California Wild Fall 1999

Habitats

Unstable Dunes

Gordy Slack

At the extreme northeast corner of Tomales Bay is the Dillon Beach dune complex, one of the largest intact dune habitats in northern California. It covers nearly 1,000 acres from Dillon Beach to Tom’s Point, and includes dune wetlands, "stable" vegetated dunes, and towering unvegetated, or "mobile," dunes that remind me more of the Mojave Desert than the northern California coast. These dunes are probably the closest surviving analogue to the sandy landscape once covering much of what is now San Francisco, and they are rare, fascinating, and beautiful in about equal measure.

Peter Baye, a 40-year-old, shaved-headed, muscular botanist who works for the endangered species division of the U.S. Fish and Wildlife Service, has agreed to show me the dunes on his day off. It is a place on which he is probably the leading biological authority, and he appears to have become a sort of naturalized native here. He looks perfectly adapted, taking long, gliding strides up the steep slopes of the sand dunes, scanning the low-lying vegetation for interesting plants, and sloshing happily into the wetlands that make these dunes so extraordinary.

We are walking south along Dillon Beach, which is almost flat and about 50 yards from shoreline to dunes. “This is perfect habitat for the threatened western snowy plover,” says Baye. “In fact, they’re here in abundance in the winter. And they nest in Point Reyes just across Tomales Bay, but no nests have been found here.”

A dog trots by on cue, a sufficient explanation for the lack of plover nests on this unprotected beach. Dogs are supposed to be on leash here, but it is a regulation almost impossible to enforce to a plover’s standards. The birds nest in exposed depressions in the sand, and they are scared to death of dogs. “They take off if a dog comes within 50 yards,” says Baye, “though they don’t seem to fear humans much at all.”

But dogs are only one management problem in the dunes complex, which is privately owned by a family that has been here since 1918. There are also cattle, which graze on the grass and other plants in and among the dune wetlands. And 60,000 tons of sand a year are hauled out of the mobile dunes and sold as construction material.

The fact that the dunes are here at all and remain in reasonably good condition, while most such habitat is long gone, is a testament to the owners’ stewardship. But as standards for the treatment of critical habitat become more stringent, and as the ecological value of this particular land becomes more obvious, environmentalists and land management agencies have begun to cast acquisitive eyes on these dunes. All of this makes Nancy Vogler, the great-granddaughter of the original rancher, very uncomfortable.

“The government thinks everybody has a price,” says Vogler. “Well maybe some do, but not this family. Our family is devoted to the land and they are not going to be selling it to anybody,” she says. Vogler, along with her husband, Bill Vogler, runs Lawson’s Landing, a resort and fishing business here named after Sylvester Lawson, Nancy’s great-grandfather.

It might not be for sale, but the land may yet be snagged in a net of permits and regulations that may make it difficult for the family to continue to operate its business.

As we move inland and begin climbing down the vegetated, landward slope of the first row of foredunes, Baye introduces me to one of the most unusual features of this system: the dune pools, or “slacks,” as they are called, that appear where the groundwater and the surface of the dunes meet.

“Dune slacks are like vernal pools,” Baye says, “except that the water in vernal pools is standing water held in place by some impermeable substrate. The water in slacks is actually passing through them.”

Like vernal pools, slacks support vegetation that can tolerate both dry and saturated conditions, and like vernal pools, slacks, because of their isolation and the strange conditions they maintain, are often home to rare endemics such as the shore chickweed, leafy pondweed, horned pondweed, and water starwort.

Baye stops suddenly and points out a rare aquatic garter snake swimming along with a red-legged frog tadpole dangling from its jaws.

The mobile dunes in this system are among the largest in central California, and they are also the most spectacular things in sight, rising above the rest of the landscape with their sharp crest ridges and intricate, wind-generated patterns. They also host a number of endangered species such as the sand bear scarab beetle. The vegetated, stable dunes contain other rare plants such as the thick-stemmed pearlwort, a subspecies of Blasdale’s bent grass, and San Francisco sand gilia. Showy Indian clover, previously thought to be extinct, was recently rediscovered here as well.

We come around a corner, and before us is a feature that illustrates the hydrological peculiarities of these dunes and the key to their tremendous ecological value: abundant fresh water in the middle of July. The wet slope of a dune has collapsed where a ten-yard-wide stream emerges from it. Picture a leaky dam with water trickling down its face and out from its base. Only this dam face is made of sand and is, in fact, the side of a dune. “In the winter this was a roiling whitewater,” says Baye, “just flowing out of the side of that dune.” This “seep,” for lack of a better word, comes out of the dune as an underwater stream and is forced up by some harder, subsurface material. Thirty or forty yards from where the stream emerges it disappears into the sand again.

“What is amazing about these dunes is that they are still a living system. And the plants and animals that live here are still evolving along with the system,” says Baye.

We climb to the top of another dune, this one with some unassuming vegetation on it. “Ah, here we are!” cries Baye, darting excitedly from plant to plant. “This is probably an undescribed plant...probably a hybrid of Leymus pacificus and Leymus mollis.” In his dozens of visits to this site he has never before found flowering specimens of this new hybrid and here we find two flowering individuals. It is the most common looking of grasses, and yet Baye touches it like he’s holding the Holy Grail.

