Dredge up his past10/3/2023 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. The butterfly is only found at Antioch Dunes National Wildlife Refuge. There may be fewer than 50 Lange’s metalmark butterflies remaining today, down from an estimated 25,000 between 50 and 100 years ago. 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 (USFW) 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. Isolated from similar habitats, the Antioch Dunes slowly developed species found nowhere else in the world. Over thousands of years, the shifting sands of time built dunes that reached 120 feet high and stretched for two miles along the San Joaquin River, about 35 miles east of San Francisco. Credit: Mark Hayes/USFWS Sand from the Port of Stockton is restoring a unique refugeīy Brandon Honig, External Affairs Specialist, U.S. The water will return to the river through outfall pipes, leaving the sand behind. Sand and water dredged from the San Joaquin River are pumped onto Antioch Dunes National Wildlife Refuge in October.
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