The Story Behind Antioch Dunes NWR

Antioch Dunes Evening Primrose

This story by former Refuge Manager Chris Bandy and Volunteer Coordintor Eileen McLaughlin was originally published in the Winter 2002/2003 issue of Tideline, the quarterly newsletter of the San Francisco Bay National Wildlife Refuge Complex. 

Antioch Dunes National Wildlife Refuge

The year was 1986. The media was awash with stories about the humpback whale that became known as Humphrey.  Sidetracking from an oceanic migration, Humphrey swam beneath the Golden Gate Bridge to begin an odyssey in and beyond the San Francisco estuary. The day came when Humphrey swam beyond the bay’s waters and headed up the San Joaquin River, past ancient sand dunes near the city of Antioch. 

On those dunes, three native species, all endangered, were surviving, if not quite thriving, under the care of the Fish & Wildlife Service and within the boundaries of the Antioch Dunes National Wildlife Refuge.

Humphrey’s unique journey drew vast crowds of people down the slopes of the dunes to the river’s edge. Their thoughts were with the survival of this magnificent marine mammal--not on the vegetation pushed aside or crushed under their feet as these eager visitors cleared paths through thickets of brush. After all, the dunes were not fenced and, to untrained eyes, bore the appearance of little more than a huge weed patch.

Indeed, “ a weed patch” was how a colleague referred to this small Refuge when I came to work at the San Francisco Bay National Wildlife Refuge Complex.  I have learned it is so much more.  Amongst the “weeds” were the last populations of naturally occurring wildflowers, the Contra Costa wallflower and the Antioch Dunes evening primrose, both listed as endangered species.  Closer and seasonally fleeting examinations also revealed that the Antioch Dunes are home to the world’s only population of the tiny Lange’s metalmark butterfly.

In the 1970s, local botanists led efforts to safeguard the dunes, to protect these species from sure extinction. As a result of their efforts and the significance of the habitat, the Antioch Dunes National Wildlife Refuge was created in 1980.  It was the very first National Wildlife Refuge established solely to protect endangered plants and an insect. Additionally, the habitat scientifically described as a riverine dune ecosystem, provides a home for other rare endemic species, some of which are listed as threatened/endangered by the State of California.  Two such species are Mason’s lilaeopsis and Suisun marsh aster. This refuge is truly one of nature’s special places.

Rare and endangered species are hardly the only unique attribute for the Antioch Dunes NWR. It is one of the few natural, essentially undeveloped areas along this highly industrialized bank of the San Joaquin River.  A state biologist mentioned she always could identify the refuge’s location while out on the river, aboard a boat. The Refuge was the only place “where green came down to the river.”

Adjacent to the City of Antioch in Contra Costa County, the Refuge is comprised of two units, the 14-acre Sardis Unit and the 41-acre Stamm Unit. Sandwiching the Sardis Unit, two six-acre Pacific Gas & Electric (PG&E) sites also provide the same habitat for the three federally-listed endangered species.  A partnership between the Fish & Wildlife Service and PG&E developed early and cooperatively, ensuring common support for enhancing the lands for the two flowers and the butterfly and, effectively, adding an additional 12 acres for wildlife protection.  Currently, plans are underway to strengthen that partnership further, stepping up joint efforts for an even more successful collaboration.

Topographically, the PG&E units rise above the Sardis Unit, serving as elevated bases for towering powerline structures. One PG&E unit abuts property used by a gypsum plant. The green of leaves there is always muted with white gypsum dust. From the far edge of the other PG&E unit, the dune drops quickly, precipitously downhill to grounds that are almost at river level, flat grounds of a chemical plant. It is this view that impresses upon a viewer how much more extensive this dune ecosystem must have been. Right here is where they stopped removing the dunes.  After so much of San Francisco burned to the ground following the 1906 earthquake, those dunes served as the source material needed to rebuild the city with bricks.


Lange's Metalmark Butterfly CaterpillarAs demonstrated dramatically during the visit by Humphrey, open boundaries bore grave danger for the future of the endangered species. Indeed, Antioch Dunes NWR has been closed to the public since 1986. This decision would have come about even without that very unusual incident. When the Refuge was open, frequent fires occurred, perhaps the accidental outcomes of picnicking visitors, with each incident destroying a significant percentage of the Lange’s metalmark butterfly population.  Fires have continued to be a danger, in the years since, now commonly started by trespassers. The largest fire, burning virtually half of the Stamm Unit, occurred in July 2002, cremating virtually hundreds of butterfly larvae, commonly known as caterpillars.

