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Bay Nature magazineApr-Jun 2012

Wanted: Sand for Endangered Butterfly

by on May 03, 2012

Lange's metalmark butterfly.Photo by US Fish and Wildlife Service.

Lange's metalmark butterfly.

Photo by US Fish and Wildlife Service.

Louis Terrazas needs sand. As assistant manager at the Antioch Dunes National Wildlife Refuge, Terrazas wants a large quantity of fine-grained, weed-free sand to create a new dune. At this tiny U.S. Fish and Wildlife Refuge devoted to a few rare plants and insects, Terrazas and biologist Susan Euing, with the help of volunteers, will plant the manufactured dune with Antioch Dunes evening primrose, Contra Costa wallflower, and naked-stem buckwheat, all endemic here. Then, they hope, the prevailing west wind will gradually transport the sand and scatter seeds to the rest of the refuge, as it had for millennia before the 100-foot sand dunes were nearly mined out by 1980. The ultimate objective is to save the federally listed Lange’s metalmark butterfly.

The Lange’s metalmark is a lesson in specialization, a strategy that has not served it well as industry and invasive weeds have encroached, and as climate change threatens it with a knockout punch. Each year, adult metalmarks emerge to breed in synchronization with the flowering of naked-stem buckwheat; adults survive just three to five days.

The population has fluctuated over the years, with a high of 2,300 in 1999. In 2011 volunteer counters found no butterflies at all in one of the preserve’s two sections. They counted only 74 in the neighboring section. There has been a concerted effort to save the butterfly since 2005, when a dip in the population triggered fears of its extirpation. The Fish and Wildlife Service contracted the Urban Wildlands Group of Ventura County to start a captive breeding program for the Lange’s metalmark.

So every year since 2007, biologist Jana Johnson and a team of volunteers have netted a few females in early September. They drive the insects down I-5 by night to Moorpark College in Simi Valley. There students monitor eggs laid by the females until larvae emerge in February. In late July or early August, the caterpillars transform into butterflies. In 2011, the team captured seven butterflies that then laid 621 eggs, from which larvae were emerging in February. Not all will make it. “It’s a tough time for us,” says Johnson. “We can’t help an egg hatch or a butterfly eclose (emerge) from the pupae.”

But she remains hopeful. “The work is promising on our front, and the Fish and Wildlife Service is working hard to restore the habitat,” says Johnson. “We just haven’t developed the perfect honeymoon suite for the species.”

Antioch Dunes National Wildlife Refuge offers one-hour docent tours monthly on second Saturdays. Call (707)769-4200 for information.

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