Rare butterflies — one species of which was previously extinct in the SF Bay Area — are returning to San Francisco, thanks to ongoing conservation efforts (and modern-day genetics).
There are indescribable amounts of beauty around every corner in San Francisco. With our litany of mosaic staircases and perched parks, flora and fauna thrive inside this incredibly urban metro. Butterflies are among our most poignant environmental indicators; these fragile insects require healthy, intact habitats in order to thrive; if the environments they live in are intact, butterfly life will flourish — and vice versa.
San Francisco has recently found itself in the midst of a favorable butterfly resurgence, with rare butterflies, one of which was thought to be locally extinct, popping up across the city.
iNaturalist users have found that coastal green hairstreak butterflies, which are also known locally as the “jewels of the Inner Sunset,” have been cataloged on the app with increasing frequency over the past two years. These exoskeletal gems are no longer considered geographically extinct.
“You can go to the parks and you can see it, and it’s pretty amazing,” Rebecca Johnson, the California Academy of Science’s community science director, told SFGATE on Wednesday, May 14th. The butterflies were first recorded in San Francisco as far back as the early 1800s. Per the outlet, Johnson hadn’t encountered the butterflies in San Francisco until 2019; fast forward six years, and these butterflies are now common sights, or at least observable, in the Presidio and the Sunset District, as well as San Bruno Mountain.
Similarly, the Xerces blue butterfly has been considered locally extinct for over 80 years; once popular along the coastal areas in San Francisco and elsewhere in the region, unchecked urbanization and wetland draining decimated their habitats. But the Silvery Blue butterflies in Monterey County — a genetically similarly species — could offer an olive branch to reintorducing a powdersy blue flying insect back to the Bay Area.
How, you ask? Through the use of genetic sequencing, of course.
“We were able to extract DNA non-destructively from a leg of one of the specimens of silvery blues that we had in the collection,” Durrell Kapan, a senior research fellow at the California Academy of Sciences, told KTVU 2. “We were able to compare the DNA from a bunch of Xerces and a bunch of silvery blue butterflies, which we hypothesized to be the closest relative, to sort of narrow down which ones were closer.”
Kapan, alongside the “great team here at the California Academy of Sciences,” hopes that restoring coastal habitats can be done in tandem with controlled reintroduction measures. The success of both means that San Francisco, as well as other restored habitats across the Bay Area, could translate into a successful repopulation effort, meaning that most of the SF Bay Area may, once again, see a powdery blue butterfly in massive numbers.
