This article is part of a series of articles highlighting the U.S. Department of the Interior’s role in and commitment to pollinator conservation. Without pollinators, humans and ecosystems cannot survive.  June 24-30, 2007, has been designated National Pollinator Week by the U.S. Senate (S. Res. 580) and the U.S. Department of Agriculture. Find out what’s happening during National Pollinator Week in your area or post your event at www.pollinator.org.

The Lange’s metalmark butterfly (Apodemia mormo langei), whose home is on a few stunted sand mounds in the Contra Costa County city of Antioch is flutter­ing dangerously close to extinction.

The U.S. Fish and Wildlife Service in California has launched an aggressive new effort to restore the butterfly’s habi­tat at Antioch Dunes National Wildlife Refuge, its only known home. The Service also plans to breed the species in captivity until its wild population can be stabi­lized and, eventually, recovered to full health.

“We have been very concerned about the butterfly population at Antioch Dunes and are taking some positive actions that we hope will be successful in helping the population to recover,” said Mendel Stewart, project leader for the San Francisco Bay National Wildlife Refuge Complex, which includes Antioch Dunes.

“The Service and its partners are undertak­ing a renewed effort to protect the butterfly’s habitat through restoration and enhancement and to ensure its survival through captive propagation.” said Craig Aubrey, leader of the endangered species recovery team at the Service’s Sacramento field office.

The two-pronged approach – habitat im­provements and captive-breeding – has worked to stabilize the population of the endangered Palos Verdes blue butterfly, a Southern California spe­cies once thought to be extinct. Conservationists hope to have equal success with the Lange’s metalmark butterfly. To help fund the project, Aubrey’s team recently earned a $250,000 federal grant from the Central Valley Project Conservation Program.

“I just think this is the one right choice we can make right now that puts us on the path to be successful,” said Dr. Travis Longcore, the consulting biologist who proposed the captive-breeding program. “While captive breeding success isn’t guaranteed, it is one option that must be attempted to prevent the species from becoming extinct.”
 
Longcore is the science director for Urban Wildlands Group, a nonprofit conservation organization based in Southern California that has overseen the successful captive-propagation of the Palos Verdes blue butterfly.

 Lange’s metalmark was first described in the 1930’s and was one of the first insects to be protected by the Endangered Species Act of 1976. It is a fragile, brightly-colored butterfly with a wingspan of about one and a half inches and is named for the grey, or metallic-colored, spots on its wings.

Unlike some butterflies that can travel for hundreds of miles, the Lange’s metal­mark does not migrate beyond the Antioch sand dunes along the south­ern bank of the San Joaquin River.

Also unlike some other butterflies that can produce multiple generations in a year, the Lange’s metalmark produces only one per year. Each annual peak count of adult butterflies is considered a critical indicator of the species’ population health.

The peak count is the highest number of adults counted once a week over the flying period from August to October.  Unfortunately, the peak counts have been declining over the last several years. While the falling numbers prompted growing concern among refuge managers and biologists, the most recent results set off alarm bells.

Last fall, biologists recorded a peak count of only 45 adult Lange’s metalmark butterflies, well below 2005’s peak of 232 and the record high of 2,342 in 1999.

Several factors are likely to blame for the metalmark’s rapid decline. A continuous invasion of exotic weeds at the refuge is choking out the butterfly’s host plant, the naked-stemmed buckwheat, and recently, several large fires have destroyed buckwheat plants and butterfly eggs and larvae.

In the 19^th century, shifting dunes as high as 100 feet dominated the south bank of the river for more than two miles. Over the past century, the dunes disappeared mainly due to sand mining to make bricks, many of which were used to rebuild San Francisco after 1906. Without the naturally moving sand dunes, the two federally listed endangered plants, the Contra Costa Wallflower and the Antioch Dunes evening primrose, as well as the Naked-stemmed buckwheat, all dune-dependent plants, are having great difficulty competing with the non-native plants such as yellow star thistle, Russian thistle, vetch and foreign grasses. The butterfly presents unique challenges because of its restricted habitat require­ments and long breeding season – and the fact that it produces only one generation per year.

The 67-acre refuge is a “biological island” of rare and unique plants and insects. Some are found nowhere else in the world. The refuge, established in 1980, is the only wildlife refuge designated to protect endangered plants and insects.

“That is literally the last remaining habitat anywhere (for these plants and the Lange’s metalmark),” Aubrey said. “That is what makes this refuge so special.”

The task facing the refuge is how to save dune-dependent native plants – and the butterfly that depends on them – when functioning sand dunes no longer exist. The native plants need the shifting sand, steep banks and clear ground of real dunes. However, the increasingly thick weed base stabilizes the soil, creating the environment for more weeds.

Vetch, the refuge’s new worst culprit, covers the ground with a thick carpet, choking out such plants as the naked-stemmed buckwheat, the butterfly’s host plant, and creating an unsuitable micro-climate for the life cycle of the butterfly. Hand-pulling vetch is difficult. “Vetch attaches itself to other plants with tendrils, making it difficult to remove without damaging natives or stripping larvae or eggs from the buckwheat,” Christy Smith, refuge manage, said.

The refuge is preparing an updated biological opinion report, outlining a new, more aggressive plan of action – more fire breaks and land clearing, more plantings of nursery-raised native plants, and increased monitoring and evaluation. The plan calls for clearing and improving 10 acres of habitat each year – twice as many acres as in the past.

Last winter and spring, refuge biologists Susan Euing and Louis Terrazas led groups of volunteers who planted hundreds of wall­flowers, evening primrose and buckwheat seedlings on newly cleared areas of sand. California Conservation Corp came in and heavily trimmed trees and cleared land for more habitat.

For now, biologists are hopeful that a new generation of Lange’s metalmark butterflies emerges this summer. They intend to capture at least five adult females, and then transfer them on potted buckwheat plants to the butterfly propagation partners. In captivity, hatched larvae will be raised to the pupae stage, then transported back to the refuge and placed at the base of buckwheat plants.

“We hope that this comprehensive approach, which involves restoration and captive breeding and developing public-private partnerships, leads to the recovery of Lange’s and the two (endangered) plants,” Aubrey said. “We want those species to be here for future genera­tions.”

For additional information, contact Jim Nickles, chief of Public Affairs for California Water Science Center, USGS, (916) 278-3016 jnickles@usgs.gov; or Susan Euing, biologist, USFWS, (510) 521-9624, susan_euing@fws.gov.