SACRAMENTO, Calif. (CN) – A collaborative effort promises help for a southern California butterfly that has struggled for existence despite being protected under the Endangered Species Act for 20 years. The Quino checkerspot, an important native pollinator, was thought to be extinct prior to being listed under the ESA in 1997 after a few tiny populations were rediscovered.
A collaborative team of biologists from the U.S. Fish and Wildlife Service’s Pacific Southwest Regional Office, the San Diego Zoo Global, San Diego State University and the Conservation Biology Institute have been working together to address the butterfly’s continuing decline through a captive rearing and release program.
Though the ESA has an impressive record of success, with 98 percent of listed species still surviving, the Quino butterfly has continued to hang on by a thread. They are threatened by urban development, climate change, drought, pollution, invasive species, grazing and wildfires. Like many other imperiled pollinators, they are also threatened by pesticide use.
The Quino population has drastically declined over the last decade, despite the best efforts of conservation groups and the Fish and Wildlife Service. “Losing the native pollinator could mean a strike against the balance of coastal sage scrub ecosystems here,” the Service said.
The U.S. Forest Service reversed its decision to allow cattle grazing in the Quino’s habitat in 2010, due to legal action brought by the Center for Biological Diversity (CBC) conservation group and its allies. The CBD has been championing the rare butterflies since its lawsuit spurred the ESA listing in 1997. The group has also fought for critical habitat for the butterflies and challenged developers on the Quino’s behalf.
“The attempt to establish captive-reared Quino checkerspot butterflies in the San Diego National Wildlife Refuge is great news for a native butterfly species that is dangerously near extinction and can use all the help we can offer,” Jeff Miller, CBD’s Conservation Advocate said.
“The Quino checkerspot went from being one of the most common butterflies in southern California to a species which is down to a handful of small populations in San Diego and Riverside counties. Quino checkerspots are threatened by urban sprawl development, increased fire frequency, spread of invasive plants, pesticides, off-road vehicles, and butterfly collectors. If the reintroduction is successful and the butterflies can breed and increase their numbers, this population on protected land could be important for recovery of the species.”
The collaboration team raised larvae in the San Diego Zoo’s Butterfly Conservation Lab, and then released them on the San Diego National Wildlife Refuge. “Quino checkerspots have been reared in captivity in the past, but this is the first time that captive-reared Quino have been returned to the wild to augment wild populations,” the refuge’s biologist John Martin said.
The butterfly’s rarity was in itself a challenge to establishing the raise and release program. There were not enough wild Quinos in San Diego County to sustain losses for a captive breeding program, so the biologists collected them from the Riverside population about 60 miles northeast of San Diego.
“The genetic work we’ve done indicates that Quino populations throughout their entire range are basically the same,” Susan Wynn, a biologist with the Carlsbad Fish and Wildlife Office said.
“Although these populations are widely separated geographically, they are genetically similar and should have similar biological needs. So we think they should do quite well.”
The team released 742 larvae last December, and another 771 last month, for a total of 1,523.
The release coincides with the butterfly’s natural period of dormancy, called diapause. When they break their diapause in the spring, biologists will be checking the protective release pods once a week looking for caterpillar activity as they emerge to feed on dwarf plantain, their primary food source.
“Humans have had a significant impact on the decline of the Quino checkerspot butterfly,” Paige Howorth, associate curator of invertebrates at the San Diego Zoo Global, said “But humans are also playing a critical role in their recovery and [the] release is an important first step in doing that.”
Photo credit: Andrew Fisher/USFWS