Lange's metalmark butterfly.(FWS photo)

Antioch, California is one of San Francisco’s far-flung suburbs. It may seem an unlikely location for an endangered butterfly, but the Lange’s metalmark butterfly (Apodemia mormo langei) has made this area its exclusive home. Once counted by the thousands in the early 1900s, far fewer survive today.  

This tiny, brightly-colored butterfly, was placed on the endangered species list in 1976, making it one of the first species to be protected under the Endangered Species Act was enacted. Its bright orange and black wings are accented by distinctive silver-grey dots at the outer edges. When at rest on plant stems, the closed wings are grey, making it appear almost invisible to the human eye.   

The Antioch Dunes National Wildlife Refuge is all that remains of a once-extensive stretch of sand dunes along the southern bank of the Sacramento-San Joaquin River Established in 1980, it was the first national wildlife refuge in the country dedicated to protect endangered plants and insects. The refuge and a few acres of surrounding lands contain most of the remaining habitat for Lange’s metalmark butterfly and two other endangered species -- the Antioch Dunes evening primrose and the Contra Costa wallflower.

Unlike some butterflies that can travel for hundreds of miles, the Lange’s metal­mark does not migrate beyond the Antioch sand dunes. As development in the area has grown, most of the sand dunes disappeared, either for industrial uses, like bricks to rebuild San Francisco after the 1906 earthquake, or paved over to build industrial plants.

And although some other butterflies can produce multiple generations in a year, the Lange’s metalmark produces only one per year, using the native, naked-stemmed buckwheat as a host plant for its eggs and larvae. Over the years, invasive plants and several large fires have crowded out and destroyed much of the buckwheat. 

Last year’s annual butterfly census, considered a critical indicator of the specie’s population health, recorded a peak count of only 45 of the Lange’s metalmark butterfly, well below 2005’s count of 232, and dramatically lower than the 1999 count of 2,342.

Recently, the U.S. Fish and Wildlife Service launched a more aggressive effort to restore habitat at the refuge and to increase the butterfly population through a new captive breeding program. Refuge Manager Christy Smith is coordinating the on-site work; biologists Chris Nagano and Dave Kelly in the Sacramento Fish and Wildlife office’s Endangered Species program took the lead on developing the captive breeding program and securing funds to pay for it.

To find out exactly how many adult butterflies are in the refuge this year, a cadre of U.S. Fish and Wildlife Service employees and volunteers participated in a butterfly census on Sept. 5.  Final census data isn’t in yet, but preliminary counts put this year’s tally a bit higher than last year.

Lending a hand

Recovery efforts would not be possible without the extensive network of partners who have worked to save the dune-dependent plants and the Lange’s metalmark butterfly. The Antioch docents lead tours of the refuge and provide the backbone of the volunteer base that supports all work on the Antioch Dunes. Another group, known as Earth Team, is comprised of students from nearby Deer Valley High School in Antioch who have taken on the task of weeding the area to allow the native plants to recover.

Other volunteers have helped as well. The California Conservation Corps have cleared built up thatch which chokes out plants such as the naked-stem buckwheat. The docents, Friends of the San Pablo Bay NWR, staff of the San Francisco Bay NWR complex; and the California native Plant Society have all helped clear weeds and plant seedlings of native plants. The San Diego Zoo’s rare plant seed bank is cultivating the naked-stem buckwheat for use in the refuge. And a volunteer from the Urban Wildland’s Group in Los Angeles has been working as a technical advisor. And the Central Valley Project Conservation Program assists with funding.

This year the Service has taken an additional step of partnering with entomologists at U.C. Riverside and Moorpark College in Los Angeles where they will work to establish two small breeding colonies. Other entomologists who are working with the refuge to recover the butterfly, as well as other native insect species, include Jerry Powell, UC Berkeley, Dick Arnold and Wes Maffei of the Contra Costa Mosquito Abatement District. The butterflies will live in netted enclosures and hatched larvae will be raised until they are old enough to be taken back to the refuge next spring. And next spring a small herd of cattle will be brought in to graze sections of the refuge and see how this may help keep down the invading grasses and weeds.

The Lange’s metalmark butterflies may be small, but they have a big circle of friends. 

Note: The Antioch Dunes National Wildlife Refuge is closed to the public to protect the sensitive habitat. On the second Saturday of each month a free docent-led walking tour is offered at 10 a.m. Call (707) 769-4200 for more information.