Recognizing that fire is one of the major threats to these species, a program to reduce “plant fuels” and build firebreaks throughout the Refuge is now underway.  Excessive numbers of coyote brush, a common native plant in coastal California, can become a fire hazard and may be removed to reduce the potential severity of wildfire. Some cleared areas are replanted with naked-stemmed buckwheat, the food-plant of the  Lange’s metalmark butterfly larvae, and other strategically located areas are left unplanted creating firebreaks.  While the firebreaks are protection from unfortunate human disturbance, they can also help bring back visitors. Firebreaks can be used as trails for guided tours held to celebrate the National Wildlife Refuge System Centennial and to offer the public first time opportunities to view blossoming wildflowers, during optimum wildlife viewing seasons.  Indeed these guided tours are envisioned as a beginning, a start toward a future of trained docents leading visitors for many, regularly scheduled walks through these wildlands.

In the meantime, there is still much to be done on the refuge.  Since 1980, much research has been completed and aided management’s understanding of this remnant riverine dune ecosystem. This background and all the associated work activity is an important record of reference. Yet much more research is needed.  Such investigations will put more tools in the hands of refuge management, tools that can be used to resolve existing problems. For instance, it will help to understand the fire effects on individual species and to identify the most effective methods for controlling invasive plants. 

High School Volunteers
For years now, the refuge has aided the self-sustenance of selected species by using greenhouse operations at the Complex’s headquarters as a means to propagate both endangered and native species. Fish & Wildlife Service biologists, under special permits, plant pot after pot with seeds harvested from the endangered plants at the dunes sites. Naked-stemmed buckwheat, a native plant critical to the Lange’s metalmark butterfly, is similarly propagated in a nursery run by volunteers. During fall and winter months, work crews of staff and volunteers have planted thousands of young plants on the refuge that were produced through these methods.

The small size of the refuge and its fragmented habitats unfortunately contribute to the invasion of nonnative weeds. Some of the most invasive nonnative plants are yellow starthistle, winter vetch, and ripgut brome. These aggressive nonnative plants, having no local, natural predators, are controlled by hand pulling, by prescribed burning, or by carefully applying herbicides.

Sand and its attributes is a major factor in the shaping for these refuge lands. Sand mining in the Sardis Unit,  occurring well before it was a wildlife refuge, drastically lowered ground levels, making it more susceptible to invasion by riparian species which now have much easier access to water. Additionally, dune ecosystems rely on blowing sand to keep their integrity.  With refuge sites blocked from virtually any such sand movement by the surrounding industrialization, a plan was developed to import sand and to create new dunes in previously cleared and flattened sectors of the Stamm Unit.  

To assist managers of the Antioch Dunes NWR and to help keep the focus on management goals and objectives, a Comprehensive Conservation Plan (CCP) was completed in August, 2002.  The CCP is a fifteen-year management plan, a tool which all National Wildlife Refuges will be completing in the next decade.  Public review of the CCP, at various stages of completion and as a final document, has generated a flurry of expressed interest in the refuge. More volunteers have come forward to assist with management activities such as planting and weeding.  Additionally, recent articles in the media regarding the CCP has had the beneficial result of producing even more public interest. Such enhanced public awareness can only be looked upon as boon, all the better for the survival chances of this special ecosystem and the endangered species it holds. 

The Antioch Dunes National Wildlife Refuge requires constant and persistent attention and will for years ahead. The long-term goal is to have helped each of the endangered species achieve self-sustaining levels alongside site-specific native populations while minimizing exotic wildlife populations and providing for suitable public use and enjoyment.  With the continued support of scientific researchers, management partners, willing volunteers and dedicated staff, it is easy to feel that the species and ecosystem enter the National Wildlife Refuge System’s Centennial Year with all due optimism and high expectation for the years ahead.  

Eileen McLaughlin is a refuge volunteer, freelance writer and former Volunteer Coordinator for the San Francisco Bay National Wildlife Refuge Complex.