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“This is a very industrial neighborhood we’re tucked into,” Louis Terrazas, a wildlife resource specialist for the refuge, said of Antioch Dunes. At the time, the 55-acre urban refuge with two non-adjacent units was also the nation’s smallest. The Service established Antioch Dunes National Wildlife Refuge for the three species in 1980, making it the first national refuge for insects and plants. The white-petaled primrose and yellow-petaled wallflower followed with listings in 1978. The orange, black and white butterfly with a wingspan of 1 to 1.5 inches, whose population likely numbered 25,000 less than a century ago, was listed as endangered in 1976. “We counted about 10 butterflies in 2020, and the total population is very likely less than 50 currently. “The population of Lange’s has been trending downward for a couple of decades now,” said Mark Hayes, a biologist with the Service’s San Francisco Bay-Delta Office. Since 2013, the Port has pumped nearly 92,000 cubic yards of sand - enough to fill more than 6,500 dump trucks - onto the dunes to support three endangered species: the Lange’s metalmark butterfly, Antioch Dunes evening primrose and Contra Costa wallflower.

Fish and Wildlife Service and Port of Stockton are trying to turn back the clock, one load of sand at a time. As industry depleted the sand over the next 70 years, the dunes’ unique species struggled to survive on dunes that eventually topped out at 50 feet. The gradual shifting of sand, however, was replaced by a rapid effort to turn it into bricks in 1906, after a devastating earthquake and fires demolished buildings in San Francisco.