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Cattle on Point Reyes National Seashore. (Credit: NPS/Rex Frobenius)

The cold Pacific Ocean waters that surround Point Reyes National Seashore support an abundance of wildlife and make for stunning views from the national park.

They also generate the frequent fogs that water the grasslands that beef and dairy cows have grazed for more than 150 years. While it’s unusual for 28,000 acres of a national park to be dedicated to agriculture as it is at Point Reyes, the relationship has worked since the park’s designation by John F. Kennedy in 1962.

Now, research by National Park Service scientists shows that preserving both the area’s agriculture and beautiful natural resources can work together.

Best practices lead to less bacteria in water

Water quality monitoring from 2000-2013 showed a decline of nearly 90 percent in fecal indicator bacteria across three watersheds in the park. This happened during a time when dairy and ranching operations there implemented best management practices for water quality.

“It’s a big change,” said Dylan Voeller, the range program manager at Point Reyes National Park. Some watersheds saw a decrease in fecal indicator bacteria of 98 percent.

Fecal indicator bacteria are a group of microorganisms that animals shed when they defecate. Some strains of E. coli, perhaps the most famous of the group, can make humans sick when ingested.

“Pathogens originating from agricultural lands are the main cause of stream impairments in the United States,” Click To Tweet the authors write in their study, which was published in Rangeland Ecology & Management in this month.

The dairies, which can hold up to 200 animals per square kilometer, and ranches, which can graze up to 64 animals per square kilometer, introduced loafing barns, manure storage ponds, fencing and alternative water supplies to keep cattle from accessing streams. In all, the livestock operations implemented 30 best management practices across three watersheds.

In a fourth watershed, where there was only limited grazing and no best management practices implemented, fecal indicator bacteria trended slightly upward.

The findings match another previous study of another watershed near the park that showed a similar decline in fecal indicator bacteria in watersheds with ranching operations after best management practices were implemented. Similar studies from around the world have shown declines as well.

A rainbow over the Pacific Ocean at Point Reyes National Seashore. (Credit: NPS)

Long term data reveals a trend

The strength of this evidence rests in the length of the park’s record of water quality monitoring.

“We’re pretty unique in that regard, to have a number of watersheds where we have this much water quality data,” Voeller said. “It’s a really cool dataset and we’re lucky to have it in a lot of ways.”

The data won’t be used in support of any regulation, though the study notes that the number of samples below the contact recreation threshold set by the San Francisco Bay Water Quality Board increased sixfold during the study period.

The data used in this study lacks the fine resolution of some others—sampling was done close to monthly—and some of the sampling stations were set in small seasonal drainages close to the developed ranch complexes likely to have bacterial contamination from nearby cattle. Still the trend is convincing.

“It’s a one to two orders of magnitude reduction,” Voeller said. “It’s a huge difference.”

It’s likely because significant contamination events aren’t occurring like they used to.

“What it’s telling me is we’re not seeing these big, big hits like they saw in the past in the park,” Voeller said.

The study also notes there could be complicating factors. Levels of fecal indicator bacteria could be impacted by soil and vegetation types, groundwater dynamics and resuspension from streambeds.

Agriculture and national park forge a long term relationship

While it’s unusual—though not unheard of—for agriculture operations to be situated within a national park, at Point Reyes the relationship is a long one, said Melanie Gunn, outreach coordinator for Point Reyes National Seashore.

The California gold rushes that brought people to the San Francisco area also brought the need to feed them. The grassy Point Reyes (which had likely been cultivated to be that way by native people before white settlers arrived) and its cool climate allowed dairy farmers to produce top notch butter and other dairy products, the National Park Service reports.

Elk at Point Reyes National Park. (Credit: NPS/Tim Bernot)

When President Kennedy designated it a national seashore, the continuance of the area’s dairies was part of the park’s charter.

New environmental planning for the park could further help water quality improve.

“We’re contemplating having the ranchers have twenty-year permits,” Gunn said. “Up till now they’ve only had five or ten years.”

Longer permits means more stability for the ranchers. That could translate to ranchers investing in more expensive practices like loafing barns, which could cost upwards of a million dollars, Gunn said. Banks might be more willing to lend money for a twenty-year investment than a shorter one.

The cattle within the park also have a role in maintaining a disappearing landscape: California’s native grasslands and prairies.

“It’s a disturbance driven ecosystem and the cattle grazing is maintaining that in a way,” Voeller said.

Now, while cattle support some needed disturbances on land, the park knows they’ll be less of the wrong kind in the water.