A tale of two species, and a lagoon

January 24, 2012
It’s unlikely that the Sharp Park Golf Course will revert to natural parkland any time soon now that San Francisco’s mayor vetoed a proposal to turn it over to the National Park Service.

But the final chapter in the story that’s pitted environmentalists against golf enthusiasts has yet to be written. Two species living on the golf course – the endangered San Francisco garter snake and the threatened California red-legged frog – are the subject of a federal lawsuit scheduled for trial in July.

That suit, brought by the Sierra Club, the Center for Biological Diversity, and four other groups, seeks to shut down golfing operations on until the city obtains federal permits to allow the killing of a certain number of protected species. San Francisco is now seeking to obtain those permits, which involves making changes to the 18-hole golf course designed to improve snake and frog habitat.

In the meantime, the future of Sharp Park remains in limbo. San Mateo County has offered to take it over, since the 417-acre property, though owned by San Francisco since 1917, is located in Pacifica. What makes the property so contentious are its ecological characteristics.

The low-lying park is at the terminus of the Sanchez Creek watershed, which makes it a natural wetland and ensures a constant influx of freshwater. That’s great for the San Francisco garter snake and California red-legged frog, which make their home in a non-tidal lagoon called Laguna Salada. The frogs lay their eggs in the lagoon, while the snakes use the freshwater habitat within the park to hunt Pacific tree frogs, and later in the season, the red-legged frogs.

But the set-up is bad, in a sense, for golfing. The golf course, including the lagoon, must be pumped in order to keep several fairways from flooding during the rainy season. The question is: can golfing and the two species coexist?

“I can’t say golf is perfect for the species, but it’s not what it’s being made out to be,” said biologist Karen Swaim. “The data shows that snakes, frogs, and golf can happily co-exist.”

Swaim, who has studied the snakes and frogs for the San Francisco Recreation and Parks Department, said most of all, the two species need a freshwater ecosystem. Pumping the lagoon and maintaining a seawall to the ocean emphasizes the park’s freshwater character, she said.


Photo by Gary Nafis

Swaim counters that there are better places to focus on restoration of the two species, such as an area with freshwater ponds and water holes in the Calera Creek watershed, south of Sharp Park.

But coastal ecologist Peter Baye said the lagoon is the key ecological characteristic of that site. If the pumping were stopped, water levels in the lagoon would rise 4 to 5 feet and the lagoon would creep outward.

A bigger lagoon would help the species survive a big wave that comes in from a large storm, which can surmount the seawall to flood the lagoon. Thirty years later, he said, snake populations are just recovering from a 1982 event, but a crash is bound to happen again.

“The snakes will live until the next big storm,” said Baye, one of the lead authors of a study sponsored by environmental groups published earlier this year. “The lagoon now is the bottom of a basin, a vessel ready to be filled.”

He said a full lagoon (one that hasn’t been pumped) would allow less saltwater into the park during a major overwash event, ensuring a less shocking uptick in salinity, which can be deadly for the frogs and snakes.

“We need to plan in or around those long-term dominant hydrological events that define the lagoon’s ecosystem,” said Baye.

In the end, the future of Sharp Park may be determined by forces outside politics and the courts. Arthur Feinstein, chairman of the San Francisco Bay chapter of the Sierra Club, said Sharp Park is in the path of sea-level rise. Forget the freshwater lagoon, Sharp Park could become marine habitat.

“Even without litigation, the golf course is in a tough place,” said Feinstein.

About the Author

Paul Hagey is a freelance science reporter based in the East Bay.

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