Extinct butterfly’s relatives reintroduced
The Xerces Blue butterfly, once native to San Francisco’s coastal dunes, became the first butterfly species in the U.S. to disappear due to human development over 80 years ago.
But after years of research and the assistance of modern technology, a butterfly species closely related to the Xerces Blue has been reintroduced to the dunes of Presidio National Park.
In collaboration with researchers from the California Academy of Sciences, park officials announced on Monday they released dozens of Silvery Blue butterflies into 50 acres of restored dune habitat last week.
“This isn’t a Jurassic Park-style de-extinction project, but it will have a major impact,” Durrell Kapan, a senior research fellow and the lead academy researcher on the project, said in a statement. “The Silvery Blue will act as an ecological ‘stand-in’ for the
Xerces Blue, performing the same ecosystem functions as both a pollinator and a critical member of the food web.”
For the project to succeed, scientists needed a subpopulation similar to the Xerces Blue — a group
adapted to San Francisco’s cool, foggy climate and dependent on the same host plant, deerweed, found in the dunes.
Scott Sampson, the academy’s executive director, believes the project could have wider implications
in the natural world, demonstrating that species displaced by human development can rebound with the right support.
“The lessons we learn from the Silvery Blue here in our backyard could serve as a model for regenerating
other ecosystems across California and beyond,” he said in a statement.
The Xerces Blue butterfly was last seen in San Francisco in 1943 before human development swept over the region where it was confined, from the Presidio to Fort Funston in present-day Richmond and Sunset neighborhoods.
However, researchers used the academy’s extensive collection of Xerces Blue specimens, some over a century old, to study its genetics. After years of analysis and fieldwork, they identified a population of Silvery Blues in Monterey County suitable for relocation.
Thriving populations of Silvery Blues in Monterey County’s foggy, sandy coastal scrub habitat were identified as the best candidates for relocation to the Presidio.
With local authorities’ approval, researchers transferred the Silvery Blue butterflies from UC Santa Cruz’s Fort Ord Natural Reserve and Garrapata State Park in Monterey County to the Presidio. The butterflies were provided with Gatorade for sustenance during the journey and marked for identification. Tracking efforts will monitor their progress.
“Our hope is that these new residents will lay their eggs and return in even higher numbers next spring,” said Lew Stringer, associate director of natural resources at the Presidio Trust.