwill led experiments that showed there was no problem with Cryptosporidium."

And they went a step further, Koopmann adds. "Livestock grazing is often evaluated as an either/or situation, either good or bad. It's not like that, and their research showed that.

"Grazing can bring many environmental benefits — it keeps invasive species in check, it provides habitat for animals and plants found nowhere else in the world — but there are problems when land is over-grazed. Their science helps us find that balance, helps us make smart land-use decisions."

It takes a toolbox

Conditions vary from ranch to ranch — soil, slope, climate, vegetation, etc. — so when it comes to rangeland watershed management, one strategy does not fit all.

"Our goal is to build a tool box, a range of methods to reduce the risk of microbial pollutants," says Tate, who holds the Russell L. Rustici Endowed Chair in Rangeland Watershed Sciences. "We don't tell ranchers and regulators which tools to use. We identify what works and what doesn't work, so they can design a water-quality management plan that's feasible and sustainable."

Nearly two decades of research by Tate, Atwill and their teams have produced key findings that inform water-quality management plans:

The biggest threat to human health from cow manure is from the youngest in the herd — most pathogens found in cows live within calves less than 4 months old. (Ten percent of adult cows shed Cryptosporidium but only 0.5 percent of them shed a strain that is infectious to humans. And most Giardia shed by cows of any age is not infectious to humans.) "We tell ranchers, early fall or spring calving is better than winter calving and to keep animals away from running water as much as possible," Atwill says. Strategic fencing can help, as well as providing water and feed in spots away from creeks.

Pathogens in cow dung die quickly in warm weather, thanks to solar radiation. And even in cold, wet weather, pathogens tend to stay trapped in the fecal pat. By timing grazing in critical watershed areas to occur during spring, summer or early fall — all Cryptosporidium can be inactivated before winter rainfall and runoff occurs.

Take care of your rangelands and riparian areas, and they will take care of you. Researchers say that well-vegetated hill slopes, riparian areas and buffers function as kidneys, trapping and holding pathogens. "For each additional yard pathogens have to travel through vegetation, there is another 30–99.99 percent reduction in potential transfer of pathogens from fecal pat to stream or lake," Tate says.

There's no silver bullet. Every few years, storms arrive so fast and furious that nothing can stop the flow of pathogens from even the best-managed land. "Half of the annual discharge of pathogens can occur during the worse storm or two of the season," Atwill says.

So management can't reduce the risk to zero. But when ranchers keep cows from loafing near running water, give pastures a rest after grazing before irrigation, care for their buffers and protect their soil, they minimize the threat.

Even during the wettest winter, rangeland run-off is generally safer than run-off from urban areas, with its full suite of potential pollutants like gasoline, garbage, motor oil, heavy metals, fertilizer and pesticides.

Keeping High Sierra and coastal water clean

In addition to extensive work on private rangelands, UC scientists are studying other areas: High Sierra mountain meadows, recreation areas downstream from public grazing land, and coastal watersheds draining to Tomales Bay (photo) where bacteria carried in runoff from dairies have caused interruptions in shellfish harvest right after heavy rains.

You can read more about the work with water quality in the Tomales Bay watershed at the UC Cooperative Extension Sonoma County website. Watch a video, Protecting the Oysters.

You can find the latest research on grazing in public lands on the UC Davis California Rangeland Watershed Laboratory website.

Read more about the California Rangeland Conservation Coalition.

Boots and Birkenstocks Bunch

Conservation and ranching are often cast as conflicting interests, and for decades that was mostly true. Most environmentalists believed grazing was the enemy of healthy ecosystems, and some still do. But over the years, science has shown it's no accident that California's annual grazing lands also encompass the state's richest plant and wildlife biodiversity.

At the same time, though, the pressure on California's rangeland owners to convert their land to other uses, like development, is steadily growing, especially because ranching can be a risky financial venture. So in 2005, a group of environmentalists and ranchers decided to see if they could work together to protect the economic viability of private rangelands and encourage sound land and habitat stewardship. They met for a summer barbeque at Koopmann's ranch in Sunol.

"For the first 30 minutes, it looked like an eighth-grade dance with boys on one side and girls on the other, staring at each other," Koopmann recalls. "Except in our case, the environmentalists stood against one wall and the cattlemen against another. But then we started talking, and knew we could make it work."

The meeting led to the formation of the California Rangeland Conservation Coalition. The group's membership list reads like a who's who in conservation, ranching and public policy — the Defenders of Wildlife, Environmental Defense, Endangered Species Coalition, Cattlemen's Association, the U.S. Forest Service and many more groups. "We call ourselves the Boots and Birkenstocks Bunch," says Koopmann.

UC Davis researchers and Cooperative Extension specialists have been central to the group's success, says Tracy Schohr, the coalition's ranchland conservation director: "They help keep rangelands functional by educating land managers and ranchers and providing the objective, accurate information we need."

This past January, the California Rangeland Conservation Coalition met at UC Davis for its seventh annual summit — and its first-ever Rangeland Science Symposium, "Managing Rangelands for Multiple Ecosystem Services." More than 400 ranchers, environmentalists, regulators and scientists filled Freeborn Hall.

"It's so good to see diverse interests working together to preserve working rangelands, which provide so many public benefits, like open space, healthy watersheds, habitat for plants and wildlife, food and fiber," Tate says.

Ranches as habitat

Look closely as you travel through California, and you can see the management practices in action. Maybe you will see the willow, cottonwood, oaks, sycamore, deer grass, blue wild rye and California wild rose and elderberry that Coke and James Hallowell planted on the family's ranch in Madera County, benefiting the tiger salamanders, great horned owls, bobcats and eagles that now roam their working ranch.

Maybe you will see the spectacular wildflowers that bloom each spring on the Avenales and Canyon ranches in San Luis Obispo County, working ranches that are also home to red-legged frogs, snakes, turtles, raptors, deer, bobcat, bear and a tule-elk herd. Rancher Steve Sinton allowed the California Department of Fish and Game to introduce the elk herd to the land he and his family oversee. Other than "quail guzzlers" — brush piles left for bird cover and a fenced riparian area — Sinton says he does nothing special to manage for wild animals. "If we do what we are supposed to do right, there is a place for them on the ranch," he says.

Or maybe you will happen upon Running Deer Ranch in Napa County, where ranchers John and Judy Ahmann, with help from several government agencies, restored eroded riparian areas, developed ponds for waterfowl habitat, provided osprey nesting areas and regenerated oaks. In 2007, the Ahmanns granted a half-mile easement to the Tuleyome Society to help stitch together 100 miles of hiking trail through the Blue Ridge Berryessa Natural Area, most of which is on federal land.

Judy Ahmann applauds the efforts to unite diverse groups to protect California rangelands. "We know that there are 5 percent of the issues we may never agree on," she says. "But why should we spend 100 percent of our time fighting when we have so many mutual goals?"

Back in Amador County on the Gansberg ranch, Chris drives past solar panels (the ranch's sole energy source) and strategically placed water troughs that draw cows away from creeks and streams. Over the years, Tate has helped take water samples on another ranch they own in Bridgeford to assure all the water that runs from their land is clean.

"If not for Ken, we would have been in trouble a long time ago," says Chris, a fourth-generation rancher who earned his UC Davis degree in agriculture production. "We love ranching, but it's not easy to make a go of it these days. UC research and extension helps make it work."


Diane Nelson is a writer for the Department of Plant Sciences.