We come upon a huge marshy meadow full of vegetation and popping with tiny vivid green Pacific tree frogs. “This,” Baye explains, pointing out subtle ridges within the meadow “is a Gegenwall pattern, a series of counter ridges that form at the base of mobile dunes along the margins of moist dune slacks. Very rare.”

We ascend another set of dunes and look west toward Tomales Bay and Point Reyes National Seashore. Trailers and mobile homes are clustered like aphids at the mouth of the bay. Fog gathers over them, like the storm brewing between environmentalists and the owners of this property. The resort includes 800 campsites, where visitors pitch tents or park recreational vehicles, and 233 privately owned trailers. Many more visitors come for the day, using the boat launches on summer fishing expeditions. In contrast to most of Marin’s high-end B&B tourist industry, Lawson’s Landing has a distinctly working-class visitor base and is mostly used by folks who’ve come to fish and dig for clams.

The problem is that for the past 42 years, Lawson’s Landing has been operating without a permit from the County of Marin. None of the hundreds of individual septic tanks that service the trailers and campsites there are up to code. The waste they produce percolates through the sand eventually passing, untreated, into Tomales Bay.

The Voglers are trying to make up for the sins of their predecessors, says Marin County planner Dean Powell. They want to put in a system that is acceptable to the county and that works environmentally, too.

But they are caught between a bay and a sand dune. Eight years ago they submitted to the county a proposal to install a new sewage treatment system that would filter their wastewater and then dispose of it through leach fields in the dunes. A leach field distributes water over a wide area and allows it to seep back down to the water table. In this case, it would flow through the sand and into Tomales Bay.

The Voglers have tried hard and in good faith to find an environmentally low-impact system that will work. “We have turned ourselves inside out trying to satisfy the environmentalists and all the agencies,” says Nancy Vogler.

And on the one hand, this new system would certainly mark progress; at least untreated sewage, and all of the nitrogen and other nutrients that sewage contains, wouldn’t be seeping into the Bay. But on the other hand, depositing all that water in the dunes could well have a significant impact on the hydrology of the dunes and the soil chemistry of the wetlands. And it is the hydrology that makes them what they are, says Baye. Furthermore, a leach field is basically a series of leaky pipes that would be buried in the sand. The dunes covering them would have to be “stabilized and restored,” to quote the Voglers’ proposal. And to stabilize mobile dunes is to kill them. Though Nancy Vogler says she hopes to stabilize the dunes over the leach field with native plants, the word “restore” here is certainly a misnomer. If a rolling stone gathers no moss, then a mobile dune gathers no vegetation either. If the vegetation takes root, the mobile dunes will no longer be mobile. If it doesn’t, the pipes will be exposed and the system will fail.

The county has its own reasons for wanting the new septic system. After 40 years of turning a blind eye on an illegal operation, pressure has mounted from the state and other agencies to square away the Lawson’s Landing irregularities. And Powell, the county planner on the case, seems to want to encourage the Voglers’ septic upgrade by granting them a construction permit without requiring what would be a very expensive environmental impact report (EIR).

But not so fast, says Catherine Caufield, the director of the Environmental Action Committee of West Marin. She thinks a close environmental review of the plan is in order, and when the proposal is released by the county in the coming weeks, if no EIR is called for, she and the members of her organization are going to do whatever they can to see that one is conducted, she says. She also acknowledges that an EIR could cost Lawson’s Landing more money than they could afford to pay. “That puts the Voglers in a difficult position, but it may give them more of an incentive to sell to some conservation-oriented land management agency,” Caufield says. “And that might not be a bad thing in the long run.”

To further complicate things, the North Marin Water District is looking for a way to handle its own waste problems in expanding parts of the small town of Dillon Beach, just one mile up the road from Lawson’s Landing. The NMWD may be considering a system similar to the leach field proposed by the Voglers, depositing their wastewater in the Lawson’s Landing dunes as well, says Powell. Of course they’d have to get permission from the Voglers to do so. And Nancy Vogler is not in a very permitting mood when it comes to government officials.

Baye stops suddenly and points out a rare aquatic garter snake swimming along with a red-legged frog tadpole dangling from its jaws.

“What is amazing about these dunes is that they are still a living system. And the plants and animals that live here are still evolving along with the system,” says Baye.

But not so fast, says Catherine Caufield, the director of the Environmental Action Committee of West Marin. She thinks a close environmental review of the plan is in order, and when the proposal is released by the county in the coming weeks, if no EIR is called for, she and the members of her organization are going to do whatever they can to see that oneis conducted, she says. She also acknowledges that an EIR could cost Lawson’s Landing more money than they could afford to pay. “That puts the Voglers in a difficult position, but it may give them more of an incentive to sell to some conservation-oriented land management agency,” Caufield says. “And that might not be a bad thing in the long run.”

Gordy Slack is an Associate Editor of California Wild and is the Editor of this web site.

cover fall 1999

Fall 1999

Vol. 52:4